Nine developers have selected Invinity’s Endurium batteries for their project bids in the UK’s long-duration energy storage (LDES) cap and floor scheme.
The first application window for the scheme closed on 9 June and the energy storage developers’ bids are now being reviewed by Ofgem to confirm their eligibility.
The aim of the investment support scheme is to accelerate the development of LDES projects for the first time in 40 years.
Invinity said it was “highly encouraged” by the number of UK developers planning to use its new Endurium batteries in their project bids.
The company said the product, released in the fourth quarter of 2024, was developed with the LDES cap and floor scheme in mind.
The batteries are each at or above the minimum 400MWh in size.
Invinity said certain developers have proposed to use Endurium for multiple projects. These include Invinity’s partner Frontier Power, which has selected Endurium batteries for approximately half of its project bid portfolio.
Invinity chief executive Jonathan Marren said: “Since this LDES scheme was first launched, the Invinity team has been engaging closely with numerous developers to submit high-quality bids ahead of the deadline.
“We are delighted with the positive feedback that we have received from our partners, with significant quantities of our UK-made vanadium flow batteries being proposed for this important scheme as a result.
“Should these bids be successful, we believe the build-out of our Endurium batteries across the country will not only help to lower energy costs for consumers but also help to provide wider economic benefits across the UK as we scale our operations.”
After eligibility is confirmed by Ofgem, the bids will move to the final assessment phase which is expected to conclude in the first half of 2026.
Successful bids are expected to generate orders for delivery between 2028 and 2030.
The cap and floor regime provides a minimum revenue floor for LDES operators to manage high capital costs and long build times, while the revenue cap lowers costs for consumers. The government introduced the scheme to encourage LDES investment and appointed Ofgem as the regulator.


