Unsuspecting passersby would never guess that a technological revolution is unfolding at the Los Olivos Pilot Zero Energy House in Livermore, California. At first glance not much distinguishes this Craftsman-style house from the other high-end residences sprouting like weeds on the dry, brown hills east of San Francisco. The 3,079-square-foot bungalow has three bedrooms, 21/2 baths, a library, and a two-car garage. Sunlight streams through the abundant windows and the French door that leads from the family room out to the garden in back. Ten-foot ceilings create an airy ambience; bamboo floors, stone-faced fireplaces, and a Sub-Zero refrigerator provide the luxury touches that homeowners have come to expect from an $800,000 purchase.
A closer examination, however, reveals discreet features that make the house extraordinary, including a set of iridescent black-glass photovoltaic panels on the roof, a strangely squat water heater in the garage, and a small weather sensor sprouting from the side of the house near two sets of louvers. The most telling detail is the power-monitoring panel, a digital utility meter mounted in the hallway. At night or on overcast days, the meter indicates that the house draws current from electric lines in the usual manner. When it is sunny outside, the process reverses, and electricity from rooftop photovoltaic cells, which can generate up to 2.6 kilowatts of power at high noon, flows outward. Over time the numbers should average out so that there is no net electricity drawn from the power grid. That means that the annual electric utility bill will come to a nice round $0.00.
