Enhanced geothermal systems (EGS) are the focus of a new $9-million clean energy project, co-led by Tim Kneafsey of the Department of Energy’s (DOE’s) Lawrence Berkeley National Laboratory and Douglas Blankenship of Sandia National Laboratories. The project, EGS Collab, has the goal of providing the technical support required to commercialize EGS through research and experimentation.
Geothermal systems rely on three components: heat, fluid, and permeability. They harness heat that originates from below-ground rock fractures and travels via water. Thus, traditional geothermal systems only function near active volcanoes or in areas subjected to high temperature gradients, such as Nevada.
EGS may introduce an ability to skirt these restrictions by engineering fracture networks. To find out, South Dakota’s Sanford Underground Research Facility (SURF) will create and test small-scale fracture networks 1500 m (4921 ft) below the ground.
“We will be putting instrumentation within tens of meters of the fractures and will be able to detect fracturing at a higher resolution than what has ever been done before,” said Kneafsey. “The goal is to work toward increasing our understanding of fracturing and fluid flow in EGS, which could provide a significant amount of electricity, as a large quantity of accessible hot rock lies untapped across the United States.”
To put this significant amount of electricity in more precise terms, where the continental United States currently produces 3.5 GW of electricity, employing EGS could provide more than 100 GW.
“Although geothermal energy production is already used effectively, there is a lot we need to learn about how to create and develop an EGS reservoir,” said Kneafsey. “This project will seek to understand the relationship between permeability creation and heat extraction in crystalline rocks under certain stress and temperature conditions.”
The project is intended to dovetail with DOE’s Frontier Observatory for Research in Geothermal Energy (FORGE), accelerating its success by providing additional data. FORGE currently explores drilling and reservoir simulation techniques as well as flow testing and well connectivity, and EGS Collab will add more monitoring and imaging tools to the repertoire.
In addition to Berkeley and Sandia, EGS Collab will run with the support of labs including Lawrence Livermore, Idaho, Los Alamos, Pacific Northwest, Oak Ridge, and the National Renewable Energy Laboratory (NREL).
“We’re going to use the best techniques to understand these fractures,” said Kneafsey. “This collaboration includes some of the world’s most skilled and experienced scientists and engineers in the areas of subsurface process modeling, monitoring, and experimentation.”