Contact Energy chief executive Dennis Barnes is to leave the business early next year.
Barnes joined Contact from former parent company Origin Energy in April 2011.
During his tenure, the firm reworked its Wairakei geothermal field, including commissioning a bioreactor to reduce discharges into the Waikato River and constructing its new Te Mihi power station there.
At the same time, the firm optimised the Ahuroa gas storage facility and Stratford peakers, shut the Otahuhu B power station in Auckland and re-established itself as a stand-alone business when Origin sold out in 2015. Throughout that period it also significantly restructured its retail activities, including testing bundled offers with broadband, and has repositioned its commercial and industrial business to help businesses reduce their emissions.
Barnes says 2019 will be his last full year in the role.