Page 55 - Energize October 2021

TECHNICAL

Solar panels on half the world’s roofs

could meet its entire electricity

demand – new research

by Siddharth Joshi, University College, Cork; James Glynn, Columbia University, New York; and Shivika Mittal, Imperial College, London.

ooftop solar panels are up to 79% cheaper than they were in 2010. These plummeting Method
costs have made rooftop solar photovoltaics even more attractive to households and We designed a programme that incorporated
Rbusinesses who want to reduce their reliance on electricity grids while reducing their data from over 300 million buildings and
carbon footprints. analysed 130 million km² of land – almost
But are there enough rooftop surfaces for this technology to generate affordable, low- the entire land surface area of the planet.
carbon energy for everyone who needs it? After all, it’s not just people who own their own This estimated how much energy could
houses and want to cut their bills who need solutions like this. Around 800 million people be produced from the 0,2 million km² of
globally go without proper access to electricity. rooftops present on that land, an area
A new paper in Nature Communications presents a global assessment of how many roughly the same size as the UK.
rooftop solar panels we’d need to generate enough renewable energy for the whole world We then calculated electricity generation
– and where we’d need to put them. Our study is the first to provide such a detailed map of potentials from these rooftops by looking at
global rooftop solar potential, assessing rooftop area and sunlight cover at scales all the way their location. Generally, rooftops located in
from cities to continents. higher latitudes such as in northern Europe or
We found that we would only need 50% of the world’s rooftops to be covered with solar Canada can vary by as much as 40% in their
panels in order to deliver enough electricity to meet the world’s yearly needs. generation potential across the year, due to

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