November 24, 2025 Issue

The Earth is burning up. Science is clear: fossil fuels are to blame. What to do about it? Stop using fossil fuels; use an alternative such as hydroelectricity, nuclear energy, solar power, wind power. These are the alternatives most commonly mentioned. But there’s another one, not often considered, that might be the most promising of all – geothermal power.  Rivka Galchen writes about it in this week’s New Yorker. She tells how it works:

In some ways, the process of harnessing geothermal energy is simple. The deeper you dig, the hotter the temperatures get. For direct heating, you dig relatively shallow wells (typically several hundred metres deep), to access natural reservoirs of hot water or steam, which can be piped into a structure. For electricity, wells are dug farther down, to where temperatures are above a hundred and fifty degrees Celsius. (In Iceland, this temperature is reached at around one thousand to two thousand metres deep.) Pressurized steam spins a turbine that in turn spins a generator. Thermal energy (steam) is translated into mechanical energy (the spinning turbine), which is translated into electrical energy (via the generator). Geothermal energy is essentially carbon-free, it is available at any time of day and in any weather, and it leaves a small—albeit very deep—footprint on the landscape.

Galchen visits the Krafla Geothermal Station in Iceland. She points out that “more than a quarter of the country’s electricity comes from geothermal.” But not every country has Iceland’s hot springs and volcanoes. In landscapes that lack these turbulent geological features, the costs and uncertainties of drilling deep in search of sufficient heat have curtailed development. This, she says, “partly explains why, in the field of clean energy, geothermal is often either not on the list or mentioned under the rubric of ‘other.’ For decades, both private and government investment in geothermal energy was all but negligible.”

But, as Galchen reports, “All this has now changed.” She writes,

In the past five years, in North America, more than a billion and a half dollars have gone into geothermal technologies. This is a small amount for the energy industry, but it’s also an exponential increase. In May, 2021, Google signed a contract with the Texas-based geothermal company Fervo to power its data centers and infrastructure in Nevada; Meta signed a similar deal with Texas-based Sage for a data center east of the Rocky Mountains, and with a company called XGS for one in New Mexico. Microsoft is co-developing a billion-dollar geothermal-powered data center in Kenya; Amazon installed geothermal heating at its newly built fulfillment center in Japan. 

My favorite part of Galchen’s piece is her description of a project that aims to demonstrate the feasibility of an ambitious geothermal system to serve Cornell University’s seven-hundred-and-forty-five-acre campus. She writes,

In the summer of 2022, a rig set up not far from Cornell’s School of Veterinary Medicine drilled for sixty-five days through layers of shale, limestone, and sandstone, passing beyond the geologic time of the dinosaurs to a crystalline basement dating to the Proterozoic eon, more than five hundred million years ago. 

What a marvelous sentence! I think geothermal is the way to go. When Lorna and I built our house here on Prince Edward Island, we installed a geothermal furnace. It heats the house in the winter and cools it in the summer. I highly recommend it.