Types of Solar Technology
Passive Solar
Buildings can be designed to collect, store, and distribute solar energy as heat. Referred to as passive solar buildings, they maximize absorption of sunlight through south-facing windows and use dark-colored, dense materials in the building to act as thermal mass - they store the sunlight as solar heat. In order to take the best advantage of solar gain (the increase in temperature in a space, object or structure that results from solar radiation), a passive-designed building will have an east-west axis with the front of the building facing south. Find more information on how to design a passive solar home at DOE's "Energy Savers" website.
Even if you have a conventional home with south-facing windows but no thermal mass, you probably still have passive solar heating potential. To maximize passive solar heating, keep windows clean and install window treatments that enhance this type of heating, reduce nighttime heat loss, and prevent summer overheating.
Photovoltaics
A solar photovoltaic (PV) module is an array of cells containing semiconductor materials that, with the help of an inverter, convert solar radiation into direct current electricity that can be used in a home or business. A PV array can be placed on a roof, or it can be mounted on the ground. If a solar PV system is connected to the power grid, any excess electricity that it produces is fed into the grid and credited on the customer's electricity account. When the sun isn't shining, a PV system cannot produce electricity; however, the grid will supply additional electricity that is needed to the connected system, as necessary. The U.S. Energy Information Administration’s "Solar Explained" web feature provides more details on Photovoltaics and Electricity.
PV systems are quiet and non-polluting, and they can also help to reduce electricity bills. They are also becoming more and more affordable. Massachusetts is one of the most affordable places to install solar. To learn about the solar incentive programs available in Massachusetts, see the related links section below.
Does Solar Work in Massachusetts?
According to the report, “Renewable Energy and Energy Efficiency Potential at State Owned Facilities and Lands,” the Commonwealth's annual average of insolation (defined as the sun's energy) is sufficient for photovoltaic systems to generate energy. Furthermore, solar modules actually operate better in colder weather and are relatively unaffected by snow. The panels are installed at an angle, which is necessary to catch the sun's radiation and also helps prevent snow collection on the array. If snow does collect, it melts quickly. For more information on the Commonwealth’s suitability for solar, see the map, "U.S DOE Solar Projects Map," through the U.S. Energy Information Administration’s “Solar Explained" web feature.