R.I.’s First Anaerobic Digester Expected by End of Year


JOHNSTON, R.I. — Rhode Island’s new composting law appears to have produced one of its first new businesses: a large food scrap-to-energy digester.

The $18.9 million project broke ground near the Central Landfill on May 28. The facility plans to begin accepting up to 250 tons of food scrap daily by the end of the year. It will open just as the state’s composting law takes effect, Jan. 1, 2016. The legislation, passed in 2014, requires large restaurants, grocery stores, hotels and food makers to either donate their leftover food to food pantries or farmers or ship it to a composting facility or food digester.

An institution must only comply if it produces at least 104 tons of food scrap annually and a commercial compost facility or digester exists within 15 miles of the institution. Until the new facility opens, Earth Care Farm in Charlestown is the state’s only commercial composter.

Earth Care Farm uses open piles, known as windrows, to turn food scrap and other organic material into nutrient-rich, Class-A agricultural compost.

The new facility, to be built by Israeli-based Blue Sphere Corp., will use a closed-tank fermentation process, called anaerobic digestion, to create methane, a burnable gas more potent that carbon dioxide when it comes to climate emissions, and a soil amendment. The methane will fuel generators that have a capacity to generate up to 3.2 megawatts of power.

Blue Sphere says uneaten food will be its primary source of energy, rather than other organic material such as yard waste and paper. According to the Environmental Protection Agency, Rhode Islanders throw away 150,000 tons of wasted food annually.

National Grid has 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 an extension that must be approved by the state Public Utilities Commission.

The power-purchase agreement was awarded in 2011 to Orbit Energy Inc. of Raleigh, N.C. The company will be the operator of the Rhode Island facility. It expects to employ five or six full-time workers.

Using a technology designed and built by Austep of Italy, the anaerobic digestion process will take place in two 2.5-million gallon tanks.

During the recent dedication, Michael OConnell, executive director of the Rhode Island Resource Recovery Corporation, the operator of the Central Landfill, said he will be glad to have the food scrap diverted from the waste stream.

Blue Sphere recently opened its U.S. office in Charlotte, N.C., with plans to build 11 other biogas plants. Blue Sphere broke ground on its first biogas-energy facility in Charlotte in March. The $27 million 5.2-megawatt project has the capacity to power more than 3,000 homes. All of its new biogas facilities are expected to be running by 2018. The company wants to open anaerobic digesters in other densely populated states that also have composting laws such as Massachusetts and Connecticut.

“This is the best area in the United States to do anaerobic digester business,” Blue Sphere CEO Shlomi Palas told ecoRI News.

Entropy Investment Management, a renewable energy investment firm based in Charlotte, will finance the project in Johnston and other projects.

A separate company, NEO Energy of Portsmouth, N.H., has plans to build an organic waste-to-energy digester at the Quonset Business Park in North Kingstown. Construction has yet to begin but the company said the project is moving ahead and plans to be operational by the end of 2016.


Join the Discussion

View Comments

Leave a Reply

Your email address will not be published. Required fields are marked *

Your support keeps our reporters on the environmental beat.

Reader support is at the core of our nonprofit news model. Together, we can keep the environment in the headlines.


We use cookies to improve your experience and deliver personalized content. View Cookie Settings