When properly developed and managed, geothermal systems are a clean, abundant, and reliable source of renewable energy. Use of geothermal energy for electricity generation or for direct use conserves non-renewable and more polluting resources. Installed geothermal electricity generation capacity world-wide is equivalent to the combustion of nearly 30 million tonnes of coal or the output of about 10 nuclear plants.
Geothermal energy is effectively a renewable resource that does not consume any fuel or produce significant emissions. Although some geothermal fields have been degraded, none have ever been exhausted and sustainable development is possible. Geothermal energy also has the advantage over other renewables that it is independent of climatic variation.
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.
There are geothermal generation opportunities on either side of Auckland (i.e. Northland and the Taupo Volcanic Zone), the principal demand centre for electricity in the North Island. Proximity to Auckland, assuming sufficient transmission capacity, provides an efficient, low-cost electricity supply option. Geothermal fields are also commonly coincident with major forests and their energy-intensive processing industries, allowing symbiotic development of each resource.
An important aspect of recent investment in geothermal projects is the development of partnerships between power generators and Maori trusts. Maori commonly have the land access rights to geothermal fields, and geothermal projects are increasingly delivering economic benefits to local Iwi.