ESA's Gravity field and steady-state Ocean Circulation Explorer (GOCE) satellite might have burned up in Earth's atmosphere back in November 2013, but the wealth of data gathered by the probe before its demise is still being utilized to great effect. A team of scientists has used the readings to produce an online tool designed to make it easier than ever to locate potential geothermal energy extraction sites.

Launched on March 17, 2009, the GOCE was the first Earth Explorer mission satellite to reach orbit. The mission studied the variations in the force of gravity on the surface of the Earth, brought about by both the rotation of the planet and the position of geological features such as mountain ranges and ocean trenches. Over its four and a half year lifespan, the satellite mapped variations in the gravity field with great accuracy and detail.

The recorded data is now making possible a new tool, created by a team of scientists from the International Renewable Energy Agency (IRENA) and the European Space Agency (ESA), that it is hoped will help mankind better harness a form of subsurface heat known as geothermal energy. Originating from sources such as magma and hot springs, the energy can be harnessed as a sustainable resource, but the locating, exploring and measuring of the underground sites can be problematic and expensive.

Using gravity measurements recorded as part of the GOCE mission, the online tool consists of two informative maps that combine to depict characteristics unique to geothermal reservoirs, making it easier to identify target areas with high geothermal potential.

A "free air" gravity map details geological structures, while a "Bouguer" gravity anomaly map combines GOCE data with global topography information, showing difference in crustal thickness. The tool is thus able to highlight certain areas, such as those where the Earth's crust is thinnest or where young magmatic activity is present, helping to narrow the search for geothermal reservoirs.

While the tool doesn't eliminate the need for detailed seismic measurements and ground surveys, it does help inform exactly where those tests should be conducted.

"These maps can help make a strong business case for geothermal development where none existed before," said Hennin Wuester, Director of IRENA's Knowledge, Policy and Finance Center. "In doing so, the tool provides a shortcut for lengthy and costly explorations and unlocks the potential of geothermal energy as a reliable and clean contribution to the world's energy mix."

Geothermal energy is a huge, largely untapped resource. It's hoped that the new tool, which wouldn't have been possible without the data from the GOCE mission, will encourage its exploitation.

Source: ESA

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