Krafla is one of Iceland's most active volcanoes. Image: Shutterstock
Scientists drilling in the Krafla volcano in Iceland discovered a source of energy they weren’t expecting.
Geologists from the University of California Riverside got a unique opportunity to study magma when it appeared unexpectedly in the lower 9 kilometres of an exploratory geothermal well they were drilling. The molten rock flowed into the well 2.1 kilometres from the surface, forcing the scientists to abandon the drilling.
The aim had been to drill a geothermal well 4.5 kilometres deep, but their efforts hadn’t been in vain. The leader of the team, Wilfred Elders says in the press release “While the magma flow interrupted our project, it gave us a unique opportunity to study the magma and test a very hot geothermal system as an energy source.”
In Iceland, 95 percent of home heating and one third of the electricity is produced from hot water and steam that naturally occur in volcanic rocks. Elders explains the ability to generate electric power from geothermal steam improves the higher the temperature and pressure of the steam itself.
“As you drill deeper into a hot zone the temperature and pressure rise, so it should be possible to reach an environment where a denser fluid with very high heat content, but also with unusually low viscosity occurs, so-called ‘supercritical water.’ Although such supercritical water is used in large coal-fired electric power plants, no one had tried to use supercritical water that should occur naturally in the deeper zones of geothermal areas.”
“When the well was tested, high pressure dry steam flowed to the surface with a temperature of 400 Celsius or 750 Fahrenheit, coming from a depth shallower than the magma. We estimated that this steam could generate 25 megawatts of electricity if passed through a suitable turbine, which is enough electricity to power 25,000 to 30,000 homes.
“What makes this well an attractive source of energy is that typical high-temperature geothermal wells produce only 5 to 8 megawatts of electricity from 300 Celsius or 570 Fahrenheit wet steam.”
