Officials from the Department of Energy and Climate Change visited a “world first” liquid-air energy pilot plant adjacent to a biomass power station in west London earlier this month, it has emerged.
The representatives from DECC were there to see a technology in action that had been supported by a £1.1 million government grant, Highview Power Storage, its developer, said. The system uses liquid air to store power at times when demand is low. Highview claims the technology could offer the solution to storing excess energy from renewables such as offshore wind at off-peak times.
The system in Slough operates by using excess electrical energy to drive an air liquefier. The liquid air is stored in an insulated tank at low pressure, which functions as the energy store. When power is required, liquid air is drawn from the tank and pumped to high pressure. Ambient 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 generator.
Typically, pumped hydro, a gravitational method of storing energy in the form of water, makes up 99% of the world’s energy storage capacity, as in Dinorwig in Snowdonia, Highview said. The company added: “However, pumped hydro is not a perfect technology; [it has] limited geological suitability in that is requires mountains and is not always near the point of demand; and it requires millions of litres of water.”
Highview said: “But critically, liquid air can easily be stored in the same low pressure tanks as used by the LNG industry – it is hundreds of times more energy dense than water, therefore taking up far less space, and the process does not need large mountains or lakes.”
Toby Peters, Highview Power Storage chief operating officer, said: “Whereas many companies were focusing on fast response but relatively small scale battery technologies, we started out five years ago to develop a system which could deliver affordable long duration, large-scale energy storage.
“We identified this as the big gap in the market and today we are now seeing urgent demand for a large-scale solution which can be deployed where pumped hydro is not available.”
The market for such technologies in Europe could be worth €500 billion by 2030. National Grid has reportedly forecast British reserve capacity to grow from 3.5GW to 8GW by 2020. Highview Power Storage is using the pilot plant in Slough to prove the viability of its technology but said it was also in discussions with potential partners in the UK over building a “multi megawatt” plant. It emphasises that components required to develop such systems already exist so there will be no need to create new factories.
The company said: “[We do] not intend to be a manufacturer of the technology but a developer and application engineer, designing the units for specific market applications and marshalling the supply chain arrangements to ensure delivery of products to customers to the right specification at the right time.”
The biomass plant to which Highview’s technology is co-located is run by Scottish and Southern Energy.