Decarbonisation of grids requires long-duration energy storage

https://www.economist.com/technology-quarterly/2022/06/23/decarbonisation-of-electric-grids-reliant-on-renewables-requires-long-duration-energy-storage

by lxm • 4 years ago

29 92 4 years ago

economist.com

anovikov• 4 years 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• 4 years 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.

kkfx2• 4 years ago

And that's the issue, no different than hydrogen: we can do that, but in sooooo limited quantity that's practically useless.

NelsonMinar3• 4 years ago

The table in the article indicates a 70-80% round trip efficiency for electricity storage to liquid CO2.

usrusr6• 4 years 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.

pfdietz11• 4 years 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.

kragen12• 4 years 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.

elif2• 4 years 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.

yayachiken2• 4 years 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.

elif2• 4 years ago

I dunno battery battery storage is pretty mature in terms of production, and doesn't depend on a continuous source of CO2 emissions to function.

My house is grid negative from about 11:00 to 19:00 with about 2 months of engineer salary in battery and solar.

It seems like the first and only step available to anyone outside of massive power tycoons, and if I repeat the investment for just a couple more years, it is also the last step.

I think the media reports on anything clickable, but also probably hopium technologies endorsed by energy tycoons to facilitate kicking the can.

mynegation• 4 years 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.

usrusr6• 4 years ago

We won't ever get anywhere close to a surplus as long as we don't have storage that would be buying up energy when supply exceeds demand.

zackees5• 4 years 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• 4 years ago

No it's not.

e2le• 4 years ago

How so?

SECProto4• 4 years ago

Nuclear is safer than wind, on par with solar[1]. Got a source that says otherwise?

https://ourworldindata.org/safest-sources-of-energy

bryanlarsen6• 4 years ago

Safer, but not cheaper. Even with batteries.

zackees5• 4 years ago

It’s only more expensive due to extremely absurd regulation.

ZeroGravitas9• 4 years ago

And, it's not safer.

It's roughly as safe as renewables, and they're both much safer than fossil fuels, particularly coal, but you have to use obviously out of date stats to suggest anything else regarding renewables vs nuclear and the trend is clearly in renewables favor, even if it wasn't continuing to get cheaper, which it is, which gives you more safety-per-buck too.

freemint2• 4 years ago

We do want to electrify the world, don't we? This using nuclear leaves us with three options:

- every country runs it's own homegrown nuclear power plants

- a few first world companies run power plants in every country, making them dependent and complaint

- nuclear plants are in "safe" countries (which hopefully remain safe) and their electricity gets distributed to dependent "unsafe" countries via a global power grid

Which of those solutions do you prefer?

wronglyprepaid5• 4 years 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...

exyi• 4 years 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

wronglyprepaid5• 4 years 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...

anonuser1234562• 4 years ago

I honestly do not understand this push to have 'inclusive energy policy'. WTF. The point is a net carbon reduction. If poor people need dirty energy while rich people subsidize the technology development WHO CARES.

NelsonMinar3• 4 years 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

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• 4 years ago

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.

anonuser1234562• 4 years 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.

nradov2• 4 years 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.

NelsonMinar3• 4 years 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_Plan...

ZeroGravitas9• 4 years 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)

pfdietz11• 4 years 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.

bryanlarsen6• 4 years 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.

binbag2• 4 years ago

But isn't the point that if you want to electrify more industry while eliminating thermal power generation then you will need massive energy storage to cover the gaps in real time energy supply from renewables..? If you rush and do what you are saying without finding an efficient way to store a surplus of energy then you will have blackouts come winter.

wronglyprepaid5• 4 years ago

If you rush and do what you are saying without finding an efficient way to store a surplus of energy then you will have blackouts come winter.

But this is only a problem while the economy is still in transition[1], once the transition has completed this will not be a problem.

https://www.whitehouse.gov/briefing-room/statements-releases...

freemint2• 4 years ago

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

bryanlarsen6• 4 years 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• 4 years ago

Serious studies of this question:

* https://netzeroamerica.princeton.edu/ (US, but takeaways apply more broadly)

* World-wide: 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

adrianmonk• 4 years 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• 4 years 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.

kragen12• 4 years ago

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.

Decarbonisation of grids requires long-duration energy storage

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