Regulators have approved Maui Electric Co.’s plan to buy electricity from the second phase of First Wind’s wind farm on a ridge above Maalaea.

The expansion adds 21 megawatts of generating capacity to the 30 megawatts currently produced at the Kaheawa Wind Farm.

The structure of the power purchase agreement reduces the rate MECO pays for the electricity as the amount it buys increases. MECO did not disclose the actual price it will pay because it is in negotiations to buy power from with another wind farm operator on the island.

With the expansion the number of wind turbines at Kaheawa expands to 34 from 20. The second phase also includes a 10 megawatt battery storage system that will help smooth out fluctuations in output associated with wind power.