To tap geothermal resources for electricity production, fluid has to flow among hot rocks in the subsurface and then be drawn to the surface in the form of steam or hot water. However, while underground heat exists everywhere, many locations lack adequate water or conditions that facilitate the fluid flow necessary to recover that heat energy. In such cases, EGS can be used to create an artificial underground reservoir to tap that heat for energy, DOE says. 

In order to use EGS to tap into geothermal resources requires drilling into the subsurface and using wells to draw hot water to the surface. Constructing and operating those wells can be costly, so methods to build those wells and assess their performance that reduce costs can make geothermal electricity a clean, cost-effective option, DOE says.

In addition, while traditional energy storage batteries, which typically store electrical energy, reservoir thermal energy storage (RTES) technology can store thermal energy directly in underground reservoirs for 100 or more hours without the need for electricity, says the DOE, which is funding a RTES demonstration project to illustrate the capabilities of the technology. The demonstration project is expected to show that RTES can reduce industry-produced carbon emissions by at least 85 percent by 2035, and that such reductions can help steer the U.S. to a net-zero-emissions economy by 2050, DOE says.

The Clean Air Task Force (CATF), which is an advocacy organization focused on deployment of low-carbon energy and other climate-protecting technologies, is “pleased” the DOE is “supporting targeted next-generation geothermal innovation through its funding initiatives, particularly in areas CATF has identified as critical to superhot-rock geothermal,” Terra Rogers, director of the organization’s Superhot Rock Geothermal Energy section, told The Driller in a written statement.

“Supporting research and development for emerging clean energy technologies is an essential government function,” Rogers added. 

The organizations receiving funding, how much each is to receive, and what each project is expected to do are as follows:

• Clemson University, $4.880 million, to develop an AI-enabled, photoacoustic imaging tool for high-temperature and high-pressure well logging in order to assess geothermal well integrity without active cooling.
• Innovative Downhole Solutions Inc., $2.5 million, to develop a durable ultrasonic measurement tool capable of operating for 24 hours in high-temperature geothermal environments to assess wellbore construction materials and practices.
• Lawrence Berkeley National Laboratory, $2 million, to develop a tool for geothermal borehole integrity evaluation, designed to assess wellbore integrity in extreme conditions without the need for down hole electronics.
• Los Alamos National Laboratory, $3.674 million, to develop a high-resolution acoustics-based tool to provide high-fidelity data for evaluating EGS components under extreme conditions.
• Schlumberger Technology Corp., $10 million, to develop a wireline tractor-conveyed system for long-term integrity modeling of cement and casing.
• Project Development Solutions, Inc., $7.899 million, to conduct a RTES demonstration project at Kern Front Oil Field in Bakersfield, Calif., pairing subsurface geothermal reservoirs with a steam system and process heat off-taker. 

Upon reviewing the grants, Rogers said, “the work being done by these and future DOE-funded projects will be vital in achieving higher temperatures, including superhot conditions, which can unlock the full potential of next-generation geothermal energy in the U.S.”

Read the announcement.