GE Oil & Gas wants a larger role in the energy storage sector, and to that end has signed a global licensing and collaboration agreement with Highview Power Storage, a UK based supplier of large-scale liquid air energy storage (LAES) systems. Under the agreement the two companies will explore opportunities to integrate Highview’s LAES technology in peaking power plants where GE gas turbines and gas engines are, or will be, installed with the aim of increasing power plant efficiency, grid reliability and the distribution of renewable energy.
Highview’s LAES technology uses liquid air or nitrogen as the storage medium to provide long-duration energy storage that is essentially portable. The technology also can convert low-grade waste heat into power, which provides a further opportunity to increase the overall efficiency of a host power plant.
Since 2011, Highview’s LAES technology has been operating at a grid-connected 350 kW/2.5 MWh pilot plant hosted by Scottish & Southern Energy at the company’s 80 MW Slough Heat and Power biomass plant near London. In February 2014, the UK Department of Energy & Climate Change awarded Highview and Viridor, a U.K. recycling, renewable energy and waste management company, more than £8 million to build a new 5 MW/15 MWh LAES demonstration plant at a Viridor landfill gas-to-energy plant in the UK. The LAES facility will be powered by a GE turbo-generator and shol be able to demonstrate the technology at commercial scale for the first time when it begins operating in the spring of 2015.
With Highview’s LAES process, ambient air is drawn in, cleaned, compressed and then refrigerated. Once liquefied, it is stored in an insulated storage tank at low pressure during off peak demand periods. When power is required, the liquid air is drawn from the tank, pumped to high pressure and sent to a (patented) evaporation and cold recycle unit designed by Highview, in order to capture and then later recycle the cold energy required for the liquefaction process. The regasified air is then heated by waste energy from the exhaust of the gas turbine or engine, and expanded in a multi-stage process gas expander which drives the generator to produce electricity.
The technology is said to be scalable from around 5 MW to significantly greater than 50 MW, but even at this size does not require gas storage on the scale of geological formations.