THREE cutting-edge businesses are set to benefit from a share of £30m (US$37m) in funding from the government as part of plans to develop technologies that will store renewable energy for later use.
Storing energy will be crucial as countries push towards using cheap, clean, renewable energy. According to a study by McKinsey, long duration energy storage (LDES) has the potential to deploy 1.5 to 2.5 TW of power capacity by 2040 while helping 1.5 to 2.3bn t/y of CO2 equivalent from reaching the atmosphere. However, to supply enough LDES facilities to reach renewable targets will require significant reductions in the cost of LDES technologies – a scenario that could be achieved with the help of government support, McKinsey said.
First launched in June 2021, the Longer Duration Energy Storage Demonstration (LODES) competition is designed to do just that. The £69m initiative is one of ten key priority areas within the government’s £1bn Net Zero Innovation Portfolio, and it has already awarded £6.7m to projects during phase 1 of the process.
The competition is designed to cover three key energy storage technology categories capable of providing longer duration storage capability and flexibility services to the electricity grid. These include electric, thermal, and power-to-X – an umbrella term referring to technologies which convert electricity into a fuel storage medium (e.g. hydrogen, ammonia, biomethane).
Now in phase 2, the winning projects that will go on to fully deploy and demonstrate their technology are: Cheesecake Energy (CEL) based in Nottingham; Synchrostor in Edinburgh, Scotland; and Invinity Energy in Scotland.
The Cheesecake FlexiTanker
Recipients of £9.4m to test their FlexiTanker technology, CEL plans to install energy storage systems in a new mixed-use development in Colchester, which is being set up as a microgrid to manage local grid constraints.
The site will have a solar farm of up to 8MW and a central heat pump that will store excess electricity generated by solar power.
FlexiTanker uses electricity to charge the system by powering an electric motor to drive an air compressor – a process that creates high pressure air, and a lot of heat. The generated heat is then captured and stored separately in a thermal store, alongside the high-pressure compressed air held in an air tank, which by now has been cooled to ambient temperature The battery is then discharged by running the process in reverse, using the heat in the thermal store to re-heat the high-pressure air, e, and expanding it through the expanders. This in turn drives a generator at constant speed, creating high quality AC electricity.
CEL’s system can supply full power for up to 20 hours for more than 25 years. This is at a fraction of the cost of lithium ion storage over a 5–10 year lifetime and, unlike lithium-ion, FlexiTanker can be fully recycled, with the lowest lifetime environmental footprint, the firm said.
Synchronous solutions
Meanwhile, in Edinburgh, Synchrostor will receive £9.4m to build a 1 MW pumped thermal energy storage (PTES) demonstration plant that will be connected to the grid.
Synchrostor says its PTES is based on a high-pressure, positive-displacement, multi-cylinder ‘compressor-expander’ machine. In the charging cycle, the system uses electricity to run the compressor, raising the pressure and temperature of an operating gas.
Thermal storage material is heated by the gas in a heat exchanger and the material can be stored in an insulated storage silo at atmospheric pressure. The gas leaves the heat-exchanger and enters the expander where it drops in pressure and in temperature.
A second heat exchanger allows the cold gas from the expander to cool another flow of storage material. The very cold material then leaves the heat exchanger and is sent to a cold storage silo. The gas then returns to the compressor and the cycle continues until the full storage depth has been met or the operator chooses to only partially charge the system, Synchrostor explains.
Then, in the discharging cycle, everything reverses: the gas and the material flows change in direction, the compressor becomes an expander, the expander becomes a compressor, and the electric motor becomes a generator to return energy to the grid.
The system has very little energy loss when charged, and it should last for about 20 years, the firm added.
New take on old tech
Invinity Energy will receive £11m to develop and manufacture their 7MW, 30MWh 4-hour vanadium flow battery (VFB), “the largest grid-scale battery ever manufactured in the UK”, the firm claims.
Along with being a proven, decades-old storage technology, flow batteries exhibit far greater capacity retention and less performance degradation over time than lithium-ion batteries. They are also safer than lithium-ion batteries as they cannot catch fire, more durable as they do not degrade with use, and more than 97% recyclable at the end of their 25+ year life, Invinity said.
Dubbed VFB LEAD (Vanadium Flow Battery Longer Duration Energy Asset Demonstrator), the project will see a 30 MWh Invinity VFB system deployed at a key node on the National Grid, the location of which has yet to be confirmed. The battery, which will be capable of delivering more than 7 MW of power on demand, will use the fast-response and high-throughput characteristics of Invinity’s battery technology to provide a broad range of services to the grid.
“With a capacity equivalent to the daily energy use of more than 3,500 homes, this battery will be the largest ever to be manufactured in the UK. Approximately six times larger than Invinity’s battery system at the Energy Superhub Oxford, it will also be one of the world’s largest flow batteries. Furthermore, with the ability to deliver full power for a discharge duration of over 4 hours, it is expected to be the largest long duration battery asset connected to the UK grid,” Invinity said.
