Hot Rocks are a Core Asset (eco-business.com)
New engineering techniques mean that hot rocks in the Earth’s crust are second only to hydroelectric schemes as the most productive source of renewable energy, with huge potential to cut greenhouse gas emissions.
Many countries with volcanoes have long used hot rocks and steam to generate electricity, but new engineering methods promise a boom in geothermal energy.
The deeper you drill into the Earth’s crust, the hotter the rocks get − and the heat that is radiating upwards from the core of the planet is constantly replaced. Japan, Iceland, Italy, New Zealand and the US, among other nations with volcanoes and hot underground water, have long exploited this for generating electricity and heating.
But now engineers have found that they do not need to look for naturally-occurring hot water. They can inject cold liquids into the hot rocks and bring it back to the surface through a second borehole to generate electricity. Unlike other renewables that can be variable, the hot rocks produce constant power 24 hours a day.
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