The McNeil Power Plant in Burlington's Intervale has produced power from wood chips for going on three decades. When it went online in 1984, it was state of the art.
For John Irving, who helped design the plant back in the 1970s and has been its manager ever since, McNeil has defined his career.
"This is the standard by which all other biomass plants are judged and we're very proud of it," Irving said.
For many, McNeil, which is jointly owned by Burlington Electric and Green Mountain Power, is the poster child of Vermont industrial-sized biomass. At 50 megawatts, it's second only in base-load production to Vermont Yankee. It's one of two industrial-scale plants operating in the state. The other, in Ryegate, went online 20 years ago and produces less than half McNeil's output. Currently two other plants are on the drawing board; one in North Springfield and one in Fair Haven.
For all of these projects the issues of economics and potential impacts on the environment have been front and center, and in each case, McNeil provides valuable lessons.
"No biomass plant can produce energy, can produce electricity at a 60 percent efficiency unless you have a large thermal customer," Irving said.
Both McNeil and Ryegate do not use their waste heat. Experts say that's one of the least efficient uses of biomass.
"If all you're using that heat for is to create steam pressure to turn a turbine to generate electrons, only about 25 percent of the potential energy of that fuel source goes into a usable form of energy. So 75 percent of that energy is lost in the form of waste heat," said Adam Sherman of the Vermont Energy Investment Corporation.
Irving readily admits McNeil was designed to play a much different role.
"You could do aquaculture, you could grow fish, you could grow tomatoes-- you could do all of these things. And they looked at all those different things and we haven't done any of those, but that doesn't mean the plant is a failure," he explained.
Not only is McNeil less efficient, critics say it-- and others like it-- emit more carbon dioxide than a coal-fired plant; emissions that experts say contribute to climate change. Josh Schlossberg with the group Energy Justice says making more McNeils doesn't make sense.
"If we're moving forward with clean energy, if we can send robots to Mars, surely we can focus on energy that doesn't have a smokestack. That's like 18th century stuff," Schlossberg said.
While Irving admits the CO2 output for biomass is higher, he says the emissions are cleaner than most wood stoves and fall well under state and federal requirements.
"When we built the plant, carbon wasn't an issue because nobody was worried about greenhouse gases or knew that CO2 was an issue at all," Irving said. "For years the world has thought if you harvest wood properly and burn it properly, it's CO2 neutral at worst."
Experts say it's the economics of energy more than anything else that will ultimately determine whether new biomass plants get built.
Upstairs in the control room at McNeil, operators can control the energy output every hour of the day depending on fluctuations in energy market prices.
With the price of natural gas at rock bottom, McNeil and Ryegate have used various subsidies to stay competitive. In the case of McNeil, it comes in the form of a nitrogen oxide scrubber installed 4 years ago. The equipment allows McNeil to sell renewable energy credits out of state. Credits that, ironically, are worth more than the power the plant produces.
"It's frankly easier and cheaper to build a natural gas combined cycle plant than it is to do a biomass plant or coal plant or an oil plant or a wind turbine or solar if you don't have subsidies," Irving said.
The Legislature last session required the Agency of Natural Resources to more closely examine greenhouse gas impacts and assess efficient use of forests when considering new industrial biomass projects.
Mike Snyder, the commissioner of the Vt. Forests, Parks and Recreation Department, is the part of the team mandated to carry that out.
"Our role is to say we want to see anybody who proposes to use forest products in any way in Vermont that's important and potentially could go bad. Our role is to ensure that projects-- not to push for or against them-- but to make sure that the right questions are asked and that they are in the public good. And that if they go forward they go forward in the best possible way," Snyder said.
Determining biomass's place in Vermont's energy future.
Friday, April 18 2014 10:13 PM EDT2014-04-19 02:13:23 GMT
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