In order to gather geothermal energy, developers have typically had to fracture solid rock by pumping fluids into wells at high pressure. The approach has raised concerns about the potential to trigger earthquakes and contaminate aquifers. But an energy company in Connecticut says it has found a way to gather the energy without fracturing the rocks: “[The technology] uses a kind of solid-state heat exchanger—what the company calls a ‘heat nest’—at the bottom of wells. The nest draws heat away from the surrounding rock more efficiently, with the help of a highly conductive grout that encases the heat exchanger.”
What’s the Big Idea?
“Enhanced geothermal systems (E.G.S.) represents a promising source of clean power generation in geographies that lack the ideal combination of underground heat, water, and rock permeability needed for conventional geothermal.” The practice of sourcing power from Earth’s warm core, however, has trigged small but potent earthquakes near geothermal drilling sites. “The problem, called ‘induced seismicity,’ led to the cancellation in 2009 of a project in Basel, Switzerland, after the high-pressure fracturing of rock around the well caused hundreds of seismic events, some large enough to damage property.”