[Providence Journal] The new house going up on the hillside overlooking the beachfront community of Bonnet Shores looks like many others in the neighborhood, with its sweeping porch and expanses of windows. But there are many important differences. The roof is covered with photovoltaic panels that turn sunlight into electricity. Out back, a bottomless sand filter septic system will treat the house’s wastes more thoroughly than just about any other technology. And out front, a crew has drilled a 750-foot well that will provide water, not for drinking, but for heating and cooling.