If I had a eurocent for every time a Climate Change denier-sceptic told me that if I really, truly believe that Carbon Dioxide causes Global Warming I should just stop breathing…well, I’d be rich enough now to afford to buy the whole of Belgium, or at least most of economically-depressed Wallonia. Mmm…Waffles.
But seriously, holding your breath in the form of Compressed Air Energy Storage (CAES) is one of the big flashing signs for the future of ReSmoothing, smoothing Renewable Energy supply, that is.
As we all now know, thanks to the continual moans of the anti-Wind Farm brigade, Wind Power, and other forms of Renewable Power are variable, or intermittant. Look ! See ! Some days in Winter the wind drops to practically zero…in North Western Europe.
And even though the wind is always blowing somewhere in the World, and even though we can build a super Supergrid over a very large geographical area to draw in many kinds of Renewables, we do still need Energy Storage to cover us for the bad patches.
Hydropower in general is fairly productive, but sometimes overweighty.
(The Three Gorges dam in China, once in operation, was so large it changed the rotation of the Earth ! https://www.theenergylibrary.com/node/11435)
Pumped Hydro Energy Storage (PHES) has been going on for decades in parallel with the general Hydropower drive. What do you think some of the artificial lakes around Europe are for, precisely ? Decoration ?
But it’s been so successful that the limit for Hydropower development has probably been reached in most appropriate geographies.
So we have to do other things as well.
Apart from Flow Batteries (giant Fuel Cells), which require lots of metal and sometimes metals in short supply, the headliners appear to involve building underground caverns for things, for which you don’t need lots of metal, just suitable geological formations :-
https://www.greentechmedia.com/articles/read/epri-on-renewable-energy-compressed-air-energy-storage/
https://www.theoildrum.com/node/6053
This is what all the retiring Petroleum Engineers will end up doing : finding suitable sites for pumped underground storage. When the lemon/turkey/dead duck of Carbon Capture and Storage fails to attract enough money to make it out of the nest.