New Scientist: It’s been a difficult week for geothermal power. A US firm scuttled its plans to tap heat locked in northern California, The New York Times reports. A day earlier, Associated Press reports, concerns about setting off earthquakes prompted the cancellation of a Swiss geothermal project linked to small tremors in Basel in 2006 and 2007. Such plants work by pumping water into hot rocks several kilometres down, forcing small cracks in the rock to expand. Steam escapes through the …