Compressors for world’s first liquid air energy storage plant
5 Sep 2011
Slough, UK – Atlas Copco compressors are being employed in a new cryogenic process developed by Highview Power Storage to store off-peak electric energy by liquefying air.
Using off-peak electricity, the Highview CryoEnergy System pilot plant operates by extracting ambient air from the surrounding environment: the gas is cleaned, compressed by Atlas Copco compressors, and then cooled until the air undergoes a phase change to a liquid. The liquefied air is stored in an insulated tank at a temperature of ?196° C.
When power is required, liquid air is drawn from the tank and pumped to high pressure. Ambient, or above ambient, waste heat is applied to the liquid air via heat exchangers, resulting in a phase change from liquid air to a high pressure gas which is then used to drive a turbine and power generator. The liquefaction stage is accomplished by integrating Atlas Copco compressors within Highview’s 300kW/2.5MWh CryoEnergy system.
An integrated, oil-free ZR 700 VSD water-cooled screw compressor, with specially modified inlet pipework, operates within the recirculation system while the main air feed for the liquefaction plant is supplied by a ZR 250 VSD rotary screw compressor. The Atlas Copco installation is completed with a low-pressure ZS45+ VSD blower.
“The screw compressors supplied by Atlas Copco offered the best compromise in price, performance and delivery,” said Rob Morgan CTO, Highview Power Storage.
Highview’s CryoEnergy System pilot plant, hosted by Scottish and Southern Energy’s Slough Heat and Power plant, UK, uses commercially available components that have proven performances and life times. Utility-scale energy storage has become big business with an estimated £365billion market forecasted over the next 10 years.
Highview plans to scale up the system to a 10MW/40MWhs commercial demonstrator: “As we scale up the technology, we will … be discussing with Atlas Copco how their own advanced compressor technology can support our projects in the future,” said Morgan.
