Man-made geothermal systems that emulate natural ones could, by some conservative estimates, produce a total of 100 gigawatts of cost-competitive electricity over the next 50 years.

MADISON, Wis. - University of Wisconsin-Madison geoscientists and engineers

are working with industry partners and the U.S. Department of Energy to
develop a highly detailed monitoring system for geothermal wells.

Man-made geothermal systems that emulate natural ones could, by some
conservative estimates, produce a total of 100 gigawatts of cost-competitive
electricity over the next 50 years. But to get there, energy providers need
more sophisticated systems for gathering and analyzing data about the rock
mechanics and hydrology at work.

The research team - including geological engineering and geoscience
Professor Kurt Feigl, geological engineering Associate Professor Dante
Fratta, geoscience Assistant Professor Mike Cardiff, geoscience Professor
Cliff Thurber, and geoscience Professor Herb Wang - has converged on Brady
Hot Springs in Nevada to turn a relatively small geothermal field into a
proving ground for a system that could be scaled for wider and deeper
fields.

The project is the first in North America to use fiber-optic cables to
measure rock properties in a geothermal field, though it's common for energy
companies to use the technology in oil exploration. "Locating oil
underground is tough, but in geothermal wells, the challenge is finding hot
water," Feigl says.

In the last five years, advances in fiber-optic technology have enabled
cables to gather around a terabyte of detailed seismic and temperature data
per day. "We have one channel every meter, whereas a typical seismic survey
would have one channel every 30 or 40 meters," says Joe Greer, a business
development manager at Silixa, one of the industry partners involved in the
project.

The project's scope spans from fundamental geoscience to maximizing the
production of electricity from geothermal wells. Feigl says there's still a
great deal to be learned about fractures and deformation in rocks, and the
information will in turn help the DOE, Silixa and Ormat Technologies follow
the hot water through a complex underground landscape - and pursue the
long-term goal of commercializing enhanced geothermal systems (EGS).

EGS are man-made geothermal wells created by injecting additional fluid into
naturally heated rock areas that are not already saturated with fluid. This
process opens up existing fractures in the rock, allowing the water to
circulate through the area and transport the geothermal heat so that it can
be converted into electricity.

"We have a real opportunity to create better, more efficient reservoirs, and
that could lead to the deployment of EGS on a broader scale," says Lauren
Boyd, the EGS program manager for DOE. "We have to understand what our
fracture network looks like before we try to create a reservoir."

Boyd says the DOE chose to fund the project in part because of the
UW-Madison team's unique combination of strengths in geoscience and data
analysis.

"It was very clear that Kurt and his team have a really clear understanding
of these challenges that we're facing, and it brings a creative approach to
integrating technologies," Boyd says.