University of Washington

The stout house built into a hillside in Jayuya, a rural municipality in the mountains of central Puerto Rico, hasn’t been connected to the electrical grid for six months. Someone inside suffers from sleep apnea, and his family has relied on a noisy generator — and the gas it consumes — to power the machine he needs each night. Outside, under the thin smile of a crescent moon, four engineers from the University of Washington complete their work. Soon a new solar/battery nanogrid will power the sleep-aid machine: no gas, no fumes, no cacophony.