SWISS CITY’S GEOTHERMAL PLAN IN DOUBT AFTER TREMORS
01.11.07 - Leído 93 veces. Enviar esta notaEfforts to tap energy deep below the earth’s crust to provide power for homes in the Swiss city of Basel may have to be scrapped after setting off tremors
BASEL, Switzerland; January 10, 2007.- The plan to use geothermal energy to generate electricity for 10,000 homes and heat for 2,700 others is on hold after it caused earth tremors twice in less than a month, prompting frightened residents to flood emergency services with calls.
“We had expected the experiment to cause minor tremors. But so far we do not know in detail why the quakes were bigger than expected,” said Stefan Wiemer of the Swiss Seismological Service.
In the Swiss model, geothermal energy is generated through high-pressure injection of water into hot granite at a depth of 5,000 metres. This produces steam used to drive turbines.
A firm working on the US$67 million project has handed a report to the city government and is waiting for a decision on its future.
A first quake in early December lasted 20 seconds and registered 3.4 on the Richter scale. Water pumped into the depths set off a second, slightly weaker quake on Saturday.
Basel, a seismic region, was almost completely destroyed by an earthquake in 1356. Small tremors, often barely perceptible, are common.
Experts say the deeper water is pumped below the earth’s surface the harder it is to predict whether it will set off stronger tremors.
(Reuters)
