The move stems from an agreement in which Highview and project partner Viridor were awarded government funding by the Department of Energy and Climate Change to build a pre-commercial scale 5MW Liquid Air Energy Storage technology demonstrator. The plant is now undergoing final commissioning.
A LAES facility offers a new way of storing electrical energy, like a battery, but on a grid-scale power plant platform. Electrical energy is created when the daily demand cycle from the grid is not high enough to receive it – with examples including renewables like wind, solar and tidal power that are generated based on the weather, not demand.
A solution then would be to be able to store electrical energy for a few hours when demand is low and release it again when demand, and in some instances the price, is higher. A LAES facility uses a large gas compressor to turn air to a liquid then store it in insulated, pressurised tanks, which keeps it as a liquid. In order to generate power the air is heated and allowed to expand again, the pressure then pushes a gas turbine around to generate power.
Air turns to liquid when refrigerated to -196°C, which is usually achieved by a cycle of compression, cooling and expansion, it can then be stored in conventionally insulated, ambient pressure vessels at very large scale. Exposure to ambient temperatures causes rapid re-gasification and a 700-fold expansion in volume, which is used to drive a turbine and create electricity.
Highview’s technology draws from processes from the turbo-machinery, power generation and industrial gas sectors.
Stuart Nelmes, head of engineering at Highview, said: “The beauty of this system is that each component part of the process is built using tried and tested technology, which we know works and has established performance parameters. The centrifugal fans sourced from Halifax Fan, one of the UK’s leading suppliers, driven by WEG motors, one of the worlds most recognised brands, therefore fitted our remit very closely.
“The LAES system comprises of three primary processes: a charging system, an energy store and a power recovery stage. The energy efficiency of each stage is crucial to the economic viability of the project. Because we have to power the system with the electricity we generate or buy it from the grid the energy efficiency of each component is very important.
“Halifax has developed its centrifugal range to maximise energy efficiency and WEG offers a very energy efficient IE3 motor as standard so this also influenced our decision. Every little helps in this situation.”