Most discussion of energy storage that I’ve seen has focused on batteries, with occasional mentions of pumped hydro. But in the last week, I’ve seen announcements of big investments in quite different technologies. Goldman Sachs just put $250 million ($US, I think) into a firm that claims to worked out the bugs that have prevented the use of compressed air storage until now
And several companies are working on gravity storage (raising and lowering massive blocks) to store and release energy
Underlying these points is a crucial fact in physics/engineering: Any reversible physical process is an energy storage technology.
That’s why concerns about the variability of wind and solar power will come to nothing in the end
Energy storage technologies differ in lots of dimensions, including efficiency (the proportion of stored energy that is released), speed of discharge, and the time for which energy can be stored without being lost. Conversely, an energy supply system has demands that vary on all the correspond dimensions. In particular, the storage time dimension can vary from milliseconds (the instant power needed to maintain system stability against shocks) to months (storage between seasons).
John Quiggin 
Very interesting. Sounds promising for remote disused mines. I’ll await further input.
“Hydrostor secures financing to complete Australia’s first compressed air storage facility
“Canada’s Hydrostor has closed US$37 million (AU$54,6 million) in growth financing. The company plans to use the funding to complete construction of the 5 MW/10 MWh Angas Project in South Australia and to advance its 2 GW pipeline of large-scale advanced compressed air energy storage projects.
SEPTEMBER 21, 2019
MARIJA MAISCH
https://www.pv-magazine-australia.com/2019/09/21/hydrostor-secures-financing-to-complete-australias-first-compressed-air-storage-facility/
Yet Arena project page says;
“Hydrostor Angas A-CAES Project
“This pumped hydropower project has been discontinued.”
https://arena.gov.au/projects/hydrostor-angas-a-caes-project/
*
Hydrostor project in Broken Hill;
“Broken Hill compressed-air energy storage facility to inject $457m into economy, company says
Posted Thu 10 Jun 2021
“Storage to make power ‘more reliable’
…
“Broken Hill experienced a major power outage more than a decade ago.
“The entire city relied upon two backup diesel turbines for a week and fuel needed to be trucked in from Adelaide.
“Hydrostor Australia director Greg Allen said the plant would make power more reliable in Broken Hill and enable new renewable energy projects in the region.
“What really stimulated the development of this opportunity was to improve the reliability of supply of electricity to the Broken Hill region due to some of the limitations of the existing 260-kilometre transmission line,” he said.”
…
https://www.abc.net.au/news/2021-06-11/broken-hill-compressed-air-energy-project-economic-impact/100204650
https://www.hydrostor.ca/broken-hill-energy-storage-centre/
I really like Tony Seba’s idea of ‘Super Power’. In this scenario wind and solar become so cheap over time that it is worthwhile to greatly ‘over build’ ( not the correct term ). This vastly reduces the need for storage as well as supplying a huge amount of extremely cheap energy 80% of the time. The whole economy will reconfigure around very cheap but perhaps slightly unreliable electricity supplies, with storage where absolutely essential. Think free car recharging at the local shops or workplace but maybe not all the time.
Currently excess energy is seen as a problem that must be curtailed, but he points out that wasting nearly free clean energy is irrational.
Seba’s RethinkX group currently has a 50 page report on the concept and is really worth reading. One interesting implication is that we are in for an abundant future rather than a miserable one.
The report requires an email but I am pretty sure you can use a fake one and then just download it. Link here.
All this is well and good but I don’t trust where we are headed when corporations are still in charge of production science and their bought and suborned governments refuse to fund impact science.
There are some major problems up in north Qld. with where wind turbines are being placed: along ridges destroying important habitats and turning range ridges into moonscapes with access roads. Sure we need to phase out fossil fuels. We may also find we need to moderate our total consumption to not destroy too much habitat. But many people are still too fixated on endless human growth and human plenty.
Ikon, I’m not a huge fan of windmills either – but the people have spoken. Fortunately the damage might not be very permanent and they can be removed if necessary at end of life. Bit different to a coal mine.
My preference would be some nuclear – specifically thorium – in the mix, but again, that’s not a goer, at least currently.
Hopefully turbines will eventually be mainly in deep ocean ( over the horizon – please ). I always thought placing them in the roaring forties would be ideal ( south of Tasmania ) but the tech probably isn’t there yet.
Storage is one problem, but another is transportation. Right now you can easily move energy nearly anyplace on earth using a boat or truck. It will certainly be worked out, but transportation is an issue.
Is interseasonal storage really being seriously considered anywhere? To some extent it happens naturally with flow hydro, since reservoirs fill up in winter and are run down n summer, but that’s adaptation to necessity. I suspect it will always pay to cope with seasonal varation y overbuild, especially as wind and solar are seasonally complementary n middle latitudes. The Germans worry more about this than most, and their chief concern is the “Dunkelflaute” (dark doldrums), periods of a few calm weeks in winter with clouds blocking solar and no wind, Weeks not months, from long historical records. This is one reason why they are so keen on hydrogen, a drop-in replacement for the fossil gas currently stored in vast salt caverns at Etzel in Saxony.
You wouldn’t notice this in backward Australia, but V2G is coming, this year, in volume electric cars from VW and Hyundai and a few pickups from Ford, VW are even getting into the electricity business via V2G, in Germany at least. They have a large home advantage – a very high retail electricity price generating large savings to V2G car-owners, uniform and sensible national technical and regulatory standards, and technically literate policymakers. They have stolen a march on Tesla, which resists V2G, possibly because it will destroy Tesla’s overpriced domestic storage battery business.
Good2go: There is this neat Victorian invention called electricity, which travels long distances on thin wires, already in place.
Don’t want to be pedantic (okay, yes I do) but humans didn’t invent electricity. They discovered it. 😉
“Towards the effecting of works, all that man can do is to put together or put asunder natural bodies. The rest is done by nature working within.” – Francis Bacon.
I suspect that, like integrating more than a couple of percent of wind and solar has proved solvable, the storage (and demand management and efficiency and agreed load shedding and interconnectors and etc) problem will be solvable.
Most of all it needs clear signals that the energy transition isn’t optional; if these industries have to do it they will build solutions – and those solutions will work and the economic alarmist fear will be shown to be unjustified – but as long as they don’t have to they won’t.
I also think ‘seasonal storage’ isn’t going to happen for electricity, and it will be cheaper to roughly get it right with a judicious mix of solar and wind, and generate more than you need most of the time.
Given that at least 20% of energy is needed for chemical feedstocks and fuels and making metals, there is huge potential for flexible demand: making these while the sun shines or the wind blows, and storing this ‘energy’ in a large pile or hole in the ground.
Not that this ‘last few percent’ issue is particularly relevant right now: decarbonising the first 90% is roughly 9 times as important as the last 10%, and is the urgent business of the next decade or two.
“Most of all it needs clear signals that the energy transition isn’t optional”.
The clear signal is that they are now cheaper than conventional and getting even cheaper. Intermittency is the only real ‘problem’ and that can be sorted out by ‘overbuilding’ and some storage. Excess electricity will be available most of the time and industry and consumers will reconfigure to take advantage of this almost free, but variable energy.
I agree that storage is a solvable problem. There is still scope for significant disruption and negative social impact if the transition is poorly managed, however. I think the interesting policy work will be in convincing the government not to sit back and watch as cheap solar and wind flood markets, but to actively work toward a reliable and safe energy system.
If you are interested in V2G, this piece by (Aussie?) Marija Maisch at PVMagazine is detailed and informed:
https://www.pv-magazine.com/2022/01/15/the-weekend-read/
Short take: V2G is fixed technically at the car/bus/van and grid levels. (Damaging the battery is a non-problem, Intelligent battery management prolongs working life.) The remaining problems are the cost of the intelligent charger, and the lack of a sensible regulatory framework for mass deployment rather than pilot projects.
As James tells us, V2G seems better yet: “They have stolen a march on Tesla, which resists V2G, possibly because it will destroy Tesla’s overpriced domestic storage battery business.”
“Gravity Could Solve Clean Energy’s One Major Drawback
“Finding green energy when the winds are calm and the skies are cloudy has been a challenge. Storing it in giant concrete blocks could be the answer.
…
“This tower is a prototype from Switzerland-based Energy Vault, one of a number of startups finding new ways to use gravity to generate electricity. A fully-sized version of the tower might contain 7,000 bricks and provide enough electricity to power several thousand homes for eight hours. Storing energy in this way could help solve the biggest problem facing the transition to renewable electricity: finding a zero-carbon way to keep the lights on when the wind isn’t blowing and the sun isn’t shining. “The greatest hurdle we have is getting low-cost storage,” says Robert Piconi, CEO and cofounder of Energy Vault.”
…
“The most important question facing Energy Vault is whether it can get the cost of its buildings low enough that it makes gravity the most attractive form of energy storage. Since 1991, the cost of lithium-ion batteries has fallen by 97 percent, and analysts expect that price to keep dropping in the coming decades. “Really, any storage technology has to compete against lithium-ion, because lithium-ion is on this incredible cost-reduction trajectory,” says Oliver Schmidt, a visiting researcher at Imperial College London. Over the next couple of decades, hundreds of millions of electric vehicles will roll off production lines, and almost every single one of them will contain a lithium-ion battery. In mid-2018, Tesla’s Gigafactory was producing more than 20 gigawatt hours of lithium-ion batteries every year—more than the total grid-scale battery storage installed in the entire world. The boom in electric vehicles is driving the cost of lithium-ion down, and energy storage is coming along for the ride.”
…
https://www.wired.com/story/energy-vault-gravity-storage/
We have been tolerating a level of brittleness, that should be unacceptable, ever since we electrified. Not saying our leaders are good people. But their conduct was always worse than it had to be, even on the simple basis that you can’t ever afford an adversary to get anywhere close to your electricity grid. So this brings the concept of “imminence” into question when considering going to war against a threat. This problem of storage can be solved. I think its a real problem. I think we need to solve it with overkill. Once we do we can go full steam ahead on these alternative energy sources.
“The most important question facing Energy Vault is whether it can get the cost of its buildings low enough that it makes gravity the most attractive form of energy storage.” Conceptually we don’t need to be as extreme about things as all that. Supposing you have a seven story building that is not pyramidal. But sufficiently tapered to let it be water-cooled by way of water sprinkling at the top that dehydrates before it hits the ground. The top two floors are there for water storage. They are pumped up there with renewables for all water uses, not excluding fire protection. And gravity fed on demand. Plus there is extra basements for both battery storage and storage needs otherwise. So already there you have some level of storage, just from simple concepts of building design. Cheap air-conditioning through evaporation. All kinds of things going on. The main thing is to have government property development alongside the privateers. To keep each other honest.
James Wimberley
The interseasonal storage problem has been considered in a number of articles at reneweconomy.
https://reneweconomy.com.au/how-much-seasonal-energy-storage-will-we-really-need/
https://reneweconomy.com.au/seasonal-energy-storage-is-a-tricky-issue-for-our-renewable-future-20478/
https://reneweconomy.com.au/we-will-need-more-wind-than-solar-for-100-pct-renewables-and-lots-of-storage/
https://reneweconomy.com.au/energy-storage-its-not-just-size-that-counts-but-how-long-it-lasts-34857/
The work of the Blakers team at ANU in this space is referred to in these articles.
Despite the environmental and cost problems of Snowy Hydro 2.0 it will address some of the interseasonal problem.
The other solution is a consequence of us really going for the renewable energy super power option. The massive build of solar and wind energy capacity implied by this option – 4 or 5 times our current electricity generating capacity – means that even on low wind periods during winter there will still be enough energy generated to run what needs to be run, and the hydrolysers etc will not be turned on during these seasonal lows.