Solar energy arrays are not yet as common as slate shingles and squirrels on the roofs of Chevy Chase homes. But renewable energy from the sun is a growing presence.

Drive around Chevy Chase neighborhoods and you’ll spot them–glass panels set on south-facing roofs. Some arrays are just a couple of panels. Some cover almost the entire south-facing side of a roof.

Solar energy is a supplement, not a replacement, for conventional energy sources like electricity from Pepco and natural gas from Washington Gas. Large arrays, like the one pictured above on Dorset Avenue, installed by Solar City, may generate more electricity than the house consumes on a bright, sunny day. When that happens, the solar system is engineered to sell excess energy back to the power company’s energy grid. The home owner gets a credit for the energy sold back to the company. This makes sense, because it helps the power company meet peak energy demands, which typically occur on hot summer afternoons, without needing to build more generating plants or burn more coal.

Smaller systems, like the one at left on Chevy Chase Boulevard, may have more limited goals. This one, installed by Capital Sun Group, Ltd., is designed to heat water for the backyard swimming pool and to supply basement space heating through a fan coil system.

According to experts, the ability of a solar array to pay back the homeowner’s investment depends on many factors, beginning with the amount of sunlight a rooftop receives. The arrays are not inexpensive, but there are some tax incentives for installing them.

Photos © Bob Cullen