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Geothermal test drilling underway in Garfield County

By December 16, 2023March 4th, 2024No Comments

By Dave Reed

A few weeks ago I watched as a team from PanTerra Energy set up a drill rig behind the Third Street Center, five blocks off Carbondale’s main drag. Dressed in overalls and hard hats, the workers methodically swung pipe sections into place, adjusted controls and mixed up drilling mud. Off to one side, a field geologist examined core samples through a microscope.

Photo courtesy of Aaron Orelup.

It all looked and sounded much like drilling operations around Rifle and Parachute. But while the techniques were similar, this project was exploring for a different kind of energy: geothermal.

A coalition of Carbondale interests, including the town and CLEER (Clean Energy Economy for the Region), won a $716,000 Department of Energy grant to design and model a large-scale system to heat and cool buildings in a 16-acre section of Carbondale. Last month’s drilling of a 500-foot-deep test well was the first step in the process, to determine if the ground under the site has the necessary thermal properties. (The initial results look good.)

This is not your father’s geothermal. It doesn’t need hot water or steam to work. Instead, it taps into a much, much more common resource – the natural, ambient temperature of the ground beneath us.

If you’ve been in a cave or a root cellar, you know what that ambient temperature feels like. It’s kind of chilly, actually. But thanks to heat pumps – which are basically reversible air conditioners – we can use electricity very efficiently to concentrate the heat that’s in that thermal mass and move it around. Ground-source heat pumps, as they’re called, use the ground as a sort of battery, drawing heat from it in cold weather and sending excess heat into it in the summer.

Ground-source heat pumps are extremely energy-efficient, and a number of buildings in our area have them, but the systems are expensive because of the cost of drilling or earthmoving. What’s innovative about the proposed Carbondale project is that it’s being designed to serve a larger “district,” and the greater economies of scale are expected to make the overall system cost-competitive.

The district also comprises a mix of building types, from institutional buildings like the Third Street Center and the library to townhomes and teacher housing. That’s a big advantage because different buildings will utilize heating and cooling at different times, making more efficient use of the system.

Plus, the system is scalable. Think of the loop as infrastructure, like an irrigation ditch or broadband cable. Buildings can connect to the loop that circulates ambient temperature water from the bore field(s). As more buildings join the loop, more boreholes can be drilled to fuel the system. The loop can be extended to take in additional parts of town. The more buildings on the system, the cheaper the cost and the greater the reduction in greenhouse gas emissions.

OK, but you may be wondering why we need a new way to heat and cool buildings. I have four answers for that.

First, consider the Third Street Center. It’s widely praised as a model of energy efficiency. Rooftop solar panels provide 100 percent of its annual electricity use. But what isn’t often mentioned is that it’s heated with natural gas. That’s the story with many of our institutional buildings – even the ones that are considered “green” still produce considerable emissions from heating, and retrofits aren’t cheap. The geothermal system being studied in Carbondale is a potentially affordable solution.

Second, if district-scale geothermal is cost-effective then it’s a business opportunity, and that’s a beautiful thing. The vast majority of our clean energy infrastructure will be built and financed by the private sector, so companies need to see that there’s an attractive rate of return in it. And by the way, if a clean technology is profitable then it’s also good for the climate, because we’ll get more emissions reduction for our bucks if we invest them in the most cost-effective strategies.

Third, there will never be one silver bullet to supply all our energy needs or to reduce our emissions. As utilities know very well, it takes a diversity of energy sources to match demand, each with unique advantages and tradeoffs. By delivering heat about five times more efficiently than natural gas, and doing it 24/7, geothermal could play a significant role in enabling the electric grid to meet the increased demand expected in the coming decades.

Finally, I believe that geothermal development could be a powerful driver of job creation and economic diversification for our region.

As I watched those drill rig workers in Carbondale, I marveled at their specialized skills and their incredible productivity, gained from years of experience in the oil and gas industry. And what I saw was the exciting, hopeful prospect of them redeploying those skills in an adjacent field, maintaining our region’s prosperity while continuing its heritage of energy production, and in the process enhancing our environment and leaving our home better than we found it.

I think that’s a future we can all get behind.

This column was originally published in the Dec. 15, 2023 edition of the Glenwood Springs Post Independent.

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