Energy storage technology developer Isentropic has won £14 million (US$22 million) in project funding and equity investment from the UK’s Energy Technologies Institute (ETI) to build its Pumped Heat Electricity Storage (PHES) system.
The ETI support will allow Isentropic to build a full-scale, grid-connected demonstrator of its PHES device. Isentropic will use the funds to develop and deploy a 1.5MW/6MWh electricity storage unit on a UK primary substation owned by Western Power Distribution in the Midlands region.
The ETI, a partnership between the UK Government and six leading international energy and energy technology companies, has previously commissioned 36 renewable and low carbon projects worth £138 million. However, this is the first time it has made an equity investment in any of the companies it has funded.
Dr David Clarke, ETI Chief Executive, says: “Our investment strategy here is two-fold. Firstly we are providing financial support to allow the company to develop this technology further and staff up accordingly. Secondly we are using our position to expand the testing of this new UK technology to seek to identify the large-scale deployment potential to help provide affordable clean and secure energy solutions for the future.”
Isentropic says its PHES technology offers the prospect of being the lowest cost solution to the intermittency problems of renewable energy sources, such as wind. The technology is environmentally friendly, has no geographical constraints, is compact and can demonstrate a round trip efficiency of 75%. It could be rolled out to some 5 000 substations across the UK, it says.
The PHES is made up of two gravel-filled, steel “silos” that store and release energy using argon gas circulated by an electric motor. The gas is compressed in one insulated silo to reach 500°C, before being pumped into the other unit where it cools as its heat is slowly absorbed by the gravel.
The argon is then expanded back to its original pressure, which brings its temperature down to about 160°C, and pumped back into the first silo, where it is reheated by the gravel. Once the store is saturated, the cycle can be reversed to release the energy from the gravel to drive an electrical generator – making the system a kind of Brayton-cycle heat-engine.