Blog

Use Earth’s heat, scientists suggest

http://www.iol.co.za/scitech/science/environment/use-earth-s-heat-scientists-suggest-1.1676123

April 15 2014 at 09:29am By Tony Carnie

Unlike conventional geo-thermal technologies that derive energy from volcanic or hydrothermal heat via the Earths molten core, enhanced geothermal energy systems exploit latent heat from the radioactive decay of deep rock formations.

Durban – South Africa should give more serious thought to digging deep underground to tap the buried heat of the Earth to generate more electricity.

This is the suggestion from geology and climate change researchers who suggest significant volumes of renewable power can be generated from using the latent heat of rock to produce steam and electricity.

Writing in the latest issue of the SA Journal of Science, researchers Taufeeq Dhansay, Professor Maarten de Wit and Professor Tony Patt say most early measurements of heat flow in South Africa were taken in the Witwatersrand area, which contains some of the world’s oldest and thickest rock structures.

Because these rock crusts are up to 2.5 million years old and up to 300km deep, early measurements showed relatively low heat flow measurements.

However, more recent measurements taken in other parts of the country, where the Earth’s crustal rocks are younger and thinner, suggest that geothermal energy could be viable using a technology called low-enthalpy enhanced geothermal energy.

Unlike conventional geo-thermal technologies that derive energy from volcanic or hydrothermal heat via the Earth’s molten core, enhanced geothermal energy systems exploit latent heat from the radioactive decay of deep rock formations such as granite.

To harness this energy, tunnels and wells up to 6km deep are dug into the earth so that water can be injected under high pressure and pumped back to the surface after absorbing some of the latent heat.

– The Mercury