Geothermal energy is the heat from the Earth. Resources of geothermal energy range from the shallow ground to hot water and hot rock found a few miles beneath the Earth's surface, and down even deeper to the extremely high temperatures of molten rock called magma.
Geothermal power is cost effective, reliable, sustainable, and environmentally friendly but has historically been limited to areas near tectonic plate boundaries. Recent technological advances have dramatically expanded the range and size of viable resources, especially for applications such as home heating, opening a potential for widespread exploitation. Geothermal wells release greenhouse gases trapped in the earth, but these emissions are much lower than those of fossil fuels. Geothermal power has the potential to help mitigate global warming if widely deployed in place of fossil fuels.
The Earth's geothermal resources are theoretically more than adequate to supply humanity's energy needs, but only a very small fraction may be profitably exploited. Drilling and exploration for deep resources is very expensive.
It has been shown that customers would be willing to pay a little more for a renewable energy source like geothermal. But as a result of government assisted research and industry experience, the cost of generating geothermal power has decreased by 25% over the past two decades.
New Zealand has an abundant supply of geothermal resources both on the North and South Island with high temperature resources primarily centered on the Taupo Volcanic Zone and Ngawha in Northland. New Zealand was one of the first countries in the world to develop large-scale geothermal electricity generation in the 1950s. Geothermal energy is currently our second-most used fuel for renewable electricity generation, after hydro, supplying over 14% of our electricity in 2012. There is also significant potential for expansion of geothermal energy in New Zealand.