NBC Bucklin Point Biogas Combined Heat and Power Project

BiogasNBC’s Bucklin Point Wastewater Treatment Facility (WWTF) uses anaerobic digestion to stabilize sludge generated through the wastewater treatment process. Anaerobic digestion reduces the volume of sludge and produces methane containing biogas, a renewable energy, as a by-product. Harnessing the energy from the biogas through an efficient combustion process is both economically and environmentally beneficial (methane is a very powerful greenhouse gas).

The Bucklin Point WWTF produces approximately 250,000 standard cubic feet/day of biogas containing 60% methane which is equivalent to the heating demand of about 250 average sized homes on mid-winter’s day. A major portion of this biogas is burned in an on-site boiler to heat the facility’s three sludge digesters. Excess biogas is flared.

CHP SystemUsing $25,000 in grant funds from the Rhode Island Office of Energy Resources, NBC conducted a study on how to use this biogas more effectively. NBC’s Biogas Renewable Energy Study concluded that it is both technically and economically feasible to use the biogas to generate electricity and useful heat as part of a 600 kW Combined Heat and Power (CHP) system equipped with a reciprocating engine. A CHP system produces both electricity and useful heat increasing the overall efficiency of the fuel. The NBC estimates that the CHP system will be able to generate as much as 4,000,000 kWh/year of renewable electricity and 23,000 MMBTUs/year of useful heat. This process will result in energy cost savings and an estimated reduction in carbon dioxide emissions of more than 1,000 metric tons (1,100 tons) per year.

NBC, as of June 2011, has completed a detailed Feasibility Study with respect to using biogas to generate electricity and useful heat at the Bucklin Point WWTF, conducted preliminary investigations into local environmental and health and safety impacts including air emissions and noise, and selected a Biogas Energy Project Team from the engineering firm of Brown and Caldwell to complete the final design of the Biogas CHP System. The Bucklin Point WWTF Biogas CHP Project is expected to be completed and operational in October 2012.