What are the benefits of Middlebury College using biomass?
- 40% reduction in net emissions of carbon or 12,500 metric tons
- eliminates 1 million gallons of Number 6 fuel oil
- transfer to a local, renewable resource
- education of students and the public about energy use
- research into new fuel sources, such as willows that local farmers can grow on marginal lands
- support for locally manufactured green technology
- stimulation of the local and state economy
- less dependence on foreign oil
- used for heating and cooling campus buildings
What is biomass?
Biomass is fuel derived from plants, such as trees, grass, soybeans and corn. Middlebury College uses wood chips in its biomass plant.
Does the biomass plant burn wood?
Actually the biomass plant isn’t “burning” wood. Unlike a household woodstove, it uses a highly efficient gasification process. In this gasification process, wood chips are super-heated in an oxygen deprived environment, where they smolder creating gasses. These gases are ignited to heat water in the boiler, producing steam to heat the campus.
Additionally, the filters in the biomass facility are rated to remove 99.7 % of the particulates from the exhaust. Most of what you can see coming out of the smoke stack is actually steam. Overall the emissions produced by the biomass plant are not greater than those that result from Number 6 fuel oil. In fact, burning wood produces significantly less emission of sulfur compounds, which contribute to acid rain.
Is biomass gasification carbon neutral?
Burning biomass releases CO2 into the atmosphere, but this carbon can be sequestered by growing forests. Although current accounting rules for carbon count biomass as carbon neutral, these accounting rules are under increased scientific scrutiny. Two sections of our senior seminar in environmental studies (ENVS 401) in 2009-2010 studied aspects of this question. In order for biomass to be carbon neutral, we must make sure the land where the biomass is coming from continues to grow biomass to capture carbon. Our current biomass comes from Vermont and New York, two heavily forested states where recent forest growth has exceeded forest harvests. If this remains the case, these forests can help provide a regional sustainable system of biomass that is carbon neutral over a period of time. We will continue to monitor the science, accounting rules, and local forest conditions regarding biomass and carbon.
How is the 12,500 tons of CO2 calculated?
The 12,500 tons of carbon dioxide is calculated by estimating the amount of Number 6 fuel oil that is not burned because of the 20,000 tons of woodchips used as fuel instead each year. That amount equates to about 1.078 million gallons. There are 0.01167 tons of CO2 equivalents per gallon of Number 6 fuel oil. The amount of CO2 equivalents in 1,078,000 gallons of burned fuel oil equates to 12,500 tons. As noted above, although burning biomass releases CO2, that CO2 can be sequestered in a relatively short period of time (decades) in our region.
How many wood chips does Middlebury’s biomass plant use?
The biomass gasification plant uses approximately 20,000 tons of wood chips annually, which during peak heating means 2-3 truckloads of chips are delivered daily. A Biomass Fuel Assessment was prepared by Vermont Family Forests to determine the availability of such a supply in the local area.
Where do the wood chips come from and are they sustainably harvested?
The College works with Cousineau Forest Products to source wood chips within a 75-mile radius. Middlebury is working with the broker to develop a procurement policy to provide us with more information about our suppliers' practices and help us understand the extent to which ecologically sustainable forestry practices are being used.
Does Middlebury College have plans to produce its own biomass?
Middlebury, in collaboration with the SUNY School of Forestry, is in the midst of a promising 4-year research project on College lands to test fast-growing willow shrubs as a locally produced fuel source. Local farmers could grow willows on their marginal land and chip it without needing costly new equipment. The result: more income for local farmers, and less fuel used in shipping Middlebury’s fuel stock.
Is biomass now the only fuel source used for heating and cooling the campus?
No. Middlebury still burns fuel oil in addition to wood chips to provide adequate heating and cooling to the campus.
What happens to the ash?
Ash is collected and used at the College composting site.
What else is sustainable about the biomass plant?
The biomass plant uses the excess pressure from the steam to co-generate approximately 3-5 million kilowatt-hours of electricity per year. Also, the heat from the exhaust is used to preheat water going into the boiler.
What is the College’s long-term goal for reducing its carbon emissions?
Does the College have a plan for reducing the rest of their carbon footprint?
Yes. In 2008, a team of people from across campus developed a climate action implementation plan for Middlebury College. This plan emphasizes the need for institutional commitments coupled with participation from individuals and departments. Based on these recommendations, the College is pursuing pilot projects related to solar thermal, wind, and increased efficiency for campus buildings. Among other efforts to reduce net carbon emissions, the College also recently signed a 10-year contract to purchase biomethane to be produced on area dairy farms by digestion of cow manure. The College in the process of trying to raise the $2 million it will take to put in place the infrastructure needed. If successful, the College anticipates that it would come close to achieving our goal of carbon neutrality.
How much did the biomass project cost and what is the payback?
The project cost $12 million which includes the construction costs for an 8,000 sq. ft. addition to the existing service building and alterations to other space within the existing building, the biomass gasification system (Chiptech, Inc. of Bristol and Williston, VT) and boiler and control systems, plus design and permitting costs.
At $1.50 a gallon for #6 oil and $37/ton for woodchips the internal rate of return is 8.75% and the payback period is approximately 12 years. The switch to biomass from #6 fuel oil will save the College around $840,000 per year in fuel costs, with the expected savings increasing by 3% per year. The project will also pump $800,000 annually into the local economy through the purchase of woodchips. The expected life of the plant is 25 to 30 years.
What percent of the college’s carbon footprint will the biomass plant reduce?
The college projects that its carbon emissions will be reduced by about 12,500 tons, which represent an estimated 40 percent of the college’s 2006 carbon emissions.