Exclusive: Short circuit in NMC batteries caused fire at UK BESS project

Gresham House has confirmed that the fire that broke out at its 7 MW/9 MWh battery energy storage system (BESS) project at the former Rufford Colliery in Nottinghamshire, England, was caused by a short circuit of the NMC technology used at the site.

Nottinghamshire Fire & Rescue Service was called at 5:21 am on Friday, 1 May, to attend a fire involving a battery storage container on Colliery Lane in Rainworth. Gresham House confirmed to ESS News that the project owner worked in close partnership with the emergency services and the fire was put out “in short order”. The fire service and Gresham House confirmed there were no injuries, and all site staff were safe and accounted for, according to the project owner.

In a statement, Gresham House said: “The safety of site staff and local residents is always our utmost priority.  Following an initial investigation, we have identified that the cause was due to a short circuit of the NMC technology that this site operates.

“This technology, which accounts for less than 4.03% of the portfolio and is not adopted by any BESS purchases by GRID since 2020, is already in the process of being augmented as part of the strategy’s ongoing commitment to best practice and fiduciary duty.”

The Gresham House Energy Storage Fund (GRID) is the United Kingdom’s largest fund investing in utility-scale BESS. GRID acquired Rufford BESS in 2018, shortly after it entered commercial operations in December 2017.

At a capacity of 9 MWh, Rufford represents less than 0.5% of GRID’s installed capacity of 1.7 GWh and the fund.

ESS News understands GRID is in the process of augmenting its NMC technology sites. The process was due to start at Rufford on May 5, just four days after the fire, according to GRID. The project owner confirmed augmentation work will commence on May 18 “to ensure adherence to the highest safety standards.”

“We will continue to accelerate this augmentation process to ensure that we continue to futureproof the strategy in the best interest of local communities and our investors,” the fund said.