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Oct 30, 2024

Renewable Energy | Middlebury

Middlebury is committed to using 100 percent renewable energy by 2028. We will reach this goal through the Energy2028 initiative. Middlebury College celebrated the official launch of its biomass

Middlebury is committed to using 100 percent renewable energy by 2028.

We will reach this goal through the Energy2028 initiative.

Middlebury College celebrated the official launch of its biomass gasification plant with a reception, tours, and a lecture by author, activist, and Middlebury Scholar in Residence Bill McKibben on February 19, 2009, at McCullough Student Center.

Biomass is fuel derived from plants such as trees, grass, soybeans, and corn. Middlebury uses locally sourced wood chips, which are superheated in a low oxygen chamber where they smolder (not burn) and emit wood gas. Oxygen is introduced on the backside of the boiler causing the gas to ignite, producing heat (at temperatures of over 1100° F) to make steam that is distributed throughout campus for heating, cooling, hot water, and cooking.

A partnership between Middlebury, the Goodrich Family Farm in Salisbury, Vanguard Renewables, and Vermont Gas Systems has led to a first-of-its-kind system that will begin supplying the main campus with RNG in 2021. Read more about Middlebury’s commitment to 100 percent renewable energy.

Exhaust from the gasification process circulates through a cyclone separator and then through a series of filters. This filtration system is rated to remove 99.5 percent of particulates, so most of what comes from the smokestack is water vapor.

Other energy-efficiency measures include using the exhaust from gasification to preheat the water entering the boiler and the excess pressure from the steam to cogenerate approximately 3–5 million kilowatt-hours of electricity per year, which is distributed throughout campus. And local farms use the ash produced in gasification as a soil amendment.

Highlights:

A 40-percent reduction in net emissions of carbon eliminates one million gallons of #6 fuel oil and instead supports a local, renewable resource. The biomass plant also serves as a place to educate students and the public about energy use and research into new fuel sources. And purchasing local wood chips stimulates the local and state economy and creates less dependence on foreign oil.

Highlights:

Biomass gasification has been successful, but not without issues. Small fires in the plant led to modifications, and we developed our own patents to increase the safety and efficiency of the process.The plant has a 25-year life expectancy, and we are continuously assessing new technologies to be well-informed about our options beyond that.

Burning biomass releases carbon into the atmosphere, but this carbon can be sequestered by growing forests. Although current carbon accounting rules count biomass as a neutral source, these accounting rules are under increased scientific scrutiny. Two sections of a senior seminar in environmental studies (ENVS 401) in 2010 studied this. In order for biomass to be carbon neutral, the land where the biomass is coming from must continue to grow biomass to capture carbon. Using data from the U.S. Forest Service, the class determined that the 20,000 tons of wood chips Middlebury burns represent less than one percent of the net growth of the forests in the region where we obtain the chips.

Middlebury 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.

Middlebury sources wood chips within a 75-mile radius 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. Middlebury is working to develop a system 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.

The Willow Project

In 2006, Middlebury partnered with SUNY College of Environmental Science and Forestry to test the feasibility of growing willow trees as a fuel source for the biomass plant. The trees were planted on 10 acres adjacent to Middlebury’s Organic Farm over a three-year period. In 2011, the willows were cut and chipped and tested in the biomass plant. After various analyses, Middlebury concluded that willows are not a feasible fuel source.

The biomass gasification plant uses about 25,000 tons of wood chips annually, which is two or three truckloads of chips delivered daily during peak heating. A Biomass Fuel Assessment was prepared by Vermont Family Forests to determine the availability of such a supply in the local area prior to its implementation.

Middlebury uses natural gas in addition to wood chips to provide adequate heating and cooling to the campus. #6 fuel oil is also used as a backup.

The project cost was $12 million, which includes the construction costs for an 8,000-square-foot addition to the existing service building, alterations to other spaces within the existing building, the biomass gasification system, boiler, and control systems, plus design and permitting costs.

At $1.50 a gallon for #6 fuel oil and $37 a ton for wood chips, the internal rate of return is 8.75 percent and the payback period is approximately 12 years. The switch to biomass from oil saves Middlebury around $1,000,000 per year, with the expected savings increasing by 3 percent per year. The project will also pump $1,000,000 annually into the local economy through the purchase of wood chips. The expected life of the plant is 25 to 30 years. We are continuously assessing new technologies with an eye toward greater efficiency for the plant and to be well-informed about our options when the plant is retired.

At the urging of students, Middlebury built a 143-kilowatt, 1.5-acre solar farm on Route 125, west of McCardell Bicentennial Hall. The 34 solar trackers on the farm are from AllEarth Renewables, a company based in Williston, Vermont. AllEarth manufactures the innovative solar energy systems, called AllSun Trackers, which feed electricity into nearby power lines. A research grade set of photo voltaic monitoring sensors and instruments was also installed to collect and store data for research by Middlebury faculty and students.

The solar farm produces about 243,000 kilowatt-hours each year—more electricity than is used annually in Forest, a student residence hall. The solar panel energy production report shows monthly progress and reports.

In 2015 Middlebury became the exclusive purchaser of electricity from nearby South Ridge Solar Farm. In combination with the campus solar farm, 5 percent of campus electricity is now solar generated.

In 2016, Middlebury entered into a power-purchase agreement with Wilber Solar on a 500-kilowatt project, which will bring our supply of solar electricity on campus to about 8 percent of what we use annually.

In 2011, Middlebury was the first undergraduate liberal arts college selected to compete in the U.S. Department of Energy’s Solar Decathlon, an international competition to design, build, and operate solar-powered houses that are cost effective, energy efficient, and aesthetically pleasing. That house, Self-Reliance, won first place in three of the ten categories. In 2013 Middlebury placed eighth overall with a design called InSite. Both homes now serve as undergraduate housing on campus.

Solar panels have been installed on the Franklin Environmental Center, the Solar Decathlon’s Self-Reliance and InSite houses, and Farrell House. Together these produce about 259 kilowatt hours a year. In addition, two solar hot water systems have been installed in student housing.

Middlebury’s location in mountainous Vermont makes us a strong candidate for producing renewable, carbon-neutral wind power on campus. From our 10-kilowatt wind turbine that’s been spinning since 2005 to studying wind data at the Middlebury College Snow Bowl to determine if a turbine can be installed there, Middlebury is continually looking for opportunities to increase our wind-power output.

Originated as a project in an environmental studies class and funded from an Environmental Council grant, Middlebury’s 10-kilowatt wind turbine produces more than 8,000 kilowatts annually—roughly equivalent to the annual energy consumption of a home—and provides approximately 15 percent of the electrical needs of the facility.

In 2006, the Middlebury College Snow Bowl was the first U.S. ski resort to institute carbon-neutral operations across its facilities through offsets from Native Energy.