The answer to America’s energy problems could be right under our noses—or, rather, right over our heads. According to a recent study by the Energy Department’s Renewable Energy Laboratory (NREL), America’s rooftops are full of untapped potential. In fact, up to 39 percent of America’s energy could be generated just by installing photovoltaic (PV) solar panels on urban rooftops.

Popular Science reports that NREL analyzed rooftops in 128 cities across the United States, representing about 23 percent of all buildings in the U.S., according to an NREL press statement. The researchers assessed the buildings' suitability for hosting PV solar panels and measured how much power could be generated by each location. They found that 83 percent of small buildings had the technical potential to host PV panels on part of their rooftop areas, while 26 percent could host an entire rooftop’s worth of panels.

Researchers say that their findings far exceeded previous estimates of the amount of power that could be generated by rooftops alone. Their analysis estimates that rooftops have a technical potential of 1118 gigawatts of capacity and 1432 terawatt-hours of annual energy generation, which would equal 39 percent of America’s total electricity sales (based on 2013 numbers).

However, it’s important to note that researchers analyzed technical potential only. That is, they considered resource availability and the availability of space without also analyzing economic or political factors—which means that while America may have the space for rooftop solar panels, it may not currently have the political will or a plan of action.

"An accurate estimate of PV's technical potential is a critical input in the development of regional deployment plans," explains researcher Pieter Gagnon. "Armed with this new data, municipalities, utilities, solar energy researchers, and other stakeholders will have a much-improved starting point for PV research and policymaking, both regionally and nationwide."

[h/t Popular Science]