Geothermal energy is a relatively low-cost and indigenous generation option that can contribute to New Zealand's growing demand for electricity. It is uniquely reliable, with geothermal power stations typically achieving load factors of 95%, compared to typical load factors of 30 - 50% for hydro and wind power stations. The Wairakei power station has operated at a load factor of more than 90% for over 40 years with low operating costs. This inherent reliability makes geothermal generation a valuable component in a diverse electricity supply system such as New Zealand's.