Two Eastern Massachusetts municipalities are making the most of assistance from the sun when compacting trash and reducing litter in public places.

Newton recently added 18 BigBelly Solar Intelligent Waste Collection Systems to the five already in operation since 2006. And Hopkinton acquired three, valued at a total of $13,000.

"I'd like to see more go in," said Nancy Dourney, chair of Hopkinton's Sustainable Green Committee.

Also in use in Boston and Cambridge, BigBelly Solar Compactors are equipped with solar panels on top. They can contain five times as much waste as a standard 55-gallon trash can's capacity, necessitating less frequent trash pick-up than required by traditional receptacles.

BigBelly compactors also are in use in Pasadena, Calif., New York, Chicago, Philadephia and Little Rock, Ark., among additional locations.

Best used in high-traffic locations, the receptacles save energy, reduce trash collection, and use natural resources. Newton's are located in city squares while Hopkinton's were installed at an athletic complex, the high school, and a local park.