A recent study from the University of Sussex reveals a compelling possibility: if all suitable rooftops around the globe were covered with solar panels, they could meet approximately two-thirds of the world’s electricity demand. This shift could pave the way for a complete transition away from fossil fuel-based energy generation, significantly reducing pollution resulting from human activities.
The researchers analyzed satellite data to ascertain the total area available for installing rooftop solar panels worldwide, taking into account factors such as roof slope and shading from adjacent buildings. Their findings indicate that rooftop solar installations could generate a total of 19,483 terawatt-hours of electricity, which represents about two-thirds of global electricity consumption, estimated at 29,664 terawatt-hours in 2023. Notably, this potential output exceeds the total electricity generated from fossil fuels in 2024, which is projected to be 17,718 terawatt-hours. Fossil fuel generation primarily relies on coal and methane, both of which are significant sources of pollution.
The study underscores that if solar panels were installed on all suitable rooftops, current fossil fuel electricity generation could be entirely replaced, thereby greatly diminishing pollution from human activities. The East Asia region, with its high number of buildings due to a large population, and Africa, despite having a low housing stock but high solar potential, are identified as having considerable potential for solar panel deployment.
Furthermore, the research suggests that implementing rooftop solar panels could potentially lower global temperatures by 0.13 degrees Celsius. While this reduction may appear modest, it constitutes a significant portion of the 1.5 degrees Celsius
However, the study also issues a warning: as global temperatures continue to rise, the efficiency of certain types of solar panels may decline, leading to a decrease in overall electricity generation capacity. Therefore, timely action on climate change will enhance the effectiveness of this strategy. On a positive note, optimizing the tilt angle of solar panels can improve their efficiency. The foundational scenarios in the study assume horizontally installed solar panels, but employing optimal tilt angles or solar tracking technology could enhance efficiency by up to 39%. This means that if solar tracking panels were installed on rooftops worldwide, they could not only meet two-thirds of electricity production needs but potentially fulfill the entire demand.
It’s important to note that this study focuses solely on rooftop solar projects and does not account for large-scale grid-connected solar projects. If solar power plants were constructed in certain desert areas, this could further enhance global solar potential and assist in the restoration of desertified regions. While rooftop solar could ideally satisfy current electricity demands, changes in electricity consumption patterns will necessitate additional energy sources to cover remaining needs. Ideally, these energy sources should also be clean, as the cost of renewable energy has fallen below that of fossil fuel-based electricity generation.
Moreover, solar energy may not be suitable for certain applications, such as nighttime electricity use, thereby creating a need for energy storage solutions (which can be achieved through electric vehicles, home battery systems, or grid energy storage) or other low-carbon power generation methods (such as wind, hydro, or nuclear energy), especially when they are cost-effective.
