Biomass proponents in Western Mass. look to McNeil Generating Station in Vermont to see how a successful plant can operate
By Stan Freeman
October 17, 2009
Photos by Stan Freeman / The Republican
The operator of a front-end loader picks up a pile of wood chips to be burned in the McNeil Generating Station in Burlington, Vt.
BURLINGTON, Vt. – People’s fears 30 years ago would seem familiar today: soaring oil prices were creating an energy vulnerability.
In Northern Vermont, people’s response back then would also seem familiar: Biomass!
In 1978, in this politically progressive city on the shores of Lake Champlain, residents voted by a three to one margin, for the Burlington Electric Department to build the world’s largest wood-burning power plant to take advantage of the state’s rich forest resources.
The McNeil Generating Station began operation in 1984 very near a residential section of the city. Fueled by wood chips brought in by rail cars, it produced 50 megawatts of power, enough electricity for about 30,000 homes.
The plant also became a laboratory for all the biomass plants that would follow, as well as a grounding in reality for the often heated debates in communities considering biomass plants.
Would the skies blacken with soot from the smokestack? Would local rivers be fouled? Would the health of nearby residents deteriorate?
The McNeil station, which has been closely watched by environmentalists, has not fouled the air or the water or noticeably hurt the health of residents of Burlington. (Indeed, the Centers for Disease Control named the city the healthiest in the nation in 2008.) But such biomass plants do raise concerns for environmentalists, especially as proposals for them proliferate across New England, including three for the Pioneer Valley in Russell, Springfield and Greenfield.
Some believe the region’s forests could be overharvested to feed them.
“I don’t think people comprehend how strong the push for biomass could be in the future and what the impact on the forests could be,” said Stephen C. Crowley, who heads energy and climate change programs for the Vermont chapter of the Sierra Club.
“There is no question we could strip our forests beyond their sustainable ability. Once biomass starts looking like a profitable thing, for sure, people are going to go in that direction. So it’s important to look at the conflict before it becomes a conflict,” he said.
The McNeil plant, which is comparable in size to plants proposed for Russell and Greenfield, began operation in 1984, burning wood chips.
“This plant was built as the result of the oil embargo of the 1970s,” said John M. Irving, the McNeil plant’s manager who has won praise from environmentalists for how he has guided the operation there.
“Oil was $25 a barrel, and the sky was the limit. People were having to gas up their cars on odd or even days and they wanted to take control of the situation. Most of Burlington’s power came from a coal-fired plant and it was getting old. All the available hydropower in Vermont had pretty well been developed and Three Mile Island had just happened,” he said.
The plant was located right in the city, very near where the Winooski River empties into Lake Champlain and within shouting distance of residential neighborhoods.
Was the location a mistake? Probably so, said Irving.
“The reason is that the Burlington Electric Department is a municipal utility and traditionally, municipal utilities wanted their power plants to be in town so they had control over it and so those were local jobs. Also, we pay $1 million a year in property taxes, and they didn’t want that to go into someone else’s coffers,” he said.
But instead of transporting wood from rural forests to the urban plant, it would have made more sense to locate the plant near the forests and send the power into the city, he said.
Christopher M. Kilian, an attorney for the Vermont office of the Conservation Law Foundation, which helped negotiate the environmental permit for the plant, agreed.
“Generally people are supportive of McNeil, and my organization has generally been supportive of sustainable biomass,” he said. “But this is really not a very well conceived location for this plant.”
When it was originally licensed, the plant was required by the state to have pollution control equipment that would limit particulate emissions from its stack to a standard “far more stringent” than similar plants at the time, according to a report written for the National Renewable Energy Laboratory in 2000.
“In actual operation, the stack particulate emissions are about ... 10 percent of the state requirements and about 1 percent of the ... particulate standards that were typical of solid fuel stations built when McNeil was built,” the report said.
On most days, there is little indication that anything is coming from the plant’s 257-foot smokestack. Water vapor from the plant’s evaporator is the most prominent issuance. Indeed, because of the advanced pollution control equipment on the plant, the concentration of particles in the neighborhoods immediately around the plant is lower than might be found in a yard of a home with a wood stove, said Richard A. Valentinetti, director of air quality programs for the Vermont Department of Environmental Conservation.
He said the plant is very well run.
“You have to realize the plant is a municipally owned plant in a very progressive city and they have a strong environmental ethic even though their basic mission is to produce the cheapest power possible. The management of the plant and probably the influence of politicians in Burlington have been the key aspects in terms of its success in meeting environmental standards,” he said.
“The management of the plant is as important as the pollution control equipment going on the plant, and the management at McNeil has been really exceptional,” Valentinetti said. “You can’t write that into a permit.”
The McNeil plant also sends treated waste water into the Winooski River. Ann Smith, the program director for Friends of the Winooski River, said she knows of no complaints about the effect if this on the river. “The plant hasn’t been controversial in that respect at all.”
Since McNeil began operation a quarter century ago, the major problem that developed there was dust rising from rail cars as they unloaded wood chips by the plant. The fine particles were settling into surrounding neighborhoods. The problem was solved to neighbors’ satisfaction by covering and enclosing the unloading area.
In fact, it is not the operation of the McNeil plant that concerns environmentalists. It is the operation of plants like it that have yet to be built. Even if air and water pollution from them is as well controlled as they apparently are from McNeil, the strain on forests may be too much, they worry.
Currently, there are at least 10 utility-scale biomass plants proposed for New England that are well along in the permitting process, including seven of more than 25 megawatts – two in Connecticut in Watertown and Plainfield, one in North Springfield, Vt.; one in Berlin, N.H.; in addition to three in the Pioneer Valley.
Kilian said that when the environmental permit was granted for McNeil, it contained a very strong forest management requirement.
“We worked on making sure there was a condition that really dictated how the wood supply for the facility needed to be harvested. The primary focus was on assuring that there was at least a relatively local supply of wood,” he said.
“It’s critical that in the context of a regionwide effort to develop biomass facilities there has to be a realistic evaluation of the fuel base. We can’t just build these plants willy-nilly and expect the forests will be there to support them,” he said.
Matthew Kelty, a professor of natural resources in the department of natural resources conservation at University of Massachusetts, has been studying the future of biomass plants in New England.
“For a long time, foresters have thought that having a reasonable amount (of biomass plants) would be great because it would allow us to do better forest management. We’d be able to take out poor quality trees (which biomass plants use) and allow the better trees to grow,” he said.
“But our estimates were that about three of these 50-megawatt plants (in Massachusetts) would use up about the annual growth of our forests,” Kelty said.
“These plants are in the free market, though. So who knows how many will be developed. And there will be some close to our borders in other states. So we could start overharvesting at some point,” he said.
While they encourage renewable energy projects that would lessen the dependence of the state on foreign energy supplies, Massachusetts environmental officials were concerned enough about warnings from foresters about the potential threat of too many biomass plants that they temporarily halted the permitting process for those proposed in the commonwealth in the spring and called for a “white paper” on the issue.
A request for contractors for the study went out in June and one is scheduled to be chosen in mid-October.
Kelty said new state regulations about how trees can be harvested for the plants are likely to result from the study.
“One of the things that is the most important is to limit the amount of whole tree removal. They cut down the tree and pull it out to chip it up. The tops of the trees, the twigs and needles and leaves, go into the chipper as well and that’s where all the nutrients are. It could become a problem is they take away all the soil nutrients,” he said.
“In states like Minnesota, Wisconsin and Pennsylvania, they are starting to propose regulations that 30 percent of the trees cut have to have the tops left in. Some people have proposed cutting all the tops off and leaving them in. We always used to do that when we used to cut big sawtimber. You always cut off the crown and left it there,” he said.
In addition to tightened rules for how forests are harvested, more needs to be understood about how trees absorb and store carbon, the basis, at least in theory, for the “carbon neutral” advantage that biomass plants are supposed to have over coal and oil-fired plants, say forestry researchers.
Yes, burning trees gives off carbon dioxide, a greenhouse gas, but the trees that are burned spent their lives absorbing carbon dioxide during photosynthesis, then storing the carbon and releasing oxygen. If they had died in the forest and decomposed, they would have released that carbon back into the environment anyway.
Kilian, of the Conservation Law Foundation, said it annoys him to hear opponents of biomass plants make the statement that the plants can release as much carbon dioxide as a coal-fired plant, while conveniently leaving out the fact that the trees that go into the furnace absorb carbon dioxide while they are growing and coal in the ground does not, making biomass plants, theoretically, carbon neutral.
“A lot of the complaints that arise are really complaints where people are concerned about siting the plant near them. Their arguments are just another way to trying to stop a project,” he said.
He called discussions of whether biomass plants are truly carbon neutral “like trying to figure out how many angels can dance on the head of a pin.”
“It seems ridiculous when you have Brayton Point (New England’s largest coal-fired plant, in Somerset, Mass.) The problem of coal plants is of such a massive magnitude that we shouldn’t be devoting a lot of time and effort to arguing whether or not the biomass model is perfect,” he said.
“However, I think biomass is a renewable fuel that can be harvested and then burned in a facility in a manner that is carbon neutral,” Kilian said.
Crowley, of the Sierra Club, said the understanding of the carbon cycle “is an area of science that is not settled. How much do different aged stands take up in carbon? There is some suggestion that the earlier studies that are now taken as gospel where not all that thorough. Older stands, according to new studies, do much better at sequestering carbon.”
Kelty said, “There is a lot of carbon in a big tree. So if you cut it down, things are not going to be carbon-neutral in the next five years because the new trees have to grow in and sequester the carbon. It becomes far more difficult a problem (than was thought) because of the time involved.”
“Personally, I think that biomass should be looked at as one part of the mix of wind and solar and other sorts of things, but that biomass used appropriately can help us for the next 30 or 40 years as we move to other sources,” he said.
This conveyor belt, front right, conveys wood chips into the McNeil Generating Station.