|EGS cutaway diagram. Click to enlarge.|
The US Department of Energy (DOE) issued a Funding Opportunity Announcement (FOA) for up to $90 million over four years to advance the research, development and demonstration of next-generation geothermal energy technology to harness the earth’s interior heat extracted from hot water or rocks.
Currently, DOE has up to $10.5 million available for immediate award under this FOA, with the remainder subject to change and to Congressional appropriations. The FOA addresses the need for additional technical understanding of enhanced geothermal systems (EGS) to accelerate the technology to a state of commercial readiness.
Geothermal energy is a clean, reliable, scalable, renewable energy source and these geothermal projects will help the US tap domestic heat sources that were previously out of reach.—Assistant Secretary of Energy Efficiency and Renewable Energy Andy Karsner
EGS are systems of engineered reservoirs created by drilling deep wells into hot rock, fracturing the rock, and circulating a fluid through the wells to extract heat. According to a study released early in 2007 by the Massachusetts Institute of Technology (MIT) entitled The Future of Geothermal Energy (earlier post), EGS represents a large, indigenous resource that, with a reasonable investment in research and development (R&D), could provide the US with 100,000 megawatts of cost-competitive electricity, generating capacity by 2050, or 20% of current electricity generation.
While EGS reservoirs have been designed, built, and tested in various locations throughout the world, a number of technical hurdles remain before EGS production facilities will reach commercial production rates and life spans.
Through this FOA, DOE will concentrate on issues related to EGS reservoir creation, operation, and management. In the long-term, the work aims to create, sustain, replicate and commercialize EGS technologies, while in the short-term these projects will develop and demonstrate technologies that are useful to both hydrothermal and EGS geothermal projects.
To reach these goals, this FOA will address two topic areas:
Component Technologies R&D: The R&D projects under this topic area will meet the R&D needs identified in DOE’s EGS Technology Evaluation Report (2008). Projects will address aspects of engineered reservoir creation, management, and utilization at high temperatures up to 300°C and depths as great as 10,000 meters.
System Demonstrations: The projects under this topic area will allow testing and validation of stimulation techniques for improving productivity of wells or increasing inter-well connectivity at existing geothermal fields. Use of available or experimental technologies from geothermal, petroleum or other relevant industries will be considered.
DOE anticipates making up to 26 awards through this competitive funding opportunity, which is open to industry and academia. In addition to the $10.5 million funding for fiscal year (FY) 2008, and subject to annual Congressional appropriations, up to an additional $30 million is expected to be available for awards in FY 2009. Additional funding up to $49.5 million is expected to be available in FY 2010, subject to change and Congressional appropriations.
A minimum of 20% private sector cost share is required for R&D projects and funding for the awards is subject to Congressional appropriations. Recipient cost share requirements for demonstration projects will be up to 50% and vary by both the phase of the award and the activities within a particular phase. Applications for this funding opportunity are due on or before 12 August 2008.
Following the publication of the MIT report, the DOE and support staff at the national laboratories ran an internal eight-month program to review the assumptions and conclusions of the MIT report.
The later report, An Evaluation of Enhanced Geothermal Systems Technology (2008), concluded that MIT’s assumptions were reasonable and within the bounds of a balanced systems analysis. However, the DOE team decided that MIT conclusions about the amounts of investment needed to achieve competitiveness and produce 100,000 MWe were not supported.
The DOE report found that there are three critical assumptions about EGS technology that require thorough evaluation and testing before the economic viability of EGS can be confirmed:
Demonstration of commercial-scale reservoir. This requires stimulation and maintenance of a large volume of rock (equivalent to several cubic kilometers) in order to minimize temperature decline in the reservoir. Actual stimulated volumes have not been reliably quantified in previous work.
Sustained reservoir production. The MIT study concludes that 200°C fluid flowing at 80 kg/sec (equivalent to about 5 MWe) is needed for economic viability. No EGS project to date has attained flow rates in excess of ~25 kg/sec.
Replication of EGS reservoir performance. EGS technology has not been proven to work at commercial scales over a range of sites with different geologic characteristics.
These assumptions can be tested with multiple EGS reservoir demonstrations using today’s technologies. However, as this evaluation shows, Research and Development should be conducted in parallel with field projects to fill some long-term technology gaps. The key technology requirements for immediate development stemming from this evaluation include:
- Temperature-hardened submersible pumps
- Zonal isolation tools
- Smart tracers
- Monitoring and logging tools
- Coupled models to predict reservoir development and performance
Experience from the conventional geothermal and petroleum industries provides a solid foundation from which to make technology improvements. In the long-term, significant reduction in drilling costs will be necessary to access deeper resources, and the cost of conversion of the energy into electricity must be reduced. These improvements will rapidly move EGS technology forward as an economically viable means of tapping the nation’s geothermal resources.
In related internal DOE news, Ed Wall, formerly the Program Manager for the Vehicle Technologies Program, has moved over to become Program Manager for the Geothermal Technologies Program, beginning immediately.
Separately, the BLM and US Forest Service issued a Draft Programmatic Environmental Impact Statement (PEIS) for geothermal leasing in the West, including Alaska. (Earlier post.)
Geothermal Technologies Program website
Geothermal Resources Council website