Rooftop solar could power the world, finds Irish-led study

The project mapped the landmass of the entire world, assessing the rooftop potential of more than 300 million sample structures from small outdoor sheds to mega-factories.

Based on the computer models they constructed from this analysis, the team found that making use of all suitable rooftops would generate more electricity than the world in total used in 2018.

The models allow for major variations in available daylight around the world depending on region, latitude and seasons.

Experts from the MaREI Centre for Energy, Climate and Marine at University College Cork, worked with reseachers from Columbia Unversity in New York and Ahmedabad Unversity in India on the extensive mapping and measuring project.

They said solar was already on track to provide 25-49pc of global electricity needs by 2050, with rooftop solar making up 40pc of that output.

With the right policies, however, they found rooftop solar alone had a global potential to generate 27 petawatt hours of electricity per year.

“This potential of 27PWh per annum from rooftop solar is very significant,” said Professor Brian Ó Gallachóir.

“For comparison, our total electricity use in all homes around the world was 6PWh in 2019.

Rolling out solar on such a scale would require major investment but the study shows seven trillion dollars could install 10PWh of solar that would serve all the electricity needs of 3.72 billion people.

For context, seven trillion dollars is the same amount of money US President Joe Biden pledged to invest in infrastructure in the US over a decade as part of his ‘build back better’ package.

The findings show for the first time the full potential for solar, measurements of which are usually restricted to industrial sized installations.

They also illustrate how the energy needs of the 800 million people around the world who have no access to electricity could be served relatively easily.

The report notes that the cost of solar installation fell between 42-79pc from 2010 to 2019 and it continues to fall.

“These results are very timely in the context of the global climate change conference in the UK next month,” said Prof Ó Gallachóir.