 The Castaic Power Plant has six reversible 250,000 kilowatt main units and one conventional 55,000 kilowatt auxiliary unit.By comparison the largest generators at Hoover Dam are 130,000 kilowatts.The plant rating is 1,247,000 kilowatts (Nominal installed capacity is higher (over 1,500 MW), however when all main units are operating at full load in generate, they are de-rated by friction losses from the water flow in the Angeles Tunnel).