Researchers from the University of Geneva have studied the seismic activity recorded during the drilling of a geothermal well and shown that it did not spark any major earthquake.
Although stopping climate change is challenging, it is imperative to slow it down as soon as possible by reducing greenhouse gas emissions. But how can we meet the growing energy demand while reducing our use of polluting fossil fuels? Geothermal energy is an efficient, non-polluting solution but in certain cases geothermal operations must be handled with care. Reaching the most powerful sources of available energy means drilling deep into the layers of the earth’s crust to find geothermal fluids with high energy content (hot water and gas released by magma). Yet, the deeper we drill the greater are the subsurface unknowns controlling the stability of the Earth’s crust. Destabilising the precarious equilibrium at depth with geothermal wells may reactivate the geological layers causing earthquakes. Researchers at the University of Geneva (UNIGE), Switzerland, working in collaboration with the University of Florence and the National Research Council (CNR) in Italy, have studied the seismic activity linked to a geothermal drilling in search of supercritical fluids. They discovered that the drilling did not cause uncontrolled seismic activity. This drilling under such critical conditions suggests that the technology is on the verge of mastering geothermal energy, paving the way for new sources of non-polluting heat and electricity. You can read all about the results in the Journal of Geophysical Research.
The scientific community agrees that CO2 emissions need to drop by 45% by 2030 and that 70% of our energy must be renewable by 2050. But how can these targets be met? Geothermal power – a renewable form of energy – is part of the solution. A number of countries, including Switzerland, are already exploiting geothermal energy to produce heat from shallow wells. Until 1,500 metres such technology normally presents little risk. “To generate electricity, however, we have to drill deeper, which is both a technological and a scientific challenge”, points out Matteo Lupi, a professor in the Department of Earth Sciences in UNIGE’s Faculty of Science. In fact, drilling deeper than 1,500 metres requires special care because the unknown factors relating to the subsurface increase. “Below these depths, the stability of the drilling site is more and more difficult and poor decisions could trigger an earthquake.”
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