The investors in US energy storage developer Broad Reach Power have agreed to sell a 50% stake to funds managed by Apollo.

The Apollo Funds will acquire the stake from existing investor EnCap Investments and its co-investment partners Yorktown Partners and Mercuria Energy.

EnCap and its co-investment partners will retain the other 50% stake and, together with the Apollo Funds, commit to invest up to $400m of additional equity to fund Broad Reach’s continued expansion and growth pipeline.

Broad Reach has more than 1.4 gigawatt hours of storage assets in operation or under construction and controls a 21GW portfolio of utility-scale wind, solar and energy storage power projects across the country.

“At Apollo we have been highly active in the energy transition, and we are thrilled to join EnCap in this investment in Broad Reach, which in our view is the premier energy storage leader in the US,” said Geoff Strong, senior partner and co-head of infrastructure and natural resources at Apollo.

“Broad Reach has a scaled, high-performing platform that is well positioned for strong continued growth, particularly as the shift to more intermittent clean energy increases volatility and drives demand for energy storage.”

Corinne Still, principal at Apollo, commented “This transaction unites Apollo with a terrific shareholder group that has demonstrated significant conviction, commitment, and success in building a large and nimble clean energy platform.

“We look forward to collectively supporting Steve and his team in their future growth.”

EnCap has been one of the most aggressive pioneer investors in the fast-growing US battery storage business.

EnCap’s energy transition platform established Broad Reach in 2019 by bringing together professionals with extensive experience in battery storage systems and proven developers with long track records in renewables.

The acquisition by the Apollo Funds will also represent the first sale by EnCap’s $1.2bn Energy Transition Fund I.