Tuesday, February 26, 2008

Harvesting Energy from Compost


The proliferation of small-scale power plants is skyrocketing across New England as many communities are tapping into abundant, natural sources of energy--from Cow Power in Vermont to a plan in Boston to use Fall foliage for something other than to attract tourists.

A staff writer for Boston.com, Andrew Ryan, revealed the innovative scheme for tapping yard clippings, leaves, and food scraps to produce heat and electrical power. "Urban decay, redefined" describes a plan to generate electricity for up to 1,500 homes and heat for a rooftop greenhouse from the power of compost.

The project, which is still in the early conceptual stage, would take the city's 6,000-ton composting program indoors. For more than a decade, leaves and yard clippings have been collected each spring and fall and trucked to a muddy clearing off American Legion Highway in Roslindale. The undulating mound is almost two stories tall, loaded with tan, brown, and black leaves in various states of decay. On a recent afternoon, white steam gushed from the pile, evidence that microorganisms were hard at work, generating heat that pushes the internal temperature near 130 degrees, said Nora Goldstein, executive editor of BioCycle magazine.

In an enclosed facility, officials would recycle heat and biogas released when leaves, grass clippings, and other organic material decay. Biogas includes methane, which would fuel a turbine, generating up to 1.5 megawatts of power, and carbon dioxide, which would nurture plants in the greenhouse.

"There have been pieces of this that have been done other places, so there isn't as much of a worry that it would fail," said Tom L. Richard, director of the Institutes of Energy and the Environment at Penn State University. "But it is new enough and innovative enough that it would hopefully be an example that other places in the country could follow."

The move toward collecting energy from materials we normally consider "waste"--whether cow pies or maple leaves--is an indicator that we can solve many of our energy needs simply through resourcefulness and ingenuity. Why build more coal and nuclear power plants when abundant renewable energy sources surround us?