Bill would mandate rooftop solar on new homes and commercial buildings


Massachusetts lawmakers proposed a bill that would require rooftop solar on new residential and commercial buildings.

The Solar Neighborhoods Act (H.D.3098) would mandate that solar panels be installed on the roofs of newly built homes, apartments, and office buildings. A companion bill, S.D.159, was filed in the Senate.

A bill summary said that all new buildings would need to be built “solar-ready.” Within one year of the bill’s passage, the Department of Energy Resources (DOER) would develop and adopt amendments to the state’s building code to ensure that roofs are strong enough to support solar panels, that available roof space is maximized, and that buildings can make room for necessary electrical infrastructure.

For single-family homes, the solar energy system would need to produce enough electricity each year to meet 80% of the average demand for similar houses. For other buildings, DOER would set minimum solar energy system requirements.

Buildings may be exempted if the roof is too shaded, if a solar hot water system or other renewable energy technology is installed, or if the building has a green roof. The DOER also could grant exemptions to affordable housing developments.

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The House bill is modeled after a similar policy in California.

In 2018, California became the first state to require that all new homes be built with solar panels starting in 2020. The mandate is expected to significantly expand the country’s leading solar market, which currently has more than 29 GW of installed capacity.

Last year, Environment America began championing rooftop solar mandates in 10 states, including Massachusetts. A report from the environmental advocacy group found that such a mandate in the Bay State would add more than 2.3 GW of solar capacity by 2045. That’s almost equal to Massachusetts’ total installed capacity, including utility-scale solar, of about 2.9 GW.

One town near Boston already requires new commercial and multi-family buildings to include rooftop solar.

Last legislative session, the state’s Joint Committee on Telecommunications, Utilities, and Energy gave a favorable report to similar legislation. However, the solar bill did not advance to a vote on the floor of either chamber.

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