There are three principle types of geothermal resource. The simplest to exploit is a source of hot underground water which either reaches the surface naturally or can be tapped by drilling boreholes. Where there is no underground water source, anomalies in the crust can create regions where the rock close to the surface is much hotter than usual. This hot rock can be accessed by drilling and though it is not practical to exploit the heat today, experimental work may make its use possible in the future. The third, and richest source, is the magma itself. This contains by far the greatest amount of heat energy but because of the temperatures and pressures found within it, this is also the most difficult geothermal energy source to exploit.
Estimating the amount of energy in the crust of the earth that could be exploited for power generation is not easy. It has been suggested that there is between 10 and 100 times as much heat energy available for power generation as there is energy recoverable from uranium and thorium in nuclear reactors. Certainly, the resource is enormous.
Was this article helpful?
The solar Stirling engine is progressively becoming a viable alternative to solar panels for its higher efficiency. Stirling engines might be the best way to harvest the power provided by the sun. This is an easy-to-understand explanation of how Stirling engines work, the different types, and why they are more efficient than steam engines.