According to recent reports, in the near future the Boston Water and Sewer Commission (BWSC) building at 980 Harrison Avenue will be taking advantage of clean, renewable solar energy to provide about seven percent of its electricity.

Seven percent may seem like a tiny amount, until you consider the size of the water and sewer commission’s new building, or the fact that the utility, established in 1977, serves more than one million residents; that is, 88,000 drinking water ratepayers, and a resident population of 590,000 that almost doubles with the commuter population during the day.

The roof-mounted system, on top of the BWSC’s relatively new and energy-efficient building, will be installed by the concerted efforts of electrical contracting firm Fischbach & Moore, headquartered in Boston; Newton-based solar developer Rivermoor Energy; and Cambridge-based renewable energy consulting firm Zapotec Energy.

The cost of the project is estimated at about $1,075,000, and the 240-kilowatt array is expected to be operational by May. The seven percent, in fiscal terms, represents about $45,000 in electricity savings per year, and is also expected to create at least 15 “green” jobs during the quarter the solar array takes to construct.

Boston city officials also expect to get about $900,000 in production incentives from Mass Energy Consumers Alliance in Massachusetts (operating under the auspices of the Energy Consumers Alliance of New England, or ECANE). ECANE purchases renewable energy credits, or RECs, at $0.03 per kilowatt hour on three-year contracts.

The Boston-area electricity provider is NStar, whose rates – thanks to an order issued by the Department of Public Utilities (DPU) – remain among the lowest on the East Coast. NStar, whose generation mix includes a surprising portion of Canadian hydro (Hydro Quebec), also, and unfortunately, reflects New England’s preponderance of coal-driven (65 percent) generation, though NStar is slowly improving that footprint – if primarily at the behest of the Massachusetts renewable portfolio standard, which operates through renewable energy credits, or RECs, and mandates 15 percent by 2020, and incremental increases of one percent yearly thereafter for new resources. The mandated in-state solar photovoltaic target is 400 megawatts.

The BWSC solar array was evaluated in a 2009 commission report, which also included evaluation of building energy efficiency measures (lighting and HVAC) and their effectiveness in reducing energy use and improving the agency’s carbon footprint.

While noting that “solar photovoltaic electric generation installations qualify for rebate financing through Massachusetts Technology Collaborative, the state agency responsible for developing renewable energy”, the report also noted that $550,000 had already been budgeted for the solar installation, making it quite clear the direction executives intended to take to improve carbon emissions.