Short answers, pulled from the story.
Solar power is the conversion of energy from sunlight into electricity, either directly using photovoltaics or indirectly using concentrated solar power. Photovoltaic panels use the photovoltaic effect to turn light into an electric current, while concentrated solar power uses lenses or mirrors to focus sunlight into heat that drives a steam turbine.
Charles Fritts constructed the first solar cell in the 1880s, and in 1884 he installed the world's first rooftop photovoltaic array, using 1%-efficient selenium cells, on a New York City roof. The silicon solar cell was created in 1954 by Gerald Pearson, Calvin Fuller and Daryl Chapin, following the work of Russell Ohl in the 1940s.
In 2025, solar power generated 9% of global electricity. In 2024 it generated over 1% of primary energy, or 2.7% by the substitution method, and added twice as much new electricity as coal.
Utility-scale solar PV costs fell by 85% between 2010 and 2020, making utility-scale solar one of the cheapest sources of electricity for new installations in most countries. Because photovoltaic systems use no fuel and modules last 25 to 40 years, upfront capital and financing make up 80% to 90% of the cost.
China has about half the world's solar power and grew to host the largest solar equipment manufacturers. Over 40% of global polysilicon manufacturing capacity is in Xinjiang in China.
Photovoltaic systems use solar panels to convert sunlight directly into electric power, and over 90% of that market is crystalline silicon. Concentrated solar power uses mirrors or lenses to concentrate sunlight into heat that makes steam to drive a turbine, but it costs over twice as much as PV and supplies less than 1% of solar power.
Concentrated solar plants store heat in high-temperature molten salts, while photovoltaic systems increasingly use rechargeable batteries to hold a daytime surplus for use at night. Most home batteries are lithium-ion, mainly lithium iron phosphate since around 2021, and grid-connected systems can also send excess electricity into the network for a credit through net metering or feed-in tariffs.