Guest essay by Eric Worrall

The CCP has decreed that five years from now, batteries and compressed air energy storage prices will drop by 30%. But even if these promises are more than hot air, a 30% reduction is nowhere near enough.

Climate Change: China to slash costs of energy-storage systems for industry to leapfrog the world by 2030, according to five-year plan

The production cost of large chemicals-based energy-storage systems will be cut by 30 per cent by 2025, putting the industry on path to leapfrog the world by 2030Compressed air energy-storage technology would realise “engineering applications” in units with 100 megawatts of capacity, according to the government’s plan

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Published: 8:30am, 24 Feb, 2022

China’s government plans to cut the cost of energy storage systems by 2025 to help local industries leapfrog the world as the vanguard of novel energy storage technology five years later.

The production cost of large chemicals-based systems will be cut by 30 per cent by 2025, while compressed air energy-storage technology would realise “engineering applications” in units with 100 megawatts of capacity, according to a five-year plan drafted by the National Development and Reform Commission (NDRC) and the National Energy Administration (NEA). The document has been sent to local government and central government-administered enterprises for implementation.

“By 2030, China’s new energy storage should see well-rounded market-based development, with proprietary technology, world leading innovation and manufacturing capabilities,” said the industry development plan for 2021-25.

Energy storage is a key part of the Chinese government strategy to decarbonise the energy system and put the world’s second-largest economy on the path to achieve carbon neutrality by 2060. Affordable energy storage is vital in turning solar and wind energy into commercially viable substitutes of fossil-fuel energy, helping to compensate for the industry’s volatility and reliance on weather patterns.

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Read more: https://www.scmp.com/business/article/3168078/climate-change-china-slash-costs-energy-storage-systems-industry-leapfrog

In my opinion there is a very obvious tell that these promises were drafted by politicians rather than engineers.

Compressed air energy storage suffers a fatal thermodynamic flaw.

When you compress a gas, the gas heats up. When you decompress the gas, to withdraw energy from your storage unit, the gas sucks heat out of the environment. Ice starts rapidly forming around the decompression system.

Ice is a good heat insulator. This is a big problem, especially in winter, because unless the decompressed air heats up to ambient temperature before it is used to drive a turbine, you lose an unacceptable amount of the energy you tried to store. So you either have to severely limit decompression / energy withdrawal rates, to minimise ice formation, or you have to chip away and physically remove the ice as it forms.

A serious compressed air storage system would produce a lot of ice.

Maybe China has a solution – they have some pretty clever engineers. But in my opinion, compressed air storage is a technology which appeals more to accountants and politicians than to engineers. Looks great on paper, awful in practice.