Decarbonisation of grids requires long-duration energy storage
economist.com
economist.com
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.
Link says vanadium flow batteries last many years and tens of thousands of cycles. Regeneration sounds fairly simple as well.
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)
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.
The first 4 items are relevant here:
> Electricity systems with zero direct CO2 emissions can be built more cheaply by using additional technology options. The examples here are simply a toy model to put an upper bound on the costs for a very simple setup. Additional generation technologies which may reduce costs include using existing hydroelectric generators, biomass from sustainable resources (such as waste and agricultural/forestry residues), offshore wind, concentrating solar thermal, geothermal, ocean energy, nuclear and fossil/biomass plants with CCS. Two additional dispatchable technologies are provided under "advanced assumption settings". Additional storage technologies include redox flow batteries, compressed air energy storage, etc. Other options include allowing demand to adapt to renewable profiles (demand-side management).
> No import or export capacities with other regions are assumed, so each region must meet the baseload profile by itself. Existing and planned transmission grid connections between regions can reduce costs by up to 20% by smoothing wind over a continent-sized area (see e.g. this paper or this one).
> Including energy demand sectors other than electricity, like transport, heating and non-electric industrial demand can offer additional flexibility (e.g. load-shifting by battery electric vehicles and thermal storage for electrified heating), see e.g. this paper or this one.
> Costs here are for completely decarbonised electricity systems. Reaching lower levels of decarbonisation is much cheaper and doesn't necessarily require any storage at all. A non-zero carbon dioxide emission target and options for fossil-fuelled generators can be set under "advanced assumption settings".
They also made this nice interactive animation to demonstrate the impact of cross border flows:
https://viz.japangrid.researchvitae.com/pypsa-eur-animation/
Someone else said, that's a big if, since 99% renewable is probably much cheaper.
When they said you can try it yourself, I thought they were disagreeing with that point, which I, and the people who made the model, agree with.
(As another example, the current US strategy is to get to 95% low carbon electricity and then shift focus to electrifying more things, as that has a bigger impact on carbon at that point, and helps to absorb variability.)
Now, I'm not sure what point they were making.
(Well, not quite, because it ignores seasonality of demand, and if that's out of sync with seasonality of supply then more long term storage might be useful.)
Sure, the model is wrong. All models are wrong, but some are useful.
One thing they didn't include in the model, but do mention is the electrification of other sectors, which would require a lot of green hydrogen to be produced. This increases the electricity generated, and also introduces a big modulatable load, which means more hydrogen would be 'stored' but less would need to be burned, which then makes it ambigous if that actually counts as storage, particularly as you could choose to burn it if necessary but then use it for other puproses, like fertilizer, if you didn't need it. I see green hydrogen as the main marketplace competitor to long term storage, so this distinction is important in my view.
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...
Without racism should be a property, not an identity. (I would go further: without bigotry). Ditto carbon.
Valuing lives is important. New ones. Black ones. Old ones. Gay ones. Etcetera. (All lives [will] matter [when ** lives matter])....
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.
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.
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.
Unfortunately, there is not enough (economically extractable) Lithium to go around. Experts estimate a Lithium "hole" of up to 300.000 tons of missing yearly production by 2030.
There is nothing we can do about it, only prospecting for more Lithium, reducing red tape for Lithium mining (with all the negative environmental impacts), or further increasing efficiency of Lithium use in batteries. As you said, Lithium battery technology is mature, so we have hit diminishing returns here.
This is why the feasibility of sodium batteries that was announced a year or so ago was such a big deal. Getting Sodium (e.g. from table salt, mined as excess in potassium mines, with a price of around zero) is easy and cheap.
* 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
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.
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.
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.
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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.
[1]: https://www.whitehouse.gov/briefing-room/statements-releases...
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...
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.
If this was true why is the US economy doing so well in the transition off carbon based fuels while being the most inclusive in history[1]?
> This is especially true if you do not classify nuclear energy as green energy
But nuclear is not green [2], and labelling it as such is just green washing.
[1]: https://www.whitehouse.gov/cea/written-materials/2022/01/20/...
[2]: https://edition.cnn.com/2022/07/06/world/eu-votes-natural-ga...
Because we have not gotten to the point where storage, and particularly long term storage, would make sense to build. I mean, why synthesize a chemical fuel when we're still burning so much natural fuel?
Long term storage is a last 10-20% thing.
Efficiency would just be one variable in that calculation.
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#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 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?
When a compressed gas expands and does work, its thermal energy is converted to work, and the temperature declines. There is no "energy of compression" in the gas aside from its thermal energy content. The internal energy of an ideal gas is a function only of temperature, not of pressure.
Adiabatic CAES ideally stores ALL the energy invested during the compression into the thermal store. The compressed gas is just there as an entropy sink, so that this stored thermal energy can be converted back to work efficiently. But that's just what the "cold" in a PTES system is, too. Ideally, the efficiency of the two systems is the same.
I can't tell you exactly where your model goes wrong, but I really believe that you must be missing something.
Possibly this is less of a problem than I imagine it to be for adiabatic CAES; my knowledge of these systems is obviously pretty sketchy.
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_dis...
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-d...
I'm not claiming it as a 100% accurate source, as it was just what I found with a quick google - I agree using a range of data points for each energy source would be more rigorous. Do you have a better source that uses ranges for the different energy options?
[1] https://en.wikipedia.org/wiki/Fukushima_Daiichi_nuclear_disa...
I don't think that Mayak is relevant, as it is a secretive, poorly regulated nuclear weapons production facility. Similarly, the impacts of Therac-25 [1] patients or the Goiania Incident[2] don't get counted against nuclear energy.
> People often focus on the marginal differences at the bottom of the chart – between nuclear, solar, and wind. This comparison is misguided: the uncertainties around these values mean they are likely to overlap.
> The key insight is that they are all much, much safer than fossil fuels.
> Nuclear energy, for example, results in 99.9% fewer deaths than brown coal; 99.8% fewer than coal; 99.7% fewer than oil; and 97.6% fewer than gas. Wind and solar are just as safe.
https://www.nextbigfuture.com/2020/09/chinas-nuclear-energy-...
What do the men who planned the solar and wind rollouts think?
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.
For people still retro-fitting solar (which will grow in absolute terms), the increased efficiency means they get more power per trip to the roof than the past installs, further lowering the deaths per TWH generated (this also impacts mining related deaths as PV efficiency of manufacture has been increasing, getting more TWH per unit of material).
- 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?