According to the study, a theoretical maximum of 19,500 TWh of electricity could be generated by rooftop photovoltaics (RPV) each year if every suitable roof was equipped with solar. Combined with load shifting and battery-electric storage, this would be enough to meet 65 per cent of current global electricity consumption.   

The study also found that the widespread deployment of RPV could help reduce global temperatures by up to 0.13 °C before 2050 by displacing fossil-based generation from energy grids. Data from the International Renewable Energy Agency indicates that the levelised cost of electricity for solar is now in the range of £30 to £50 per MWh. In contrast, new nuclear projects are estimated at between £100 and £150 per MWh. The researchers suggest that government policies should reflect solar’s economic advantages. Their work is published in Nature Climate Change.

“Solar is now outcompeting nuclear power in cost, deployment speed and environmental risks,” said study co-author Prof Felix Creutzig, a climate and policy researcher at the University of Sussex.

“Given its immediate carbon reduction benefits governments should consider shifting incentives toward rooftop PV instead of nuclear. This goes for cooler countries like the UK as well as those with more obvious solar potential.”

The study advocates for global cooperation to deploy rooftop solar panels. Despite being the continent with the world’s highest solar energy resources, Africa accounts for only one per cent of RPV installations. High carbon intensity and large building stocks mean that East Asia has the highest potential in RPV for climate change mitigation. Meanwhile, North America and Europe, despite lower solar intensity, have a high combined installation potential of over 4,300 GW or 25 per cent of global capacity based on their high building stock.

“Beyond carbon savings, reducing fossil fuel dependence also means cleaner air and better energy security,” Dr Creutzig continued.

“With so much untapped potential in solar it’s hard to see how governments can justify investing in nuclear, or as yet unproven carbon capture projects.”