Boston, MA

Massachusetts Water Resources Authority


Borrego Solar Systems completed work for the Massachusetts Water Resources Authority (MWRA) on the design and installation of a roof-mounted photovoltaic system at the Deer Island Treatment Plant, in Boston Harbor.

The Deer Island roof-mounted project was conceived in response to Governor Patrick’s Executive Order 484, “Leading By Example – Clean Energy and Efficient Buildings,” issued April 18, 2007. That Executive Order sets ambitious standards for the reduction of energy use and greenhouse gas emissions by state agencies, as well as increased use of renewable power – 15% of state government energy use by 2015, 30% by 2020.


The 100kW DC (STC) roof mounted MWRA project presented some unique design and installation challenges due to the plant’s roof configuration and various shading obstacles. Borrego Solar was able to utilize, now closed, international architecture and engineering firm Cubellis’ innovative designs to overcome these hurdles and make this project a reality. The arrays were installed on top of the Residual/Odor Control Building and this site was selected for its large unobstructed roof section that could easily accommodate photovoltaic arrays. The roof was also ideal because it  was resurfaced three years prior to the installation, leaving it in good condition and able to handle substantial wind loads. The energy produced by these solar panels annually will offset the equivalent of 83 metric tons of carbon dioxide.


By taking advantage of the MA Commonwealth Solar rebate program the $870,000 Deer Island solar panel project was funded by a $310,000 Clean Renewable Energy Bonds (CREBs) loan and $560,000 from the Division of Energy Resources. Electricity produced by the solar panels will be used on-site to reduce the amount of electricity purchased by Deer Island. The solar installation will be qualified as a Massachusetts Renewable Portfolio Standards Program (RPS) renewable generation unit and MWRA can sell the Renewable Energy Certificates for solar as it currently does for digester gas.

MWRA has made a major commitment to reduce energy consumption at its facilities in an effort to reduce both operating costs and environmental impacts. Energy audits at the Deer Island Treatment Plant, the Carroll Treatment Plant and the Chelsea facility, along with the new initiative such as the Deer Island solar panels, have provided annual energy savings of about $730,000.

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