Since the turn of the century, solar power has expanded faster than any other energy source. Once costly and confined to niche uses, modern solar modules are easy to install and operate, producing cheap electricity worldwide.
Global solar capacity has surged:
– 228 GW in 2015, about 1% of global electricity
– 759 GW in 2020, roughly 3% of demand
– 2,919 GW in 2025, about 10% of global energy (surpassing nuclear at 9%)
If current growth continues, global capacity could reach about 9,000 GW by 2030 — enough to supply over 20% of global demand.
China leading the way
China is far ahead in capacity. In 2025 it added about 315 GW, bringing total capacity to roughly 1,300 GW. China produces more than 80% of the world’s solar panels. Solar now supplies about 11% of China’s electricity, and coal’s share has fallen from around 70% a decade ago to about 56%, driven largely by rapid renewables expansion.
EU expanding solar grid
The European Union has about 406 GW of solar capacity, covering roughly 13% of its electricity demand; coal now supplies about 9%, down from about 25% in 2015. Greece, Cyprus, Spain and Hungary each generate over 20% of their electricity from solar. Germany leads Europe with about 119 GW installed, followed by Spain with about 56 GW.
US solar growth despite policy setbacks
The United States ranks third with about 267 GW of solar, meeting roughly 8% of its electricity needs (up from around 1% in 2015). Over the same decade, coal’s share in the US fell from about 34% to 17%.
Other growing markets
India (136 GW) and Japan (103 GW) each derive a significant share of electricity from solar (India around 8%, Japan about 11%). Brazil generates about 10% of its electricity from solar; combined with hydro, wind and biomass, roughly 88% of Brazil’s power comes from renewables. Pakistan and South Africa have also seen rapid increases in solar share over the past decade.
Solar is getting cheaper
Sunlight delivers far more energy to Earth in an hour than humanity uses in a year. With less than 1% of global land covered in panels, solar could meet global energy demand. Improvements in module efficiency and mass production have cut prices roughly 90% over recent years. Large utility-scale solar parks in sunny regions can produce electricity for around 1 euro cent (1 US cent) per kWh; in Germany utility solar costs about 4–5 euro cents per kWh. Rooftop solar often costs less than half average retail electricity prices; adding battery storage typically increases costs by about 2–3 cents per kWh.
For comparison, Fraunhofer Institute estimates current generation costs roughly: nuclear 14–49 euro cents/kWh, coal 15–29 cents/kWh, natural gas 15–33 cents/kWh.
System impacts and benefits
In 2024, 632 GW of new power capacity was added worldwide: about 72% was solar, 18% wind, 4% gas, 3% coal, 2% hydro and 1% nuclear. Cheap solar is reshaping transport and heating: EVs charged with rooftop solar can be much cheaper to operate (in Germany, savings versus diesel/gasoline can exceed 80%). Heat pumps are generally more economical than oil or gas heating; in the EU households typically save over 30% on heating bills, with greater savings if the electricity is supplied by household solar.
Future outlook and challenges
Early forecasts undershot solar growth: in 2020 the IEA forecast about 120 GW of new solar in 2024, but roughly 597 GW were installed that year. Many experts now expect solar to become the world’s dominant power source. A model from Lappeenranta-Lahti University suggests a globally cost-effective mix could see about 76% of energy from solar, 20% from wind, with the remainder from hydro, biomass and geothermal.
Key challenges remain: expanding and modernizing grids, dramatically increasing storage capacity for nighttime and seasonal needs, integrating distributed storage (including vehicle batteries), and accelerating digitalization to balance supply and demand (for example, smart charging of EVs when solar supply is abundant).
This article was originally published in German.