The global capacity of rooftop solar power grew by 49% in 2022. Overall, the installed amount of rooftop solar grew from 79 gigawatts to 118 gigawatts last year and it is projected to reach 159 gigawatts by the end of this year. By comparison, a typical nuclear power plant can produce 1 gigawatt; a gas-powered power plant is typically half a gigawatt.
Rooftop solar constitutes a relatively small fraction of the total global installed solar capacity, which is dominated by utility-scale solar arrays. Total installed solar capacity rose from 950 gigawatts to 1,177 gigawatts last year and is projected to reach 1,518 gigawatts this year. That is enough power to meet more than half the electricity demand of the European Union.
The rapid growth of solar power can only continue if there is more energy storage put in place to manage the peaks and troughs in solar output. Countries will also need to upgrade their power grids to be able to transport excess solar power from where it is generated to where it is needed. Bottlenecks in the grids of most of the leading solar-producing nations are already interfering with further solar development.
The overall potential for rooftop solar is based on the number of rooftops that would be suitable for solar power, which depends on the size, shading, orientation, and location of the roofs. According to the National Renewable Energy Laboratory, rooftops in the United States have the potential for more than 1,000 gigawatts of solar capacity. Currently, only about 4% of US homes have rooftop solar.
Photo, posted November 16, 2022, courtesy of Oliver Knight via Flickr.