Patrick Strange has resigned as Transpower's chief executive to pursue other interests.
Dr Strange has been in charge of the national power grid since 2007.
Transpower chairman Mark Verbiest said on Thursday that Dr Strange has successfully led the company through its major capital investment programme, including the construction of the transmission line through the central North Island.
Transpower is in the process of completing its major transmission programme and Dr Strange will continue as chief executive until early 2014.
Mr Verbiest says Dr Strange has led Transpower through a very challenging period.
