Study Finds Nearly Half of All Power Could Come From Rooftop Solar Panels

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As Americans look to reduce the environmental impact of fossil fuels and turn toward more renewable sources of energy to meet the constantly growing demand for electricity, a promising solution may be right above our heads. A new report by the National Renewable Energy Laboratory demonstrates that if all suitable roofs were covered in solar panels, they would generate 1,118 gigawatts of solar power annually—a staggering 40% of the power that Americans consume each year.

Even more compelling is the fact that these current figures only take into account roof top panels and do not consider the immense potential of ground-mounted photovoltaic (PV) systems. The authors assert that actual generation from PV systems could far exceed these estimates through installation in alternative areas such as canopies over open spaces

and through the integration of PV systems into building facades. As technology continues to improve, the authors of the study expect to see an even greater increase in the energy output of solar panels. The results of the current study are sensitive to assumptions about module efficiency, which is currently estimated at 16%. If overall module efficiency increases to 20%, which is reflective of the current premium systems, the potential estimate of energy production would increase by about 25%.

This new study doubles the figures from a 2008 study by the same organization, which estimated a potential annual generation of 664 gigawatts from solar panels. The authors attribute the higher numbers to improved module performance, higher estimates of suitable rooftops, and better methods of calculating PV performance.

While the results of this study are no doubt promising, they do come with one major caveat. Since the authors only estimated technical potential, the results do not reflect the practical requirements of integrating rooftop solar panels which would include a flexible grid, supporting infrastructure, and a suite of enabling technologies.