Middlebury

 

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.