At its meeting on June 2, the Medfield Board of Selectmen listened to an intriguing presentation from Mark Sandeen, a member of the Select Board in Lexington. In February, Lexington had opened its new Hastings Elementary School as a net-positive building: an all-electric building that uses no fossil fuels and that generates more energy than it consumes in its operation. Mr. Sandeen had been invited by Fred Davis, chair of the Medfield Energy Committee, to be part of a presentation by the MEC to the Board of Selectmen. The MEC asked the board to charge the MEC and Arrowstreet, the Dale Street Planning Committee architectural firm, to figure out together whether a new school building for Medfield could be constructed as a fossil fuel-free building, at a total lifecycle cost that equals (or is less than) that of a more conventional building.

In his introductory remarks, Fred Davis pointed out that this is already proven technology, implemented in a number of schools in Massachusetts.

As Mark Sandeen explained, the Hastings School is an 110,000-square-foot elementary school building that is going to house 645 students on a regular basis, the second (and larger) of two net-zero school buildings now operating in Lexington. Several features enable the building to produce more than enough energy to meet its own needs: a tight envelope reduces those needs by 50%; in addition to solar panels on the roof, solar canopies were erected on the parking lots around the building. An electric heat pump will move heat from the ground during the winter months, and it will cool the building during the summer by pumping heat out of the building back into the ground. The annual energy needs of the building were calculated at 970,000 kilowatt hours of electricity; the solar installations on the rooftop and the canopies are projected to produce 1.1 million kilowatt hours per year. An extensive battery system was installed to lower peak demand in the building.

An additional benefit of this design is that the Hastings School is the healthiest school building ever erected in Lexington; increased and improved air circulation creates an environment that is most conducive to student learning.

The Lexington facility will, on an annual basis, produce more energy than it consumes. The net-zero-energy features, along with incentives from the Massachusetts Department of Energy Resources, provide substantial net dollar benefits to the town from Day One. Under a worst-case scenario (if revenue is lower than expected and expense higher than expected), Sandeen projects a net income to the town (annual dollar benefits exceeding annual bond payment) in the range of $30,000. Under moderate conditions, the projection of net benefit goes up to around $100,000/year.

Mr. Sandeen’s talk is available as part of the video taken of the Selectmen’s meeting on June 2, which has been posted on YouTube by Medfield TV (the MEC presentation begins at 57.53).

As Medfield’s project is just entering the design phase, this is the perfect time to think about making the Dale Street School an all-electric Net Zero building. At the end of the presentation, the Selectmen were definitely interested in the concept and charged the MEC and Arrowstreet with creating scenarios informed by Mr. Sandeen’s presentation.

The MEC is working on a number of fronts to reduce carbon emissions in Medfield. If you would like more information or to help with these efforts, contact Fred Davis, MEC chair.

Fritz Fleischmann is a resident of Spring Street.