07:37 AM EDT, 04/24/2024 (MT Newswires) -- TransAlta Corporation ( TAC ) on Wednesday announced that the combined 300 MW White Rock East and White Rock West wind facilities in Oklahoma began commercial electricity production, boosting the company's portfolio in the U.S. to 820 MW in net operating renewable energy capacity.

TransAlta ( TAC ) shares dropped 4.9% in pre-market trading in New York.

The White Rock wind facilities, which are in Caddo County and supply electricity to Amazon Energy, has 51 Vestas wind turbines and is the first of the company's two wind projects in Oklahoma to achieve commercial operations. On Feb. 22, the company entered into a 10-year transfer agreement with an AA- rated customer for the sale of approximately 80 per cent of the expected production tax credits (PTC) to be generated from the White Rock wind facilities.

"We are also pleased to announce our first long-term contract to supply production tax credits to a taxable counterparty in the U.S.," said John Kousinioris, TransAlta's ( TAC ) president and chief executive, said in a statement. "We have secured favourable pricing on approximately 80% of the expected generation of PTCs, which will provide another stream of contracted revenue that secures long-term cash flows from White Rock and further diversifies the contracted cash flows from our renewable portfolio."

The remaining PTCs are expected to be sold through spot transactions or contracted at a later date.