Cryogenic Energy Storage for Renewable Refrigeration and Power Supply

 

cold storage

Image copyrightHIGHVIEWImage captionThe demonstrator cold storage plant works alongside an existing landfill gas generation site

The article claims that the world's largest cold energy storage plant is being commissioned at a site near Manchester. The cryogenic energy facility stores power from renewables or off-peak generation by chilling air into liquid form. When the liquid air warms up it expands and can drive a turbine to make electricity. The 5MW plant near Manchester can power up to 5,000 homes for around three hours. The company behind the scheme, Highview Power Storage, believes that the technology has great potential to be scaled up for long-term use with green energy sources.

 

The article explains that electricity demand varies, influenced by factors like time of day and season. The National Grid is prepared for surges in demand, with power stations on stand-by ready to crank up the power. However, dealing with these peaks and troughs will become increasingly difficult as coal-fired power stations close down and more intermittent renewable energy like wind and solar comes online. In 2015 renewables provided almost a quarter of UK electricity. 

 

Cryogenic storage works by using renewable or off-peak electricity to cool air down to -190 degrees C, which turns it into a liquid. It's then stored in an insulated tank, similar to a large thermos flask. To release the stored energy, the liquid air is exposed to ambient conditions causing it to expand back into a gas. The volume increase is huge, about 700 times, which is used to drive a turbine to generate electricity. Highview Power's demonstrator plant is next to Pilsworth landfill gas generation site. The large insulated tanks sit across the road from a collection of gas engines. These engines burn methane gas produced from decomposing rubbish to generate electricity. The waste heat from this process is captured and used to increase the efficiency of the cryogenic process.

 

Dr Sheridan Few, Research Associate at the Grantham Institute, Imperial College London, described a phenomenon unique to this technology. "There's the storage of the energy, and the generating of the energy. You can make use of waste cold and waste heat... because you're putting both electrical and thermal energy in, the amount of electrical energy you get out, can in some cases end up being more than the electrical energy you put in."

 

A graphic explaining how the cold storage plant works in three stages: 1) Charge: Offpeak or excess electricity is used to power an air liquefier, which produces liquid air. 2) Store: The liquid air is stored in a tank at low pressure. 3) Discharge: To recover power the liquid air is pumped to high pressure, evaporated and heated. The high pressure gas drives a turbine to generate electricity.

Image copyrightHIGHVIEW - How the cold storage plant works in three stages

 

See full article at http://www.bbc.co.uk/news/science-environment-37902773 

This project has received funding from the European Union’s Horizon 2020 Research and Innovation Programme under Grant Agreement No 691761.

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