Whatever Happened to Geothermal Energy?

The world's greatest source of power lies a few miles under our feet. Geothermal energy, which draws on the heat from the Earth's interior, could supply the present global energy demand for more than 30,000 years.

The trick is tapping into it. Geothermal energy accounts for less than a half-percent of global energy consumption, according to the International Energy Association.

Most of the active geothermal plants are located in volcanically active places, like Iceland, where the Earth's outer crust is thin.

"Conventional geothermal has limited use because the required geology is not found everywhere," said geophysicist Roy Baria of the company Mil-Tech UK LTD.

Baria and others are engineering non-conventional places where the heat is farther down and there is no room for water to flow. These geological enhancements can have their drawbacks: One project in Switzerland was shut down earlier this year due to induced earthquakes.


Hot-button issue

A typical geothermal plant captures steam escaping from underground and uses it to turn turbine blades that generate electricity. The first such power plant began in Italy in 1904 and continues to work to this day.

Considered a green technology, geothermal does raise environmental concerns. In certain cases, steam extraction can allow other gases, like carbon dioxide (CO2), to escape. However, the amount of CO2 released per kilowatt-hour of electricity is only a few percent that of coal-fired power plants.


Source: http://www.livescience.com/environment/071204-geothermal-energy.html