Great Sandy Bottom Pond Water Treatment Plant Level II Energy Audit
Weston & Sampson was contracted by Massachusetts Department of Energy Resources (MA DOER) to perform an American Society of Heating, Refrigeration and Air Conditioning Engineers (ASHRAE) Level II energy audit for the Great Sandy Bottom Pond Water Treatment Plant in Pembroke, Massachusetts. Construction of this primary drinking water treatment plant was completed in 1989 and helps serve a population 34,133 through 11,112 service connections in the towns of Abington and Rockland, Massachusetts, with potable water for public consumption, as well as water for fire suppression. Water production at this plant is an average of 1.46 million gallons per day (MGD), with a maximum capacity of 3.81 MGD.
The facility uses electricity and natural gas in its operation. The maximum summer peak demand is 222 kilowatts (kW) and the annual electrical energy use at the plant is 1,239,400 kilowatt-hours (kWh), at a cost of $143,412 ($0.1157 per kWh). The annual natural gas use at the plant is 9,310 therms at a cost of $8,619 ($0.93 therm). The total annual energy use for operating the plant is on the order of 5,145 million British Thermal Units (MBTU) at an audited cost of $152,483 per year. The cost of water treatment as a function of energy use is $276 per million gallons of finished potable water, which excludes water pumped during back flushing.
Weston & Sampson evaluated potential energy conservation measures in the area of lighting, water heating motor replacement, operational measures, and energy supply measures that, combined, could reduce electric demand by 26 kW and reduce consumption by 171,452 kWh, saving up to $112,587 in energy costs annually. The majority of the cost savings would result from better energy supply contract opportunities, where the cost of energy would be reduced from $0.1256 to $0.07348 per kWh, and could be reduced further to $0.05052 kWh through use of the default rate offered by National Grid under tariff for the rate class.