Berkeley Is Digging a 400-ft. Hole to Reduce Emissions With Geothermal

Researchers at the University of California, Berkeley are moving to reduce the school’s carbon footprint with geothermal heat pumps, weaning its buildings off of fossil fuels. 

Most of the school is currently powered by a single natural gas power plant, which gets an assist from power supplied by utility company PG&E. But that plant is nearing the end of its 40-year life, and, to Kira Stoll, chief sustainability and carbon solutions officer at UC Berkeley, ready to be phased out. 

“It’s old, and it’s getting toward the end of its useful life,” Stoll said in a press video on the geothermal project published last week. “What we’d like to do is move away from those fossil fuels and decarbonize the energy that we use in our campus buildings.” 

The plan is to recycle heat released by the school’s electronics (computers, heating and cooling systems, and the like), and pump it underground for storage using a liquid. In the winter, the heat can be pumped back up into buildings to provide warmth, and the same system can cool buildings in the summer, when underground is cooler than aboveground.

 Stoll said she hopes a move toward geothermal for heating and cooling will reduce Berkeley’s overall emissions by 80 per cent, with wind and solar power eventually providing for the rest of the school’s energy needs. 

Dr. Kenichi Soga, professor in mineral engineering, is leading the charge in figuring out the best way to do that. The first step was to identify the quality of rock formations underneath Berkeley’s campus, and how equipped they are to store heat collected from campus buildings. 

He’s starting with fiber optic sensors: In January, 2021, Soga and a team of researchers, including students, drilled a 400-foot borehole on campus into which they strung a tube with heated fluid and a fiber optic sensor that measures temperature underground via light pulses. The fiber sends a pulse of light underground that, when reflected back up through the hole, offers information about the rock quality and temperature of a certain location on the fiber. 

Based on the quality of light sent back through the fiber, Soga and his team can deduce how deep each data point is, and thus, how hot certain points in the ground get when hot fluid is piped underground. “The question is, is our rock good enough to store the heat?” Soga said in the video. “And we need to find that out.” 

UC Berkeley is one of a handful of schools across North America that are exploring geothermal energy. Carleton College, in Northfield, Minnesota launched a geothermal project that captures excess heat from cooling systems to provide warmth for heating systems with success—60 miles of piping underneath campus have helped cut its energy use by nearly 30 per cent.

“The question is whether that heat will go out into the atmosphere,” where it is wasted, Soga said in the video, or “can we use that heat and then store it?” 

The plan is to start with a single building before scaling up, creating a network between buildings across campus through which they exchange recycled heat with one another. It could see the school’s carbon footprint, which is equivalent to what comes with powering some  50,000 California homes, Skoll said, plummet. 

“We have a target of having zero carbon energy for our buildings by the year 2035,” she said. “We really have to do something, and we have to do something soon. Why would we reinvest in some old technology?”