Hanover — The ambitious green energy goals announced over the weekend by Dartmouth College President Phil Hanlon could have a major impact on an unassuming building near the Dartmouth green — the college’s 119-year-old power plant.
Administrators at Dartmouth College are weighing a wide range of alternative fuel sources and efficiency measures to help them meet the objectives, which include reducing greenhouse gas emissions by 50 percent by 2025, and 80 percent by 2050.
Under some scenarios, Dartmouth’s power plant could remain at its current location. But some of the energy alternatives under consideration would require significant retrofitting, if not the outright relocation, of the facility.
Among the most economical options to replace No. 6 fuel oil, the carbon-heavy fuel that Dartmouth currently uses to heat its campus, is biomass — wood, most often delivered and burned in pellets or chips.
Biomass is cheaper than No. 6, an advantage that would allow the school to invest its fuel savings in capital improvements to its energy system, said Frank Roberts, an associate vice president for facilities operations and management who has done much of the initial number-crunching that Dartmouth officials are using to direct their plans.
But wood fuel is also bulkier, he said, which would mean that Dartmouth would have to move the power plant, which originally burned coal, to an as-yet unchosen location outside of downtown, should it choose to switch over.
“It goes to how much storage area you need for the wood chips,” Roberts said. “If you look at the present plant location, it used to be on the outskirts of campus many years ago when it was built in the 1890s, but now it’s kind of in the center of town.”
Andy Friedland, a professor of environmental studies who co-chaired a task force that advised Hanlon before his energy announcement, noted that fuel oil stores roughly 10 times as much energy per unit of volume as wood does.
The prospect of more truck deliveries, and larger fuel-storage needs, mean Dartmouth would likely have to build a new power plant elsewhere in Hanover if it switched to wood heat, officials said.
The current plant, which features a 175-foot brick smokestack, is located to the east of the Hood Museum of Art and burns roughly 3.5 million gallons of fuel oil each year to heat more than 5 million square feet of building space. It also produces 15 million kwh of electricity, Roberts said, about 23 percent of Dartmouth’s annual power usage.
Roberts and Friedland stressed, however, that no final decision had been made and that biomass is only one of many options that Dartmouth is considering, including biodiesel, solar, wind, geothermal energy and hydropower.
Whatever fuel system the college ultimately adopts will have to work with a new hot-water heating system that administrators plan to install.
Now, according to Roberts, roughly 40 percent of the campus uses steam piped around to heat buildings, a less efficient method whose energy costs are more prone to fluctuation.
Converting those systems, switching over to entirely renewable fuel, and making the countless other renovations and improvements needed to meet the energy goals may cost as much as $100 million, Hanlon said this past weekend.
Although various energy companies have proposed bringing a natural gas pipeline north from Lebanon to campus, with Dartmouth as their anchor customer, school officials this past weekend said they have no plans to use that resource.
Upper Valley conservation groups such as the local Sierra Club chapter have raised concerns about such a pipeline because of the environmental repercussions of natural gas, much of which is extracted through “fracking,” the fracturing of underground rock using pressurized liquid.
Each of the other possible fuel sources has its own advantages and drawbacks.
Biodiesel, or diesel fuel made from vegetable oils, animal fats and recycled grease, would require minimal changes to the power plant’s facilities, according to Roberts, but costs more per unit of thermal energy than No. 6.
Roberts said Dartmouth also was considering making a deal with solar companies who would install panels on college property and maintain ownership of that equipment while selling the electricity to the college at a discount. But although solar photovoltaic panels are a viable option to produce electricity, heating technology has not yet advanced to the point where they make sense for that purpose, he said.
Biomass, a term that can encompass such other kinds of living matter as cow waste, is already in use throughout the Twin States — in Montpelier and Burlington, Vt.; in the Springfield Power plant in Springfield, N.H.; and in the Grafton County Complex, located in North Haverhill.
Hanover Town Manager Julia Griffin said both the middle and high schools in town have biomass boilers, although, she added, “clearly Dartmouth’s plant would be much larger.”
She and Roberts noted that Dartmouth and the town would be coordinating their efforts to meet their energy goals. Hanover residents during Town Meeting next month are scheduled to vote on whether to adopt a similar mark of 100 percent renewables by 2050.
Jim Oakes, maintenance supervisor for Grafton County government, said the county power plant in North Haverhill had cut down drastically on both No. 2 fuel oil use and costs since switching to wood chips. The plant was burning about 90,000 gallons of fuel oil annually when it changed sources in 2012, he said, and now that figure is closer to 3,000.
In the fiscal year ending in 2015, the county bought about $155,000 in wood chips, Oakes said. For comparison, it would have cost about $309,000 to heat with fuel oil.
“Overall, we’ve been very pleased with this system,” he said. “Even though prices for petroleum are down, we’re still saving money.”
Oakes said Grafton County achieved these low prices by contracting out to brokers who buy wood chips from many different harvesters. He said the county government did not look into whether those producers used sustainable replanting and harvesting methods in obtaining the wood chips.
“I’m sure some of them do, and probably others don’t, but we don’t make that part of our bidding process,” he said. “I’m sure if we did we’d pay even more.”
Roberts said that Dartmouth would require that any biomass it obtained be harvested using sustainable forestry practices, and Friedland — adding that he spoke for himself, and not for the task force he co-led — expressed hope that the college, if it did pursue wood chips, would use them as a bridge to an even greener resource or combination thereof.
Friedland, who specializes in the effect of atmospheric pollution on forest ecosystems, noted that it takes many years for trees to grow back and start absorbing carbon from the atmosphere again.
“I’m a proponent of making clear that wood chips are not carbon-neutral,” he said. “If you cut them down and burn them for energy, eventually a forest will grow back in place, and eventually all the carbon you released into the air will come back into the trees.”
Roberts, for his part, noted that Dartmouth had already been making significant energy savings, reducing its greenhouse gas emissions from 85,000 tons in 2005 to 66,000 in 2015, all while adding about 750,000 square feet of building space.
Those accomplishments came through a multifaceted approach to energy efficiency, he said, and not through one catch-all solution.
“We’re not going to get there through a single approach,” he said. “We need to continue building efficient buildings, doing smart renovations of buildings, continuing our energy conservation program, continuing to look at new technologies and ... also looking at renewable sources — and it’s not just one source.
“I think people get focused on one option. It’s not just one source that’s going to make this successful.”
Rob Wolfe can be reached at rwolfe@vnews.com or at 603-727-3242.
Clarification
Dartmouth's oil-burning heating plant also produces about 23 percent of the college's annual demand for electricity, including 40 percent in the heart of its campus. An earlier photo cutline included a percentage for that latter figure, not Dartmouth's overall power consumption.