German geothermal project leads to second thoughts after the earth rumbles
Landau in der Pfalz, Germany - Government officials here are reviewing the safety of a geothermal energy project that scientists say set off an earthquake in mid-August, shaking buildings and frightening many residents of this small city.
The geothermal plant, built by Geox, a German energy company, extracts heat by drilling deep into the earth. Advocates of the method say that it could greatly reduce the world's dependence on fossil fuels by providing a vast supply of renewable energy.
But in recent months, two similar projects have stirred concerns about their safety and their propensity to cause earthquakes. In the United States, the Energy Dept is scrutinizing a project in Nthn California run by AltaRock Energy to determine if it is safe. (The project was shut down by the company last month because of crippling technical problems.) Another project, in Basel, Switzerland, was shut down after it generated earthquakes in 2006 and 2007 and is awaiting the decision of a panel of experts about whether it can resume.
... Geox officials initially denied any responsibility for the temblor and continue to dispute the government's data linking the project to the quake. The panel will, among other things, have to sort through the conflicting data presented by the company and government scientists.
"My concern is that the project leaders for different geothermal projects are about to waste public confidence as long as they don't talk openly about the seismic risks involved in their projects." said Rudolf Braun, who is the leader of the Basel study ...
Like other earthquakes that have been attributed to geothermal plants, the Landau temblor was sudden and brief and was accompanied by a sound that in some cases has been likened to a sonic boom.
... in May, the state Geological Survey for Rhineland-Palatinate, the state where Landau is located, concluded that four minor earthquakes, too small to be felt by residents, had been generated by the project.
... The epicenter was roughly 500 yards from a drill site at the plant and at about the same depth - 1.5 miles - as a steam bed that the plant was extracting heat from.
... "At this point we can neither deny nor confirm" that the power plant had anything to do with the earthquake, said Peter Hauffe, managing director of Geox.