The geothermal field at Krafla, Iceland, is yielding new insights on geothermal heat. (Peter Schiffman/UC Davis photo)
When a team of scientists drilling near an Icelandic volcano hit magma in 2009, they had to abandon their planned experiments on geothermal energy. But the mishap could point the way to an alternative source of geothermal power.
"Because we drilled into magma, this borehole could now be a really high-quality geothermal well," said Peter Schiffmann, professor of geology at UC Davis and a member of the research team along with fellow UC Davis geology professor Robert Zierenberg and UC Davis graduate student Naomi Marks. The project was led by Wilfred Elders, a geology professor at UC Riverside.
A paper describing geological results from the well was published in Geology.
When tested, the magma well produced dry steam at 750 degrees Fahrenheit (400 degrees Celsius). The team estimated that this steam could generate up to 25 megawatts of electricity—enough to power 25,000 to 30,000 homes.
That compares to 5 to 8 megawatts produced by a typical geothermal well, Elders said. Iceland already gets about one-third of its electricity and almost all of its home heating from geothermal sources.
The team was drilling into the Krafla caldera as part of the Iceland Deep Drilling Project, an industry-government consortium, to test whether "supercritical" water—very hot water under very high pressure—could be exploited as a source of power.
They planned to drill to 15,000 ft—more than two miles deep—but at 6,900 ft, magma (molten rock from the Earth's core) flowed into the well, forcing them to stop.
The composition of magma from the borehole is also providing insight into how magmas form beneath Iceland, Schiffmann said.
The team included researchers from two Icelandic power companies, HS Orka hf and Landsvirkjun Power; Iceland GeoSurvey; the U.S. Geological Survey; Stanford Univ.; New Mexico Institute of Mining and Technology; and the Univ. of Oregon, Eugene; as well as UC Davis and UC Riverside.
The work was funded by the National Science Foundation and the International Continental Scientific Drilling Program.