October 12 , 07
University of New Hampshire to Power Campus with Landfill Gas

The University of New Hampshire is poised to become one of the nation's most environmentally friendly campuses with the help of an unlikely source: trash.

In a $45 million enterprise, the school is building a pipeline to bring gas captured from the Turnkey Landfill in Rochester to UNH's campus to help power the school.

"It will put UNH and New Hampshire on the map as the leader in green for the nation," said Larry Van Dessel, executive director of facilities and design at the university.

Using landfill gas to run campus power plants is expected to drastically reduce the amount of fossil fuels the school uses and cut the quantity of greenhouse gas emissions it sends out.

The project's premise is simple: when landfill trash decomposes it naturally gives off gases, much of it methane, which is similar to natural gas. UNH officials plan to capture that gas, send it to the school in a pipeline and then use it to run power plants on campus.

With 200 acres of trash, the Turnkey Landfill is one of New England's largest, receiving about 4,500 tons of waste every day, according to Alan Davis, the district manager for Waste Management, the landfill's owner.

Once trash arrives, it is compacted and put into the landfill, then covered with soil, Davis said. Eventually an area becomes filled and then permanently covered with compacted clay, layers of soil and finally vegetation, such as grass.

The garbage remains under the soil permanently, slowly decomposing and producing about 10,000 cubic feet of gas per minute from the whole landfill, Davis said.

To capture that gas, Waste Management has installed about 300 wells and connected them to an extensive piping and pumping network that essentially sucks the gas out and sends it to a power plant on the property that Waste Management uses to run recycling and waste water plants while putting some energy onto the state grid.

The landfill gas is a little more than half methane, about 40 percent carbon dioxide, and some nitrogen and oxygen with a small of amount of other gases, Davis said.

Waste Management captures landfill gas at dozens of sites throughout the country, often sending the fuel to large manufactures such as Nestle, General Motors and Ford, Davis said. But the problem at Turnkey is that only about 40 percent of the gas extracted gets used, and the rest must be burned off. That's where UNH comes in.

Waste Management is contracted to sell about 7,000 cubic feet per minute of the gas to UNH for at least 20 years, Van Dessel said.

Three-part plan

The UNH gas pipeline project has three major components. The first is a gas processing plant to be built at Turnkey. Although Waste Management's power plants are able to use the landfill gas as it is extracted, UNH's generators cannot.

The processing plant will filter out many of the unusable gases, making the end product more than 80 percent methane before it is sent to UNH, Van Dessel said. The plant is scheduled to be up and running in late 2008, he said.

The next part of the project is the pipeline, to run from the landfill in Rochester to UNH's Durham campus. The 12.6-mile pipe, made of a high density plastic and put together in 40-foot lengths that are then melted onto one another, will run down the Spaulding Turnpike to the Pan Am Railway then to Route 4 and on to UNH, ending at the school's power plant.

Pipe sections have been a presence on the turnpike for several weeks. The pipeline is already under construction and is expected to be finished next summer, Van Dessel said.

The final project component will be a new electrical generator at the school, which will be used during the summer months.

UNH already has one generator producing a maximum 7.9 megawatts with a system that uses heat from that power plant to help warm campus buildings. But during the warm summer months, UNH's energy consumption and the need for heating declines, but the amount of gas the school will get does not.

The second generator, expected to produce about 4.6 megawatts, will use that excess summer gas with no need to capture heat from it. The generator is expected to go into use in the summer of 2009.

Once the project is completed, UNH will be able to supply much of its own campus power while hooking into the state and national grid, allowing the school to sell renewable energy credits they receive for making power with the landfill gas.

The credits are part of a push for more renewable energy and must be bought by energy companies in states that require them.

Davis, of Waste Management, said the credits can sell for $30 to $52 per megawatt hour, depending on market conditions.

For UNH, the project benefits are plentiful: the school will reduce the amount of fuel it needs to run its power plants in the face of rising energy costs while also cutting its emissions and making the campus more environmentally friendly.

"This is a wonderfully green project," Van Dessel said.