Sempra Energy announced on Jan. 2 that it agreed to sell its non-utility U.S. natural gas storage facilities in Mississippi and Alabama to ArcLight Capital Partners for $332 million in cash.

Sempra (NYSE: SRE) said the sale was part of its portfolio optimization plan announced in June.

“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,” said Joseph Householder, Sempra’s president and chief operating officer, in a prepared statement.