Mar 25, 2019 · Hypothetically, covering the country’s roads in solar technology gets us most of the way to being completely solar powered. Add in the rooftop space potential in the U.S. and we’re all the way there – NREL estimates that around 39 percent of the country’s energy use could be supplied by rooftop solar panel systems, equaling 1,118 gigawatts (GW) of solar production.