Rooftop solar might match yearly electricity generation in the United States

As per a recent study on worldwide photovoltaic potential, the United States possesses enough viable rooftop space to install an amount of solar comparable to its existing nationwide generation levels. Big data, geospatial analysis, and machine learning were used by researchers at the Ireland’s University of Cork to achieve their conclusions, which were published in Nature Communications.

Around 77,000 square kilometers of rooftop area was delineated as feasible PV surface area in the assessment (for context, Florida state is approximately 65,000 square miles). If totally covered by conventional photovoltaics, this area might produce 27 petawatt-hours, or 27 million GWh, according to the researchers. According to, this level of prospective energy would exceed total worldwide electricity consumption in 2018, which saw 6 petawatt-hours (PWh) of the electricity consumed by houses alone and over 23 PWh consumed globally.

According to the report, rooftops in the United States could produce 4.2 PWh per year on average, effectively matching the country’s current overall energy output of roughly 4 PWh per year. As per data from Energy Information Administration (EIA), fossil fuels accounted for around 60% of power generation in the United States in 2020, with renewable energy and nuclear sources accounting for roughly 20% each. According to the EIA, distributed, small-scale solar generated 42 billion kWh of power in the United States, accounting for about 1% of total generation. In that year, large-scale solar contributed 2.2 percent of total power.

There are mitigating variables in this projected PV picture, according to the authors of the Nature Communications research, such as transmission bottlenecks and the requirement for storage due to solar energy’s intermittent generation cycles. This great potential for rooftop solar could be excellent news for the American ratepayers, as it could result in some cost savings. Local Solar for All has calculated that if rooftop solar scaled up 2-4 times quicker than an all-utility-scale solar installation scenario, $109 billion in the utility bill payments might be avoided by 2030.

For people concerned about the energy sprawl, or the expansion of land for energy generating, the study is a powerful talisman. According to Clemson University research, by 2040, about 500,000 square miles of land in the United States will need to be allocated to new energy development, an area greater than Texas, due to spacing and zoning requirements. Rooftops offer an alternative to wasting otherwise valuable land.

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