Garbage in, energy out

Bangor Daily News
Wednesday, January 23, 2008


HAMPDEN, Maine — Landfill gas will be responsible for lighting 2,000 to 3,000 homes within the New England power grid by the end of the week.

Crews at the Pine Tree Landfill on Monday started testing the first engine in the $6 million gas-to-energy project, and had moved on to the second one Tuesday, according to Dan Dutile, environmental technician for Casella Waste Systems Inc., the company that owns the landfill. After tweaking the first engine for hours Monday, the generator produced a half-megawatt of electricity for 10 minutes, he said.

Dutile said he hopes to start and make adjustments to the third and final engine either today or Thursday.

Once all the flaws are identified and repaired, the engines are expected to produce more than 2 megawatts of electricity by Friday, Dutile said. By next week, when operating at its highest efficiency, the facility should be able to produce 3 megawatts of power, lighting approximately 3,000 homes within the grid. Once the engines are fully operational, the facility will run 24 hours a day, seven days a week, Dutile said.

"No later than Friday we should have all three [engines] running and producing power," Dutile said.

The project will turn methane produced by the landfill into usable electricity. In 2002 Casella, a Vermont-based company, installed a gas-extraction system to reduce odor complaints around town. The system vacuums from the landfill gases created by waste decomposition and burns them at a flare that resembles a candle. The flare can be seen from around town, particularly at night along Cold Brook Road.

Once the engines are in full operation, instead of the methane being burned off, it will be used to fuel three 20-cylinder internal combustion engines to power generators capable of producing up to 3 megawatts of electricity — enough to power 3,000 homes in the New England power grid.

The landfill is scheduled to close by 2010, and it already has limited its waste stream to construction and demolition debris and appropriate cover material, such as contaminated soils and incinerator ash. Even though the landfill is nearing closure, Casella expects to produce electricity from the gases for 15 years. Although no financial details were released, company officials expect the project to be profitable.

There are 435 landfill gas-to-energy projects in the nation, according to a U.S. Environmental Protection Agency Web site, and 29 of those are in New England.

The project is the first of its kind in the state, and both Casella and the state have learned a lot from the process, said Cyndi Darling, environmental specialist with the division of solid waste management for the Maine Department of Environmental Protection.

"We were enthusiastic from the beginning," Darling said. "It was a challenge because we don’t have regulations in the solid waste division or air bureau for a gas-to-energy plant."

DEP officials worked closely with Casella during the construction phase, and Darling said the state is working to create regulations. Members of the air bureau and solid waste division often spoke with their counterparts in other New England states to provide guidelines for the Casella project in Hampden, she said.

Although it would not be cost-effective for most Maine landfills to build a gas-to-energy facility, the larger Juniper Ridge Landfill in Old Town and Norridgewock Landfill and Transfer Station could be future candidates, Darling said.

Casella has marketed the electricity as "green power," since it would not use fossil fuels that produce large amounts of greenhouse gases. Burning methane from landfills is generally viewed among environmentalists as cleaner than many other power-producing methods.

State, local and company officials broke ground for the project in May and at the time hoped to be producing electricity by late fall. Design changes and delayed equipment delivery slowed the startup date, Dutile said.

Most of the late-arriving equipment is used to treat the landfill gas before it enters the engines. Hydrogen sulfide, which smells like rotten egg, has to be removed because its byproduct, sulfuric acid, would damage the engines, Dutile said. Additionally, the DEP limits the amount of sulfur dioxide the facility can emit in one year. Dutile said crews would continue to closely monitor emissions.

"It was a disappointment that we weren’t able to bring it on line in time" for the new year, he said.

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