Energy Storage Investments Boom as Battery Costs Halve in the Next Decade | Hacker News Reader

Energy Storage Investments Boom as Battery Costs Halve in the Next Decade

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It irks me to see predictions talked about as if past events. But this is a more solid guess than most.

Actual progress has been impressive: 85% reduction in the 2010-18 period, says the article. Graph here: [1] Getting another 50% in 10 years can probably be done from manufacturing scale alone. Giant battery pack factories seem to be going up all over.

This is something that ought to be almost totally automated, but doesn't yet seem to be. You're making large numbers of identical units for years per model, the best case for automation. Somebody will get that right soon.

Do we get more energy density? 2x more, and gasoline cars are toast.

[1] https://about.bnef.com/blog/behind-scenes-take-lithium-ion-b...

Halve the cost and I suspect energy utilities as we know them are in trouble too.

Currently solar is a no brainer in my country of Australia. Typically around a 6 year payoff for a 20 year benifit.

Batteries are about break over ~10 years payback. But if you could half that it's becomes something many people will do. And once that starts happening it's a death spiral for utilities as they will have a every reducing customer base for a business with large fixed costs. As they put these expenses onto a shrinking base it only encourages more people to swap.

So for a country with a large suburban population that has the solar battery option this is going to hit utilities hard. Their market could shrink to largely providing high density areas where households dont have the roof space to generate their own power.

Are you aware of anyone that's actually cut the grid connection?

There's a big difference between generating enough energy over a year to be net zero, and being able to instantaneously supply power from batteries and solar throughout the year.

That's a problem in Hawaii. Hawaii got rid of net metering in 2015, because the utility was paying for solar power at a flat rate regardless of demand or time of day. Homeowners can still sell power to the utility, but at something like wholesale market rate. Or they can get batteries.

Utilities fear being required to maintain electrical distribution and generating capacity and only getting revenue on cloudy days. This is a real issue in Hawaii, which has so much sun and no local fuel sources, but less of a problem elsewhere.

It's a good problem to have.

Residential batteries are currently BS. They serve three purposes IMO:

1. A degree of backup. Solar alone is crappy at backup power. Solar plus battery is okay as long as one’s house is wired appropriately to shed load.

2. They can reduce peak loads. This is called “peak shaving”. If the utility can rely on it, it can genuinely reduce equipment costs to the utility. As far as I know, almost no residential rates give any incentive for peak shaving. Commercial rates give an extremely strong incentive.

3. Batteries can arbitrage nonsensical rate schedules. PG&E will buy a limited but large amount of peak energy from me for over 50 cents/kWh, and it doesn’t really matter that I’m just selling them power that I bought from them for about 12 cents/kWh a few hours earlier. This is the magic of NEM2PS + EV-A (now unavailable, but NEM2PS + EV2-A is still available and is not all that different). It is, IMO, crazy.

Home batteries would need to come down considerably in cost (way more than 2x) to make them worthwhile without these crazy incentives.

Easier to just increase the cost of power more than 2x.

That halving will make variable renewables much more effective: https://www.vox.com/energy-and-environment/2019/8/9/20767886...

If this prediction turns out to be true, it would be a real boon for reducing carbon emissions. Changing from 7% to 40% of electrical generation is a big deal. I'm sure it's not enough, but it sounds like a start.

It's pretty much guaranteed: even current photovoltaic pricing, let alone another factor of ten down the learning curve, means energy in the daytime is super cheap to free. This creates an immense market opportunity for utility-scale storage.

And for finding ways of using energy at peak times. I could imagine everyone charging their cars at work if it turns out the electricity is cheap at that time.

Absolutely! I think demand response is going to be even bigger than storage; see https://news.ycombinator.com/item?id=20664835 for more thoughts on this.

It seems a little conservative to me - I'd expect it to do that earlier than 2040.

Let's hope we didn't just replace 40% of electricity with renewables by 2040, or we can probably kiss civilization as we know it goodbye. We need to reduce global carbon emissions by 50% by 2030 if we want a fighting chance of staying below 2°. That's much more than just electricity.

I think the chances off staying under 2 degrees are slim to none. But that doesn't mean kissing civilization goodbye either.

And for Canada and Russia it will probably be a net positive.

No companies listed in article - anyone have a list of companies developing new battery technology?

Been something I've tried researching in the past with little luck

Maxwell, now owned by Tesla. I think Tesla will become a big player in the battery tech space

Maxwell dry battery electrode tech [1] is going to rapidly drive down cell costs (while increasing energy density) for Tesla. I posit this is also how they intend to pack 200kw of storage into the 2020 Roadster.

Disclaimer: TSLA investor

[1] https://www.nextbigfuture.com/2019/02/tesla-buys-maxwell-to-...

If this tech allows BEVs a significantly higher range it would be a game changer. Currently the range is about the same as gasoline cars with a longer refueling time. For your average consumer that’s not an improvement. But if I can go 800 miles per charge all the sudden my BEV looks like an iPhone X compared to your flipphone traditional vehicle.

I think it's 20-30% better energy density than current batteries

Model S and X with the new Raven drivetrain is already pushing 370 miles of range. Very few people are going to drive 4 hours at a time without a break, definitely not going 600-800 between stops, although I could see this as beneficial to the Tesla Semi and their truck offering (where higher energy density is crucial).

So far Tesla has not really done much in terms of battery tech. Pretty much everything they are doing with 18650 cells in their cars and power walls is hardly ground breaking science. They have managed to make things look incredibly beautiful, but 18650 batteries have been around for a long time. If Tesla starts to do more with different chemistries that will be interesting.

Thermal tech and longevity have been pushed by Tesla. 18650 is a form factor not a chemistry.

Maybe start here?

http://energystorage.org/membership/members

This is just armchair analysis, but my perception from easily Googleable sources on mining & resource companies for battery tech is that it doesn’t actually look like a good investment for casual investors.

The lithium market seems crazy and susceptible to high volatility from Chinese stockpiles. Meanwhile, battery technologies, even at the high end, are becoming rapidly commoditized and experiencing price wars, meaning new investment even into state of the art battery tech probably isn’t exposed to a lot of upside because all the consumer markets it can feed into will have consumers expecting the highest quality at bargain basement prices.

The exceptions will likely be highly industry-specific and involve complex military or enterprise consumers with special needs, and I doubt casual investors will have access to information necessary to reliably speculate about those opportunities.

Seems to me that an immature market that is on its way to becoming a commodity is a great time to invest, as opposed to post commoditization

They caveat their comment with "casual investors".

To win, you'll probably have to have a quite wide basket or get lucky and pick the right companies.

Maybe. That could have described the solar photovoltaic manufacturing business in the first decade of the 21st century, but it would have been a real gamble making money trying to invest in any of the individual companies or even baskets of companies. Commoditization comes quickly, and with "too much" competition even proprietary advances benefit buyers more than manufacturers.

The fracking revolution looks similar, for that matter. So far it has delivered a lot more value to buyers of fossil fuels than to producers.

Commoditization drives down profits which will limit the returns on your investment.

Generally you want to invest in complements to things that are going to be commoditized. The drop in price and profits for the commodity drive increased profits for the consumer of the commoditized good.

In the united states the main commercial option for non-lithium batteries is Nant who is developing zinc-air batteries (but for usage alongside lithium)

Then there is Redflow out of Australia and Voltstorage in Germany.

Not sure on vanadium flow batteries

I worked for a vanadium flow battery startup which went out of business. Vanadium provides a higher degree of safety due to the chemistry not being flammable. The chemistry also cycles (charges and discharges) without degradation in energy storage capacity. However, vanadium flow batteries are far less energy dense, have moving parts (pumps), and a poor track record of reliability. There was a lot of interest in vanadium flow batteries when Li-Ion was way more expensive, but now that prices have plummeted (and will continue to do so) I don't see much of a future outside of certain applications.

Redflow is doing good targetting to telecoms for reliable power at the radio mast. Africa, Asia, Latin America rural and remote like them. They struggled to be market viable in Australia head to head with Li-ion on price but if you understand their powerbudget and want a system on standby from binary chemicals they're a good way to go. (Not a shareholder, but been following them for years)

It is in general more efficient to do basic research in universities and publish the results so that everybody does not need to do the same large amount of experiments.

Then do the productization in companies.

I don't know which part is harder regarding batteries, but I assume we have still quite a lot of basic research to do as well.

Is that how it works?

My impression was that the basic research was done in universities (with public funding) until there are some good patents, then the patents are transferred to some kind of private company that take the profits.

I don't know the procedures very well, so, I would be happy if somebody assure me that this is not the case.

Sila Nanotechnologies (https://silanano.com) is doing interesting things with battery chemistry. They recently raised a bunch of money from Daimler.

The numbers given in article the world wide battery installations are predicted in 2040 to cover about 20 minutes of world electricity consumption assuming it would be equal close to 2016 figures, where majority of world is in relative poverty. It definitely is at least two orders of magnitude too little to stop climate change. People assume the reducing emissions would stop climate change. Nope, emissions are only related to rate of change not absolute value. Reducing emissions by 90% would only slow down the change, it reducing 99% would actually stop it, and it would need to be about 100% to slowly reverse the effects of what has been done by the time humanity gets there.

I actually work on reducing emissions tangentially and am absolutely not a "denier", but I have not seen any evidence that our models are so accurate that we can predict the tipping point from halting increases to decreases within 1%.

You're probably right, but that's really nothing good. Our models are poor and despite not knowing where irrecoverable tipping points lie exactly, we blast full steam ahead with our emissions.

Just took a number which carbon is removed from air-sea-plants natural circulation. The increase in CO2 stops when emissions match the removal of CO2 from circulation as permanent basis. And that figure seems to be about 1% of our emissions. But the key issue is that those two numbers need to match in order to actually stop the climate change permanently which is so far away from every politicians discussion points. All the renewables and storage technologies fail when we start to calculate amount of material required to build them and mining of those resources. Only energy technology so far that could actually do it is nuclear. As for uranium limited reserves they are calculated about 0.1 cent per kwh price limit. It is one of those situations where emotions points towards renewables while numbers are clearly for the nuclear if people could accept tiny risk of having two bananas worth of radiation or even the extreme case of getting so high radiation dose that it would give as high cancer risk as the average alcohol consumption.

"..cover about 20 minutes of world electricity consumption..."

That seems like a meaningless metric. No one is designing a global battery system to power the entire planet. What matters is how battery systems integrate with generation systems.

"People assume the reducing emissions would stop climate change..."

Why do you assume people assume this?

Why do you think that this is a meaningless metric. It seems to me that we need at least enough storage to last for a night. Realistically we need enough storage to cover reduced production and increased demand through winter.

> It seems to me that we need at least enough storage to last for a night.

That's only the case if all your generation is from photovoltaic solar. The wind doesn't stop blowing at night, and you need a long drought for hydro to stop producing power.

Yeah good, then we need enough storage to last half a night and good enough transmission lines to get wind power from wherever it's windy to where the power is needed. That's still a lot more storage than 20 minutes.

It's cheaper under most assumptions to build enough solar panels that the reduced production during winter is still enough to cover your increased demand, rather than to build seasonal utility energy stores. See my calculations at https://news.ycombinator.com/item?id=20664835 which show that 50x panel overprovisioning is cheaper than a week’s worth of battery backup. 26 week backup would then be a higher cost than overprovisioning panels by 1300x. The actual seasonal variability in panel output is normally less than a factor of 2, nowhere near 1300. Unless you're in Antarctica or something.

I don't think we have enough room for overprovisioning panels that much. The average German for example uses 48000 kWh per year of primary energy[2]. Solar panels produce around 150 Watts per square meter peak. That means you need about 35 square meter years of solar panels per person to get to net 0. Let's say 15 square meter years because primary power consumption includes power plant inefficiencies and so on that you don't have with direct electricity.

42,339 MW of PV installations produced 39,401 GWh of energy in 2017 in Germany[1], so about 38 days of peak generation.

That means you need around 400 square meters per person at typical PV efficiencies to break even. That's already a lot. Where do you want to build 50 times that? There are 230 people per square kilometer in Germany, that's 4300 square meters per person.

[1] https://en.wikipedia.org/wiki/Solar_power_in_Germany#Statist...

[2] https://www.wolframalpha.com/input/?i=(total+energy+consumpt...

I don't understand what you mean about “square meter years”.

Germany is an especially difficult case, being very industrial, very densely populated, and fairly polar, though less so than, say, England.

Germany uses about 72 gigawatts of electricity and about 400 gigawatts of fossil fuels, according to https://en.m.wikipedia.org/wiki/Energy_in_Germany (but converted to SI units). It comprises some 82 million humans, so this works out to about 5 kW of fossil fuels per person. (Your "48000 kWh/year" comes out to 5.5 kW.) Generally 1 W thermal is worth about 0.4 W electric—less as transport fuel, more for industrial process heat, but generally about that. (I think this might be what you're saying about power plant inefficiencies?) We can take 0.5 W to be generous and we get 2–3 kW per person.

This would come out to 12–19 square meters of panels per person, using low-cost 160 W/square-meter panels, but those aren't average watts, but peak watts. Typical capacity factors (average÷peak) for PV installations in the US are 15–30%, so you'd normally need on the order of 60 to 120 square meters to get that much power on average, but the number Wikipedia is reporting for Germany is 10.6%. Maybe that's just a function of polar latitudes but it seems pretty extreme! Maybe something else is going on there, like production curtailment due to inadequate storage resources and demand response, or plants being offline due to equipment failure?

So I think that low capacity factor already incorporates some overprovisioning in that sense.

When I mentioned "50x", that was not because that's an overprovisioning ratio that is ever actually needed. I'm sorry that was unclear! It is far in excess of what is needed. I think 10x is pretty much the limit of what you need outside of the polar circle: instead of the 3.3 peak watts per average watt you'd need in Perú, you provision 33, and enough storage to get you through the night, and then you'll be fine even if every day has storm clouds blocking 90% of the light. In Germany that would be 400–600 square meters per person. Yes, that does mean covering 10–15% of the country in solar panels. The Germans would be well advised to put some of those panels in other, more equatorial countries, with lower population densities. Or work on demand response.

I mentioned the grossly excessive 50x number because even that ridiculous level of overprovisioning is still cheaper than a week-long battery storage system. (But not if you have to invade Egypt to install it, I suppose.) My point was that battery storage is far too expensive for anything where there is any alternative. In particular it is not a viable option to deal with seasonal variability. (Some other form of energy storage might be.)

Earth's population density is only 20% that of Germany, so getting the world's human population to be as energy-intensive as Germany without any demand response, you'd need to pave "only" 2–3% of it in solar panels. Fortunately or unfortunately, that includes the sea.

1 square meter year of solar panels is one square meter producing peak output 24/7 for a year, or two square meters producing peak power for half a year. Like a man-month.

I was also surprised by that low capacity factor. Before doing the math I estimated maybe 100sqm per person. The US installation averages probably benefit a lot from the deserts and being much closer to the equator. Solar is pretty bad in Germany during winter.

I agree that we most likely don't need week long battery storage btw, but mostly because of wind energy that is also available at night and during winters. We can probably get away with just over night batteries and power-to-gas for long winters.

The part I was confused about was that you said "35 square meter years per person" but I guess you mean per person per year? Then wouldn't that just be 35 square meters per person?

Wind is awesome, but I don't think the total wind resource at tower-like heights is sufficient to wean the humans off fossil fuels; but I don't have hard numbers. Maybe power-to-gas is a solution.

Thank you very much for helping me explore this!

Yes I meant you need 35 square meters producing peak power 24/7 for a whole year to power one average German's life.

The numbers I've seen suggest that in the case of Germany, wind power can get you most of the way to a carbon free economy, but you still need to cover 1-2% of the land with solar panels (i.e. all roofs and a bit of land). Under the assumption that we also improve energy efficiency by insulating homes, switching to heat pumps, and switching to electric cars. Without those efficiency improvements it was unlikely that we'd have enough space. Under this scheme we'd need a little battery storage (for a day of consumption or so), and power-to-gas for longer periods of low generation.

I'm not sure whether he has talks in English, but Prof. Quaschning has some nice resources in German about this topic.

Nitpick - I make it closer to 1 hours electricity but I agree it's way too low from a fixing global warming point of view. The figure 2,850GWh by 2040 works out about 280 Wh a head if you guess a 10bn population. For comparison a Tesla Powerwall is 13.5 kWh. Something like 100x that storage would be good if we are running on renewables.

With something like the nantenergy battery they are already talking $100/kWh and have cheap materials so it would seem quite plausible to get down to say $25/kWh by 2040 meaning you could get 40kWh for $1000 or so which I think may be a better target. (https://www.engineering.com/ElectronicsDesign/ElectronicsDes...)

Agreed, the humans will need enough short-term energy storage to cover several hours of their energy use to transition it mostly to solar, which is probably what they will do.

However, you are forgetting about atmospheric carbon capture.

For long term energy storage batteries are not ideal. Their costs increase linearly with time of storage and amount of storage. Peak shaving is an OK use for them, though.

Also batteries lose their stored energy over time.

What percentage of our global storage needs do you believe are "long term" in this dichotomy?

Is this at the "electric cars can't do my daily commute" or "electric cars can't tow my boat 600 miles without stopping, once a year" stage?

Seems like most of the world just needs solar to last until the next day with a decent chunk of that power needed immediately after the sun sets and any wind power available could get smoothed out and/or stored for the morning by the same batteries.

If an electric car can do 200km on a charge, that's 99.9% of my annual driving needs met.

The sun does not shine every day. And not equally throughout all seasons. As the percentage of renewables increases so will the gaps on bad days/weeks.

The differences can be dramatic and must be compensated some way. https://www.energy-charts.de/power.htm?source=solar-wind&yea...

Short term solution: natural gas peaker plants could be repurposed to provide power during lulls in production (better than most fossil fuels, but very expensive and still produce greenhouse gases, so can't be the solution for long)

Medium term solution: long-distance transmission, overprovision, and even more grid-scale storage (whole continents don't get cloudy & calm at once for long periods of time)

Potential long term solution: space-based solar (power is 24/7, just need lots of landing locations + distribution, because microwaves are attenuated by atmospheric moisture)

Edit: tl;dr is that for the issues, there are many potential solutions

Wont introducing net energy to the earth add to the warming?

Not substantially. The issue is that energy that would normally escape does not.

I may be incorrect, but space based solar would catch energy that would reach the earth anyway, basically shading us. So it would probably be more or less adding the same energy, but sending it to the ground rather than dispersing some in the stratosphere.

That's incorrect, sorry.

ok, but can you explain why, please?

The satellites would be in wide orbits (typically imagined to be geostationary) that would almost never be on the line between the Sun and the Earth. And if they were between the Sun and Earth, they couldn't beam power to the Earth's night side.

Yes, it would (though an interesting comparison would be ground-based renewables vs. carbon capturing land use + space based solar).

Another possible long-term, space-based alternative to reduce global warming would be space-based manufacturing. It's equally as plausible - if the economics work for space-based solar, it means either space-based-manufacturing is a thing, or launch costs have dramatically lowered

Barely. The temperature of the earth is a function of the balance between energy inputs and energy outputs. The solar input is much much more power than total human utilization, so adding "human" amounts of power won't shift the balance very much.

We're talking “long-term” here, as in when the humans are using over a thousand times as much energy as they are now, so that it's cheaper to launch solar panels into fricking space than to upgrade the ocean-carpeting solar panel rafts blanketing much of the oceans to be 90% rather than 75% efficient. So yes, even before that point, solar energy harvesting will begin to have noticeable climatic effects.

1000x would make human use ~20% of the earth system, but earth side solar wouldn't get counted twice, so it would be less. I agree that would have an impact, but I doubt the other poster was imagining the 1000x scenario.

The numbers are something like 20 terawatts for current human utilization and 100 petawatts for solar power.

Yeah, that's about what I calculated in https://news.ycombinator.com/item?id=20426368 — 130 petawatts of terrestrial insolation and 18 terawatts of world marketed energy consumption.

I think solar panels will tend to have lower albedo than the surfaces they shade (sunlight they reflect is not available for energy production, and even the 16%-efficient ones that are common today are pretty black), especially before the humans start floating them on oceans. Essentially all the energy they successfully harvest will later be converted to heat on Earth. So they will represent a positive thermal forcing in the climate system. I don't know what you mean about getting counted twice?

I don't know why anyone would propose orbiting solar panels when it's still easy to put solar panels on deserts. So I assumed that was what they were imagining, even though that's not a long-term scenario; it could happen before 2089, which is very short-term.

Solar energy gathered and utilized inside the earth energy system doesn't add energy to the system.

So if we were using 5 Petawatts of ground based solar power, we wouldn't be adding much to the overall system. Unless we stored a lot of it and shifted the heat to a different time of year.

Oh, I agree that you don't add energy to Earth just by harvesting energy that would have been absorbed and converted to heat. So a solar panel on the ocean doesn't warm up the Earth any, because the ocean is just as black as the panel. But you do add energy to the Earth by harvesting, or merely absorbing, energy that would have been reflected into space. So the same solar panel on the Salar de Uyuni will warm up the Earth. That's what my comments above about albedo are about; I'm not double-counting in the sense you thought. Does that clarify?

None of this is significant until solar power generates substantially more power than current world marketed energy consumption, which is to say, for at least a decade or three.

Thank you for helping me to explore these issues!

I'm familiar with the concept of seasons, just as I'm familiar with the concept of yearly boat trips.

But lots of people live near the equator, just like lots of people don't really ever go for long drives so rather than focus on one particularly difficult case and then giving up I was looking for some kind of rough quantification of the problem.

In analogy I'm just wondering whether the equivalent of the "daily commute" for most of the planet can be easily covered with current tech at a cost less than curent alternatives and we only need to worry about a comparitively small fraction that remains, which we could apply those savings to dealing with.

Equatorial weather patterns are not all that relevant because most of the energy consumption is at higher latitudes which experience significant seasonality.

And your daily commute/boat towing "analogy" is not really helpful because those problems are not comparable. Boat towing is an optional luxury and can be worked around at a slight inconvenience by visiting charging stations. Lack of long-term storage on the other hand can't be worked around, it requires double-spending to keep dispatchable fossil fuel plants in standby.

And I don't think there is a dichotomy either. Variability exists on a continuous time-scale from seconds to seasons, so storage solutions can expand along that continuum.

95% of the world population lives below 50 degrees N/S.

And I suspect if seasonality really does become a problem that's costly to solve, heavy industry will move down toward the equator. Ship the finished products rather than try to make them where it doesn't make sense to.

I intentionally wrote energy consumption instead of population because those distributions differ.

Short term = diurnal

Long term = weeks to seasonal

Batteries, especially that sort of cheaper battery, would be great for diurnal load leveling.

Long term storage is probably more hydrogen and mass thermal storage. The tradeoff would be capital cost per unit stored energy vs. efficiency.

Storage competes with and complements two other approaches: overinstallation of generation capacity w. curtailment, and dispatchable demand.

Curtailment involves installing more wind and PV than you need, and curtailing its output when supply > demand. A study in Minnesota found that this was cheaper than adding storage up to about 70% of the electrical power supply. Of course this creates dirt-cheap power during the curtailed periods that people can find use for (industrial thermal storage, production of hydrogen in low capital cost membraneless electrolyzers).

Dispatchable demand would involve redesign of industrial processes to operate in fits and starts. For example, today's aluminum cells do not respond well to inconstant power sources (their either freeze up or overheat and damage the lining). This was fine when the cheapest power sources were baseload sources. But perhaps an aluminum technology could be developed that would be more forgiving of variation and outages, to exploit the new situation where intermittent power is becoming the cheapest.

Of course, another approach is to move those industrial processes down close to the equator, where there is little seasonal variation in insolation. High latitude countries may become industrially disadvantaged in a renewable powered world.

Multi day storage is always an issue. X kWh stored over Y hours takes X kWh of storage but X/Y kw of generation capacity. Start talking 50 hours and the cost difference becomes huge.

PS: Though batteries inherently have some emergency storage capacity as daily deep discharge is inefficient.

> Long term storage is probably more hydrogen and mass thermal storage.

I was thinking about how multiple big heating packs[1] would stack up. Seems the Wikipedia reference[2] has the topic well covered. Tricky but possible. And apparently (duh) not a novel idea by any means[3][4].

Though the references I could find were mostly for home-size installations or for actual heating packs. Here in Norway we're blessed with lots of mountains with lakes, so we can do pumped hydro for latent storage. But for flatter countries (say our neighbors Denmark), is grid-size PCM storage viable?

[1]: https://en.wikipedia.org/wiki/Sodium_acetate

[2]: https://books.google.com/books?id=EsfcWE5lX40C&q=latent+heat...

[3]: https://www.sciencedirect.com/science/article/abs/pii/S13594...

[4]: https://ideas.repec.org/a/eee/appene/v221y2018icp522-534.htm...

I was thinking more in terms of artificial geothermal. The time constant for a sphere of bedrock to cool off goes as the square of the radius, and can easily be made to be many years. These would be very large installations, of course.

Methanol is an alternative to hydrogen. With current technologies it is less efficient to produce it and then generate electricity in fuel cells, but storing it is trivial.

All countries already have infrastructure for strategic gas reserves that are sufficiently sized to cover demand for long periods. So storing renewable energy via power-to-gas processes is probably the way to go.

Another option for seasonal variation is to overbuild. Build enough solar for winter and just discard or figure out something to do with the excess power supply in summer.

(I'm not sure that would be cheaper, it's just another possibility.)

That's curtailment. A twist on that is to install some of the solar at an angle appropriate for winter instead of summer.

If so,then it stands to reason that they would be unlikely to move to renewable power.

  What percentage of our 
  global storage needs do
  you believe are "long
  term" in this dichotomy?

Solar output in the UK varies substantially between summer and winter [1] - as does demand for heating.

As a Brit with solar panels, it would be super neat if I could generate power during the summer, store it for 6 months, and use it for heating during winter.

That would reduce my direct carbon emissions relative to the status quo, which is burning natural gas for heating during winter.

However, replacing my (fairly modest AFAIK) £222-per-year gas bill would need ~150 Tesla Power Wall packs, costing several times the value of the home being heated.

[1] https://pvoutput.org/aggregate.jsp?p=0&id=4768&sid=3764&t=m&...

For this, wouldn't it be better to pump water onto the top of a bunch of mountains in Wales?

https://en.wikipedia.org/wiki/Dinorwig_Power_Station, but more.

That's the point, isn't it? Batteries are not a panacea for energy storage needs, even with a doubling of their capacity.

There is no requirement for a panacea or super neat developments that allow individual households to store seasons worth of privately generated electricity.

For seasonal and sporadic production shortfalls in solar and wind generation, biofuels and electrically synthesized fuels can fill in. On the occasions where carbon-neutral fuel resources are insufficient - gas generation can remain as fallback (increasingly rarely) until sufficient carbon neutral fuel production is developed.

And with atmospheric CO2 capture, CO2 released by intermittent fallback fossil combustion can be scrubbed at a rate well below the peak release rate at the turbines.

Pumped water does not scale well, there are only so many mountain valleys to block. And I'd rather keep a few in a somewhat natural state (a magic "no more mountain valleys in exchange for instantly solved climate change" would be attractive nonetheless, even though I write this from a very nice, unblocked mountain valley).

But when your concern is just seasonal storage for heating, you don't need pumped storage. Just great water in a big, isolated tank, it's not even new technology. The surface per volume shrinks the bigger the system, so very large tanks can have quite nice loss numbers.

Actually, there is enormous potential capacity for pumped storage around the world.

Pumped hydro is generally used for diurnal storage. The infrastructure of the dams and turbines is darned expensive; it makes practical sense if you're filling and draining the basin (or half of it) every day, but paying pretty much the same cost to get just a single lake volume per year ... not so much.

Another "paradigm" is that full and empty batteries are shipped between regions by boat or truck as needed instead of just waiting 6 months for the planet to move through the cosmos.

Whew, that doesn't sound feasible, but I'd love for someone to do the math for me. It seems much more realistic to build HVDC lines from equatorial regions to the temperate zones, but even that is not very popular anymore as far as I know due to cost and NIMBYs.

I haven't done the math either, but I've seen serious discussions of it.

It requires zero infrastructure investments to load a hundred Tesla batteries on a truck and drive it to place with a different climate situation.

Compare that to long distance HVDC lines, which for the US are desperately needed, have been discussed for decades, and show no signs of ever getting built.

A HVDC transmission line might be a more practical way to do this.

The entire UK energy use is about 2% of the world total. So I'm guessing that the storage needs of your specific (and oddly non-grid connected) home is only a small fraction of that and doesn't affect the larger, global, back of the envelope figure I'm looking for.

Using numbers to quantify the situation is part of why I'm asking, asking (and answering) the right questions so we don't get silly answers is the other important part though.

Having short days in the winter, long days in the summer isnt a UK specific thing. As you get closer to the equator it may become less of a problem as summer air con load overtakes winter heating as the dominant load, but we are talking about large swathes of the planet that will have higher heating demand that can't reasonably be covered by solar power alone.

If you could put some kind of number on how much of a not-UK thing it was on a global scale, that would answer my original question.

Like, apoarently air con is currently 10% of all electricity and set to grow. 10 AC units will be sold every second for the next 30 years.

It seems solar plus batteries has that covered, but I'd be interested to know the ratios.

According to this [1] it looks like about a third of energy used in commercial and residential buildings is for space heating. That only accounts for some 32 Pwh of 157Pwh [2] of energy use but is greater than the 21-23Pwh of total electricity generation.

So judging by your figure of 10% of electricity usage that's 2Pwh (10% of 21-23Pwh) for air con v 10Pwh (third of 32Pwh) for space heating.

But that energy demand is mostly based on combusting fossil fuels directly, decarbonisation would require a move to electric heating which would probably involve heatpumps, and quite a lot of insulation, so I would hope that that figure would drop quite alot in the future.

[1] https://www.sciencedirect.com/science/article/pii/S136403211... fig 3.

[2] https://en.m.wikipedia.org/wiki/World_energy_consumption

https://en.wikipedia.org/wiki/Power-to-gas is probably feasible for consumer energy use (at least for people with room for solar panels). We have the facilities to store and distribute the gas already, and to the extent that additional storage would be necessary, it is fairly economical.

Replacing industrial and shipping energy with renewables is a bigger problem.

> store it for 6 months, and use it for heating during winter.

I wonder when we will get high voltage transmission systems between the northern and southern hemisphere? Actually solar farms in Southern Spain, Morocco or Arabic countries would make more sense.

Also seasonal thermal energy storage does that. Avoids solar electricity altogether, although has other limitations.

https://en.m.wikipedia.org/wiki/Seasonal_thermal_energy_stor...

>Seems like most of the world just needs solar to last until the next day

as long as it's not cloudy for a week

Did the person sizing the solar panels in this hypothetical forget that it was sometimes cloudy? Seems a rather silly mistake.

Wouldn't they have access to data predicting to within fairly narrow margins how often this would occur statistically?

I mean if cloudy weather reduces the output by a factor of 4 then you don't really need to bring long term storage into the matter to have trouble if you're going size everything on the basis that will only provide the required energy on the very sunniest days.

You are going to build panels that will provide enough energy for one day on the day it is the least sunny at the site? What do you do with the excess on sunny days?

Whatever seems useful. Or do the inverse of the power satellite idea: send the excess energy to space as microwaves.

You can turn it off. Solar panels can be turned off in nanoseconds with nothing more than a transistor. Or you can invest the zero-cost energy in something potentially useful that doesn't need a constant power supply: electrowinning metals, removing corrosion, heating the hot tub back up, making ice to run your fridge or air conditioner when there's less sun, running low-cost machine tools (the kind where the depreciation is insignificant compared to the cost of power and consumables), generating hydrogen by electrolysis to convert into methane or methanol or ethanol for fuel, baking some bread, washing some laundry, doing a short pottery firing in your kiln (<8 hours), recharging your electric car, in short any of a wide variety of processes.

or you could have some batteries, save the energy for a cloudy day, and have a smaller installation of panels.

Right, the problem is that a week’s worth of batteries is an immense cost that is reducing only slowly, while waiting a few days to wash your laundry is close to free.

Let's say you use 1 kW on average in your house. You'll need about 4 kWp of panels to supply that with a typical capacity factor of 25%—a bit more panels than that if you're in Scotland, a bit less in Perú, but about that. At current prices that's US$800 of low-cost panels.

Now consider a couple of alternatives. You can overprovision the panels by a factor of 5 so that even on cloudy days that block 80% of the light, you can continue rocking your one-kilowatt lifestyle. This costs an extra US$3200 of panels. Or you can buy, say, a week of lithium-ion batteries; say you're paying US$150/kWh for the batteries, which is in the ballpark but not exact. You need 7*24 = 168 hours of batteries, which at one kilowatt is 168 kWh. This costs US$25000. In both cases you need some power electronics (charge controllers, inverters, etc.) but this is not a significant cost difference between the two scenarios.

So 5x overprovisioning of solar panels costs you about an eighth of a week’s worth of battery storage. You can overprovision by a factor of 50 for less than the cost of that week-long battery backup. There's a trade-off between the two—more battery storage means you can get by with less panels, and vice versa—but this strongly suggests that in most cases the optimal trade-off is not going to involve multi-day battery banks.

How about a few years in the future? This year, panel manufacturers have apparently sewn up the market in a cartel, preventing prices from falling over the last few months. But sooner or later, the cartel will break down, and panel prices will return to their long-term learning curve, say 20% per year until the raw material costs dominate. In 5 years, panel costs would then be 40% of what they are today: 8¢ per peak watt instead of 19¢. No such dramatic cost reductions are on the horizon for batteries.

But in a lot of cases, shifting demand to times with cheap energy is still going to be cheaper.

Often with residential solar you run out of space. At that point you have to start adding batteries (or thermal or something) for long term storage, or stay connected to the grid.

True! But batteries are very much the most expensive of those options.

Is there any storage mechanism whose costs don't increase in the same way?

Anything that involves volumes and abundant resources.

E.g. storing hydrogen or compressed air in a salt dome decouples the power rating of your storage (MW) from the storage capacity (MWh). Similarly hydroelectric dams contain water by volume but you only need to dam a cross-section of the valley.

> Similarly hydroelectric dams contain water by volume but you only need to dam a cross-section of the valley.

I would caution that the cost of a dam does not increase linearly, either (and that most resources that are profitably dammable at utility scale have already been dammed)

Wouldn't the above description also fit flow batteries?

It's a little less clear-cut since you still need to pay a linear cost for the electrolyte, but it should be much lower than the same amount of Li-ion storage, at least in raw material costs.

Luckily, there's plenty of carbon to offset (peakers) by deploying batteries before we have to worry about long term (seasonal) storage.

However, I wouldn't be surprised if the electrification of transportation ends up making batteries be the default "long term" storage option by using EVs as flexible grid storage. There's going to be 100x more batteries rolling around than what you'd need to stabilize the grid (e.g. peakers), so I wouldn't be surprised if the grid asks more from EVs than just stability so it doesn't have to spend the additional capital for seasonal storage.

Somehow, I think people waking up to find out that their EV doesn't have the charge they expected it to have will put that idea in its place.

The idea that someone with an EV will allow the power company to randomly deplete its battery is a fantasy.

Edit: We're much more likely to see home standby generators put to that use, or home batteries (connected to solar) put to that use.

Keep in mind that we're talking about single digit percentages of a battery's capacity being used. Also, its likely that many of the EV-to-grid arrangements will be for fleet vehicles (company/city cars, plus self-driving fleets when they happen), and they will be technically sophisticated enough to negotiate that capacity sharing with the grid operators.

So you won't ever actually have a scenario you describe where a private EV will have it's battery depleted.

"likely that many of the EV-to-grid arrangements will be for fleet vehicles"

Wont these be out and about during the day when the sun is shining and need to be charged during the night? Seems like these are the opposite of storage, they would exacerbate the problem? Creating a lot of demand(lots of buses in lots of cities) charging at night, and driving during the day.

"will be technically sophisticated"

This is an assumption, though it does seem technically possible.

"scenario you describe where a private EV will have it's battery depleted"

Im an environmentalist myself, but if I wake up on the morning of my vacation, and my car is at < 100%, I'm not going to be happy. You might say you could provide a way to signal that your car needs to be at 100%, but I see a non trivial amount of people enabling that all the time.

I guess if we require every parking lot with > x spaces to have plugs for all vehicles to charge/store during the day. Still requires people to actually bother plugging them in. Of course, they would also have to plug them in during the night, and unless they are getting paid to, I dont see people going through the minor hassle if it is no benefit to them. I'm just not really optimistic about the vehicles as storage idea, sadly.

Sorry for the pessimism, but I feel like there is too much naive hand waving among environmentalists. I think we need a more realistic, critical discussion, focused on likely, probable solutions. Theres too much: "Everybody can just go out of their way too do x." Theres still people who think putting an aluminum can in a different bin is too much work. We have to work with these unfortunate realities, not just dismiss them.

> if I wake up on the morning of my vacation, and my car is at < 100%, I'm not going to be happy.

That will never happen, unless you intentionally jump through several hoops to shoot yourself in the foot.

For example, there's a company called OhmConnect that does aggregated demand response. You can sign up for it, optionally connect your smart thermostat/plugs, and bank account. When there's going to be a high load period, OhmConnect notifies you asking if you want to participate in an upcoming "Ohm Hour". If you do, they will pay you $5-10 for your trouble. So, if you had a vacation the next day, of course you wouldn't opt-in to the demand response event.

Disclosure: I am on a nonprofit board with OhmConnect.

I'm not sure long term storage will ever make sense since the capital costs are amortized across far fewer cycles. Once a year rather than once a day means 365x the capital cost. Instead over-provisioning of green generation and increasing grid capacity (to avoid risk of local week long lulls in generation) seems a much better bet.

So what is needed for that is a solution that trades lower efficiency for lower capital cost. Hydrogen burned in gas turbines may be that solution, if the cost of mediocre efficiency electrolyzers can be made low enough.

Do we know how to safely dispose these batteries?

What happened to molten salt batteries?

This is not happening, this is larger than the amount of energy demand in the US and renewables forecasted

Many such forecasts have been embarrassingly wrong as of late, grossly underestimating the pace of renewable installation.

I had assumed fold was the same as 2^x, as in the number of layers for each fold of a piece of paper.

The artice talks about a 122 fold increase in the amount the power of installed battery power, I assume that a 2^122 increase is impossible, even accounting for replacement of end of life power packs.

I believe “x-fold” means “times x“.

Exactly. For example, threefold is 3x: https://en.wiktionary.org/wiki/threefold

Perhaps a question of mere semantics but why use the word 'fold' when it means times? Is it just to sound more "sophisticated"?

Apparently “fold” is an archaic suffix that means the same thing as times. I grew up with that so I haven’t really thought about it much.

"Fold" is not archaic, but it may be more common in some regions compared to others (see "pop" vs. "soda"). The "-fold" suffix is in Webster's Ninth New Collegiate Dictionary and it does NOT have an "archaic" marking. It's also one of the answers when you ask Google to "define fold" (you have to look lower because suffixes are sorted after the main word).

I use the suffix myself; it's nice and short when you need to express the concept.

Accusing the author of using "122 fold" instead of "times 122" to sound smart with a comment containing the phrase "a question of mere semantics" just might be peak HN.

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