It occurred in a project in the eastern Swiss city St. Gallen earlier in July brings a new setback, after earlier accidents.
In 2010, 83 percent of St. Gallen's voters approved a 160 million Swiss francs (172 million dollars) credit for a flagship geothermal project. A geothermal power station was expected to cover the electricity needs of 3,000 to 5,000 households eventually and provide heat for half of the city's buildings. In early July, drilling was concluded up to 4,450 metres depth, and extraction tests prepared.
On Jul. 19 around noon, the engineers' nightmare happened: they unexpectedly encountered gas in the drilling hole, which raised the pressure. The leak was closed and water was pumped into the hole to reduce the pressure. Next morning, St. Gallen was shaken by an earthquake that measured 3.6 on the Richter scale, followed by dozens of micro-earthquakes.
Since then, all eyes are on the city in Switzerland's east. Engineers have managed to stabilize the drilling hole. Further test drilling has been cancelled. Decisions on the project's future will be taken after thorough review. Damage to earthquake-affected buildings and infrastructure was negligible, but the reputation of geothermal energy has suffered considerably.
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