It might not have been a great idea to try out a new approach to geothermal energy on a fault line. The AP reports that a utility in Switzerland that drilled wells to access hot rocks deep underground has had to shut down operations after it triggered earthquakes.

Ordinarily, geothermal energy relies on geologic formations that bring heat from deep below the earth near the surface. But research suggests that these geothermal sources barely scratch the surface of geothermal potential. (See this year's MIT report on the subject.) If engineers employ technology now used by the oil industry to drill down to hot rocks and then fracture the rocks to allow water to percolate through them, they could potentially access enough energy to supply thousands of times the United States' annual energy demand. (See also "Tapping Rocks for Power.")

Many energy companies are interested in the technology--but they're waiting to invest, wary that it might not prove practical. Ill-advised projects like the one in Switzerland won't reassure them. The engineers there expected rock slippage, the AP reports, but went ahead with the drilling anyway.

But engineered geothermal energy has another chance, according to the AP story. Now that the Swiss project is cooling off, another one, in Australia, in a more geologically stable area, has taken the lead. If that one proves successful, geothermal could be on its way to becoming a major source of world energy.