How much space would be needed for photovoltaic systems to meet the entire electrical needs of the United States?
If PV were a primary energy source, what would the world look like? Would PV collectors cover every square inch of available land? Contrary to some popular notions, the landscape of a world relying on PV would be almost indistinguishable from the landscape we know today. The impact of PV on the landscape would be low, for three reasons. First, PV systems have siting advantages over other technologies; for example, PV can be put on roofs and can even be an integral part of a building, such as a skylight. Second, even ground-mounted PV collectors are efficient from the perspective of land use. Third, adequate sunlight is ubiquitous and often abundant, and present in predictable amounts almost everywhere. As we move away from fossil-fuel energy, PV will become important because of its land-use advantages: PV’s low-impact siting for flat-plate systems. In the United States, cities and residences cover about 140 million acres of land. We could supply every kilowatt-hour of our nation’s curr
