The solar panels on top of Bill and Deborah Lord's house in Kennebunkport, Maine, are not clunky '70s-style add-ons. They make up the entire roof, creating a crisp and shiny plane ready to catch the sun. On a January day with clouds scudding overhead, Steven Strong looks up at the south-facing surface, his eyes as bright as the collectors as he surveys his design. On sunnier days water flows through tubes built into glass-covered panels that make up half the roof, getting hotter as it travels along. Eventually it drains to storage tanks in the basement to be maintained, with the help of propane heaters during winter nights, at 150* F. Some goes to meet domestic hot water needs, some to heat the house. When the thermostat in the living quarters calls for more heat, the water is pumped from the tanks through a maze of plastic pipes coiled in a thin cement layer under the 2,700 sq. ft. house's floors before returning to the basement, then back to the roof in a never-ending circle.
On the other half of the roof is a different kind of solar collector. There dark blue photovoltaic cells or PVs--panels made of silicon implanted with tiny black threads--come alive, even during an overcast winter day. Sufficently agitated, electrons in the highly conductive silicon begin swarming along the threads to metallic bands running into a cable that enters an electric panel box in the basement to serve the home's needs. "What is so elegant about this system," says Strong, "is that the electrons go and do their work and then come right back to the PV. No loss of resources."
Inside, the house is toasty at 72 degrees Farenheit from floor to ceiling, curtesy of a venting system that circulates air. The floors are warm to the touch. The windows are, too. Two invisible plastic films containing argonne, an inert gas, between them are incorporated inside the thermal panes of each window. In winter, the gas prevents heat from leaving through the glass; in summer it stops the sun from penetrating inside.
Strong loves to show off the house as does Bill Lord, a retired ABC News producer. The basement is Lord's favorite place. The two silver-wrapped 500-gal. insulated water tanks tower above him. Beside him, frenzied electrons run down cables to an electrical meter. Interesting is the digital number on the meter, especially on this cloudy day. It registers -9.00, meaning that the roof's photovoltaic panels, in addition to meeting the house's typical needs such as lights and appliances, are producing 9 extra amps (about as much as a 7-in circular saw draws), which can be sold to Central Maine Power Company, the local utility. During nights or really dark days, the Lords buy back electricity from the company. But in an average year, the Lords come out ahead, accumulating about a half-megawatt of energy that they can sell back to the utility.
