A New Global Study Refines Estimates of Rooftop Solar Potential

200,000 square km of rooftop solar could generate 27 quadrillion watt-hours of power
John Loeffler

Solar panels are one of the more exciting and promising components of any future climate change solution, and a new study says that we might be able to power the world from rooftop solar panels alone.

The study — published this month in Nature Communications and led by researchers at the University College Cork in Ireland and Columbia University's Center on Global Energy Policy (CU-CGEP), mapped 130 million square kilometers of land surface around the world, and was able to identify 200,000 kilometers of combined rooftop surface area from both commercial and residential properties.

Then, the researchers used a machine-learning algorithm to assess the different variables that could impact a given area's ability to generate electricity from photovoltaic panels to determine its solar power potential.

According to the study, 27 petawatt-hours of energy (27 quadrillion watt-hours) could be produced from the area analyzed each year, which exceeds total energy consumption for the entire world in 2018.

The capacity for any area to generate electricity from solar power varies, obviously, as does the ultimate price for that electricity locally.

The researchers found that Asia, North America, and Europe had the highest solar energy potential, though the US and UK would also pay the most for their electricity, up to $280 per megawatt-hour, while China and India would have the lowest cost, as low as $40 per megawatt-hour.

“The open data generated in this research helps to quantify, locate and prioritize investment in zero-carbon electricity systems,” said James Glynn, a senior research scholar at CU-CGEP and a co-author of the study.

“By mapping the solar rooftop potential in high resolution globally, development banks and energy agencies in developing countries are better informed as to the technology’s role in enabling sustainable development towards climate action and affordable and clean energy.”

It Will Likely Take Far More to Move Us to Sustainable Energy, but It's a Start 

While this new study's assessment of the solar energy potential of the mapped regions will make an important data point going forward when planning and investing in new carbon-neutral energy generation, it's unlikely that we'll be able to produce the number of solar panels needed to do this any time soon.

The average solar panel is about 5.5 feet by 3.25 feet, or an area of about 17.60 square feet (about 0.005364 km). To produce 200,000 square kilometers of solar panels, you'd need to manufacture more than 37 million panels. Right now, globally, we're producing tens of thousands of panels, but not nearly at the scale needed to get to 200,000 km of solar panel coverage without an enormous, world mobilizing investment.

And that is just to cover our energy consumption from 2018. Our energy consumption is set to soar thanks to all kinds of new technologies from supercomputers processing machine learning, IoT, 5G edge computing devices, smart cites, and more. 

Solar panels are an important component of an overall climate strategy, but it's only one component. There is still much more work to be done.

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