11 ms·

Decarbonisation of grids requires long-duration energy storage

29 points by lxm 4y ago

anovikov 4y ago
Bullshit! Compressed gas energy storage has an easy to calculate, and tiny (single digit %) efficiency due to heat losses (gas heats when compresses, then loses that heat, and thus pressure).
- yazaddaruvala 4y ago
  Even if you’re right about the efficiency, keep in mind that for long term grid storage it’s more about how cheaply can “enough storage” be built and maintained. Efficiency would just be one variable in that calculation.
  - kkfx 4y ago
    And that's the issue, no different than hydrogen: we can do that, but in sooooo limited quantity that's practically useless.
    - kragen 4y ago
      I'm not sure why you would think the quantities of hydrogen that can be stored are a limit in practice. Certainly we can store at least as much hydrogen in the form of methane as we have ever extracted natural gas from natural gas wells, which is decades' worth of consumption, not a mere 40 hours' worth.
      - kkfx 4y ago
        Maybe I was not clear: the quantity of green hydrogen we can produce is negligible because the amount of energy needed to extract it is so high, the amount of energy needed to compress it in a tank, respect of the rate of usage in a fuel cell makes the balance ridiculous: you need a hectare of p.v. to produce few grams per day of hydrogen or you need a good sunny day to produce enough for a mile or two in a fuel-cell powered car. At that point the entire "economy" is just marketing.
        kragen 4y ago
        Oh, that makes sense! You're coming to ridiculously wrong conclusions because you're working from ridiculously wrong data, but not about the storability of hydrogen; rather, about the relevant efficiency figures. Let's put some concrete numbers on this. Grid-scale PV in California has a capacity factor of 29%, based on a nominal efficiency of typically 21% and a nominal solar constant of 1000 W/m². This gives 61 W/m² of solar cell as a round-the-clock average. A hectare of solar cells would be 10000 m², but because solar cells are more expensive than land they are not placed edge-to-edge without gaps; I'll guess that 30%, 3000 m², is a closer estimate, but I'd appreciate better figures from real utility-scale PV installations. That's 180 kW per hectare, round-the-clock average. Hydrogen has a LHV of 120 MJ/kg, so with 100% electrolysis efficiency 180 kW would work out to 131 kg per day per hectare, using the 30% fill factor above. Actual electrolysis efficiency is only about 70% in current industrial practice, reducing this to 92 kg per day: https://en.wikipedia.org/wiki/Electrolysis_of_water#Efficiency https://en.wikipedia.org/wiki/Electrolysis_of_water#Efficien... Then we have the question of how much energy is lost in compressing the hydrogen for storage. This is a little tricky to calculate because the answer can be arbitrarily low (isothermal compression is perfectly efficient) and even adiabatic compression depends on the kind of gas you're compressing, but the electrolysis link above says, "Practical electrolysis (using a rotating electrolyser at 15 bar pressure) may consume 50 kW⋅h/kg (180 MJ/kg), and a further 15 kW⋅h (54 MJ) if the hydrogen is compressed for use in hydrogen cars.[37]." So we're at 234 MJ/kg in, 120 MJ/kg out. This gives 67 kg/day of hydrogen for our hectare. This is an average including the occasional cloudy day that happens in southeastern California; on sunny days the number is higher. 67000 grams is, I think, not accurately described as "a few grams". https://www.fueleconomy.gov/feg/fcv_sbs.shtml https://www.fueleconomy.gov/feg/fcv_sbs.shtml says current fuel-cell cars on sale in the US go 64–72 miles per kg, or, in non-medieval units, 103–116 km/kg. 67 kg (again, an average day, not a sunny day) thus gives you 4300–4800 miles, or, in non-medieval units, 6900–7800 km. 6900–7800 km is, I think, not accurately described as "a mile or two"; even though there are admittedly many different incompatible definitions of a "mile", none of them is close to 1000 km long. In extremely polar countries like Germany and the Netherlands, PV capacity factors are much lower, sometimes below 10%, so you have to divide all these numbers by a factor of about 3. So, how did you end up believing figures that were wrong by three or four orders of magnitude, and with such confidence that you were dismissing correct, factual accounts of energy economics as "just marketing"? And how can you avoid getting suckered into such swaggering delusions in the future?
- NelsonMinar 4y ago
  The table in the article indicates a 70-80% round trip efficiency for electricity storage to liquid CO2.
- usrusr 4y ago
  Heat can be separated and stored alongside (or used separately, if you happen to have an application for the heat). Modern compressed gas storage installations that don't just dump the heat to the environment are approaching the round trip efficiency of pumped storage (water), and unlike pumped storage they can basically be built wherever you want.
  - pfdietz 4y ago
    If you're going to store the heat, then you might as well reexpand the cooled compressed gas, recovering some of the energy of compression and cooling it further, and also store that "cold". You can then recover the stored energy by exploiting the hot/cold temperature difference between the two thermal stores. Doing this is functionally equivalent to adiabatic CAS, but doesn't require storage of any compressed gas.
    - usrusr 4y ago
      But why would you want to do that? A heat gradient is just about the least useful form of energy known to man. A large fraction of the total engineering effort of humanity went into trying to make energy recovery from heat gradients slightly less bad and the numbers are still terrible. Compressed gas storage gets a better cycle efficiency than that even before adding heat recovery.
      - pfdietz 4y ago
        You do that because you don't need a large underground compressed air cavity. Instead, you can store energy as heat in materials, which is among the cheapest ways to store it.
        usrusr 4y ago
        But how much cycle inefficiency would you be willing to take for that advantage? I could totally see that storage setup be a huge success at places where you have continuous or forced-schedule intermittent low intensity heating and cooling demands (data center within insulated pipe distance of a spa resort or something like that), and want to make the best out of their opposite heat demands using intermittent electricity, but for general purpose electricity where the recovery would have to go through one of the famous thermal cycles? I really doubt it.
- kragen 4y ago
  It's interesting that you claim it's easy to calculate, but you haven't copied and pasted the calculation you did, which other people seem to disagree with. Your comment would probably be more convincing if you explained the easy calculation, which should be easy for you.
elif 4y ago
I don't think this really makes sense until we have a surplus of renewable energy to run compressors. When that is the case, we will have largely addressed climate change already. Using a "surplus" of base load carbon sources to run compressors is just pushing sand into sand.
- mynegation 4y ago
  You are probably thinking of a global surplus in a sense “when renewable energy worldwide exceeds our energy needs”. But right now we have a local time based surplus (i.e. solar works during the bright days, wind farms work when wind blows etc) that does not make sense to export too far, where there is a need. Hence storing some share of this energy is important.
- yayachiken 4y ago
  Innovative technologies need time and capital for R&D. Without the climate crisis, doing this R&D only once the technology becomes required and therefore economically feasible would be fine. But with the current decarbonization targets, you cannot just build renewables until you hit a threshold, and only then start testing out storage methods while putting the green energy infrastructure industry into hibernation for 20 years. We pretty much need to do everything, right now, at the same time. This is also why there is a big economic advantage of hydrogen storage. Decarbonizing steel and ammonia production with blue hydrogen (i.e. electrolysis using electricity created with the current fossil fuel heavy generation mix) is already a big potential market which is already kind of feasible, reducing the need for government subsidies to get the tech off the ground. Once the R&D, production and sales pipelines for blue hydrogen are up-and-running, you just scale up with increasingly mature technology. Then transition the energy input from carbon-intensive to carbon-neutral. This should happen automatically, as green electricity is the cheapest form of energy, and the hydrogen production acts as an energy-sink for any surplus production, mitigating those adverse market pressures acting on renewables after you reach a certain percentage threshold on renewable energy generation. Only then you eventually ramp up the use as energy storage via normal market mechanisms. Unfortunately the media always seems to put the cart before the horse. Energy storage is not the first step, but should be the last.
zackees 4y ago
Or… we can just do nuclear, which is SAFER than solar/wind energy, and not have any issues with needing to build giant batteries.
- chess_buster 4y ago
  No it's not.
  - e2le 4y ago
    How so?
  - SECProto 4y ago
    Nuclear is safer than wind, on par with solar[1]. Got a source that says otherwise? https://ourworldindata.org/safest-sources-of-energy https://ourworldindata.org/safest-sources-of-energy
    - simon_000666 4y ago
      I call bs. This article claims that only 100 people ‘died’ from Chernobyl. https://ourworldindata.org/what-was-the-death-toll-from-chernobyl-and-fukushima https://ourworldindata.org/what-was-the-death-toll-from-cher... It pretty much totally discounts the insanely large number of thyroid cancer cases in children. Then comes up with a very optimistic scenario of survival rates based on western medical interventions. So maybe they didn’t die per say but had significantly reduced quality of life and mutations. This is a classic example of taking one vanity metric and making absolute conclusions from it rather than taking a range of data points to paint a more accurate story. I find Wikipedia shows a range of numbers that are far more likely to give a realistic picture https://en.m.wikipedia.org/wiki/Effects_of_the_Chernobyl_disaster https://en.m.wikipedia.org/wiki/Effects_of_the_Chernobyl_dis...
      - zackees 4y ago
        Yes, chernobyl was fairly harmless, just like Fukushima. Wild life in both is thriving despite the fact that the mainstream media said the radiation was so bad nothing would be able to live there. Reality doesn’t back up any of those assertions at all. Villages near fukushima ignored the dire warnings and are just fine. If this is surprising then you need to diversify your media news consumption. Rooftop solar is more deadly than nuclear when you count people falling off of roofs during solar installation as “solar deaths”, otherwise it’s safer. source: https://www.forbes.com/sites/jamesconca/2012/06/10/energys-deathprint-a-price-always-paid/amp/ https://www.forbes.com/sites/jamesconca/2012/06/10/energys-d...
wronglyprepaid 4y ago
Well this is not true because Biden has already started transitioning the US off fossil fuels without any long-duration energy storage and he is doing it in a historically inclusive manner[1]. [1]: https://www.whitehouse.gov/briefing-room/statements-releases/2021/11/15/fact-sheet-building-a-new-era-of-nation-to-nation-engagement/ https://www.whitehouse.gov/briefing-room/statements-releases...
- exyi 4y ago
  We will need it later, you can't go 100% 0 carbon without it. Just running peaker generators, figuring out how to heat/cool houses, charge EVs when there is surplus, ... are all cheaper alternatives to storage, but won't cover everything
  - wronglyprepaid 4y ago
    > We will need it later, you can't go 100% 0 carbon without it. I think this is just what capitalist is trying to make people believe, the economy will adapt and jobs are already booming as the unemployment in US is at a historic low which shows just how historically strong the economy is [1]. [1]: https://www.whitehouse.gov/briefing-room/statements-releases/2022/01/19/fast-facts-record-firsts-in-president-bidens-first-year/ https://www.whitehouse.gov/briefing-room/statements-releases...
    - mpyne 4y ago
      They're not arguing it's an economic harm to decarbonize, they're pointing out that it cannot physically be done, at all, without some way of storing energy. This is needed because otherwise you'd only get energy when the wind is blowing and the sun is shining. This is especially true if you do not classify nuclear energy as green energy, but even with nuclear providing baseload generation you would want energy storage to truly take advantage of the energy that renewable sources can provide.
      - wronglyprepaid 4y ago
NelsonMinar 4y ago
First few comments have focused on the CO2 compression storage, but that's just one of many technologies the article talks about. It's worth a read. For that matter so is this whole quarterly special section on climate change and energy technology: https://www.economist.com/technology-quarterly/2022-06-25 https://www.economist.com/technology-quarterly/2022-06-25 Pumped hydro is the largest current energy storage system we have deployed. There's a lot of interest in chemical batteries but they're expensive, particularly given how fast the batteries degrade.
- 01100011 4y ago
  https://en.wikipedia.org/wiki/Flow_battery?wprov=sfla1 https://en.wikipedia.org/wiki/Flow_battery?wprov=sfla1 Link says vanadium flow batteries last many years and tens of thousands of cycles. Regeneration sounds fairly simple as well.
  - anonuser123456 4y ago
    Vanadium is too expensive/rare to be used at scale unfortunately. But I believe there are a number of workable chemistries for non-vanadium based flow batteries currently in development.
- nradov 4y ago
  Pumped hydro is great but there are limited locations where the geography and geology allows it to work. And there are ecological concerns with building more dams.
  - NelsonMinar 4y ago
    Developing new pumped hydro definitely has drawbacks. Slightly encouraging: Switzerland just brought 20GWh of pumped storage online that can generate up to 900 MW. The project took 14 years. https://en.wikipedia.org/wiki/Nant_de_Drance_Hydropower_Plant https://en.wikipedia.org/wiki/Nant_de_Drance_Hydropower_Plan...
ZeroGravitas 4y ago
No it doesn't. It might be part of the solution, but the repeated talk about how we need some magical breakthrough before we can continue with electrification is just wrong. The most important part, is to burn less fossil fuels, and we have lots of ways to do that, and we should do whichever is cheapest and easiest first. Long duration storage comes after: - put a price on carbon and other pollution - efficiency/insulation - electrify everything - build more renewables - vary existing tech to complement renewables (e.g. hydro, waste to energy) - vary loads to absorb renewables when they are available - build short term storage to shift energy (EVs and related battery tech) - ship green ammonia/hydrogen around the world from places like chile. And then there's a place for long term storage (which is a direct competitor to green hydrogren production and may never make sense compared with doing more of that)
- pfdietz 4y ago
  Yes, it does, if you want to get to a 100% decarbonized grid with renewables most economically, and particularly if you want solar to be a substantial component of energy supply at high latitude. Yes, other things come first, but storage has to be in there. Synthesis of chemical fuels at lower latitude for use at high latitude is effectively long term storage, since once one has paid to cost of making those fuels, storing them is cheap and adds robustness.
  - bryanlarsen 4y ago
    That's a pretty big if. Most people would be ecstatic if the grid was 99% decarbonized, and 99% decarbonized is probably an order of magnitude easier than 100% decarbonized. Unless you're some place like British Columbia with massive hydro reserves.
    - pfdietz 4y ago
      You can try for yourself at https://model.energy/ https://model.energy/ If you add "Dispatchable 1", which is gas, and give it zero cost, but then put a limit on the total CO2 emission, you can get the optimal setup to get X% (X < 100) of a synthetic baseload source from wind/solar/batteries/hydrogen. Then take out hydrogen and look at the cost difference.
freemint 4y ago
No it doesn't. The sun shines 24/7/365.24.
bryanlarsen 4y ago
Long term storage is very definitely not required. If you take a look at the hourly weather data for every continent for the past 30 years, there is not a single hour where there is not wind blowing somewhere on the continent. So you can build a continental grid consisting of just wind turbines that will continuously satisfy the energy needs for the entire continent. Long term storage is cheaper than a massive continental grid with a massive overbuild of solar, but it's not required. But it illustrates the point that a lot less long term storage is required than most people expect.
spenrose 4y ago
Serious studies of this question: * https://netzeroamerica.princeton.edu/ https://netzeroamerica.princeton.edu/ (US, but takeaways apply more broadly) * World-wide: https://www.nature.com/articles/s41467-021-26355-z https://www.nature.com/articles/s41467-021-26355-z * Stanford's Marc Jacobsen is a proponent of the opposite view * Rebuttal of Jacobsen, with links to his work: https://www.pnas.org/doi/10.1073/pnas.1610381114 https://www.pnas.org/doi/10.1073/pnas.1610381114
adrianmonk 4y ago
"Requires" is problematic. Do the next N steps of the transition need to block on the availability of storage? No. But, there's another angle to view this: political feasibility. People are dragging their feet. Why? Well, what is the value proposition of switching to renewable energy? Right now, it's roughly, "Unfortunately, the reliability may be a downgrade, but saving the planet is definitely worth the sacrifice." If you made a pie chart of people's reactions, there'd be a big wedge that says "I get it! I'm in!", another big wedge that says "eventually", and another big wedge that says "nope". If cheap, effective energy storage were a solved problem (commercialized, proven in the field), then the value proposition would be, "Renewable energy will save the planet and also provide everything you're accustomed to right now." The pie chart would look better. So, because political feasibility is required, decarbonization does sort of indirectly require storage. Tangent: for this reason, I think we should give storage the same incentives that we give to solar and wind. Possibly even larger ones since solar and wind are pretty good now but storage still needs lots of work.
- techdragon 4y ago
  Thing is, other than mass produced unit technology like li-po and li-ion cells, there’s precious little available storage. I tried to get quotes from a company that sells liquid flow redox batteries, the sort of technology that should scale volumetrically but it’s just not feasible for anyone to deliver beyond small deployments. We can’t order X-kWh storage off the shelves with anything but lithium batteries at the moment and until we can, there will be serious questions asked by people…even enthusiastic people like myself, because I look at the daily cycle count and go “fuck off” I’m not replacing 25% of a lithium battery tech based energy storage every 3 years, grid scale facilities are designed around 25 year cycles and anything with less than a 10 year lifetime feels like flushing money down the drain on razor thin margins, both economically and environmentally once you account for the manufacturing costs of the lithium based energy storage equipment.
kragen 4y ago
https://archive.fo/8BgQY https://archive.fo/8BgQY The article unfortunately equivocates about the meaning of "long-duration", which could mean "a few hours", "a few days", or "a few months". It mentions "four hours", "an eight-hour buffer", "up to 100 hours," and "seasonal energy storage". The first three of these are indeed required; the last is not, which is fortunate, because it is inherently orders of magnitude more expensive. Conflating them in this way is profoundly unhelpful: it's like writing an article about a requirement for "high-speed vehicles" including both a Kia Forte (top speed 200 kph) and an SR-71 (top speed 3500 kph). But the ≈40 hours we need is further from being the 4000 hours provided by seasonal thermal storage than the Kia is from being an SR-71, which can, after all, only outrun the Kia by a factor of less than 20, not 100. The reporter can only be hoping to get away with this because of the unfamiliarity of grid-scale energy storage. Absent cost-competitive geothermal, nuclear, or kite energy (or reliance on intercontinental power transmission), decarbonization of grids definitely requires grid-scale energy storage for a few hours, and it probably requires storage lasting a few days, because even over large geographical areas there are large lulls in wind and solar. The sun doesn't shine all day and the wind doesn't blow all night. But it almost certainly doesn't require seasonal energy storage, because you can overprovision generation capacity sufficiently to provide enough essential power every week of the year. A consequence of such overprovisioning will be that in the high season (either sunny or windy, depending on your power mix, but probably ultimately sunny) you can generate several times as much energy as the essential minimum, so power-hungry applications will benefit from cheap or free energy in the high season. This is supported by the article's summary of van Gendt et al.'s report: their "most cost-effective path to a world with net-zero emissions by 2040" has 85–140 TWh of storage at a power of 1.5–2.5 TW. Dividing the numbers, that's 34–94 hours. That's energy storage for a few days, not a few months. Still, it's interesting to consider the ways we could build a seasonal energy store, even if it isn't essential to decarbonizing the grid. — ⁂ — Unfortunately, the Economist's "All charged up" table of energy storage methods doesn't mention thermochemical energy storage (TCES), compressed gas, or even lithium-ion batteries. Compressed gas, which they do mention at length in the article, is ridiculously inefficient without some kind of thermal energy storage, and the two thermal energy storage technologies they do list are not useful for seasonal storage — latent heat, i.e., phase change materials, and sensible heat, the kind of heat that makes things hot. So TCES is a crucial enabling technology for possible seasonal compressed-gas storage. As with electrical storage in flow batteries, TCES can provide thermal energy storage for as long as you like if your tanks are big enough, so in theory it's vastly superior for seasonal thermal stores, and you'd need seasonal thermal stores for efficient seasonal energy stores with compressed gas. TCES has an enormous advantage over currently-available flow batteries in the cost of the necessary materials. We'll see if the Form Energy gadget, which I hadn't heard of, pans out; that would change the equation radically, because only sand is cheaper than iron and salt. But TCES mineral feedstocks like carnallite, muriate of lime, quicklime, and bischofite are nearly so.

29 points by lxm 4y ago

Bullshit! Compressed gas energy storage has an easy to calculate, and tiny (single digit %) efficiency due to heat losses (gas heats when compresses, then loses that heat, and thus pressure).

yazaddaruvala 4y ago
Even if you’re right about the efficiency, keep in mind that for long term grid storage it’s more about how cheaply can “enough storage” be built and maintained. Efficiency would just be one variable in that calculation.
- kkfx 4y ago
  And that's the issue, no different than hydrogen: we can do that, but in sooooo limited quantity that's practically useless.
  - kragen 4y ago
    I'm not sure why you would think the quantities of hydrogen that can be stored are a limit in practice. Certainly we can store at least as much hydrogen in the form of methane as we have ever extracted natural gas from natural gas wells, which is decades' worth of consumption, not a mere 40 hours' worth.
    - kkfx 4y ago
      Maybe I was not clear: the quantity of green hydrogen we can produce is negligible because the amount of energy needed to extract it is so high, the amount of energy needed to compress it in a tank, respect of the rate of usage in a fuel cell makes the balance ridiculous: you need a hectare of p.v. to produce few grams per day of hydrogen or you need a good sunny day to produce enough for a mile or two in a fuel-cell powered car. At that point the entire "economy" is just marketing.
      - kragen 4y ago
        Oh, that makes sense! You're coming to ridiculously wrong conclusions because you're working from ridiculously wrong data, but not about the storability of hydrogen; rather, about the relevant efficiency figures. Let's put some concrete numbers on this. Grid-scale PV in California has a capacity factor of 29%, based on a nominal efficiency of typically 21% and a nominal solar constant of 1000 W/m². This gives 61 W/m² of solar cell as a round-the-clock average. A hectare of solar cells would be 10000 m², but because solar cells are more expensive than land they are not placed edge-to-edge without gaps; I'll guess that 30%, 3000 m², is a closer estimate, but I'd appreciate better figures from real utility-scale PV installations. That's 180 kW per hectare, round-the-clock average. Hydrogen has a LHV of 120 MJ/kg, so with 100% electrolysis efficiency 180 kW would work out to 131 kg per day per hectare, using the 30% fill factor above. Actual electrolysis efficiency is only about 70% in current industrial practice, reducing this to 92 kg per day: https://en.wikipedia.org/wiki/Electrolysis_of_water#Efficiency https://en.wikipedia.org/wiki/Electrolysis_of_water#Efficien... Then we have the question of how much energy is lost in compressing the hydrogen for storage. This is a little tricky to calculate because the answer can be arbitrarily low (isothermal compression is perfectly efficient) and even adiabatic compression depends on the kind of gas you're compressing, but the electrolysis link above says, "Practical electrolysis (using a rotating electrolyser at 15 bar pressure) may consume 50 kW⋅h/kg (180 MJ/kg), and a further 15 kW⋅h (54 MJ) if the hydrogen is compressed for use in hydrogen cars.[37]." So we're at 234 MJ/kg in, 120 MJ/kg out. This gives 67 kg/day of hydrogen for our hectare. This is an average including the occasional cloudy day that happens in southeastern California; on sunny days the number is higher. 67000 grams is, I think, not accurately described as "a few grams". https://www.fueleconomy.gov/feg/fcv_sbs.shtml https://www.fueleconomy.gov/feg/fcv_sbs.shtml says current fuel-cell cars on sale in the US go 64–72 miles per kg, or, in non-medieval units, 103–116 km/kg. 67 kg (again, an average day, not a sunny day) thus gives you 4300–4800 miles, or, in non-medieval units, 6900–7800 km. 6900–7800 km is, I think, not accurately described as "a mile or two"; even though there are admittedly many different incompatible definitions of a "mile", none of them is close to 1000 km long. In extremely polar countries like Germany and the Netherlands, PV capacity factors are much lower, sometimes below 10%, so you have to divide all these numbers by a factor of about 3. So, how did you end up believing figures that were wrong by three or four orders of magnitude, and with such confidence that you were dismissing correct, factual accounts of energy economics as "just marketing"? And how can you avoid getting suckered into such swaggering delusions in the future?
NelsonMinar 4y ago
The table in the article indicates a 70-80% round trip efficiency for electricity storage to liquid CO2.
usrusr 4y ago
Heat can be separated and stored alongside (or used separately, if you happen to have an application for the heat). Modern compressed gas storage installations that don't just dump the heat to the environment are approaching the round trip efficiency of pumped storage (water), and unlike pumped storage they can basically be built wherever you want.
- pfdietz 4y ago
  If you're going to store the heat, then you might as well reexpand the cooled compressed gas, recovering some of the energy of compression and cooling it further, and also store that "cold". You can then recover the stored energy by exploiting the hot/cold temperature difference between the two thermal stores. Doing this is functionally equivalent to adiabatic CAS, but doesn't require storage of any compressed gas.
  - usrusr 4y ago
    But why would you want to do that? A heat gradient is just about the least useful form of energy known to man. A large fraction of the total engineering effort of humanity went into trying to make energy recovery from heat gradients slightly less bad and the numbers are still terrible. Compressed gas storage gets a better cycle efficiency than that even before adding heat recovery.
    - pfdietz 4y ago
      You do that because you don't need a large underground compressed air cavity. Instead, you can store energy as heat in materials, which is among the cheapest ways to store it.
      - usrusr 4y ago
        But how much cycle inefficiency would you be willing to take for that advantage? I could totally see that storage setup be a huge success at places where you have continuous or forced-schedule intermittent low intensity heating and cooling demands (data center within insulated pipe distance of a spa resort or something like that), and want to make the best out of their opposite heat demands using intermittent electricity, but for general purpose electricity where the recovery would have to go through one of the famous thermal cycles? I really doubt it.
kragen 4y ago
It's interesting that you claim it's easy to calculate, but you haven't copied and pasted the calculation you did, which other people seem to disagree with. Your comment would probably be more convincing if you explained the easy calculation, which should be easy for you.

elif 4y ago

I don't think this really makes sense until we have a surplus of renewable energy to run compressors. When that is the case, we will have largely addressed climate change already. Using a "surplus" of base load carbon sources to run compressors is just pushing sand into sand.

mynegation 4y ago
You are probably thinking of a global surplus in a sense “when renewable energy worldwide exceeds our energy needs”. But right now we have a local time based surplus (i.e. solar works during the bright days, wind farms work when wind blows etc) that does not make sense to export too far, where there is a need. Hence storing some share of this energy is important.
yayachiken 4y ago
Innovative technologies need time and capital for R&D. Without the climate crisis, doing this R&D only once the technology becomes required and therefore economically feasible would be fine. But with the current decarbonization targets, you cannot just build renewables until you hit a threshold, and only then start testing out storage methods while putting the green energy infrastructure industry into hibernation for 20 years. We pretty much need to do everything, right now, at the same time. This is also why there is a big economic advantage of hydrogen storage. Decarbonizing steel and ammonia production with blue hydrogen (i.e. electrolysis using electricity created with the current fossil fuel heavy generation mix) is already a big potential market which is already kind of feasible, reducing the need for government subsidies to get the tech off the ground. Once the R&D, production and sales pipelines for blue hydrogen are up-and-running, you just scale up with increasingly mature technology. Then transition the energy input from carbon-intensive to carbon-neutral. This should happen automatically, as green electricity is the cheapest form of energy, and the hydrogen production acts as an energy-sink for any surplus production, mitigating those adverse market pressures acting on renewables after you reach a certain percentage threshold on renewable energy generation. Only then you eventually ramp up the use as energy storage via normal market mechanisms. Unfortunately the media always seems to put the cart before the horse. Energy storage is not the first step, but should be the last.

zackees 4y ago

Or… we can just do nuclear, which is SAFER than solar/wind energy, and not have any issues with needing to build giant batteries.

chess_buster 4y ago
No it's not.
- e2le 4y ago
  How so?
- SECProto 4y ago
  Nuclear is safer than wind, on par with solar[1]. Got a source that says otherwise? https://ourworldindata.org/safest-sources-of-energy https://ourworldindata.org/safest-sources-of-energy
  - simon_000666 4y ago
    I call bs. This article claims that only 100 people ‘died’ from Chernobyl. https://ourworldindata.org/what-was-the-death-toll-from-chernobyl-and-fukushima https://ourworldindata.org/what-was-the-death-toll-from-cher... It pretty much totally discounts the insanely large number of thyroid cancer cases in children. Then comes up with a very optimistic scenario of survival rates based on western medical interventions. So maybe they didn’t die per say but had significantly reduced quality of life and mutations. This is a classic example of taking one vanity metric and making absolute conclusions from it rather than taking a range of data points to paint a more accurate story. I find Wikipedia shows a range of numbers that are far more likely to give a realistic picture https://en.m.wikipedia.org/wiki/Effects_of_the_Chernobyl_disaster https://en.m.wikipedia.org/wiki/Effects_of_the_Chernobyl_dis...
    - zackees 4y ago
      Yes, chernobyl was fairly harmless, just like Fukushima. Wild life in both is thriving despite the fact that the mainstream media said the radiation was so bad nothing would be able to live there. Reality doesn’t back up any of those assertions at all. Villages near fukushima ignored the dire warnings and are just fine. If this is surprising then you need to diversify your media news consumption. Rooftop solar is more deadly than nuclear when you count people falling off of roofs during solar installation as “solar deaths”, otherwise it’s safer. source: https://www.forbes.com/sites/jamesconca/2012/06/10/energys-deathprint-a-price-always-paid/amp/ https://www.forbes.com/sites/jamesconca/2012/06/10/energys-d...

wronglyprepaid 4y ago

Well this is not true because Biden has already started transitioning the US off fossil fuels without any long-duration energy storage and he is doing it in a historically inclusive manner[1]. [1]: https://www.whitehouse.gov/briefing-room/statements-releases/2021/11/15/fact-sheet-building-a-new-era-of-nation-to-nation-engagement/ https://www.whitehouse.gov/briefing-room/statements-releases...

exyi 4y ago
We will need it later, you can't go 100% 0 carbon without it. Just running peaker generators, figuring out how to heat/cool houses, charge EVs when there is surplus, ... are all cheaper alternatives to storage, but won't cover everything
- wronglyprepaid 4y ago
  > We will need it later, you can't go 100% 0 carbon without it. I think this is just what capitalist is trying to make people believe, the economy will adapt and jobs are already booming as the unemployment in US is at a historic low which shows just how historically strong the economy is [1]. [1]: https://www.whitehouse.gov/briefing-room/statements-releases/2022/01/19/fast-facts-record-firsts-in-president-bidens-first-year/ https://www.whitehouse.gov/briefing-room/statements-releases...
  - mpyne 4y ago
    They're not arguing it's an economic harm to decarbonize, they're pointing out that it cannot physically be done, at all, without some way of storing energy. This is needed because otherwise you'd only get energy when the wind is blowing and the sun is shining. This is especially true if you do not classify nuclear energy as green energy, but even with nuclear providing baseload generation you would want energy storage to truly take advantage of the energy that renewable sources can provide.
    - wronglyprepaid 4y ago

NelsonMinar 4y ago

First few comments have focused on the CO2 compression storage, but that's just one of many technologies the article talks about. It's worth a read. For that matter so is this whole quarterly special section on climate change and energy technology: https://www.economist.com/technology-quarterly/2022-06-25 https://www.economist.com/technology-quarterly/2022-06-25 Pumped hydro is the largest current energy storage system we have deployed. There's a lot of interest in chemical batteries but they're expensive, particularly given how fast the batteries degrade.

01100011 4y ago
https://en.wikipedia.org/wiki/Flow_battery?wprov=sfla1 https://en.wikipedia.org/wiki/Flow_battery?wprov=sfla1 Link says vanadium flow batteries last many years and tens of thousands of cycles. Regeneration sounds fairly simple as well.
- anonuser123456 4y ago
  Vanadium is too expensive/rare to be used at scale unfortunately. But I believe there are a number of workable chemistries for non-vanadium based flow batteries currently in development.
nradov 4y ago
Pumped hydro is great but there are limited locations where the geography and geology allows it to work. And there are ecological concerns with building more dams.
- NelsonMinar 4y ago
  Developing new pumped hydro definitely has drawbacks. Slightly encouraging: Switzerland just brought 20GWh of pumped storage online that can generate up to 900 MW. The project took 14 years. https://en.wikipedia.org/wiki/Nant_de_Drance_Hydropower_Plant https://en.wikipedia.org/wiki/Nant_de_Drance_Hydropower_Plan...

ZeroGravitas 4y ago

No it doesn't. It might be part of the solution, but the repeated talk about how we need some magical breakthrough before we can continue with electrification is just wrong. The most important part, is to burn less fossil fuels, and we have lots of ways to do that, and we should do whichever is cheapest and easiest first. Long duration storage comes after: - put a price on carbon and other pollution - efficiency/insulation - electrify everything - build more renewables - vary existing tech to complement renewables (e.g. hydro, waste to energy) - vary loads to absorb renewables when they are available - build short term storage to shift energy (EVs and related battery tech) - ship green ammonia/hydrogen around the world from places like chile. And then there's a place for long term storage (which is a direct competitor to green hydrogren production and may never make sense compared with doing more of that)

pfdietz 4y ago
Yes, it does, if you want to get to a 100% decarbonized grid with renewables most economically, and particularly if you want solar to be a substantial component of energy supply at high latitude. Yes, other things come first, but storage has to be in there. Synthesis of chemical fuels at lower latitude for use at high latitude is effectively long term storage, since once one has paid to cost of making those fuels, storing them is cheap and adds robustness.
- bryanlarsen 4y ago
  That's a pretty big if. Most people would be ecstatic if the grid was 99% decarbonized, and 99% decarbonized is probably an order of magnitude easier than 100% decarbonized. Unless you're some place like British Columbia with massive hydro reserves.
  - pfdietz 4y ago
    You can try for yourself at https://model.energy/ https://model.energy/ If you add "Dispatchable 1", which is gas, and give it zero cost, but then put a limit on the total CO2 emission, you can get the optimal setup to get X% (X < 100) of a synthetic baseload source from wind/solar/batteries/hydrogen. Then take out hydrogen and look at the cost difference.

freemint 4y ago

No it doesn't. The sun shines 24/7/365.24.

bryanlarsen 4y ago

Long term storage is very definitely not required. If you take a look at the hourly weather data for every continent for the past 30 years, there is not a single hour where there is not wind blowing somewhere on the continent. So you can build a continental grid consisting of just wind turbines that will continuously satisfy the energy needs for the entire continent. Long term storage is cheaper than a massive continental grid with a massive overbuild of solar, but it's not required. But it illustrates the point that a lot less long term storage is required than most people expect.

spenrose 4y ago

Serious studies of this question: * https://netzeroamerica.princeton.edu/ https://netzeroamerica.princeton.edu/ (US, but takeaways apply more broadly) * World-wide: https://www.nature.com/articles/s41467-021-26355-z https://www.nature.com/articles/s41467-021-26355-z * Stanford's Marc Jacobsen is a proponent of the opposite view * Rebuttal of Jacobsen, with links to his work: https://www.pnas.org/doi/10.1073/pnas.1610381114 https://www.pnas.org/doi/10.1073/pnas.1610381114

adrianmonk 4y ago

"Requires" is problematic. Do the next N steps of the transition need to block on the availability of storage? No. But, there's another angle to view this: political feasibility. People are dragging their feet. Why? Well, what is the value proposition of switching to renewable energy? Right now, it's roughly, "Unfortunately, the reliability may be a downgrade, but saving the planet is definitely worth the sacrifice." If you made a pie chart of people's reactions, there'd be a big wedge that says "I get it! I'm in!", another big wedge that says "eventually", and another big wedge that says "nope". If cheap, effective energy storage were a solved problem (commercialized, proven in the field), then the value proposition would be, "Renewable energy will save the planet and also provide everything you're accustomed to right now." The pie chart would look better. So, because political feasibility is required, decarbonization does sort of indirectly require storage. Tangent: for this reason, I think we should give storage the same incentives that we give to solar and wind. Possibly even larger ones since solar and wind are pretty good now but storage still needs lots of work.

techdragon 4y ago
Thing is, other than mass produced unit technology like li-po and li-ion cells, there’s precious little available storage. I tried to get quotes from a company that sells liquid flow redox batteries, the sort of technology that should scale volumetrically but it’s just not feasible for anyone to deliver beyond small deployments. We can’t order X-kWh storage off the shelves with anything but lithium batteries at the moment and until we can, there will be serious questions asked by people…even enthusiastic people like myself, because I look at the daily cycle count and go “fuck off” I’m not replacing 25% of a lithium battery tech based energy storage every 3 years, grid scale facilities are designed around 25 year cycles and anything with less than a 10 year lifetime feels like flushing money down the drain on razor thin margins, both economically and environmentally once you account for the manufacturing costs of the lithium based energy storage equipment.

kragen 4y ago

https://archive.fo/8BgQY https://archive.fo/8BgQY The article unfortunately equivocates about the meaning of "long-duration", which could mean "a few hours", "a few days", or "a few months". It mentions "four hours", "an eight-hour buffer", "up to 100 hours," and "seasonal energy storage". The first three of these are indeed required; the last is not, which is fortunate, because it is inherently orders of magnitude more expensive. Conflating them in this way is profoundly unhelpful: it's like writing an article about a requirement for "high-speed vehicles" including both a Kia Forte (top speed 200 kph) and an SR-71 (top speed 3500 kph). But the ≈40 hours we need is further from being the 4000 hours provided by seasonal thermal storage than the Kia is from being an SR-71, which can, after all, only outrun the Kia by a factor of less than 20, not 100. The reporter can only be hoping to get away with this because of the unfamiliarity of grid-scale energy storage. Absent cost-competitive geothermal, nuclear, or kite energy (or reliance on intercontinental power transmission), decarbonization of grids definitely requires grid-scale energy storage for a few hours, and it probably requires storage lasting a few days, because even over large geographical areas there are large lulls in wind and solar. The sun doesn't shine all day and the wind doesn't blow all night. But it almost certainly doesn't require seasonal energy storage, because you can overprovision generation capacity sufficiently to provide enough essential power every week of the year. A consequence of such overprovisioning will be that in the high season (either sunny or windy, depending on your power mix, but probably ultimately sunny) you can generate several times as much energy as the essential minimum, so power-hungry applications will benefit from cheap or free energy in the high season. This is supported by the article's summary of van Gendt et al.'s report: their "most cost-effective path to a world with net-zero emissions by 2040" has 85–140 TWh of storage at a power of 1.5–2.5 TW. Dividing the numbers, that's 34–94 hours. That's energy storage for a few days, not a few months. Still, it's interesting to consider the ways we could build a seasonal energy store, even if it isn't essential to decarbonizing the grid. — ⁂ — Unfortunately, the Economist's "All charged up" table of energy storage methods doesn't mention thermochemical energy storage (TCES), compressed gas, or even lithium-ion batteries. Compressed gas, which they do mention at length in the article, is ridiculously inefficient without some kind of thermal energy storage, and the two thermal energy storage technologies they do list are not useful for seasonal storage — latent heat, i.e., phase change materials, and sensible heat, the kind of heat that makes things hot. So TCES is a crucial enabling technology for possible seasonal compressed-gas storage. As with electrical storage in flow batteries, TCES can provide thermal energy storage for as long as you like if your tanks are big enough, so in theory it's vastly superior for seasonal thermal stores, and you'd need seasonal thermal stores for efficient seasonal energy stores with compressed gas. TCES has an enormous advantage over currently-available flow batteries in the cost of the necessary materials. We'll see if the Form Energy gadget, which I hadn't heard of, pans out; that would change the equation radically, because only sand is cheaper than iron and salt. But TCES mineral feedstocks like carnallite, muriate of lime, quicklime, and bischofite are nearly so.