Hawaiian Electric Co.'s longtime president and chief executive officer is retiring.

T. Michael May, 61, has headed HECO for the past 13 years and spearheaded many of the company's energy efficiency programs.

He was at the helm in October 2006 when twin earthquakes off the Big Island triggered an O'ahu-wide power outage.

May will relinquish the CEO title on Aug. 1 but will remain in some capacity at HECO until the end of the year to assist in the transition.

"Under Mike's leadership, our utilities have built a strong customer-focused organization, developing innovative customer partnerships and programs," said Constance Lau, chief executive of HECO's parent company, Hawaiian Electric Industries Inc.

News of May's pending retirement comes about a month after HECO's No. 2 executive, former chief operating officer Eric Yeaman, left to become CEO of Hawaiian Telcom Inc.

HECO said it has retained executive recruiting firm Korn Ferry International to search for May's replacement.

According to the company, May will take some time off before pursuing other business opportunities. The company did not provide further details on May's future ventures.

"I am confident the company is now well positioned to meet the challenges of this changing energy market place," May said in a news release.

"I had earlier advised the board of my desire to retire but, as requested, I stayed on to help coordinate strategic planning. Now, after a 36-year business career, the time is right for me to retire."

HECO, the state's largest electric utility, supplies power to nearly 300,000 customers on O'ahu.

May joined the company in 1992 and became HECO's chief executive in 1995.

With May as top executive, HECO increased its use of renewable energy sources and became known for its energy efficiency programs.

In recent years, the company has been able to reduce electrical demand by 152 megawatts, the equivalent of the output of a large power plant.

During the 2006 power outage, a report commissioned by the company gave HECO's management team good marks for their efforts to restore power to customers.

But the report also found that the outage could have been avoided had HECO replaced several decades-old switches with ones better suited for earthquakes.