Pa. lawmakers look underground for nuclear alternative to cool data centers

State Capitol Reporter. Jaxon White. 9.2.25

As the number of data centers in Pennsylvania soars, it's nuclear energy, more than any other source, that has dominated conversations about how to produce the electricity needed to cool the power-hungry computers essential to modern commerce.

But some state policymakers are interested in a lesser-known alternative that could largely bypass the electrical grid.

Pennsylvania legislators have quietly gathered expert testimony and reviewed research on harnessing subsurface water across the commonwealth to cool the silicon infrastructure used for artificial intelligence and cloud computing.

House Energy Committee Chair Elizabeth Fiedler, D-Philadelphia, said in an interview that lawmakers have had "a lot of conversations" about the potential benefit of geothermal cooling to support new data centers across the state.

"It's very personal for a lot of members who are seeing this sort of development happening in their districts back home," Fiedler said. "So I think it's something that we're continuing to work through."

Up to 40% of a standard data center's electricity consumption is used to keep servers from overheating, according to the Electric Power Research Institute. In Pennsylvania, much of that energy already comes from nuclear power, which the U.S. Energy Information Administration credits for nearly one-third of the commonwealth's energy production.

On a mass scale, geothermal could cool "hundreds of data centers" across the state, according to a 188-page study published last month by the General Assembly's nonpartisan Joint State Government Commission. The report also suggested that lawmakers incentivize geothermal projects with state grants and tax credits.

But tapping groundwater presents its own set of concerns. A single data center evaporates up to five million gallons of water per day, according to the Environmental and Energy Study Institute, a Washington, DC-based think tank dedicated to studying sustainable energy and climate solutions.

Freshwater managers from commissions overseeing the Susquehanna River and Delaware River basins warned lawmakers last month that the amount of water needed to cool the state's data centers could stress the water supply.

Promoting it

Gov. Josh Shapiro's administration is already considering how to further geothermal technology.

For a May legislative hearing on geothermal energy, Kurt Klapkowski, deputy secretary of the Department of Environmental Protection, wrote to lawmakers about the promise of geothermal systems: "Data centers generate heat that must be dissipated. Ambient cold water can be used directly in liquid cooling systems or to chill air that can be passed over equipment."

Shapiro, a first-term Democrat, has championed data center development and energy infrastructure projects to power them, including the work to restart the shuttered Three Mile Island nuclear reactor.

Shapiro's office referred questions for this story to the DEP, which said in a statement that it "supports geothermal development" and that the state is "considering" applying for Class V primacy from the federal Environmental Protection Agency, which would give the DEP authority over geothermal permitting in Pennsylvania.

The Joint State Government Commission's report identified only one data center in Pennsylvania that uses a geothermal cooling system: "The Underground" in Butler County, owned by Iron Mountain Data Centers. The company repurposed a former limestone mine for the facility, which has a 35-acre water reservoir located 200 feet underground, according to the U.S. Department of Energy.

Iron Mountain states on its website that it utilizes the underground lake to regulate the temperatures of its data center there. Officials from the company did not respond to a request for comment.

Similar repurposing of old mines has piqued the interest of policymakers. Kaplowski noted in his testimony, "Mine pools can be a notable source of geothermal cooling water."

The Joint State Government Commission also identified more than 350 potential geothermal sites - largely in the western half of the state - located within one mile of at least one abandoned or closed mine water source, including school districts, hospitals and correctional facilities.

Growing need

Unlike geothermal systems in other parts of the world, which produce electricity by tapping underground heat and steam to power turbines, the technology is not used anywhere in Pennsylvania to produce electricity in Pennsylvania, according to the Joint State Government Commission. The geothermal systems that are running in the state only work to heat or cool spaces using water as the principal medium.

Researchers acknowledged what is widely accepted as the biggest hurdle for Pennsylvania in pursuing high-scale geothermal electricity production - the state's geology does not include areas where the planet's high-temperature mantle is near the surface, like in many western states.

Yet the commission report also issued a bold statement about geothermal's future: "It is possible that all of Pennsylvania's electric needs could eventually be met by geothermal power production."

Dan Weaver, chief executive of the Pennsylvania Independent Oil & Gas Association, said he is unconvinced that geothermal energy generation can be scaled to the output Pennsylvania needs.

Weaver helped install a geothermal heating and cooling system at Drake Well Museum in Venango County, but he noted that facilities using such systems "often still need a secondary energy source to level it out."

"I hope it works," Weaver said of the technology's potential for producing power. "I just don't know how yet."

With improved mapping and advanced drilling techniques, similar to fracking in the oil and gas industry, some researchers at Penn State believe hidden heat sources suitable for electricity production can be found in the state.

In a 2025 report, partnering with pro-geothermal nonprofit Project Innerspace, the researchers concluded that portions of northern Pennsylvania - including McKlean, Forest and Warren counties - appear to have the temperatures for potential power generation. The group lacked data from the state's southeast. But the researchers suspect the region stretching from Philadelphia to southern Lancaster and York counties may be suitable.

Still, it was the state's traditional fossil fuel resources that were the most likely source for electricity to power data centers, the researchers concluded.

"By coupling Pennsylvania's abundant natural gas resources with its subsurface cooling resources, less energy is needed to run a data center," they wrote. "This means companies can run less-expensive operations, or build larger data centers with little increase in power usage."

'The next 100 years'

Geothermal heating and cooling are not novel technologies. The Geology and Environmental Sciences Department at Lafayette College in Easton credits Prince Piero Ginori Conti of Italy with inventing the first geothermal power plant in 1904.

It's not new to Pennsylvania, either. Swarthmore College in Delaware County has a working geoexchange facility - they use the word "exchange" to emphasize how underground water wells act as a heat bank - intended to help the institution meet its goal of being carbon neutral by 2035.

"Our steam plant was built over 100 years ago, and so that infrastructure was really in need of replacement," Elizabeth Drake, Swarthmore's assistant vice president of sustainability, said before a tour of the geothermal facility beneath the school's dining hall. "That kind of opened the door for us to think about what sort of technology we wanted to invest in for the next 100 years."

Geothermal systems work by using the ground as a "heat sink," according to the U.S. Department of Energy - storing surface heat in water that's pumped underground for storage, then recirculated later to provide heat when outside temperatures are cold.

Drake said there will be 700 total subsurface wells spread across campus once the project is fully complete. The system is expected to provide heating and cooling for more than 90% of the campus, including its athletic facilities, though it's already doing so for some buildings.

Funding for the project largely came from President Joe Biden's 2022 Inflation Reduction Act. With President Donald Trump's administration pulling back on many green projects, Drake said the college was concerned about losing its funding. So far, Trump has largely left geothermal projects to continue.

Swarthmore's adoption of geothermal is a model for state lawmakers as they promote the technology. It inspired Rep. Fielder to propose state grants and tax breaks for higher education institutions that invest in geothermal projects. She has not yet introduced the bill.

Within a few years, portions of downtown Harrisburg - including some of the state Capitol Complex - could be heated and cooled using a geothermal system. Cordia Energy is in the early planning phases of a system to replace some of its 30,000-foot steam distribution system in the city.

"It's just the evolution of energy, and it's the next thing we need to do for sustainability purposes," Shawn Fiebig, Cordia's Harrisburg plant manager, said during a tour of the site.

Multiple environmental groups, including southeastern Pennsylvania's Sierra Club chapter and PennFuture, have thrown their support behind geothermal.

Researchers at Penn State found that geothermal cooling can reduce the amount of water consumed by data centers cooled with a traditional conditioning system, especially if the geothermal system is built using a closed-loop system like Swarthmore's, though the researchers did not specify by how much.

'Energy is energy'

The equipment and employee expertise needed to expand geothermal energy heavily overlap with those of the oil and natural gas industries.

That fact is an advantage for Pennsylvania. Researchers are exploring how best to convert the hundreds of thousands of abandoned oil and gas wells into geothermal wells.

John Walliser, senior vice president of legal and government affairs at the Pennsylvania Environmental Council, said his group supports geothermal expansion because "it's a low-emission energy source once it's up and running."

He also noted the crossover in expertise between the oil and gas industry with geothermal - the Joint State Government Commission found that nearly three-quarters of oil and gas jobs hold at least "moderate relevance" to the geothermal sector.

The workforce overlap is one of the appealing aspects of geothermal for state Rep. Heather Boyd, D-Delaware, who is pursuing legislation to give gas companies more authority to construct geothermal networks and sell the heat.

"Yes, we need a protected environment. Yes, we need heat and energy," Boyd said. "But we also need work."

Joint State Government Commission researchers urged lawmakers to create a clear regulatory framework for geothermal projects, define legal ownership of potential sites, and permit the repurposing of oil and gas wells for geothermal use.

All of those suggestions are expected to be addressed in bipartisan legislation planned by Rep. Arvind Venkat, D-Allegheny, and co-signed by Craig Williams, R-Delaware, and Fiedler.

Venkat, the lead sponsor of the not-yet-introduced bill, said the legislation would put Pennsylvania ahead of the geothermal electrical production he expects to become possible with a few more years of technological development.

For now, Venkat said, his proposal could help spread awareness of geothermal's potential future for heating and cooling.

It's unclear where geothermal's future stands in the current two-year legislative session. Senate Environmental Resources Committee Chair Gene Yaw, R-Lycoming, did not respond to requests for comment.

"There seems to be more immediate interest with nuclear and natural gas," Venkat said on leveraging geothermal for data centers. "But, you know, energy is energy."

Link to article: Pa. lawmakers look underground for nuclear alternative to cool data centers | Politics | lancasteronline.com

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