The state’s Public Utilities Commission chairwoman, Hermina "Mina" Morita, resigned from her position Monday.

Gov. David Ige said Morita has been instrumental in the state’s transition to alternative energy.

"For almost two decades Mina has been the acknowledged leader in the state’s efforts to reduce dependency on imported oil and to develop local, renewable and clean energy resources," Ige said when he learned Morita would not seek reappointment. "Mina has been the driving force, both at the Legislature, where she made her mark as the House Energy Committee chair, and at the PUC, behind the policies that have positioned Hawaii as a national leader in clean energy. She has dedicated her life to creating a better environment and more sustainable communities. I thank Mina for her work. She embodies the values that make Hawaii a special place."

Morita’s resignation is not immediate, but has been left open to facilitate a transition for her successor, said Cindy McMillan, communications director for the Governor’s Office.

"The transition team is actively seeking someone to fill this position," McMillan said.

Morita, who did not respond to questions about why she resigned, said she made as much progress as she could considering the unstable state of the energy sector.

"Although I am very proud of my accomplishments in the energy sector, including building public confidence in the mission and capacity of the PUC, I have done what I could in the unstable environment of the last year," Morita said in a statement. "At this juncture, Gov. Ige will now have the opportunity to appoint a new chair and take into account the knowledge and experience needed to carefully review the HEI (Hawaiian Electric Industries) acquisition, amongst other matters. I know Gov. Ige will be guided by his core value — kina­‘ole — doing the right thing for the reasons and in the right way when making this important appointment."

Morita’s resignation comes during an important time for Hawaii energy.

Two major decisions are pending PUC approval, while the commission remains understaffed.

Hawaiian Electric Co., the state’s largest electric utility, submitted its action plans for the future of Hawaii’s energy mix to the PUC in August. The proposal was submitted after the PUC, under Morita’s leadership, issued four rulings in April ordering HECO and its subsidiaries, which together provide service to Oahu, Maui and Hawaii island, to reduce electricity costs and accommodate greater amounts of renewable energy.

In December, Juno Beach, Fla.-based NextEra Energy announced it plans to buy HEI in a $4.3 billion deal. The deal requires approval from state and federal regulators, the PUC being one of them, in addition to shareholders. The deal is expected to be completed within the next 12 months, with a vote open to HEI shareholders planned for this spring.

HEI declined to comment on Morita’s resignation.

Morita was appointed by Gov. Neil Abercrombie to head the PUC in 2011. After her term ended June 30, Abercrombie kept Morita as chairwoman on a "holdover basis."

Morita served as a state representative before leading the PUC. During her seven terms as a state representative, Morita was intrustmental in passing major energy legislation.