An affiliate of private equity heavyweight ArcLight Capital Partners LLC agreed to buy a Sempra Energy subsidiary's nearly 43 Bcf of nonutility U.S. natural gas storage assets for $332 million in cash.

The facilities included in the agreement, announced Jan. 2, are the Mississippi Hub storage facility in Simpson County, Miss., which can hold 22.3 Bcf of gas, and the Bay Gas storage facility in southwestern Alabama, which has a 20.4-Bcf capacity.

"Completing this sale, along with the recently announced sale of our non-utility U.S. solar assets, enables us to reallocate capital to further strengthen our balance sheet and support Sempra Energy's future growth opportunities," Sempra President and COO Joseph Householder said in a statement.

Sempra closed the sale of its renewable project portfolio to Consolidated Edison Inc. for $1.6 billion in December 2018.

The sale of the nonutility natural gas assets to ArcLight is expected to be completed later in the first quarter.

Wells Fargo Securities LLC served as Sempra's financial adviser for the transaction, and Jones Day acted as the company's legal adviser.