How this happened: The biggest global solar innovator is China. After the 2009 economic crisis, China set up solar import agreements with the E.U., which served to support exports of the technology in the coming years. The country began investing billions in the development of renewables. China now drives innovation in the materials science behind solar (for example, the silicon used in commercial panels today is 99.9999999 percent pure). As of 2024, China produced more than 93 percent of the world’s polycrystalline silicon, nearly 97 percent of its silicon wafers, about 92 percent of its photovoltaic cells and about 86 percent of its photovoltaic modules. Last year, renewables met all of China’s new demand, allowing it to stabilize greenhouse gas emissions even as its energy requirements continued to grow. And China is by far the largest patent holder in solar technology.

The potential: Inexpensive solar systems manufactured in China are competitive with the cost of new coal and gas projects. So small-scale solar is now an option in places with developing economies where individuals can set up plug-in solar arrays. The tech doesn’t have major local environmental impacts or displace people from their homes. And the energy starts flowing immediately. Across Africa, nations installed 4.5 new gigawatts of solar capacity in 2025, a 54 percent increase from 2024—the continent’s largest solar-growth year so far. Ten U.S. states have legalized solar systems that can be set up outside your windows and plugged into standard wall outlets (some robust enough to run a refrigerator).