Anaerobic
digestion decomposes food scrap and other biodegradable material without oxygen
to create a burnable biogas for generating electricity. The food scrap also
produces a fertilizer byproduct.
Anaerobic digestion is considered a renewable energy for reducing landfill gas emissions. As a green energy, it qualifies for the state renewable energy contract program, which offers a fixed electricity pricing. The 20-year pricing project was established in 2011 as an incentive for developers of large-scare renewable energy projects such as wind turbines and solar arrays.
Orbit’s
3.2-megawatt digester project was awarded a power purchase agreement with
National Grid prior to the new legislation. National Grid agreed to buy
electricity for 9.5 cents per kilowatt-hour for the first year, followed by
annual 2 percent price increases. The contract lasts for 15 years, with the
possibility of a six-year extension that must be approved by the state Public
Utilities Commission.
The
only remaining task for the project is finding a source for the organic waste,
said Mark Corigliano, business development manager for Orbit. He's reaching out
to universities, large grocery stores and businesses to provide the food scrap
to help fill the 125-ton daily capacity for the digester.
“This
is really the last piece of the puzzle before we can start construction,”
Corigliano said.
If
food-scrap contracts are signed soon, construction can begin this fall and the
project can be operational in mid-2014, according to Corigliano.
Orbit
currently operates a smaller demonstration digester near its headquarters in
Clinton, N.C. The company plans to break ground on a 5 megawatt digester in
Concord, N.C. later this year. Projects are also underway in California and
Washington State. Two years ago, Orbit said it hoped to break ground on the
Johnston site by the end of 2011. It wasn't until October 2012, however, that
funds were secured for the project.
An
estimated 250 tons of organic waste heads to the Central Landfill daily.
According to the Environmental Protection Agency, only 2 percent of Rhode
Island’s compostable waste is diverted from the landfill.