What will it take to develop a geothermal pump that can operate miles underground in 430-degree-Fahrenheit fluids while maintaining a steady 750 horsepower?
A pair of West Coast foundations hope they have the answer: lots of cash.
The Oregon-based Foundation for Geothermal Innovation and the California-based Lemelson Foundation last week released design criteria for a race to build the next generation of "temperature hardened" electric submersible pumps (ESP), one of a number of technologies crucial to the advancement of geothermal energy on a commercial scale. The groups are prepared to offer millions of dollars to the first firm to develop an ESP that can withstand extreme subterranean heat and pressure.
"Energy from geothermal resources is affordable and abundant," said Patrick Maloney, senior program officer at Lemelson. "But the problem to date has been harnessing it. This report will hopefully provide companies and individual innovators the parameters needed to solve a key part of that problem."
The report is a result of a meeting held earlier this year at Stanford University that brought together 20 top experts in the field, including representatives from government, academia and the private sector, to look for ways to reduce fossil fuel use through an expanded adoption of geothermal.
Pump companies, universities and inventors are being asked to compete for a $5 million prize purse to be awarded in 2015. The winning firm will also receive an advance market commitment for 100 pumps, a $75 million order designed to serve as the chief incentive to innovators.
"It is rare to find a key technical challenge that can be so clearly defined for innovators to work on," said Lawrence Molloy of FGI, which is seeking support from the Department of Energy in building an incentive package to be finalized in early 2010. "We hope that this prize can help revitalize the industry."
Similar targets for geothermal pump development have been set by the Energy Department's Geothermal Technologies Program, which has found current pump models unable to sustain flow rates under advanced geothermal conditions. While geothermal resources can reach 660 degrees, pumps capable of delivering heat from below ground are designed to operate at just 375 degrees.
Enhanced geothermal systems
The new pumps are critical for "enhanced geothermal systems," in which energy is produced by fracturing dry rock at the bottom of a deep hole and then circulating water through the cracks to generate steam. In contrast, today's geothermal projects use hydrothermal systems that tap naturally occurring water deposits to provide geothermal heat.
While hydrothermal potential is estimated to be about 30,000 megawatts, the potential for EGS is greater than 500,000 megawatts, or about half of the current generating capacity of the entire United States, according to a 2008 report from the U.S. Geological Survey.
A seminal 2007 study from the Massachusetts Institute of Technology found that wide-scale commercial deployment of EGS reserves could power more than half of American homes by midcentury. And unlike intermittent wind and solar power, geothermal is available around the clock and requires much less real estate to develop.
"Geothermal energy from EGS represents a large, indigenous resource that can provide base-load electric power and heat at a level that can have a major impact on the United States while incurring minimal environmental impacts," according to the MIT study. "Further, EGS provides a secure source of power for the long term that would help protect America against economic instabilities resulting from fuel price fluctuations or supply disruptions."