Long-duration energy storage demos awarded £30m

Three energy storage projects, including what will be the longest duration battery system connected to the UK grid, have been awarded £30 million of government grants.

The projects are the latest to receive funding as part of the government’s Longer Duration Energy Storage Demonstration programme, which has so far handed out more than £69 million for the demonstration of innovative technologies that are able to store energy over days, weeks and even months.

The programme is split into two streams, each with two phases. The first stream covers demonstrations of more developed technologies in operational environments, whilst the second covers prototypes of less developed technologies.

The £30 million of funding announced by the Department for Energy Security and Net Zero on Wednesday (12 April) was awarded as part of the second phases for the building and commissioning of projects. It comes in addition to the £33 million of phase two grants allocated to five projects in November.

The first phases provided funding for preparatory work such as design, development and feasibility studies.

The biggest award made on Tuesday was to Invinity Energy System, which will receive £11 million for its stream one project to install the UK’s largest vanadium flow battery at a key node on the transmission network that has yet to be confirmed.

With a maximum power output of 7MW and a storage capacity of 30MWh, the battery will be capable of discharging at full power for more than four hours, making it the longest duration battery system connected to the UK grid. It will be roughly six times the size of the battery system Invinity has deployed at the Energy Superhub in Oxford.

The battery will be manufactured at Invinity’s factory in West Lothian, Scotland.

The two other projects have been awarded funding through the second stream of the programme.

Synchrostor has been allocated £9.4 million to build a grid-connected, megawatt-scale demonstration plant for its pumped thermal energy storage system.

To store energy, electricity is used to run a motor, which is connected to a compressor on one side and an expander on the other. The compressor raises the pressure and temperature of a gas, which is then passed through a heat exchanger. The heat is transferred to a hot store containing a low-cost, non-toxic and sustainable material.

The gas then travels into the expander, lowering its pressure and temperature, and then into another heat exchanger where it is used to cool a cold store. It then returns to the compressor to repeat the cycle.

To release energy, the process is reversed, with the compressor becoming an expander, the expander becoming a compressor, and the motor becoming a generator.

The company said process is reversible within tens of milliseconds, making the system highly responsive. It said the system is also able to achieve high round-trip efficiency using innovative heat pump and heat exchanger technology, and has a small footprint with no geographical restrictions.

The demonstration plant is expected to have a discharge duration of more than 10 hours.

Lastly, Cheesecake Energy has received £9.4 million to test its FlexiTanker technology, which utilises a similar compression and expansion cycle but stores energy as compressed air as well as heat.

The technology will initially be demonstrated at the company’s site in Nottingham, before pilot units are installed at two sites within a microgrid development in Colchester in Essex.

Announcing the awards, energy minister Graham Stuart said: “Storing energy for longer periods is vital to build a robust and secure energy system and ensure that renewable energy is used efficiently. Fortunately, the UK has a wealth of pioneering businesses that are making their mark on this industry.

“Today we’re backing three UK businesses to make their projects a reality, which will go on to play a role in our country’s energy security.”