SOUTH HADLEY — Mount Holyoke College hopes to celebrate its bicentennial in 2037 by declaring the campus carbon neutral, and the liberal arts college has already taken significant steps toward that goal as it moves into phase three of a new geothermal heating system.

Construction on the project started in 2023, but Mount Holyoke began planning the project five years prior. After the college’s board of trustees endorsed moving away from fossil fuels, the institution underwent a study in 2019 to decide the best carbon-free heating option, ultimately landing on ground source heat pump systems that store summer heat in 240 wells 600 feet below the Earth’s surface, then transfer it through over 26 miles of distribution piping.

But constructing a new heating system, which is currently estimated to cost $180 million, in buildings over a century old challenged the college’s original eight-phase plan. According to Carl Ries, vice president for finance and administration and treasurer, not only do piping and heating units cramp space-restricted residence halls, but concealing the pipes requires deconstructing and reapplying plaster to older plaster. In the middle of the second phase of the project, it became clear to Ries that building a new geothermal heat system needed a more comprehensive look at Mount Holyoke’s historic buildings.

“It’s given us the opportunity to think, do we actually want to take the opportunity to renovate where we can before we complete the entire building conversion to geothermal?” Ries said. “We don’t want to go into a building, put in radiators, not renovate it and then come back five years later and renovate and put in air conditioning.”

While a majority of the project revolves around replacing the campus’s steam heating plant with a geothermal heating and cooling system by 2030, the project has begun to expand into a larger campus renewal effort as it moves into its third phase next March. That phase calls for adding new windows for better insulation, air conditioning and interior renovations. The efforts ensure Mount Holyoke’s heat, and buildings, last for its future generations of students.

“I think that we kind of went into it thinking that we were going to put the geothermal system in, we’re gonna flip the switch and we’re gonna walk away,” Ries said. “But the reality is, is that it actually kind of created this whole ecosystem of change that has to be looked at, and it has to be tackled really meaningfully. Otherwise, we’re going to get 10 years down the road, and we’re going to look back and it’s like we didn’t do anything to the buildings.”

As explained by Karla Youngblood, associate vice president for facilities management, Mount Holyoke’s geothermal heat system harvests heat from the air using air-source heat pumps, and heat emitted from buildings. That heat warms water, which then travels through distribution piping and deposits the heat underground for later use. As summer transitions to autumn and winter, the water in the pipes will absorb the heat from the ground, where it will travel to one of the campus’s three energy areas. Once there, industrialized heat pumps raise the temperature from 55 degrees Fahrenheit to around 131 degrees Fahrenheit. When hot, the water completes its loop, warming buildings between 50 and 60 degrees Fahrenheit.

“We are limited to how we can insulate these masonry buildings without creating indoor air quality concerns, but the college has been proactive with almost all of our attics and roofs, which are insulated, and we’re starting on a window replacement project that’s running in parallel with the with the hot water conversion,” Youngblood said.

This same process happens in reverse to provide air conditioning to buildings, with industrial chillers replacing the heat pumps. Ries and Youngblood said the original scope of the project did not include air conditioning, but the addition improves the comfort and health of students. Only three resident halls, North and South Rockerfeller Halls and Mead Hall, will definitely receive air conditioning, but all buildings will be connected to the cooling infrastructure.

“What’s nice about adding air conditioning is we’re taking that waste heat we pull out of the buildings, and that’s what we’re putting in the ground to pull from later,” Youngblood said. “And that’s why air conditioning makes the system more balanced.”

By capturing heat emitted from buildings and recycling it back into the system, Youngblood said every bit of energy used to heat up water is squeezed out so that no heat will go to waste. In fact, the plant is 600% more effective than a standard boiler or chiller.

The geothermal plant will not create its own electricity, but rather source energy from the South Hadley Electric Lighting Company. According to Youngblood, 90% of the municipal lighting corporation’s grid portfolio consists of carbon-free energy sources.

“It’s different from what Amherst and Smith College are facing,” Ries said. “They have a steeper hill to climb trying to find additional sources for energy that is carbon free or green ... For us, it’s less of a hill to climb because it’s right there.”

The first two phases of the project converted all but one of the science complexes, dining halls and Blanchard Community Center to the new heat distribution system. The chilling plant under Kendade Hall was also expanded, adding more piping and two simultaneous heat pump chillers to both heat and cool water until the new energy center is built. Roughly a third of the distribution piping was constructed during second phase, stretching under Skinner Green and across campus.

For the third phase, Mount Holyoke will drill over 200 wells below the rugby field, where heat will be stored for later use. Mount Holyoke will begin prepping for construction in May 2025, then build the wells from June to October.

Emilee Klein can be reached at eklein@gazettenet.com.