> However, because it is physically not possible to charge and discharge the battery at the same time, such trades have to be prevented.
The authors are observing that, if electricity prices are negative and your battery is not perfectly efficient, then you would like to charge and discharge simultaneously to get paid for wasting energy, but you can’t.
This is a silly limitation. Surely the power electronics or even just the control algorithms in a BESS could be slightly modified to consume power, get warm, and not transfer any current to or from the battery cells, effectively taking advantage of the BESS’s heat sink to sink excess power and sell that service.
More seriously, in a world with occasional negative prices, you would want your battery to be able discharge itself, without exporting power, in a controlled and power-limited manner so as to avoid overheating. And the optimization algorithms should factor this in. I wonder if real grid-scale BESS systems have this capability.
ZeroGravitas · 21h ago
Not sure if it's discussed in the paper but apparently in Australia there have already been recorded instances of batteries charging with negative price electricity and then selling back that electricity at a still negative but closer to zero price and so profiting.
When I first heard it, it seemed wild that they couldn't hold on for the price to go back above zero, but I guess if we're talking high frequency trading it makes more sense. They might have bought and sold many times while the price is different levels of negative before switching to charging up in preparation for the later price rises.
And the round trip inefficiency helps too.
petertodd · 20h ago
That's not as ridiculous as it sounds!
As you know, negative electricity prices mean that someone is willing to pay you to dispose of electricity they need to generate for some reason. For example, a conventional steam-turbine-based electricity plant might prefer to just keep running for a brief period of time when demand is low, rather than subject their equipment to a power cycle, which increases their maintenance costs. There's other, dumber, examples based on stupid contracts and badly designed solar... but this example is a reasonable one that exists for good engineering reasons.
The battery provider in this circumstance is profiting from their ability to accept power when demand to dispose of electricity is particularly high. When that need goes down, they can reasonably profit by dumping that energy on someone else who is also able to dispose of the electricity. But at a lower cost. E.g. imagine an big industrial refrigerated storage facility that can consume some excess energy by supercooling their refrigerators. But they can't consume unlimited excess energy, because at some point their warehouse just gets too cold, and they don't have unlimited refrigeration capacity anyway.
So in this simplified example, the battery storage service is getting paid a lot of money to quickly absorb a lot of energy, which they then dump more slowly to the refrigerated warehouse (and similar providers) as the surplus diminishes, in anticipation of another surplus in the near future.
eru · 2h ago
> That's not as ridiculous as it sounds!
I'm not sure: why doesn't someone 'just' put up a few resistive heaters and fans to benefit from negative prices?
Turskarama · 1h ago
Because it doesn't happen often enough to be worthwhile, you're better off just building a battery and being able to make profit every day.
kurthr · 19h ago
If it was so profitable, why wouldn't the electricity utility do it themselves? Certainly, they have the scale, infrastructure, and pricing power to do it.
Oh, that's right. This is supposed to be wealth transfer.
adrianN · 6h ago
If you find a hundred dollars on the ground you don't pick it up because in an efficient market somebody else would have already picked it up, hence it can't be real?
0cf8612b2e1e · 18h ago
Even if the arbitrage exists, it does not mean you are equipped to profit from it. Furthermore, the rapid installation of battery capacity means that the profit margin for this activity is likely to dwindle as more entrants try and do the same thing.
rcxdude · 14h ago
What do you mean by electricity utility? Which organisation specifically? The electrical supply is usually formed of multiple organisations with different responsibilities, which usually works pretty well, but it generally means that e.g. storage, transmission, and generation are not one single organisation.
nwbort · 11h ago
Yes, including because firms at one level of the supply chain (eg, transmission) are in many countries precluded from operating in another level (eg, generation).
bee_rider · 19h ago
I’m just guessing but it probably isn’t so profitable. More like a “you already have the batteries, so why not?” type thing.
schmidtleonard · 19h ago
Someone at the generation facility ran the numbers and found that the grid was able to dispose of excess energy for peanuts but installing and maintaining a dedicated electronic load cost more than peanuts.
I'd recommend digging elsewhere for conspiracy bait. This is a mild curiosity at best.
petertodd · 17h ago
> This is a mild curiosity at best.
Exactly. There are genuine economic/engineering reasons for negative prices to occasionally exist. But in a well-designed, well-run, grid price will be negative only a small minority of the time. It just doesn't make sense to install a bunch of expensive equipment to provide this service when sufficient capacity exists from "happy accidents" like spare battery storage.
In the long run, better managed solar and wind should make negative prices a fairly rare event.
eru · 2h ago
Once you sign up customers for 'cheaper electricity, but you have to agree to the occasional loadshedding', you can probably also sign them up for a bit of 'oh, and please burn some more electricity, when we tell you to'.
The former is already happening and useful, the latter would be a relatively simple and easy add-on that could be used to offer ever so slightly cheaper electricity.
jounker · 40m ago
My washing machine has a timer. I do the wash when local electricity rates are near zero.
eru · 37m ago
Yes, and you could imagine telling your utility: just kick off the laundry anytime in this time interval, in return for cheaper electricity.
hinkley · 18h ago
This is why we don’t move data center load to the coldest available data center to reduce the AC power fraction of the cost. The cost of electricity is a significant fraction of the overall cost but not high enough to make up for stranded assets. Computers not running during their best years is expensive.
But I’m not sure that’s entirely correct, and maybe it’s time to revisit this.
Any system that is selling responsiveness as part of their service has to keep a certain amount of equipment sitting idle. That’s just how queuing theory works. So while you cannot move all server load to the coldest available zone, we should still be able to run that center near capacity and use the hottest one for all reserve capacity.
Power plants also have to deal with fines for exceeding emissions limits, but I suspect the problem here is that Bayesian analysis tells them that if a plant has to kick on early for some reason (early school release day, or another plant exceeded a maintenance window), it will still be needed for sure an hour from now, so it’s better to leave it running for 45 minutes doing nothing than to cycle it.
jandrese · 17h ago
Your electric utility could be doing this if they were more forward thinking and installed grid scale batteries, but that's not their business model so they don't do it.
eru · 2h ago
Well, if other people are allowed to install batteries, then it might be fine that the utility isn't doing that. They don't need to do everything themselves.
pfdietz · 19h ago
One reason, that I understand has applied in Germany, is when taxes are applied both to the electricity the storage firm buys and to that which it sells. This puts a damper on the whole thing unrelated to any actual technical or economic realities.
foobarian · 14h ago
> and then selling back that electricity at a still negative but closer to zero price and so profiting.
How is it not better to discharge the batteries instead? I guess if you don't have that hardware option integrated into the platform maybe, but otherwise...
adiabatichottub · 18h ago
I don't know why it rankles me to think that generated power should be fed into a dump load just to make the storage owners extra money. Even though it's inefficient at the system level, it shouldn't be harmful releasing energy that would have been eventually dissipated as heat anyways. And yet it still just feel wasteful to me.
I had to go search my bookshelf for this one:
"There has been an increasing awareness among engineers of the last two decades that machines can perform a useful purpose in many applications, even though their characteristics do not conform to the orthodox standards of goodness. The main objective of the engineer is to make money -- to exploit economically the physical properties of materials. Economic considerations, however, do not stop at the first cost of an article, nor at the running cost, but extend to everything connected with that article in the situation in which it is to be used."
Eric R. Laithwaite, Induction Machines for special purposes
nhecker · 13h ago
My shallow understanding is that utilities and grid operators need to manage the supply/load ratio carefully to keep the grid's operating frequency in a very narrow band, centered around 50 or 60 Hertz. If supply outstrips demand, and assuming supply can't react [quickly enough], the operating frequency starts to rise as all the rotating masses connected to the grid gain momentum from the additional power. If the operating frequency increases too much outside of design parameters that could end badly.
So one solution is to incite demand (with negative rates) for folks to ramp up their use of electricity (into e.g., a dump load resistor bank), bringing demand back in line with supply, and bringing the operating frequency back under control.
I hate the waste, agreed. But it would be irresponsible of the operator to bank that extra supply energy into the momentum of spinning things owned by the consumers just so they could pull it out later by intentionally under-supplying. E.g., an aquarium's big water pumps designed to spin only so fast or produce so much pressure might not like being operated at 110% the rated speed at random times of the day.
The grid connected thermostats, where the energy provider has (some amount of) control over when you heat/cool your house are pretty unpopular (I know people who have had their AC turned off during heat waves and were not very pleased). But this seems like an application of that that people would like? And most people would probably even be happy with just dramatically reduced/free heating/cooling and not actually needing to get paid. And of course it has the added benefit of actually using the energy in a useful manner, rather than just wasting it.
eru · 2h ago
I suspect you can make these things work, but it's not 'free': organising a bunch of retail customers and dealing with them takes a lot of effort.
> (I know people who have had their AC turned off during heat waves and were not very pleased)
I suspect they probably agreed to pretty harsh control in the name of cheaper electricity, but actually were only willing to tolerate relatively small amounts of loadshedding. I wonder whether better contracts can help align expectations here in the future. Eg allow the electricity company to set your aircon's thermostat up to 3K warmer (or something like that), but not turn it off completely?
colechristensen · 15h ago
>I don't know why it rankles me to think that generated power should be fed into a dump load just to make the storage owners extra money. Even though it's inefficient at the system level, it shouldn't be harmful releasing energy that would have been eventually dissipated as heat anyways. And yet it still just feel wasteful to me.
This is one of those efficient market things where you need to manage the market in order that wasteful things happen sometimes... but that waste is an opportunity.
If you and your competitor are both in the business of dumping energy into heat, you're going to compete with each other for access to that money.
Then one of you is going to try to find a way to make _more_ money with that energy and find something quickly scalable with not-too-high idle overhead costs to do with that energy besides just flowing through a resistor.
Negative prices are a sign of an inefficient market or just the lag time between a changing landscape of resources and someone to utilize them.
If there's a free resource someone's going to figure out how to use it, just let it hang out for a while and the problem fixes itself.
Especially with solar energy, this is just going to be a thing. There's a certain balance where overprovisioning is cheaper than storage and so you just do that. Then you wait for industry (or consumers) to figure out how to take advantage of the intermittent cheap energy.
eru · 1h ago
> Then one of you is going to try to find a way to make _more_ money with that energy and find something quickly scalable with not-too-high idle overhead costs to do with that energy besides just flowing through a resistor.
Yes, exactly.
Which reminds me of the occasional story about how one native group or another was so in tune with nature, because they used every part of the (insert important animal here).
Modern economies obviously use all parts of the animal, for exactly the reason you outline.
> Especially with solar energy, this is just going to be a thing. There's a certain balance where overprovisioning is cheaper than storage and so you just do that. Then you wait for industry (or consumers) to figure out how to take advantage of the intermittent cheap energy.
Yes, though you also need to make sure that regulations don't get in the way. Or at least not too badly.
One example I can think of is forcing utilities to charge people by net-metering, forcing the utility to implicitly pay the same price for electricity as they charge. We don't do that for eg used car salesmen.
hwillis · 21h ago
> Surely the power electronics or even just the control algorithms in a BESS could be slightly modified to consume power, get warm, and not transfer any current to or from the battery cells, effectively taking advantage of the BESS’s heat sink to sink excess power and sell that service.
Unless you specifically design for it (specifically, with a dummy load), the efficiency of the system is inversely proportional to its ability to do this. You need a secondary system.
The power system can connect the battery terminal to in or to out, so if you switch both on at once you effectively bypass the battery. It's called shoot-through current and is generally considered a destructive process. If you can switch on and off fast enough you could limit it to a non-destructive level, but in practice most systems will not switch fast enough. They are designed to operate with the battery load, which is at minimum ~10x higher resistance than the transistor itself. In practice it is often 100s of times higher.
That's where the efficiency comes into it. If a power system is 98% efficient (pretty normal- this does not include power lost to heat in the battery itself), that means the electronics can only burn 1/50th as much power as normally passes through the system. Worse, when you put the switch into shorted position it will try to pass 50x its rated current. You need to switch much faster -certainly more than 50x faster- and that will probably put it outside its operating region.
It is relatively easy to just have a large resistor, but it is not very well suited to use battery power systems. Batteries are very low impedance, and the power system exists to transform to a lower voltage and higher current. Resistors are cheaper when they are higher voltage, so the power system is a hacky kludge.
The overall solution is just more batteries. Oversupply is a transient problem and always will be.
ACCount36 · 18h ago
> Unless you specifically design for it (specifically, with a dummy load), the efficiency of the system is inversely proportional to its ability to do this. You need a secondary system.
Many multicell BMS already have this kind of "power shedding" capability. They use it for cell balancing - to equalize voltage between cells with slightly different characteristics. This is desirable despite the power waste, because it reduces wear, increases charging efficiency and allows battery packs to last longer.
Some battery packs are also designed to be able to dump enough power into heat to be able to keep the batteries warm during extreme cold.
ranma42 · 18h ago
The amount of power you can dump for balancing is just a fraction of the charge/discharge power (because it only needs to offset differences in self-discharge rate). So you still need a proper dummy load when you want to dump more.
Similarly, the heatsinking capacity of the battery is designed for charging/discharging losses (say 5% of charge/discharge power).
jordz · 22h ago
I work in the industry making hardware and software for large scale commercial and grid scale storage.
There are several challenges with this, safety, thermal runaway, and life cycle of the asset which has a limited amount of cycles.
Also the architecture of the system for the AC inverters and the DC side can come from very different places in the supply chain and aren’t as vertically integrated leaving you in a position where you can’t actually make this work without compromising something in the supply chain. That being said we are talking about a LOT of energy in these systems and to dissipate that much heat you’d need a load bank.
andoma · 20h ago
Our house have geothermal heating (heatpump conncted to 160m drilled hole, pretty common in Scandinavia). The heatpump supports having a coolant loop for cooling the house in the summer. Thus the heat pump pretty much exchanges heat from the house to the well (heating it up ever so slightly). It would certainly be possible to insert a resistive dummy load on that loop and just store that heat in the bedrock as well.
frabert · 19h ago
This! Or, if you don't have geothermal heating but have an electric water heater, maybe temporarily increase the temperature it goes to: maybe it's normally set to go to 65C, then when you detect that you have negative prices and your batteries are full and your water already hot, maybe heat the water to 70C and store that little bit of extra energy as heat! If you have thermostatic valves in your bathrooms, you won't even notice the difference except by the fact that your water heater now can apparently hold a little bit more water than usual :)
holri · 4h ago
I have a heat pump for hot water and calculated this with an offered floating energy tariff.
It is not economical because the high net tariffs are not floating but fixed per kwH and negative / very low prices are seldom here and only for a short period of time available.
cogman10 · 18h ago
Assuming regular negatives (more than once a day) you could also tie the heating to the grid prices with maybe an hour buffer around your high water usage times to make sure you are up to temp.
Modern water heaters will keep temp for a shockingly long period of time.
_trampeltier · 21h ago
I know a country, the national train company turns lots of outside lights on (daytime), if the price is negative.
cyri · 14h ago
Yes that is the SBB in Switzerland but they do not turn the lights, instead they turn on the heaters for the track switches.
Not sure if that is all rumours.
_Algernon_ · 18h ago
Great for the local insect population.
matthewdgreen · 19h ago
Wouldn't that discharge the battery and hence contribute to battery wear, by wasting a charge cycle?
triceratops · 20h ago
If you have free energy the obvious thing to use it for is carbon capture.
rtkwe · 19h ago
The big problem there is you have these intensely capital expensive capture plants sitting idle around 75% of the time. Also the processes may not gracefully start and stop though maybe you could smooth that out by building a huge battery bank along with the CC plant to effectively run a full duty cycle with 'free' energy. That bumps the capital costs up again though so the economics get tricky.
rcxdude · 14h ago
Yeah. Anything that's designed to use nearly-free or negative-priced energy from the grid needs to be cheap to build and easy to start and stop (The former being one of the main issues with the 'bitcoin mining as grid management' idea).
rtkwe · 14h ago
In theory if you run it using negative priced energy you could maybe run with older less efficient hardware that's not viable for current mining that would be much cheaper, if you can source it. I'm thinking older ASICs for BTC for example where the best in class kHash/W has moved on and the price doesn't support running the older devices but the negative price would offset that by giving a reliable return on time to offset the extra energy burned.
It'd take a far amount of math to figure out if that tips it over though I don't feel like tackling haha.
ZeroGravitas · 2h ago
The real low hanging fruit is energy use you were going to do earlier/later anyway but where timing isn't important.
It's half century old tech and usually the only thing missing is a financial incentive to do so.
bee_rider · 19h ago
I wonder if desalination would be another good use. But, yeah, it is probably just a matter of how fast the processes can absorb extra power.
positr0n · 1h ago
The problem is desalination plants cost billions. You're not going to make money building one then running it the 1% of the time the price of electricity is negative.
cogman10 · 17h ago
District heating and cooling would be an excellent sink for the power.
Water needs a lot of energy to cool or heat, concentrated at a district, you could easily absorb a lot of energy at negative prices.
XorNot · 6h ago
Electric heating elements aren't free nor infinite in capacity. You'd pay a lot of money for a rarely used asset that has to be replaced by something else most of the time because people want their heating to be reliable.
burnt-resistor · 7h ago
Supercapacitors ready to soak up power to charge batteries whenever rates stabilize.
XorNot · 7h ago
Supercapacitors are much more expensive then batteries with much shorter lifespans to boot (years, versus decades).
raphaelj · 22h ago
Couldn't the battery just do, as an example, 1 minute long charge then discharge cycles?
For example, if the electricity price is -28€/MWh (like today in Germany), and your battery efficacy is 80%, you could get paid 28€/MWh charging, then only pay back 22€ discharging, generating a 6€/MWh profit.
7thaccount · 21h ago
The wholesale energy markets don't have sub 5-minute granularity anywhere that I'm aware of. In the US, 1-hour is standard in the day-ahead markets and 5-minutes is standard for the spot markets.
There is also the problem that your battery would likely degrade fast depending on the technology.
borner791 · 18h ago
Balancing.. thats probably 1-0.5% of the BESS capacity. The impedance of LFE cells are so high when charged pretty small amounts of energy can slosh around before a protection disconnect, over voltage for example
fluorinerocket · 14h ago
Find area near shore, stick two big electrodes in water a mile apart, energize circuit when price is negative, profit!
idiotsecant · 14h ago
I am in the power generation industry and I have honestly wondered why nobody does this. I figure getting the interconnect big enough to make meaningful money is both prohibitively expensive and a lengthy delay.
CoastalCoder · 9h ago
Or put them closer together and generate all of the chlorine gas, H2, and O2 a girl could want!
4gotunameagain · 22h ago
The solution is actually what's called a "dummy load". Get paid to waste energy and heat up the planet a tiny bit more, gotta love it.
Workaccount2 · 20h ago
I know this is grossly pedantic, but not matter what that electricity is used for, it will end up "heating up the planet a bit more". Energy is a waterfall whose base is heat.
_Algernon_ · 18h ago
Fossil fuels contain energy that are not in the form of heat, so electricity from fossil fuels would heat the planet even ignoring greenhouse effect. If from renewables, however, the energy has been previously extracted from the environment, thus being neutral in terms of heating the planet.
Not that it matters, because the effect would be miniscule in any case.
pomerange · 19h ago
Technically if you power a laser shooting into space with solar panels you are cooling the planet, but you are ofcourse right in practice and on the scale of the universe!
stavros · 1h ago
That sounds like a good way to waste tons of energy during negative electricity prices to me! Shoot it into space.
thebruce87m · 21h ago
Can’t we power a big laser and point it at space or something instead? Anyone got a dumber idea?
beAbU · 21h ago
There are so many things that are energy intensive and not really economically viable: co2 capture, crypto mining, "green" hydrogen, we could see a world soon where a large scale BESS would have an on-site dummy load that does something useful with that electricity
Analemma_ · 18h ago
The problem with all those things is that they are ridiculously capital intensive to set up, and then they sit idle 80% of the time Worse, the whole point of negative electricity prices is that they're an inefficiency in the market which ideally will eventually be optimized away. Then what do you do with your billion-dollar plant that can only run with negative prices that no longer exist?
adgjlsfhk1 · 14h ago
You're assuming the way they get optimized away isn't by these sorts of plants.
karmakurtisaani · 20h ago
I guess the problem with building a pure energy waster is that it could only operate every now and then, and it's not guaranteed to see negative prices in a few years from now. So, might not be all that profitable.
BobaFloutist · 15h ago
Use the electricity to heat up a lump of iron to a very high temperature, than use electromagnets to fling it into space?
yetihehe · 13h ago
If you heat up iron to very high temperature (>770°C), it's much harder to fling it using electromagnets.
BobaFloutist · 13h ago
Ah that's annoying. Fine, we use the electricity to heat...uh...molten salt encased in stone, and to pull back a very big heat-proof slingshot, and after a threshold it lets go and launches it into space.
wcoenen · 21h ago
Presumably the negatively priced energy came from solar panels, so those sun rays were going to heat the planet anyway. The same still happens with a dummy load, just with extra steps in between to convert to and from electricity.
With enough solar panels deployed, you could still argue that they change the albedo of the Earth and therefore it's temperature.
eisa01 · 21h ago
Related, do Solar PV panels need any extra equipment to curtail instead of feeding into the grid?
Aside from software integration to remotely control household PV systems, is there anything else needed to curtail during negative price events?
nick3443 · 20h ago
If the inverter is smart enough, nothing else would be necessary
eisa01 · 18h ago
Thanks! Google managed to find more details on Reddit when I searched now
Not necessarily. There's also reflection involved.
Now to figure out how much exactly you need to take into account the solar panel absorption spectrum & the albedo of the earth.
fer · 21h ago
>"dummy load"
You mean crypto miner.
michaelt · 21h ago
Surprisingly, not always.
If I buy a device for $100 that, given free electricity, will mine $500 of cryptocurrency in its useful life - I can easily lose money if I run it less than 20% of the time.
And I doubt electricity is negative priced >20% of the time.
bee_rider · 19h ago
Yeah, there are a ton of plans in this thread for what to do with excess energy. The problem is, that’s the wrong question. The goal is to answer the question “what should we do with excess energy where we don’t mind building the capacity, but then only rarely running it.”
Rather than coming up with some grand scheme, maybe it would be good if our dishwashers and washing machines could listen to the grid and activate when power cost was negative. (We may need to coordinate a bit though, so we don’t all activate at once).
wcoenen · 18h ago
I have an electricity contract with dynamic pricing that changes every hour based on the day-ahead electricity market for Belgium. I know what the prices for the next day will be around 13h10. I charge the car whenever the prices are lowest: around noon in the sunny months, at night during winter, preferably weekends. I save around 25% of my electricity bill like this. (More in summer, less in winter.)
So it's already possible to incentivize people correctly with price signals, at least in some regions of the world. But people are not yet familiar with this. I guess that will change as the pricing between dynamic and traditional contracts keeps diverging. With a traditional contract, you are essentially paying the average evening peak price all the time. With a dynamic contract, you get access to the cheaper and even negative rates.
rtkwe · 19h ago
In some areas negative prices account for up to 25% of hours so it's a decent number but still a rough number of spins up and down and a lowish duty cycle. A solution might be to build battery capacity along side these loads to effectively buffer the negative cost power to be able to run continuously. That would skyrocket the initial capital investment though.
bee_rider · 18h ago
Yeah, batteries are just the sort of expensive/straightforward solution.
If you think of it, a dryer is sort of a combination of a flywheel and a heating element, so it should be the over-provisioner’s best friend. IMO a real failure has been not taking advantage of our appliances.
rtkwe · 18h ago
The issue there is connectivity and most residential customers don't pay spot prices so you need to upgrade their meters as well or build metering into the appliance so they can get credit for the energy they burn off. Plus you're looking at putting a lot of extra cycles on equipment not built as well as it used to be so you're burning the useful life of a hard to repair device and probably not getting paid enough to cover that, plus they more and more designed to burn as little energy as possible.
I know there are some places where this happens though but it's more along the lines of the devices delaying their start until energy is cheap rather than being used as loads to shed excess capacity afaik.
bee_rider · 17h ago
> I know there are some places where this happens though but it's more along the lines of the devices delaying their start until energy is cheap rather than being used as loads to shed excess capacity afaik.
This is what I meant, sorry for the ambiguity. Load the washer up and kick it off whenever energy is cheap. I don’t care when it happens other than, like, that it happens once a day, so why not defer this to the power company, right?
rtkwe · 17h ago
Like I said support isn't really there for a lot of electric customers. I pay a single flat rate for electricity so there's no point in time shifting consumption.
Also there are downsides to having clothes just sit there for hours potentially before you dry them. They can get pretty dank from the moisture and for dryers some clothes need to be removed immediately when the cycle finishes.
Could we use it for some kind of carbon capture process?
Leherenn · 20h ago
I think it's pretty clear with the constantly increasing durations of negative prices, so far we haven't found a way to do so profitably. Carbon capture or anything else for that matter.
Anything that would really love free energy also cost a lot to build and maintain/operate besides electricity. So much that a few hundred hours of free (or even better than free) energy a year is far from enough when you need >90% uptime to make sense. Maybe it makes you go from 95 to 85%, but still clearly it's far more than there are sunshine hours.
grues-dinner · 20h ago
It's basically the idea behind things like hydrogen electroysis with excess energy.
The problem is that things that can use bulk energy productively like electrolysers, hydrocarbon crackers, smelters, AI training farms, etc. are very expensive and having them on warm standby but idle most of the time waiting for good grid weather makes for bad returns on the capital expenditure and operational costs.
noitpmeder · 21h ago
Isn't this the basic description of what a gravity battery should provide?
horsawlarway · 20h ago
No, because his situation is basically that the gravity battery is already sitting at its max height.
He's just trying to burn energy because a negative rate means he's getting paid to use it.
So sure - it's great to give that energy a functional use first (ex - charge his batteries) but eventually he runs out of functional ways to use the energy but could still be making money by using it.
Enter the desire for a dummy load.
rtkwe · 18h ago
Pumped hydro could do that if they had a way to bypass (either physically or electrically) their turbines on the downhill portion of the loop. Just pump water up and back down without extracting the energy. Then you have a dummy load that isn't just a power sink and is already designed to handle the relatively rapid switches on and off.
horsawlarway · 13h ago
Yeah, but dummy loads are cheap. Probably cheaper than changing any designs in other places.
It's straight forward to add a giant resistive load that just converts electricity back to heat.
I can get 10kw heaters for just a couple hundred bucks or 1.5kw heaters for literally $20 usd. And that also switches on/off easily.
For hydro... just boiling water with a heater is going to be pretty much unbeatable if we're playing the "waste energy" game. No need to approximate it slowly with your pump motor and risk other infrastructure.
quickthrowman · 6h ago
Giant resistors cooled with fans are cheaper and easier to maintain than pipes and pumps.
hollerith · 6h ago
That is what (diesel powered) locomotives do to get rid of electrical power created by using the wheel motors for braking.
New designs store the power in batteries, but most locomotives used in the US still have a compartment filled with fans and resistors instead.
thescriptkiddie · 13h ago
there are no circumstances under which it makes sense for energy prices to actually be negative. it is a sign of a market behaving very badly. propping up prices by intentionally wasting energy only treats the symptom not the cause.
AnotherGoodName · 13h ago
It’s only ever brief and essentially a penalty to power generators for not turning off the generation in a reasonable time
looofooo0 · 22h ago
Good luck trying to get rid of such an amount of heat anyway near your batteries.
_trampeltier · 21h ago
Some years ago, I helped with battery load tests in a nuclear power station. The constant test load was just a big (~500kW) heater. We burned the battery energy for 5 hours. So it's easy possible to do such things.
horsawlarway · 20h ago
Exactly this.
And the same thing for residential scale is literally just a ceramic space heater running at ~1500w.
They're dirt cheap, usually have temp safety checks built in, work on a residentially sized circuit, and are available everywhere.
I needed a cheap and consistent load to do LFP battery testing, and I could spend $5,000 for a real test unit, or $21 for a ceramic heater that will do basically the same thing.
If you've already got the monitoring for the batteries/inverters, a heater is a GREAT load choice.
I'm not sure that this really is a completely off-the-shelf stove element. But obviously, the technology is basically identical to what you'd have on your stove.
_trampeltier · 19h ago
It is cery common for Frequency Inverter for AC Motors to have a break resistor. It's expensive to push energy back to the grid with from an inverter. So in most case just a break resistor is used. Just if you break a lot and a long time it is worth to buy an inverter who can do it. If you have multiple axis in a machine, often they are coupled with DC, so the break energy is used by another drive.
petertodd · 17h ago
Yup. On a much bigger scale it's common for the power supplies going to electric trains to do this too. They like to use regenerative braking because it's efficient. But the electricity grid can't always handle the extra power, so in some designs they have a backup mechanism to dissipate the power if needed; diesel-electrics usually just have a big bank of air-cooled load resistors on the roof.
A neat example of regenerative braking being important is the London Underground: they've had a persistent problem with high temperatures in the subway, of which a decent % is actually heat from trains braking. By using regenerative braking rather than putting that energy into the tunnels as heat, they can transport that energy outside the tunnels, keeping them cooler.
doener · 22h ago
Well in times of negative energy prices wouldn't it even be good if the air conditioning ran at full capacity?
WJW · 22h ago
Depending on how powerful your air conditioner is, it would rapidly start cooling down the building to a temperature which is too low to still be comfortable. You could maybe buffer this with more thermal mass, but then you are back in the game of storing energy and might as well just get extra batteries.
amluto · 16h ago
Many heat pumps already have a mechanism for deliberately wasting energy for defrosting the coils. I bet that the same hardware with a different control algorithm could be convinced to heat out the outdoors without much net change in indoor temperature. (The solution involving the smallest amount of extra hardware is to run the system in reverse periodically. There are other solutions.)
Whether the negative energy price is enough to balance wear on the system and potential noise is a different question.
sib · 17h ago
Why not place the air conditioner next to a large electric space heater?
Energiekomin · 22h ago
In summer? If its not getting to cold for you.
In winter yes also if its not getting to warm for you, but also heating water is easy enough. But you don't need that much hot water
Potentially also cooling down your fridge more and your freezer. But that is not that much energy.
While that works, it would still be quite a waste. It would be a lot better to save it and discarge it later
KeplerBoy · 22h ago
Yes, it's not much of an issue if you have free energy.
lazide · 22h ago
It only makes sense if you have ‘more than free’ energy you need to get rid of, because not getting rid of it causes problems. Similar to flaring natural gas, but for actual electricity.
This is not a common occurrence or situation, or shouldn’t be anyway, or someone is screwing up pretty badly somewhere.
KeplerBoy · 20h ago
Electricity prices around here (Austria) are negative around noon on most summer days. They pay you to waste all that solar energy people are feeding into the grid.
No comments yet
bee_rider · 19h ago
Is it really screwing up? If solar panels are cheaper than batteries, then you can over-provision the solar panels and then you won’t need to use the batteries as much, so you can probably get away with smaller installations.
My gut would expect it to approach $0 if full communication were possible, based on the instinct that most people would run their dishwashers if the energy cost was $0.
lazide · 17h ago
Solar panels don’t produce excess power that needs to be dissipated - just don’t invert the unneeded current, and that’s it.
‘Overproduction’ in this sense is from something like a spinning generator which starts to overspin, or an inverter which oddly starts to overvolt the output for some inexplicable reason.
KeplerBoy · 17h ago
That only works if the grid operator has control over the inverters, which they often don't have.
We currently have the situation where operators of solar farms of all sizes get a fixed amount of money for each joule they feed into the grid. Of course those people have zero interest in turning down their inverters when the sun is shining and there's already a surplus in the grid.
infecto · 20h ago
It’s actually quite common. You have base load generation stations and your highly variable solar and wind. There are often times when the power at a wholesale rate dips below zero. It’s too costly to turn off your base load plants and maybe both solar and wind are generating above normal.
lazide · 17h ago
Solar inverters can just not draw the solar current, and wind can generally just change the pitch on their rotors at the individual level. The only ones that generally can not help ‘over produce’ are baseload power stations as they have actual physical inertia in very large turbines and can’t respond as quickly to demand.
petertodd · 17h ago
Baseload power stations sometimes over-produce on longer timescales than just a few seconds because they'd rather not turn them off for maintenance/operational reasons. E.g. imagine you have a big biomass boiler feeding a steam turbine. Turning it off for an hour or two means everything cools down, which is a thermal stress, reducing lifetime compared to keeping it at constant power.
But yes, certainly poorly managed solar/wind that doesn't have good mechanisms to turn off in response to lack of demand is mainly the issue. In the future, when control systems are better, I'm sure negative pricing will be much less common.
infecto · 17h ago
Right but keep in mind these events are generally short lived and depending on the market there may be reliability guarantees that keep these open or specific federal funding rates.
But like I said before when rates go negative you will typically see it in occurrences where you have abnormal conditions (wind and solar generating at the same time) or aggressive night winds. And it does not happen long enough to need to curtail generation.
AndrewDucker · 21h ago
With variable sources of electricity it can be cheaper to have capacity at a level that you sometimes overproduce than to have a capacity that produces at a lower level, and so mostly needs a backup source of power.
ic_fly2 · 22h ago
I have programmed batteries / algos to do this in some European markets. This is being done right now.
The yield you could make from batteries in the UK dropped from double digits to 2% in 8months once some hedge funds figured out how to build and bid (or commission companies like my employer) batteries in the UK short term reserve market.
There are a few firms in northern Jutland and London specialised in this sort of trading.
baq · 21h ago
At least the grid is better off and it’s not all approximately zero sum…
friendzis · 1h ago
That's a very bold statement.
Huge part of the reason why negative prices exist in the first place is separation of generation and transmission. With pay-as-clear model negligible-variable-costs generators (i.e. renewables) can bid at zero and pump more into the grid than the local segment can drain, requiring artificial balancing sinks. However, the cost of artificial sinks fall on the grid as transmission costs and are not reflected in the wholesale market.
bob1029 · 20h ago
I'd make the same argument for the other markets they operate in.
baq · 18h ago
The REIT ones e.g. are much less clearly positive than this and e.g. the variance swap and co. folks at least have the decency to be so exotic that nobody cares either way.
dschaurecker · 17h ago
Are/where you already trading at a second to sub-second level on the continuous intraday markets? How did you backtest your strategies then, if so? Or is backtesting, e.g. for parametric extensions of the optimization, not yet quite relevant?
azernik · 18h ago
Sometimes the efficient market happens to you (and that's good)
Horffupolde · 22h ago
That’s yield over what base?
jillesvangurp · 18h ago
Battery production rates are creeping up to multiple twh/year now. This is accumulating to a lot of battery sitting around in vehicles, domestic storage, grid storage, etc. Mostly the goal of these batteries of course isn't supporting the grid but some other use case. But if it's plugged in, it could potentially be available for selling power. Right now, most EVs can't contribute power. But that's something that is starting to change. Small experiments with thousands or tens of thousands of vehicles have already been done and seem to work fine. Now imagine tens of millions of vehicles being part of the grid. That's a serious amount of stand by power for absorbing excess power or dispatching power when needed.
Another interesting aspect is that as grid demand fluctuates, a lot of cables are under utilized at least some of the time. Which means there is plenty of capacity for charging batteries provided there is excess generation and cable capacity. A lot of that power currently gets discarded instead. Batteries allow better use of this excess power. And having a lot of local battery means that cable capacity can be freed up as well when needed and then recharged when demand reduces.
And then finally battery prices are coming down. With sodium ion cell production ramping up in several places, things could get quite a bit cheaper. These don't depend on scarce metals or materials. And they last quite long as well (relative to NMC).
giantg2 · 17h ago
"Right now, most EVs can't contribute power"
Nor should they. People don't want to be cycling their batteries and reducing their life. This use case would be better served by batteries that are designed for that purpose instead of being designed to be light for a vehicle.
schiffern · 16h ago
EV can grid cooperate without adding charge/discharge cycles. You just intelligently schedule the charging.
This is how most Time-of-Use metering already works. The driver sets a minimum battery percentage to charge immediately (eg 40% range, enough to reach the local hospital), and then schedule a time when the car should be fully charged (eg 80% by 7AM). The software just Does The Right Thing, using the same prediction and bidding algorithms as stationary batteries.
The search term is "V1G" (a cheeky reference to unidirectional V2G).
SirFredman · 40m ago
Indeed. I live in The Netherlands and use the Jedlix app to schedule charging, which works in this way. The grid operator can use this to selectively create or shed load in a specific area, which helps to stabilize the grid. Really nifty.
inetknght · 16h ago
> People don't want to be cycling their batteries and reducing their life.
More battery cycles just costs money. For the right price, I'd do it.
But more than that: I don't want to be stranded without power in my vehicle because someone in the electric grid made poor power management decisions and decided to offload that decision to consumers.
eldaisfish · 16h ago
as with anything, it's not just money. Losing battery capacity in an EV is a hassle. A hassle because you charge more frequently, a hassle because you will eventually need a battery change, and so on. What is the price of all that hassle?
That said, most EV incentive programs use around 10% (often less) of an EV battery capacity so the actual effects are barely noticeable.
crazygringo · 8h ago
> What is the price of all that hassle?
A price that can be measured in money. How much more does it need to pay to be worth any extra hassle?
So in a sense it is just money. Money is hassle, fundamentally. It's a hassle to make it and you spend it to save other hassles.
Dylan16807 · 5h ago
And since lots of EV batteries seem to lose capacity very slowly after the first 10-15%, and you can keep your battery trading in the happiest range, there's a lot of potential for the extra hassle to be worth the paycheck.
usefulcat · 16h ago
In general I agree with that, but I think it really would depend on the price. For at least some people it would surely be worthwhile for the right price.
giantg2 · 16h ago
If the price is high enough, EVs still lose out since you can make more profit creating battery farms with cheaper batteries that are cheaper to replace. You can't make it expensive enough to cover the replacement of a Tesla battery without making it attractive enough for someone else to use ea more efficient model.
wongarsu · 8h ago
That assumes that EV batteries are used to 100% and will reach end-of-life together with the rest of the car or before the rest of the car. That is increasingly untrue. If your EV battery would outlive your car then you can use some of those "extra" cycles at very low marginal costs (until there is an efficient market for used EV batteries for old cars).
Another factor is that not all charge/discharge cycles are the same. Going between 60% and 80% five times is a lot lighter on the battery than going between 0% and 100% once. Which pairs great with EV batteries, because their batteries are deliberately oversized compared to average use to account for uncommon events.
wjnc · 17h ago
Future: Cycle the power when profitable, replace the batteries when depleted enough? Batteries in cars are many times the domestic demand of a given home, at least in temperate climates.
tomas789 · 17h ago
They are almost the same batteries. Different form factor but same thing. They are rolled from the same lines.
giantg2 · 16h ago
Grid level batteries use many different forms. You even have stuff like pumped hydro and controlled drop concrete. Even if the battery cells are exactly the same, the replacement cost is much higher in a vehicle due to the configuration.
HankB99 · 18h ago
> A lot of that power currently gets discarded instead.
How is power discarded? I would expect peaking generation to be cut back or perhaps even base load plants can reduce output. (AFAIK "base load" means they are expected to be kept operating continuously whereas "peaking" is designed to start up when needed and shut down when not.)
jillesvangurp · 14h ago
wind mills are weather vaned (i.e. not broken, but deliberately turned off), solar panels excess energy is curtailed (prevented from going into the grid) and usually transformed into heat on the panels or in inverters.
As for baseload. It's one of those waffly terms that's rarely specified in GW that is needed. Which as it turns out is far less than we used to have given that much of it was replaced with wind and solar over the last decade or so. The real question is how low can we go with this stuff before we need some more solutions. Some would say all the way but the consensus is that the last 5-10% might get very hard and costly.
Either way, having some peaker plants on stand by ready to spin up over the course of hours/days while batteries slowly deplete is probably a good short term compromise. Replacing spinning mass (fly wheels) with batteries seems a particularly popular and very cost effective use for batteries.
qeternity · 17h ago
> How is power discarded
It isn’t, not at scale in any traditional sense.
mschuster91 · 18h ago
> That's a serious amount of stand by power for absorbing excess power or dispatching power when needed.
... and a serious issue should one of the few large manufacturers or remote-control dispatcher/trader companies get hacked. The outage in Spain a few weeks ago was just a small warning, probably caused by a technical malfunction. But now imagine this being used as a side track in an act of war? The first day of the Russian invasion of Ukraine was accompanied by the hack of Viasat satellites, which led to 5.800 wind turbines shutting down due to a lack of remote control capabilities [1]. Now imagine the large Chinese inverter and power bank controller vendors that often enough just white-label for other brands? That's a whole lot of a different game now.
> and a serious issue should one of the few large manufacturers or remote-control dispatcher/trader companies get hacked. The outage in Spain a few weeks ago was just a small warning, probably caused by a technical malfunction.
If everyone agrees, you can use grid frequency/phase to coordinate, and not a separate realtime communication system. Grid interactive demand/response is a proven way to manage supply and load.
When your section of the grid is stressed, supply power or abstain from charging; when your section of the grid is abundant, charge.
Coordination is useful too, of course; predictive charging is helpful, and you wouldn't get that only by monitoring the grid; you also want to know somehow that a supply or load is scheduled to be added or removed at time X, or was unexpectedly removed and will not be reconnected for some time. And the system operator would want to know about capacity in many dimensions.
mschuster91 · 17h ago
It doesn't work that way. Maybe in the US where everyone seems to do their own shit, particularly in Texas, but here in Europe our grid literally spans the entire continent, from Portugal through into Ukraine's front lines, and from Norway even down towards Africa. It's a three phase grid that is in synchronized phase everywhere. Like, literally everywhere.
Grid frequency cannot be used at scale to coordinate energy production as a result, because the grid elements themselves don't know why the frequency is going down on its own or where the cause is. For that you need to monitor the country or region crossing to see where energy is flowing and aggregate this.
Drop a couple gigawatts from the production side, for example, all at once and the frequency will immediately drop, only not crashing due to the mechanical inertia of the large power plants. Immediately, electricity and physics will lead to current balances redistributing and automated systems will kick in (e.g. gas peaker plants ramp up in a matter of seconds, battery storage kicks in even faster). But when too much capacity gets dropped, the available spare capacity isn't enough and eventually the first lines will trip due to overcurrent or frequency deviation. That is what happened in Spain, made worse by the fact that inverters don't have mechanical inertia and so immediately more inverters dropped out for safety reasons as the frequency sagged too much for their protection circuits. The inverse, adding a couple of gigawatts of consumers, causes the same effect.
That's also why very large consumers such as smelters must contact the local electricity distributor in advance before any load change - dispatch must know precisely when the consumer will drop or add load, so that other plants can be regulated up or down to avoid too much of a sag or hike in frequency.
Symbiote · 13h ago
Minor, but it's from Denmark (Jutland) south.
There's a separate Scandinavian grid for East Denmark (Zealand) and north.
(And the British Isles are their own grid.)
mschuster91 · 12h ago
Yeah I knew about the Brits but you're correct, it escaped my mind that the Nordics run their own zone [1]. But you're a bit outdated too, turns out - the most North point is the Baltics these days, they switched away from the Russian grid a few months ago [2].
Of course the Ukrainians are now much less dependent on central power generations out of necessity. It turns out that all those big power plants and electricity distribution centers make for nice drone targets. The Russians did far more damage with that than with their satellite hackery. Those 5800 wind turbines came back online and are mostly still operational.
The lesson here is that distributed power is a good thing in war time scenarios but you might want to pay attention to digital security. Central power generation becomes a tempting target.
Now the good news with Chinese stuff is that a war is not imminent and we have the benefit of hindsight and can do something about that.
mschuster91 · 12h ago
> Now the good news with Chinese stuff is that a war is not imminent and we have the benefit of hindsight and can do something about that.
We are and we have been at war with China (and Russia and North Korea, fwiw) for many years at this point. The ongoing cyberwarfare from either country is more than enough to warrant this label, the problem is we were and are governed by chickens who refuse to accept the reality we are living in and still think that kowtowing to China's every demand will save our economies.
dachworker · 22h ago
I'm not at all familiar with this whole field, but why would you publish a trading strategy if it has potential? Why not sell it to a hedgefund, at least? Or is this research formally publishing what industry is already doing?
throw-qqqqq · 22h ago
Seemingly profitable strategies are actually published all the time in finance literature.
Some also work (usually only for a short amount of time if profitable), most don’t really work at all for various technical reasons (lookahead bias, model doesn’t account for slip/trading costs or assume infinite liquidity or a portfolio too large to realistically rebalance etc.) and some again work, but have unfavorable risk-adjusted return profiles compared to simpler strategies.
yxhuvud · 21h ago
Or in the case of batteries: Requires a whole lot of hardware to be bought to get a reasonable economy of scale.
dschaurecker · 17h ago
Most real-world optimizations for flexible storage assets currently work across multiple markets, sometimes also with more sophisticated boundary conditions. What we show is that high-frequency trading on the continuous intraday market is relevant, especially when training for more optimal parametrized strategies.
It also seems like a sensible idea to publish details and theories about an idea, not necessarily a finished trading product though ;)
chardz · 18h ago
On top of what others have mentioned, this paper also sidesteps forecasting electricity prices, which is already a very complicated problem (particularly in U.S markets where we have zonal pricing) needed to build profitable battery systems that actually operate on the grid.
I've had a few chats with some folks working on battery startups, and I think the more conventional approach is to forecast prices + run an optimization to find optimal storage decisions. You could measure the system's performance by looking at how well the algorithm does when it has perfect information about prices (obviously, when you have perfect information about prices it is trivial to optimize the battery).
dschaurecker · 17h ago
Our two follow-up papers are addressing exactly this (for Europe)! We are extending our high-frequency continuous intraday approach (CID) with a forecast-based day-ahead bidding stage, and subsequent CID forecast updates.
I'd also be quite interested in strategies for grid-scale BESS trading in the US' real-time markets. Do you know more about it, or could forward me to someone who would be willing to talk about it? ;)
chardz · 11h ago
I'm afraid I'm not too familiar with BESS in particular, and the people I spoke to are probably not too keen on sharing much (which is generally true of those who work in U.S markets). Unfortunately it's all very opaque.
I'd be happy to provide you the names of the firms I spoke to over email, if that would be of use!
loehnsberg · 22h ago
There‘s still a lot of work left to do to go from an academic prototype to live trading: real-time data, market access, SCADA, compliance & legal, security, … Also you must be a physical player that owns the battery and/or right to use it and not just do paper trading.
7thaccount · 21h ago
There is "virtual" (paper) trading in the day ahead markets in the US, but it's just for amounts of energy. You can't make a fake battery for the grid operator to optimize.
Gys · 22h ago
Is the trading strategy making substantial returns (at least a few percent) on the full investment (batteries, electronics, subscriptions)? Otherwise this is only relevant for battery owners that benefit already by other means (using the battery at night for home owners, for example).
h4kor · 22h ago
This isn't a trade "just on paper". You need real hardware integrated into the grid.
Energiekomin · 22h ago
The authors are from universities. Publicly funded.
And its not like they can just do that and get rich. Its particular for/with battery storage systems.
Basically making battery storage systems more interesting for investors to invest into.
thelastgallon · 19h ago
Just use EVs. EVs are primarily energy storage devices, some people get to drive them about 20 - 30 mins/day. The remaining 23 hours, it is a energy storage device. It can absorb excess power when price is negative, and can even supply power back to the grid when prices are high!
rafaelmn · 18h ago
Sounds like deprecating a >10k battery pack on a >30k vehicle and reducing your max range with power cycles to earn pennies.
thelastgallon · 17h ago
Its more than pennies[1]. By several orders of magnitude. Car batteries now last longer the rest of the car lifespan, it will be millions of miles soon.
In my country for home consumers the difference between day/night rates is 10-20c/kWh. With spot pricing I can see it working to cover the post commute power spike - but you're effectively doubling your commute discharge rate and pushing charge levels to suboptimal levels.
Batteries might work but at 80% capacity they are worth significantly less than new - both in terms of utility and resale value.
Maybe if battery range gets extended so far that even at 80% capacity it's an overkill - like 1000mile batteries - I could see myself doing something like this - but at current ranges and charging setups - I'll skip the few dozen euro a month.
gpm · 7h ago
On the other hand battery prices are dropping exponentially. There's a good argument to be made that your battery is a depreciating asset not (just) because it's degrading, but because the technology is getting cheaper, and thus you should extract as much value from it as possible as quickly as possible (and then replace it).
The caveat to this market is who knows how much of a premium you'll end up paying to replace the battery given that it's attached to a certain model of car.
rafaelmn · 3h ago
> On the other hand battery prices are dropping exponentially.
Are they ? I keep hearing this but in practice the price of an EV is still dominated by the battery pack and the movement in EV prices is anything but exponential. China started pushing out the affordable EVs but that's because they are using less efficient/cheaper chemistry and even with better packaging they are significantly less energy dense.
I've seen Toyota announce 1000 miles solid state battery - if battery tech was dropping exponentially that should be cheaper than ICE in a few years - I would take the opposite side of that bet.
two_handfuls · 19h ago
Yes, exactly this has been proposed with "smart car chargers," along with other things you can do if the grid operator has some control over a bunch of grid-connected equipment. It hasn't taken off as far as I know, probably because that means the car battery wears out more.
The "virtual power plants" are the closest thing to this idea that is actually done in practice. That's individuals who own batteries joining some collective that then sells to the grid the ability to reduce demand a bit. Tesla did a pilot program with its Powerwalls iirc.
bee_rider · 19h ago
This seems like building more batteries (just, with extra hardware).
An EV could be good for this sort of thing, but I guess it would have to sit around at less than 100% charge, to have the capacity.
bufferoverflow · 19h ago
We almost never charge our EV to 100%, to not degrade the battery faster.
bee_rider · 18h ago
But, if you are going to offer “absorbing energy from the grid as a service” the capacity you have to offer can only be
<absolute max that you are willing to charge your battery to> - <minimum that you are willing have your battery sitting at>
There definitely could be some gap there, but it does depend on the car sitting at less than “full” (however you define full).
b0a04gl · 15h ago
> “Our method is able to solve over 24 million optimization problems in less than 90 minutes.”
that line is doing heavy lifting. sounds insane until you look closer
they batch out embarrassingly parallel, lowdimensional problems
no live latencies, no network I/O, no grid API jitter. just hammering a static dataset in memory. real markets stall, disconnect, price slippage, queue delays. none of that here. so yeah, 24 million looks cool in the abstract, but under the hood it's just cleanroom compute; feels like they optimised the benchmark more than the actual system
loehnsberg · 14h ago
Assuming you add all the annoying details that algo trade execution brings, the algorithm still provides the answer on which position to take within a few microseconds, which is what you want if you trade in a limit order book.
b0a04gl · 14h ago
true, you want microsecond decisions at the core, no doubt ; but that’s only half the game. an ideal action in clean memory isn’t the same once it hits fragmented liquidity, stale quotes, partial fills. if the algo doesn’t account for execution drift or book pressure post-placement, the microsecond edge fades fast. so yeah, fast compute’s necessary but not sufficient without modelling the messy tail end too
saltspork · 21h ago
In Australia 5 minute spot pricing is now accessible to many residential customers via retailers like Amber electric. With volatile pricing and a large home battery subsidy from the re-elected government, batteries can quickly pay for themselves through arbitrage alone.
EMHASS is an interesting tool to perform the optimisation.
philjohn · 19h ago
Yep, been using EMHASS for the last couple of years in the UK.
I have a large array (12.8kWp east/west split) but a low export limit of 5kW. In the winter it's charging overnight at 7p per kWh (Intelligent Octopus Go) and then using that stored energy during the day to avoid importing at peak rates, and in the summer it makes sure to discharge most of the battery before the peak generation hours so that battery charges from power which would otherwise be curtailed (discharge to minimise import on my SolarEdge system, but charge from clipped power would also work).
No comments yet
jakewins · 20h ago
Similarly in Europe; spot market with a big single pay-as-cleared spot auction for every quarter-hour, and then a continuous auction for the same periods closer to delivery, similar to the normal stock market. Millions of residential devices are traded there right now
dschaurecker · 17h ago
Thank you all for the interest in our paper, it is cool to see that people are interested in the topic!
Imagine software that could run on EVs, Powerwall-type batteries, computers/tablets/smartphones, and so on, which would automatically charge and discharge for passive income. Essentially algorithmic trading, but with power instead of stock. You'd just have to configure any necessary time ranges and charge percentages, e.g. maybe your EV needs to be at 25% by 8am and again by 5pm on weekdays in order to make your daily commute.
Maybe some EVs will start to come with built-in crypto miners to burn negatively priced power when the battery is at capacity. Maybe Lyft/Uber and Waymo/Cruise will take advantage of it by increasing and lowering rates based on the price of power (if they don't already).
7thaccount · 21h ago
Sorry to be the bearer of bad news, but this isn't novel and something that's been talked about for a long time. The industry term I've most heard is "prices to devices". You of course need retail to participate more in the wholesale markets, but there are a lot of barriers - some technological, some regulatory. Some companies did this in ERCOT, but there was a big backlash when customers got $20k bills after Winter Storm Uri as they didn't understand what they were signing up for.
The FERC passed Order 2222 which is a bigger step in that direction by forcing the regional wholesale markets to allow aggregators to aggregate up the smaller stuff that is normally considered noise.
Dylan16807 · 5h ago
> Some companies did this in ERCOT, but there was a big backlash when customers got $20k bills after Winter Storm Uri as they didn't understand what they were signing up for.
It would be a bit weird but you could have your home supply at a fixed-ish rate and your EV on a separate meter riding the raw market.
If you can prevent too much cheating.
infecto · 20h ago
And while not making money, there has been a lot of talk around Virtual Power Plants, that is unifying the larger demand devices to help stabilize the grid in times of peak demand.
7thaccount · 17h ago
Virtual Power Plants (VPPs) are essentially the same thing as the Distributed Energy Resource Aggregators (DERAs) I mentioned above. I guess a VPP is technically a more general term and could also refer to the same concept under different structures like in a micro grid.
The industry has a ton of jargon (literally thousands of acronyms amongst the US regional markets) and in many cases there are 8 terms that mean the exact same thing.
infecto · 17h ago
Not sure I follow but seems like a weird thing to mention. The DERA is the who, the VPP is the what. Similar but far from essentially the same thing.
7thaccount · 11h ago
The DERA is frequently discussed as being both the market entity as well as the collective what. Language is weird.
buu700 · 21h ago
Interesting, thanks. That doesn't sound like bad news at all.
7thaccount · 17h ago
No I guess not. It can sometimes be a little sad though when you think you've come up with some grand new idea and it's been done.
rtuin · 20h ago
This type of service is becoming increasingly prevalent among European energy suppliers for their residential customers. Beyond providing a revenue stream for consumers this model aggregates distributed energy resources (home batteries, EV's, PV systems) into a one virtual power plant. This enables the storage of surplus energy generated during solar peaks and dispatch back to the grid during periods of high demand. I find it a fascinating domain to work in!
datadrivenangel · 21h ago
I wrote a book on this in 2020 and was already somewhat late to the party, as people were running actual pilot programs a decade earlier!
Also large industrial consumers have been participating in similar approaches for decades. See the crazy clever trading schemes that Enron used to do fraud and drive up prices.
bfayers · 20h ago
I run predbat (https://springfall2008.github.io/batpred/) to achieve something like this with my Home Assistant install to manage my home battery. It can also manage EV charging but I haven't needed to do that yet due to how my tariff works. (Very cheap fixed period overnight).
Energiekomin · 22h ago
Thats what bi-directional charging is for and its already becoming political to force the industry to support this.
And we already have energy provider which provide a tarif for exactly this.
The only idea i hate is the mentioning of crypto. Not only is it waste, it converts the energy in heat which needs to get disipated and potentially wastes even more energy to get this heat away from the current location (ac).
Aeroi · 18h ago
pretty sure nodal energy market trading, duck curve arbitrage is the whole profit play for the tesla power wall/autobidder and the Base Power startup coming out of ERCOT. There is definitely a land rush from energy firms and GIS guys to front run land purchasing near solar buildouts and to build as much grid scale battery storage as possible. The percent swings can be huge. Also a huge rush for this in the Northeast now that the offshore wind contracts have been cancelled.
ccheney · 15h ago
I find Autobidder fascinating, they've been at this for awhile. When I saw this HN post I thought the paper may have come from Tesla themselves.
A world where individuals are incentivized to use some wasted space to place low maintenance automated trading batteries to make a little money on the side seems like it'd be an interesting solution to the renewable energy storage problem. Put a few units in otherwise useless locations like on roofs or in between highways and make some cash, sounds like a decent investment.
Would there be any expected problems in doing such distributed power storage on a very large scale around the grid that you'd have to account for? Perhaps issues with synchronization, power flow or the possibility of large scale drops in avaialble stored power at times?
soared · 21h ago
Outside of the grid level, maintenance, security, and safety of batteries is important. Many Americans have a garage to securely store their $30k+ car, bike/etc - similar security may be necessary (literally or for the feels) for expensive batteries.
No comments yet
fifilura · 22h ago
Or preferably your EV? Requires no extra space or extra investment...
Energy overproduction is going to become a serious viability problem for baseload generators, which in time will significantly affect grid reliability. Rolling blackouts will become the norm unless we figure out a serious scalable solution to this.
potatoicecoffee · 21h ago
seems dumb to have electricity needing to be wasted when there is seawater to desalinate
Majromax · 21h ago
> seems dumb to have electricity needing to be wasted when there is seawater to desalinate
That's a much more complicated problem. On an energy market, you have only one price to look at, and the battery operator can always buy, sell, or hold energy. The article here talks about optimizing this problem at 5-minute to several-hour intervals.
If you drop excess power into desalination, however, now you have two prices to worry about: energy and water. I also doubt we have 5-minute spot markets for water, so the operator must probably commit to some medium-term water delivery regardless of price.
This means that a desalinating firm takes on much more risk. This might still be profitable, but it's a long-term play based on a deep model of expected energy prices (i.e. knowing that energy is "always" almost free at noon in summer) rather than short-term time-shifting.
mikeyouse · 20h ago
Desal plants are also extraordinarily expensive and need to operate at very high 'capacity factors' in order to payoff the capital investment that was required to build them. Operating for a a few hours every day because your operating costs are low/negative only works if you don't have a hugely expensive piece of infrastructure depreciating as you wait for those prices to come down.
amoshebb · 19h ago
could we build them different if the goal is just to waste excess energy?
Why couldn’t it just be a giant heating element and some sort of steam condenser at the top and some way to flush it periodically?
It might burn some laughable 3kWh per kg of water, but who cares? every water utility on the coast could add a few megawatts of tea kettles and get opportunistic little splashes of water in volumes small enough they can probably already handle them and the brine discharge would be so small, disperse, and infrequent it’d be easier to deal with, and it’d basically cost nothing
Nasrudith · 20h ago
Industrial processes like desalination tend to call for some optimal amount of near 24-7 utilization (barring maintenance and such) for capex reasons and efficiency. You want to use it as much as possible to get the most bang for your buck. The entire reason why there are these excess power periods is because we cannot predict accurately how much power we would really need.
lazide · 17h ago
Desalination plants really don’t like being ‘throttled’, and are quite capital intensive. Stopping production for any length of time can even destroy the plant, if not done very carefully. Similar for geothermal, though the specific details are different.
Even free power would likely not be worth using if it was sporadic, and it’s extremely energy intensive. So that really is saying something.
msgodel · 18h ago
Energy futures you say? Oh boy I've heard this one before...
Dylan16807 · 5h ago
That kind of association is why you can buy futures in just about every crop except onions. The fact that you can structure fraud around a specific kind of future doesn't make them special or a bad idea. One major fraud should not bias us forever.
NooneAtAll3 · 17h ago
explain?
msgodel · 16h ago
That's what the infamous company Enron was running: simultaneous energy futures brokerage and market making. Their market making part blew up and they hid it from everyone for a while until the rest of the company did. It was a massive scandal. It was pretty similar to what FTX was doing just with energy instead of crypto.
ada1981 · 22h ago
If anyone is interested in Batteries, I highly recommend following NAATBATT.org on LinkedIn and joining their newsletter.
Obama set this org up as a senator to help bring lithium ion batteries supply chain to the US and it since evolved into the trade association for all things batteries.
Jesus! Why finance people are so hell-bent in extracting rent from every single thing, pervert it, make sure the incentives are all pointed to the shortest run while socializing all the costs to the rest of us?
yxhuvud · 21h ago
If this was implemented in full scale, then it would .. stabilize energy prices towards the mean, and make the energy transmission more stable and resilent in general. I'd happily pay some overhead for that, as it also mean the network can accept more cheap energy sourced from wind and solar.
rcxdude · 14h ago
This is the kind of thing that is funding the massive expansion in renewable energy build-out at the moment. The whole reason there's an energy transition happening is that solar and wind and batteries are cheap enough you can make a lot of money building them, and that'll remain true until basically the whole grid is renewable (finally kicking out the expensive gas turbines), and the average price drops to reach cost of supply.
(And the kind of optimisation that happens with this kind of paper is really in the margins stuff. It generally helps the predictive power of the grid, and usually doesn't make much money once more than one group starts doing it, since it's pretty cheap to run and the margins shrink quickly)
ic_fly2 · 22h ago
More money made with batteries means more batteries installed. How is that a bad thing?
cess11 · 22h ago
Profit motive commonly has obscene consequences, like destroying food instead of using it to feed the hungry.
rcxdude · 14h ago
This tends to more to do with food supply security and costs of distribution than anything else (as well as political opposition to socialising food supply).
i.e. if we want to avoid food shortages, we need to overproduce the raw goods and therefore waste some. Transporting and transforming those raw goods into food that someone can eat still costs money, it's not just so farmers can get paid. We probably should still actually make sure no-one goes hungry, but that does actually involve some cost and effort on the part of the government, and the challenge there is mainly political elements who don't like the idea of someone getting something for free.
yxhuvud · 21h ago
While true that it happens in certain cases, the onus of showing that it would be the case in this specific case is still on you.
cess11 · 18h ago
I basically just did, that's how markets of this kind work. If it is more profitable to warm the wind along a mountain side than some cold person, then that person will stay cold.
Poverty and misery in the world are mainly caused by this kind of mechanism.
daedrdev · 13h ago
When the grid has to much money for 10 seconds, the cost of finding an having a productive asset that is ready to accept such a short burst of energy means that paying people to throw it away can easily be cheaper, leaving you with net positive money that can be used towards keeping people warm. Real systems involve tradeoffs, and so there will always be some short enough time frame where throwing away energy is better for society and human welfare than building infrastructure to use it. Everyone already using the energy gets it for free when prices are negative.
yxhuvud · 16h ago
If it is profitable to produce heat, it means prices are negative. If prices are negative, then that is true also for cold people.
On the other hand if prices are high, and someone has sells electricity that was bought when prices were close to zero, then the cold people will get warm for cheaper than if there wasn't a battery.
Sorry, but you really make no sense.
cess11 · 15h ago
Manufactured scarcity and related phenomena are really, really common. You should probably look into themes like the tendency of the rate of profit to fall and planned obsolescence and so on, and then explain why this specific case of coked yuppie market would be immune to them.
rcxdude · 14h ago
In this case there are two things that contribute: one is cost of distribution, which means that it does in fact cost something to get the electricity to the cold person, and the second thing is the kind of structures which help insulate consumers from extreme prices: most people pay a fixed rate for electricity despite the variation in the wholesale price, which means that while they may pay some amount while the price is negative, they are also not paying a small fortune when the price goes up massively. This could probably be done better, though, and things are changing which would do make electricity free or negatively priced for some end-users when there's excess in the grid, while still insulating them from extremely high prices (they're still going to be paying something for the insurance, though).
yxhuvud · 15h ago
Again, more players in the market (both batteries and the renewables they enable) and the base fact that batteries pull prices toward the mean means that if anything, they would be exactly one of the mechanisms to avoid manufactured scarcities.
cess11 · 3h ago
Why would this specific application of this type of market be immune to rent seekers, manufactured scarcity, wasting or withholding resources for profit, oligopolies and so on?
What makes this application of this social regime so different from e.g. food or medicine?
aitchnyu · 21h ago
No need of speculators. A utility purchases cheap off peak power and extremely costly peak power and pass the costs to the consumer. If the utility pays homeowner with BESS something comparable to peak power rate, they can recover their investment quickly.
yxhuvud · 21h ago
Such an utility would be a speculator.
driverdan · 21h ago
Except this is exactly what you want to happen. The reason electricity prices range is because of supply and demand. Batteries help smooth out the supply curve.
In the short term adding more batteries may allow someone to generate income using this strategy but long term what it will do is push electricity prices down and prevent power generation from being overwhelmed. As the battery "market" gets crowded profit margins will fall and everything will reach an equilibrium.
This is a great demonstration of how capitalism works and why it's beneficial.
lazide · 22h ago
Smart People with money are willing to give it to people if they can make them more money.
Why would anyone give them money if they were just going to throw up their hands and go ‘well, nothing we can do I guess!’.
There is of course the risk that the money gets burned instead of more money getting made, which is the risk in risk/reward.
Rent seeking type behavior tends to happen when there are no obvious ‘green field’ type endeavors to invest in. Or when risk appetites are trending negative.
Note - many of those people with money that want to use it to make more money are retirees, pension funds, etc.
baq · 21h ago
Capitalism is the only form of communism that works on longer time frames. Periodic resets are still needed, otherwise the monopolist becomes the ruler.
formerly_proven · 20h ago
Negative prices are mostly caused by unreasonable terms towards generation plants. E.g.: requiring the grid to take every kWh generated and paying a fixed price over a 20-year term. This of course encourages capacity to be built with no flexibility. Why not dump your solar power into the grid? You're getting paid, the state guarantees for that... the negative prices are someone's elses problem.
The authors are observing that, if electricity prices are negative and your battery is not perfectly efficient, then you would like to charge and discharge simultaneously to get paid for wasting energy, but you can’t.
This is a silly limitation. Surely the power electronics or even just the control algorithms in a BESS could be slightly modified to consume power, get warm, and not transfer any current to or from the battery cells, effectively taking advantage of the BESS’s heat sink to sink excess power and sell that service.
More seriously, in a world with occasional negative prices, you would want your battery to be able discharge itself, without exporting power, in a controlled and power-limited manner so as to avoid overheating. And the optimization algorithms should factor this in. I wonder if real grid-scale BESS systems have this capability.
When I first heard it, it seemed wild that they couldn't hold on for the price to go back above zero, but I guess if we're talking high frequency trading it makes more sense. They might have bought and sold many times while the price is different levels of negative before switching to charging up in preparation for the later price rises.
And the round trip inefficiency helps too.
As you know, negative electricity prices mean that someone is willing to pay you to dispose of electricity they need to generate for some reason. For example, a conventional steam-turbine-based electricity plant might prefer to just keep running for a brief period of time when demand is low, rather than subject their equipment to a power cycle, which increases their maintenance costs. There's other, dumber, examples based on stupid contracts and badly designed solar... but this example is a reasonable one that exists for good engineering reasons.
The battery provider in this circumstance is profiting from their ability to accept power when demand to dispose of electricity is particularly high. When that need goes down, they can reasonably profit by dumping that energy on someone else who is also able to dispose of the electricity. But at a lower cost. E.g. imagine an big industrial refrigerated storage facility that can consume some excess energy by supercooling their refrigerators. But they can't consume unlimited excess energy, because at some point their warehouse just gets too cold, and they don't have unlimited refrigeration capacity anyway.
So in this simplified example, the battery storage service is getting paid a lot of money to quickly absorb a lot of energy, which they then dump more slowly to the refrigerated warehouse (and similar providers) as the surplus diminishes, in anticipation of another surplus in the near future.
I'm not sure: why doesn't someone 'just' put up a few resistive heaters and fans to benefit from negative prices?
Oh, that's right. This is supposed to be wealth transfer.
I'd recommend digging elsewhere for conspiracy bait. This is a mild curiosity at best.
Exactly. There are genuine economic/engineering reasons for negative prices to occasionally exist. But in a well-designed, well-run, grid price will be negative only a small minority of the time. It just doesn't make sense to install a bunch of expensive equipment to provide this service when sufficient capacity exists from "happy accidents" like spare battery storage.
In the long run, better managed solar and wind should make negative prices a fairly rare event.
The former is already happening and useful, the latter would be a relatively simple and easy add-on that could be used to offer ever so slightly cheaper electricity.
But I’m not sure that’s entirely correct, and maybe it’s time to revisit this.
Any system that is selling responsiveness as part of their service has to keep a certain amount of equipment sitting idle. That’s just how queuing theory works. So while you cannot move all server load to the coldest available zone, we should still be able to run that center near capacity and use the hottest one for all reserve capacity.
Power plants also have to deal with fines for exceeding emissions limits, but I suspect the problem here is that Bayesian analysis tells them that if a plant has to kick on early for some reason (early school release day, or another plant exceeded a maintenance window), it will still be needed for sure an hour from now, so it’s better to leave it running for 45 minutes doing nothing than to cycle it.
How is it not better to discharge the batteries instead? I guess if you don't have that hardware option integrated into the platform maybe, but otherwise...
I had to go search my bookshelf for this one:
Eric R. Laithwaite, Induction Machines for special purposesSo one solution is to incite demand (with negative rates) for folks to ramp up their use of electricity (into e.g., a dump load resistor bank), bringing demand back in line with supply, and bringing the operating frequency back under control.
I hate the waste, agreed. But it would be irresponsible of the operator to bank that extra supply energy into the momentum of spinning things owned by the consumers just so they could pull it out later by intentionally under-supplying. E.g., an aquarium's big water pumps designed to spin only so fast or produce so much pressure might not like being operated at 110% the rated speed at random times of the day.
related links:
https://fnetpublic.utk.edu/frequencygauge.html (you can watch the grid frequency fluctuate in real-time, here!)
https://en.wikipedia.org/wiki/Stuxnet
https://en.wikipedia.org/wiki/Utility_frequency
> (I know people who have had their AC turned off during heat waves and were not very pleased)
I suspect they probably agreed to pretty harsh control in the name of cheaper electricity, but actually were only willing to tolerate relatively small amounts of loadshedding. I wonder whether better contracts can help align expectations here in the future. Eg allow the electricity company to set your aircon's thermostat up to 3K warmer (or something like that), but not turn it off completely?
This is one of those efficient market things where you need to manage the market in order that wasteful things happen sometimes... but that waste is an opportunity.
If you and your competitor are both in the business of dumping energy into heat, you're going to compete with each other for access to that money.
Then one of you is going to try to find a way to make _more_ money with that energy and find something quickly scalable with not-too-high idle overhead costs to do with that energy besides just flowing through a resistor.
Negative prices are a sign of an inefficient market or just the lag time between a changing landscape of resources and someone to utilize them.
If there's a free resource someone's going to figure out how to use it, just let it hang out for a while and the problem fixes itself.
Especially with solar energy, this is just going to be a thing. There's a certain balance where overprovisioning is cheaper than storage and so you just do that. Then you wait for industry (or consumers) to figure out how to take advantage of the intermittent cheap energy.
Yes, exactly.
Which reminds me of the occasional story about how one native group or another was so in tune with nature, because they used every part of the (insert important animal here).
Modern economies obviously use all parts of the animal, for exactly the reason you outline.
> Especially with solar energy, this is just going to be a thing. There's a certain balance where overprovisioning is cheaper than storage and so you just do that. Then you wait for industry (or consumers) to figure out how to take advantage of the intermittent cheap energy.
Yes, though you also need to make sure that regulations don't get in the way. Or at least not too badly.
One example I can think of is forcing utilities to charge people by net-metering, forcing the utility to implicitly pay the same price for electricity as they charge. We don't do that for eg used car salesmen.
Unless you specifically design for it (specifically, with a dummy load), the efficiency of the system is inversely proportional to its ability to do this. You need a secondary system.
The power system can connect the battery terminal to in or to out, so if you switch both on at once you effectively bypass the battery. It's called shoot-through current and is generally considered a destructive process. If you can switch on and off fast enough you could limit it to a non-destructive level, but in practice most systems will not switch fast enough. They are designed to operate with the battery load, which is at minimum ~10x higher resistance than the transistor itself. In practice it is often 100s of times higher.
That's where the efficiency comes into it. If a power system is 98% efficient (pretty normal- this does not include power lost to heat in the battery itself), that means the electronics can only burn 1/50th as much power as normally passes through the system. Worse, when you put the switch into shorted position it will try to pass 50x its rated current. You need to switch much faster -certainly more than 50x faster- and that will probably put it outside its operating region.
It is relatively easy to just have a large resistor, but it is not very well suited to use battery power systems. Batteries are very low impedance, and the power system exists to transform to a lower voltage and higher current. Resistors are cheaper when they are higher voltage, so the power system is a hacky kludge.
The overall solution is just more batteries. Oversupply is a transient problem and always will be.
Many multicell BMS already have this kind of "power shedding" capability. They use it for cell balancing - to equalize voltage between cells with slightly different characteristics. This is desirable despite the power waste, because it reduces wear, increases charging efficiency and allows battery packs to last longer.
Some battery packs are also designed to be able to dump enough power into heat to be able to keep the batteries warm during extreme cold.
Similarly, the heatsinking capacity of the battery is designed for charging/discharging losses (say 5% of charge/discharge power).
There are several challenges with this, safety, thermal runaway, and life cycle of the asset which has a limited amount of cycles.
Also the architecture of the system for the AC inverters and the DC side can come from very different places in the supply chain and aren’t as vertically integrated leaving you in a position where you can’t actually make this work without compromising something in the supply chain. That being said we are talking about a LOT of energy in these systems and to dissipate that much heat you’d need a load bank.
Modern water heaters will keep temp for a shockingly long period of time.
It'd take a far amount of math to figure out if that tips it over though I don't feel like tackling haha.
Heating water, cooling water, pumping water, charging batteries, running power hungry machines.
It's half century old tech and usually the only thing missing is a financial incentive to do so.
Water needs a lot of energy to cool or heat, concentrated at a district, you could easily absorb a lot of energy at negative prices.
For example, if the electricity price is -28€/MWh (like today in Germany), and your battery efficacy is 80%, you could get paid 28€/MWh charging, then only pay back 22€ discharging, generating a 6€/MWh profit.
There is also the problem that your battery would likely degrade fast depending on the technology.
Not that it matters, because the effect would be miniscule in any case.
With enough solar panels deployed, you could still argue that they change the albedo of the Earth and therefore it's temperature.
Aside from software integration to remotely control household PV systems, is there anything else needed to curtail during negative price events?
https://www.reddit.com/r/energy/comments/1iu2kkz/solar_curta...
Now to figure out how much exactly you need to take into account the solar panel absorption spectrum & the albedo of the earth.
You mean crypto miner.
If I buy a device for $100 that, given free electricity, will mine $500 of cryptocurrency in its useful life - I can easily lose money if I run it less than 20% of the time.
And I doubt electricity is negative priced >20% of the time.
Rather than coming up with some grand scheme, maybe it would be good if our dishwashers and washing machines could listen to the grid and activate when power cost was negative. (We may need to coordinate a bit though, so we don’t all activate at once).
So it's already possible to incentivize people correctly with price signals, at least in some regions of the world. But people are not yet familiar with this. I guess that will change as the pricing between dynamic and traditional contracts keeps diverging. With a traditional contract, you are essentially paying the average evening peak price all the time. With a dynamic contract, you get access to the cheaper and even negative rates.
If you think of it, a dryer is sort of a combination of a flywheel and a heating element, so it should be the over-provisioner’s best friend. IMO a real failure has been not taking advantage of our appliances.
I know there are some places where this happens though but it's more along the lines of the devices delaying their start until energy is cheap rather than being used as loads to shed excess capacity afaik.
This is what I meant, sorry for the ambiguity. Load the washer up and kick it off whenever energy is cheap. I don’t care when it happens other than, like, that it happens once a day, so why not defer this to the power company, right?
Also there are downsides to having clothes just sit there for hours potentially before you dry them. They can get pretty dank from the moisture and for dryers some clothes need to be removed immediately when the cycle finishes.
Anything that would really love free energy also cost a lot to build and maintain/operate besides electricity. So much that a few hundred hours of free (or even better than free) energy a year is far from enough when you need >90% uptime to make sense. Maybe it makes you go from 95 to 85%, but still clearly it's far more than there are sunshine hours.
The problem is that things that can use bulk energy productively like electrolysers, hydrocarbon crackers, smelters, AI training farms, etc. are very expensive and having them on warm standby but idle most of the time waiting for good grid weather makes for bad returns on the capital expenditure and operational costs.
He's just trying to burn energy because a negative rate means he's getting paid to use it.
So sure - it's great to give that energy a functional use first (ex - charge his batteries) but eventually he runs out of functional ways to use the energy but could still be making money by using it.
Enter the desire for a dummy load.
It's straight forward to add a giant resistive load that just converts electricity back to heat.
I can get 10kw heaters for just a couple hundred bucks or 1.5kw heaters for literally $20 usd. And that also switches on/off easily.
For hydro... just boiling water with a heater is going to be pretty much unbeatable if we're playing the "waste energy" game. No need to approximate it slowly with your pump motor and risk other infrastructure.
New designs store the power in batteries, but most locomotives used in the US still have a compartment filled with fans and resistors instead.
And the same thing for residential scale is literally just a ceramic space heater running at ~1500w.
They're dirt cheap, usually have temp safety checks built in, work on a residentially sized circuit, and are available everywhere.
I needed a cheap and consistent load to do LFP battery testing, and I could spend $5,000 for a real test unit, or $21 for a ceramic heater that will do basically the same thing.
If you've already got the monitoring for the batteries/inverters, a heater is a GREAT load choice.
I'm not sure that this really is a completely off-the-shelf stove element. But obviously, the technology is basically identical to what you'd have on your stove.
A neat example of regenerative braking being important is the London Underground: they've had a persistent problem with high temperatures in the subway, of which a decent % is actually heat from trains braking. By using regenerative braking rather than putting that energy into the tunnels as heat, they can transport that energy outside the tunnels, keeping them cooler.
Whether the negative energy price is enough to balance wear on the system and potential noise is a different question.
In winter yes also if its not getting to warm for you, but also heating water is easy enough. But you don't need that much hot water
Potentially also cooling down your fridge more and your freezer. But that is not that much energy.
While that works, it would still be quite a waste. It would be a lot better to save it and discarge it later
This is not a common occurrence or situation, or shouldn’t be anyway, or someone is screwing up pretty badly somewhere.
No comments yet
My gut would expect it to approach $0 if full communication were possible, based on the instinct that most people would run their dishwashers if the energy cost was $0.
‘Overproduction’ in this sense is from something like a spinning generator which starts to overspin, or an inverter which oddly starts to overvolt the output for some inexplicable reason.
We currently have the situation where operators of solar farms of all sizes get a fixed amount of money for each joule they feed into the grid. Of course those people have zero interest in turning down their inverters when the sun is shining and there's already a surplus in the grid.
But yes, certainly poorly managed solar/wind that doesn't have good mechanisms to turn off in response to lack of demand is mainly the issue. In the future, when control systems are better, I'm sure negative pricing will be much less common.
But like I said before when rates go negative you will typically see it in occurrences where you have abnormal conditions (wind and solar generating at the same time) or aggressive night winds. And it does not happen long enough to need to curtail generation.
The yield you could make from batteries in the UK dropped from double digits to 2% in 8months once some hedge funds figured out how to build and bid (or commission companies like my employer) batteries in the UK short term reserve market.
There are a few firms in northern Jutland and London specialised in this sort of trading.
Huge part of the reason why negative prices exist in the first place is separation of generation and transmission. With pay-as-clear model negligible-variable-costs generators (i.e. renewables) can bid at zero and pump more into the grid than the local segment can drain, requiring artificial balancing sinks. However, the cost of artificial sinks fall on the grid as transmission costs and are not reflected in the wholesale market.
Another interesting aspect is that as grid demand fluctuates, a lot of cables are under utilized at least some of the time. Which means there is plenty of capacity for charging batteries provided there is excess generation and cable capacity. A lot of that power currently gets discarded instead. Batteries allow better use of this excess power. And having a lot of local battery means that cable capacity can be freed up as well when needed and then recharged when demand reduces.
And then finally battery prices are coming down. With sodium ion cell production ramping up in several places, things could get quite a bit cheaper. These don't depend on scarce metals or materials. And they last quite long as well (relative to NMC).
Nor should they. People don't want to be cycling their batteries and reducing their life. This use case would be better served by batteries that are designed for that purpose instead of being designed to be light for a vehicle.
This is how most Time-of-Use metering already works. The driver sets a minimum battery percentage to charge immediately (eg 40% range, enough to reach the local hospital), and then schedule a time when the car should be fully charged (eg 80% by 7AM). The software just Does The Right Thing, using the same prediction and bidding algorithms as stationary batteries.
The search term is "V1G" (a cheeky reference to unidirectional V2G).
More battery cycles just costs money. For the right price, I'd do it.
But more than that: I don't want to be stranded without power in my vehicle because someone in the electric grid made poor power management decisions and decided to offload that decision to consumers.
That said, most EV incentive programs use around 10% (often less) of an EV battery capacity so the actual effects are barely noticeable.
A price that can be measured in money. How much more does it need to pay to be worth any extra hassle?
So in a sense it is just money. Money is hassle, fundamentally. It's a hassle to make it and you spend it to save other hassles.
Another factor is that not all charge/discharge cycles are the same. Going between 60% and 80% five times is a lot lighter on the battery than going between 0% and 100% once. Which pairs great with EV batteries, because their batteries are deliberately oversized compared to average use to account for uncommon events.
How is power discarded? I would expect peaking generation to be cut back or perhaps even base load plants can reduce output. (AFAIK "base load" means they are expected to be kept operating continuously whereas "peaking" is designed to start up when needed and shut down when not.)
As for baseload. It's one of those waffly terms that's rarely specified in GW that is needed. Which as it turns out is far less than we used to have given that much of it was replaced with wind and solar over the last decade or so. The real question is how low can we go with this stuff before we need some more solutions. Some would say all the way but the consensus is that the last 5-10% might get very hard and costly.
Either way, having some peaker plants on stand by ready to spin up over the course of hours/days while batteries slowly deplete is probably a good short term compromise. Replacing spinning mass (fly wheels) with batteries seems a particularly popular and very cost effective use for batteries.
It isn’t, not at scale in any traditional sense.
... and a serious issue should one of the few large manufacturers or remote-control dispatcher/trader companies get hacked. The outage in Spain a few weeks ago was just a small warning, probably caused by a technical malfunction. But now imagine this being used as a side track in an act of war? The first day of the Russian invasion of Ukraine was accompanied by the hack of Viasat satellites, which led to 5.800 wind turbines shutting down due to a lack of remote control capabilities [1]. Now imagine the large Chinese inverter and power bank controller vendors that often enough just white-label for other brands? That's a whole lot of a different game now.
[1] https://en.wikipedia.org/wiki/Viasat_hack
If everyone agrees, you can use grid frequency/phase to coordinate, and not a separate realtime communication system. Grid interactive demand/response is a proven way to manage supply and load.
When your section of the grid is stressed, supply power or abstain from charging; when your section of the grid is abundant, charge.
Coordination is useful too, of course; predictive charging is helpful, and you wouldn't get that only by monitoring the grid; you also want to know somehow that a supply or load is scheduled to be added or removed at time X, or was unexpectedly removed and will not be reconnected for some time. And the system operator would want to know about capacity in many dimensions.
Grid frequency cannot be used at scale to coordinate energy production as a result, because the grid elements themselves don't know why the frequency is going down on its own or where the cause is. For that you need to monitor the country or region crossing to see where energy is flowing and aggregate this.
Drop a couple gigawatts from the production side, for example, all at once and the frequency will immediately drop, only not crashing due to the mechanical inertia of the large power plants. Immediately, electricity and physics will lead to current balances redistributing and automated systems will kick in (e.g. gas peaker plants ramp up in a matter of seconds, battery storage kicks in even faster). But when too much capacity gets dropped, the available spare capacity isn't enough and eventually the first lines will trip due to overcurrent or frequency deviation. That is what happened in Spain, made worse by the fact that inverters don't have mechanical inertia and so immediately more inverters dropped out for safety reasons as the frequency sagged too much for their protection circuits. The inverse, adding a couple of gigawatts of consumers, causes the same effect.
That's also why very large consumers such as smelters must contact the local electricity distributor in advance before any load change - dispatch must know precisely when the consumer will drop or add load, so that other plants can be regulated up or down to avoid too much of a sag or hike in frequency.
There's a separate Scandinavian grid for East Denmark (Zealand) and north.
(And the British Isles are their own grid.)
[1] https://de.wikipedia.org/wiki/Verband_Europ%C3%A4ischer_%C3%...
[2] https://www.entsoe.eu/news/2025/02/09/entso-e-confirms-succe...
The lesson here is that distributed power is a good thing in war time scenarios but you might want to pay attention to digital security. Central power generation becomes a tempting target.
Now the good news with Chinese stuff is that a war is not imminent and we have the benefit of hindsight and can do something about that.
We are and we have been at war with China (and Russia and North Korea, fwiw) for many years at this point. The ongoing cyberwarfare from either country is more than enough to warrant this label, the problem is we were and are governed by chickens who refuse to accept the reality we are living in and still think that kowtowing to China's every demand will save our economies.
Some also work (usually only for a short amount of time if profitable), most don’t really work at all for various technical reasons (lookahead bias, model doesn’t account for slip/trading costs or assume infinite liquidity or a portfolio too large to realistically rebalance etc.) and some again work, but have unfavorable risk-adjusted return profiles compared to simpler strategies.
It also seems like a sensible idea to publish details and theories about an idea, not necessarily a finished trading product though ;)
I've had a few chats with some folks working on battery startups, and I think the more conventional approach is to forecast prices + run an optimization to find optimal storage decisions. You could measure the system's performance by looking at how well the algorithm does when it has perfect information about prices (obviously, when you have perfect information about prices it is trivial to optimize the battery).
I'd also be quite interested in strategies for grid-scale BESS trading in the US' real-time markets. Do you know more about it, or could forward me to someone who would be willing to talk about it? ;)
I'd be happy to provide you the names of the firms I spoke to over email, if that would be of use!
And its not like they can just do that and get rich. Its particular for/with battery storage systems.
Basically making battery storage systems more interesting for investors to invest into.
Tesla Electric customers report making as much as $150 a day https://electrek.co/2023/07/05/tesla-electric-customers-repo...
In my country for home consumers the difference between day/night rates is 10-20c/kWh. With spot pricing I can see it working to cover the post commute power spike - but you're effectively doubling your commute discharge rate and pushing charge levels to suboptimal levels.
Batteries might work but at 80% capacity they are worth significantly less than new - both in terms of utility and resale value.
Maybe if battery range gets extended so far that even at 80% capacity it's an overkill - like 1000mile batteries - I could see myself doing something like this - but at current ranges and charging setups - I'll skip the few dozen euro a month.
The caveat to this market is who knows how much of a premium you'll end up paying to replace the battery given that it's attached to a certain model of car.
Are they ? I keep hearing this but in practice the price of an EV is still dominated by the battery pack and the movement in EV prices is anything but exponential. China started pushing out the affordable EVs but that's because they are using less efficient/cheaper chemistry and even with better packaging they are significantly less energy dense.
I've seen Toyota announce 1000 miles solid state battery - if battery tech was dropping exponentially that should be cheaper than ICE in a few years - I would take the opposite side of that bet.
The "virtual power plants" are the closest thing to this idea that is actually done in practice. That's individuals who own batteries joining some collective that then sells to the grid the ability to reduce demand a bit. Tesla did a pilot program with its Powerwalls iirc.
An EV could be good for this sort of thing, but I guess it would have to sit around at less than 100% charge, to have the capacity.
that line is doing heavy lifting. sounds insane until you look closer they batch out embarrassingly parallel, lowdimensional problems no live latencies, no network I/O, no grid API jitter. just hammering a static dataset in memory. real markets stall, disconnect, price slippage, queue delays. none of that here. so yeah, 24 million looks cool in the abstract, but under the hood it's just cleanroom compute; feels like they optimised the benchmark more than the actual system
EMHASS is an interesting tool to perform the optimisation.
I have a large array (12.8kWp east/west split) but a low export limit of 5kW. In the winter it's charging overnight at 7p per kWh (Intelligent Octopus Go) and then using that stored energy during the day to avoid importing at peak rates, and in the summer it makes sure to discharge most of the battery before the peak generation hours so that battery charges from power which would otherwise be curtailed (discharge to minimise import on my SolarEdge system, but charge from clipped power would also work).
No comments yet
Tldr: most applications of free energy have capital costs that far outweigh the free energy harvest potential.
Imagine software that could run on EVs, Powerwall-type batteries, computers/tablets/smartphones, and so on, which would automatically charge and discharge for passive income. Essentially algorithmic trading, but with power instead of stock. You'd just have to configure any necessary time ranges and charge percentages, e.g. maybe your EV needs to be at 25% by 8am and again by 5pm on weekdays in order to make your daily commute.
Maybe some EVs will start to come with built-in crypto miners to burn negatively priced power when the battery is at capacity. Maybe Lyft/Uber and Waymo/Cruise will take advantage of it by increasing and lowering rates based on the price of power (if they don't already).
The FERC passed Order 2222 which is a bigger step in that direction by forcing the regional wholesale markets to allow aggregators to aggregate up the smaller stuff that is normally considered noise.
It would be a bit weird but you could have your home supply at a fixed-ish rate and your EV on a separate meter riding the raw market.
If you can prevent too much cheating.
The industry has a ton of jargon (literally thousands of acronyms amongst the US regional markets) and in many cases there are 8 terms that mean the exact same thing.
Also large industrial consumers have been participating in similar approaches for decades. See the crazy clever trading schemes that Enron used to do fraud and drive up prices.
And we already have energy provider which provide a tarif for exactly this.
The only idea i hate is the mentioning of crypto. Not only is it waste, it converts the energy in heat which needs to get disipated and potentially wastes even more energy to get this heat away from the current location (ac).
https://www.tesla.com/support/energy/tesla-software/autobidd...
https://www.tesla.com/support/energy/tesla-software
Would there be any expected problems in doing such distributed power storage on a very large scale around the grid that you'd have to account for? Perhaps issues with synchronization, power flow or the possibility of large scale drops in avaialble stored power at times?
No comments yet
That's a much more complicated problem. On an energy market, you have only one price to look at, and the battery operator can always buy, sell, or hold energy. The article here talks about optimizing this problem at 5-minute to several-hour intervals.
If you drop excess power into desalination, however, now you have two prices to worry about: energy and water. I also doubt we have 5-minute spot markets for water, so the operator must probably commit to some medium-term water delivery regardless of price.
This means that a desalinating firm takes on much more risk. This might still be profitable, but it's a long-term play based on a deep model of expected energy prices (i.e. knowing that energy is "always" almost free at noon in summer) rather than short-term time-shifting.
Why couldn’t it just be a giant heating element and some sort of steam condenser at the top and some way to flush it periodically?
It might burn some laughable 3kWh per kg of water, but who cares? every water utility on the coast could add a few megawatts of tea kettles and get opportunistic little splashes of water in volumes small enough they can probably already handle them and the brine discharge would be so small, disperse, and infrequent it’d be easier to deal with, and it’d basically cost nothing
Even free power would likely not be worth using if it was sporadic, and it’s extremely energy intensive. So that really is saying something.
Obama set this org up as a senator to help bring lithium ion batteries supply chain to the US and it since evolved into the trade association for all things batteries.
https://www.linkedin.com/company/naatbatt-international/
(And the kind of optimisation that happens with this kind of paper is really in the margins stuff. It generally helps the predictive power of the grid, and usually doesn't make much money once more than one group starts doing it, since it's pretty cheap to run and the margins shrink quickly)
i.e. if we want to avoid food shortages, we need to overproduce the raw goods and therefore waste some. Transporting and transforming those raw goods into food that someone can eat still costs money, it's not just so farmers can get paid. We probably should still actually make sure no-one goes hungry, but that does actually involve some cost and effort on the part of the government, and the challenge there is mainly political elements who don't like the idea of someone getting something for free.
Poverty and misery in the world are mainly caused by this kind of mechanism.
On the other hand if prices are high, and someone has sells electricity that was bought when prices were close to zero, then the cold people will get warm for cheaper than if there wasn't a battery.
Sorry, but you really make no sense.
What makes this application of this social regime so different from e.g. food or medicine?
In the short term adding more batteries may allow someone to generate income using this strategy but long term what it will do is push electricity prices down and prevent power generation from being overwhelmed. As the battery "market" gets crowded profit margins will fall and everything will reach an equilibrium.
This is a great demonstration of how capitalism works and why it's beneficial.
Why would anyone give them money if they were just going to throw up their hands and go ‘well, nothing we can do I guess!’.
There is of course the risk that the money gets burned instead of more money getting made, which is the risk in risk/reward.
Rent seeking type behavior tends to happen when there are no obvious ‘green field’ type endeavors to invest in. Or when risk appetites are trending negative.
Note - many of those people with money that want to use it to make more money are retirees, pension funds, etc.