BURLINGTON — Two miles down the street from the state’s largest single producer of power, the McNeil Generating Station, a standing-room-only crowd gathered Tuesday to listen to representatives of the city’s electric utility, scientists and members of the forestry industry debate McNeil’s merits and whether it should be expanded.
The plant creates 248,700 megawatt hours of electricity in an average year — enough, roughly, to meet demand across the city. It produces that power, mainly, by burning wood chips, using largely low-grade wood such as branches or diseased trees left over from logging jobs.
Burlington Electric Department operates the station, and it’s owned jointly by the Burlington utility, Green Mountain Power and Vermont Public Power Supply Authority, or VPPSA.
Recently, the utilities have been moving toward forming a district energy system by capturing wasted steam heat from the plant and sending it to the University of Vermont, UVM Medical Center and the Intervale Center, which is located next door to McNeil.
Underground pipes would carry thermal energy in the form of steam or hot water. Using the power plant’s waste heat and steam would offset emissions that come from using natural gas by a projected 16% in Burlington.
While McNeil has been operating since 1984, when it replaced a coal plant, the urgency of climate change has brought new conversations about whether burning wood for energy — long considered to have “net-zero” emissions by Vermont and other entities around the world — helps or hurts the effort to reduce planet-warming carbon dioxide in the atmosphere.
Tuesday night’s panel included six speakers with expertise in climate change, greenhouse gas emissions accounting, the forestry industry and Burlington’s energy system.
The three most vocal panelists were Darren Springer, general manager of Burlington Electric Department; William Moomaw, a lead author on five reports from the Intergovernmental Panel on Climate Change; and Juliette Rooney-Varga, an environmental science professor at the University of Massachusetts Lowell.
Much of the conversation focused on emissions at McNeil — and how they’re counted.
In 2022, McNeil emitted 375,540 tons of carbon dioxide from its smokestacks, according to Burlington Electric Department. When measured this way, biomass emissions are similar to emissions from a fossil fuel plant, but the energy source is considered to have net-zero emissions — and is not counted in Vermont’s emissions data — because trees grow back to replace those that were cut and burned.
Springer said that more trees have grown in the private timberlands where McNeil gets its wood, and that the carbon storage and sequestration from that growth more than neutralizes the emissions.
“When you convert the carbon into CO2, which is the greenhouse gas that we’re all concerned about, you get 24.3 million tons of additional forest CO2 between 2007 and 2020,” he said.
But Moomaw and Rooney-Varga questioned whether the new, young trees sequester and store the emitted carbon fast enough, especially as the Earth rapidly reaches 1.5 degrees Celsius of warming, which is widely considered a tipping point after which disastrous consequences would be extremely difficult to avoid.
Rooney-Varga demonstrated the flow of emissions and sequestration using two cups of water. Water in one cup represented carbon in the atmosphere, and water in the other cup represented carbon in forests.
“If I harvest and burn the wood, I’m doing this,” she said, and poured water from the cup representing the forest into the one representing the atmosphere. Carbon also accumulates in forests, she said, and poured water back into the forest cup.
It’s easy to argue about how fast those flows are happening, she said, and that’s the most complex question surrounding biomass. But she argued that, if left alone, trees would continue to store and sequester more carbon, and emissions from the plant would be avoided.
“We need to be careful about what we’re giving biomass credit for,” she said. The fact that biomass energy is considered net-zero assumes that two parts of the system exist: one that cuts and burns trees and another that grows them. Therefore, it credits the energy usage with the regrowth of trees. But Rooney-Varga questioned that point, saying that if biomass wasn’t used for energy, the trees would continue to grow and likely draw even more carbon out of the atmosphere.
In response, Springer argued that McNeil is a necessary energy producer, and without it Vermont would likely be getting more energy from natural gas.
“The thing about McNeil that is important from a reliability standpoint is it can store fuel on-site, and it can be dispatched when we need energy,” Springer said. “That’s similar to how some fossil fuel plants can run. Many renewable plants can’t operate that way.”
That’s particularly important in the winter, he said, when energy demand and prices go up. Without McNeil, in fiscal year 2023 Burlington Electric would have needed to increase its rates by 20% to compensate for higher power costs, according to the utility’s website.
McNeil is also part of a larger economic system. Members of the forestry industry, including forester and panelist Harris Roen, argued that the low-grade wood market is essential for those who work in forests.
“The wood, at least that I send to McNeil … is the tops and the branches. The trees are getting cut anyways for the saw logs. It’s not, in my mind, going to reduce a whole lot of the amount of trees getting cut, by not sending them to McNeil,” Roen said.
A member of the audience who identified himself as a forester said the money he receives for selling low-grade wood enables him to cut fewer large trees.
Springer and others argued that the district energy project would make McNeil more efficient by making use of energy that is currently wasted.
Rooney-Varga argued that, even if the new system would make the plant more efficient, it would “prolong Burlington’s commitment to this plant. It would invest in keeping this plant going.”
“And I think that is a risky proposition for a city that is committed to climate action — and also in a changing policy environment,” she said.
Rooney-Varga pointed to Massachusetts, which recently passed a law declaring that biomass energy can no longer be considered renewable. She suggested Vermont could follow suit.
Meanwhile, lawmakers in Vermont recently passed the Affordable Heat Act in an effort to reduce emissions from the heating and cooling of buildings. The new law sets a path for designing and preparing to implement a clean heat standard, which is intended to incentivize a transition to heating sources that pollute less.
If lawmakers vote to implement the clean heat standard, McNeil’s district energy project would likely be recognized as a project that reduces emissions, Springer said on Tuesday — a point likely to face criticism from environmentalists.
The project, Springer said, is “pretty close to moving forward.” It is currently going through an Act 250 permit process.
Gene Bergman, a member of Burlington City Council’s Transportation, Energy, and Utilities Committee, thanked the public for turning out for the three-hour meeting.
He said the committee plans to continue talking about how to meet all priorities at once: conserve more forest, support the forestry industry’s need to sell low-grade wood and “increase the efficiencies and reduce emissions at the stack.”
“Wouldn’t that be frickin’ amazing?” he said.
