15 Illuminating Facts About Solar Energy

With the Sun offering the Earth with its most abundant energy source, humans have been using solar technology for millennia. But the use of solar energy has exploded in recent years, with the world producing more than a trillion kilowatt-hours of solar electricity. Here’s more information on these facts, plus other milestones and statistics from the evolution of the solar industry.

1. The Earth receives 173,000 terawatts of solar energy continuously. Not only does that figure make solar energy the world’s most abundant energy resource, it’s also 10,000 times the world’s total energy use, according to the National Oceanic and Atmospheric Association.
   

2. Solar technology dates back more than two millennia. Humans used magnifying glasses to concentrate sunlight and make fire in the 7th century B.C., according to the National Renewable Energy Laboratory (NREL). And in the 3^rd century B.C., Archimedes purportedly focused reflected light to torch Roman ships attacking Syracuse.
   

3. A 19-year-old discovered the photovoltaic (PV) effect in 1839. At the age of just 19, French physicist Alexandre-Edmond Becquerel discovered that he could generate electricity by placing silver chloride in an acidic solution, attaching it to platinum electrodes, and exposing it to sunlight, per National Geographic. That discovery led to the development of the solar cell.
   

4. But PV is just one type of solar technology. As the Archimedes legend attests, sunlight can also be concentrated to generate heat and electricity. But solar technologies can even be as simple as passive systems that use sunlight to warm or ventilate buildings.
   

5. Bell Laboratories demonstrated the first practical silicon solar cell in 1954. Engineer Daryl Chapin, chemist Calvin Fuller, and physicist Gerald Pearson’s solar cell — the efficiency of which was just 6% — powered a small toy Ferris wheel and a radio transmitter in the demonstration, according to APS News. The New York Times wrote at the time that the achievement “may mark the beginning of a new era, leading eventually to the realization of one of mankind’s most cherished dreams — the harnessing of the almost limitless energy of the sun for the uses of civilization.”
   

6. Vanguard 1, the first satellite powered by solar cells, launched in 1958. And that spacecraft was only the second satellite launched by the United States, as NASA reports. Though its solar-powered transmitter stopped working in 1964, Vanguard 1 ranks as the oldest satellite to still be orbiting the Earth.

7. The operation of solar energy technologies does not produce air pollution or greenhouse gases. Therefore, solar energy can be indirectly positive for the environment when supplanting or supplementing other energy sources, as the U.S. Energy Information Administration reports.
   

8. Solar has a carbon footprint that’s a fraction of that of natural gas and coal. International Panel on Climate Change data shows that the median lifecycle emissions of solar energy — including the manufacture, installation, and maintenance of PV modules — is 41 grams of CO2-equivalent emissions per kilowatt-hour of electricity generated (gCO2eq/kWh) for rooftop solar and 48 gCO2eq/kWh for utility solar. By comparison, the median lifecycle emissions of natural gas is 490 gCO2eq/kWh and that of coal is 820 gCO2eq/kWh, according to the data.
   

9. Solar PV accounted for around 5% of global energy generation in 2022. When combined with carbon-free generation sources like nuclear and hydropower, that percentage rises to 38% for that year, according to findings the NREL publicized in September 2023.
   

10. But solar PV also accounted for 56% of new electricity in 2022. “It’s impressive to see how solar is dominating the current sales,” Sarah Kurtz, a fellow with NREL’s National Center for Photovoltaics and a professor at the University of California, Merced, said in the NREL news release. “We’re interested to see how much fossil generation expansion there is in the 2023 data for next year’s recap article. It could be that carbon-free energy sources will be consistently supplying almost all of our new generation capacity very soon.”
    

11. The world’s solar electricity generation grew from 300 million kilowatt-hours (kWh) in 1989 to 1.28 trillion kWh in 2022. U.S. Energy Information Administration (EIA) statistics also show that China generated the most solar electricity in 2022 (416 billion kWh), followed by the United States (205 billion kWh), Japan (93 billion kWh), India (92 billion kWh), and Germany (58 billion kWh).
    

12. The United States’ consumption of solar energy rose 4,247,570% in under four decades. The United States consumed 0.018 billion BTUs of solar energy in 1984 and 764.58 trillion BTUs of solar in 2022, according to EIA data.
    

13. Hundreds of thousands of workers work in solar in the U.S. The country’s solar industry boasted more than 263,000 workers across all 50 states as well as the District of Columbia and Puerto Rico as of 2022, according to IREC. The Solar Energy Industries Association (SEIA) adds that the solar industry has provided the American economy with more than $60 billion of private investment.
    

14. The cost of solar is dropping. In the United States, the average cost of a utility-scale PV system dropped from $3.56 per watt in 2011 to $1.03 per watt in Q1 of 2024, according to SEIA data.
    

15. The U.S. solar industry is expected nearly triple by 2028, according to one estimate. The SEIA projects that country’s solar industry will rise from 142 gigawatts-direct current (GWdc) to 236 GWdc between 2023 and 2028.