The Otahuhu power station site holds two plants; Otahuhu A (open cycle gas turbines, now synchronous compensation) and Otahuhu B (a 404 MW combined cycle). The station is owned and operated by Contact Energy. The first generating units at Otahuhu were open cycle gas turbine Stal-Laval units, commissioned in 1968. In 1978, a further two generating units were added, twin pack units using Rolls Royce Olympus gas turbines. Due to the age of these gas turbines, they have been retired from service. The generators remain in use in synchronous compensate duty, providing reactive power to the grid.