Power stations are usually ugly. In addition, coal, oil, and gas power stations are turning out to be expensive writeoffs for power companies, particularly facilities that are not very old. The new IDTechEx report, “Stationary Energy Storage Without Batteries: Grid, Microgrid, UPS, Trackside 2021-2041” has the answer – repurposing as energy storage.

Raghu Das, CEO of analyst firm IDTechEx explains, “We all know that renewables increase intermittency so we need more and more energy storage – delayed electricity. Cost reduction of solar generation is the fastest and its increasing share means two problems – dead at night, feeble in winter. Wind power can be dead for weeks in some regions and that only adds to the problem. Lithium-ion batteries currently favored for stationary storage self-leak over weeks let alone seasons and they are not the easiest to scale to GW levels or improve to 20year life, easy recycling or even best safety.”

That leaves other forms of battery and various battery-less solutions. They not only come to the rescue; they can hugely assist with the stranded assets of the clean-up from fossilfueled power stations to hydro dams and pumped storage on waterways that are drying up.

Das continues, “We can get creative here. Siemens Gamesa has pointed out that its thermal energy storage using volcanic rocks is best at GW levels and capable of storage for weeks. They propose that it can be used in repurposed polluting power stations, employing the buildings, the steam turbine systems and the power transmission. At IDTechEx we also see large redox batteries used in such buildingswith the existing power transmission. Indeed, gravity storage that erects towers may be ugly in a city but acceptable at existing power stations or up the side of a hydro dam. Liquid-air storage can also go nicely into an obsolete power station. Additionally, the power station buildings and land can be covered in solar panels. Full writeoffs are avoided. Permissions are more readily granted than is the case for new industrial sites.

He finds that Redox Flow Batteries (RFB) will produce a better Levelised Cost of Storage (LCOS) than lithium-ion in some of the new demand scenarios. Fewer expensive materials, longer life, repairable, and no fade over the years are part of that calculation. See more in the IDTechEx report, “Redox Flow Batteries 2021-2031”.

For stationary energy storage, RFB may have the second-largest sales in 2031 after lithium-ion batteries. The world is running short of pumped storage sites and their approval and erection is pitifully long. Lithium-ion batteries suffer ongoing shortages of raw materials and, like pumped storage, their environmental credentials are increasingly questioned. Lift-off in solarhouse batteries and electric vehicles will aggravate lithium-ion shortages.

Seasonal storage with no leakage calls for battery-free solutions with IDTechEx seeing great potential for gravity storage in various formswhen they are proven. It could even employ on-site the trashed smokestacks and cooling towers of obsolete power stations making them less ugly. Compressed air underground should also be successful for longterm storage but it needs special locations. The Siemens Gamesa thermal storage looks excellent for hours to days of storage, with no troublesome materials.

However, IDTechEx is careful to point out that although the primary need is for delayed electricity, there is some scope for using electricity to make stored low-grade heat that is then used as heat because it has neither the capacity nor the temperature to be converted back into electricity. There is also the option of using surplus electricity to make chemicals such as hydrogen or for longterm storage, more appropriate chemicals. However, neither option will efficiently run electrics, from vehicle charging to climate control and industrial needs when they are required at a later time.

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