Electrical grid interconnection and net metering

Massachusetts has laws and regulations in place to ensure that solar electric systems are safely installed and seamlessly connected to the electricity grid.

Most Massachusetts homes with solar electric systems can interconnect to the electrical grid, allowing you to purchase power from the electric distribution company when the solar electric system is not producing as much electricity as you are using. Utilities may require a special inspection prior to interconnection to ensure that the solar electric system complies with established technical, performance, and safety requirements.

If you have a solar electric system under 10 kW, you can sell any excess power they produce back to your utility and receive a credit on your electric bill valued at almost the full retail rate for the power produced. This practice is called net metering. As a solar electric system produces electricity, the net meter will spin backwards, just as it spins forward when you consume electricity. At the end of each billing period, you are billed for the net electricity consumed over the entire billing period. This is the difference between the amount of electricity delivered from the electric grid and the electricity generated by the solar electric system and put onto the grid. You receive net metering credits for any net excess electricity, which can be applied toward future electricity bills.

If you install a system over 10 kW, you may receive net metering credits at a reduced rate. Your utility company will be able to confirm net metering rates dependent on system size. Customers considering systems over 10 kW should discuss with their installer the availability of net metering in their area, as some utility service territories may have reached net metering capacity caps for systems over that size. See the state’s Net Metering Guide for additional details.

Solar Massachusetts Renewable Target (SMART) program

SMART is a solar incentive program that promotes cost-effective solar development in the Commonwealth. It is a production-based incentive that is paid directly by investor-owned electric utilities in Massachusetts to solar electric system owners, based on the amount of electricity produced. Once a system is approved to participate in the program and an incentive rate is calculated, a typical residential system will be eligible to receive incentive payments for 10 years. Incentives are issued by utilities on a monthly basis via check or electronic payment. For more information, see the Incentives, Ownership Options & Financing article.

Local permitting

Installation of a solar electric system will require the same local approval as any other building construction or electrical work. A building and electrical permit will need to be pulled by the installer, and inspections will be required to verify that the installation meets state and local code requirements.


Massachusetts law requires that solar electric systems be installed by Massachusetts licensed electricians. In addition, there are various training and certification programs which many installers go through, such as those offered by the North American Board of Certified Energy Practitioners (NABCEP).

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