MNN Galleries

10 surprisingly easy sources of alternative energy

Nov. 30, 2009, 11:27 a.m.
Hot Rock Power

Photo: Australian National University

7 of 12

Hot rock power

Hot rock power is a new type of geothermal power that works by pumping cold saltwater down to rock which has been heated by conduction from the Earth’s mantle and by the decay of radioactive elements in the crust. As that water heats up, the energy created can be converted into electricity by a steam turbine. The advantages of hot rock power are that the output can be easily controlled and it can provide energy 24/7.