size. To power an entire building, a large solar array is required. It’s unfortunate that photovoltaic technology is still in its infancy but, for now, we must build large arrays to compensate for the inefficiencies of single panels. A bulky mechanical orientation Solar energy is reduced by overcast skiessystem may also be required to turn the panels as they follow the sun across the sky. Batteries, too, can take up a fair amount of space.