Solar Energy 101 How It Works and Its History

In just an hour and a half, enough sunlight strikes the earth to power the entire world for a year. Our society relies on electricity for everything from our smartphones to city infrastructure and increasingly, even our cars. Yet in 2023, solar energy accounted for just over 5% of the electricity generated in the United States. So if there's enough sunlight to power the world and we have the invention of solar panels, why are we only using a fraction of it? When we think of solar energy, the image that often comes to mind is that of solar panels on rooftops or sprawling across fields. These panels, known as photovoltaics, are at the heart of solar energy generation. But they aren't just sitting there catching sunlight, they're working at a microscopic level. Here's how it works. These photovoltaic solar panels use the radiation captured from the sun to generate electricity. When sunlight hits solar panels, which are made of dozens of solar cells, the energy from individual photons is absorbed by electrons in the material. These energized electrons become conductive, creating an electric current much like electricity flowing through a metal wire. This energy is then harnessed as a power source. These solar panels can be found on rooftops across the world and generate enough solar power to run the homes they are attached to. Energy from large solar farms join a mix of sources supplying utility-scale power for regional and national grids. Now the journey to harnessing solar power began thousands of years ago, over 6,000 years ago to be precise. During the Neolithic Age, Chinese villagers developed solar architecture, building their homes to face south to heat them during the winter. Later, the Greeks and Romans used glass as a means to trap the heat in their homes and bathhouses. These techniques were adopted in various ways around the world in the following centuries. But a radical step forward came in 1883 when Charles Fritz invented the first solar cell in New York City. His early rooftop panels using selenium had less than 1% efficiency, far too low to power anything. Then history's favorite young Swiss patent clerk, Albert Einstein, submitted a paper in 1905 on the photoelectric effect, which introduced a new theory of light. It also won him the Nobel Prize for Physics in 1921. This laid the groundwork for modern solar technology. Initially, photovoltaic cells used selenium, but it wasn't very efficient. That changed in 1954 when scientists at Bell Labs, searching for a way to power remote telephone lines, switched to silicon as a semiconductor. This improved efficiency to 6%, revolutionizing the industry and setting the stage for solar's future. Despite this technological leap, solar power didn't immediately take off commercially, but it did with NASA. During the space race with Russia, NASA first used solar panels to power the tiny Vanguard 1 satellite's radio in 1958. In the 1960s, the agency deployed solar power for unmanned probes and lunar surface experiments during the Apollo missions. By 1998, when the International Space Station launched, it was powered almost entirely by solar energy. The technology has only advanced since then, with newer, ultra-thin solar arrays now generating with 30% efficiency for the ISS. Today, solar power has become one of the most common renewable energy sources. In 2023, renewables made up 23% of the electricity generated in the U.S., with 5.1% coming from solar, making it the country's fastest-growing source of electricity. Today's solar panels have come a long way from the 1% efficiency Fritz saw in 1883. The average efficiency now sits at around 21%, with the world record at an astonishing 47.1%. Solar power is no longer a futuristic concept. It's powering homes, schools, and even deep-space probes. It's more efficient, cheaper, and lighter than ever before. Yet, despite these advances, solar still faces challenges. While the U.S. solar industry is projected to grow at a rate of 14% until 2028, potential legislative changes, delays in transmission lines, and labor shortages could slow progress. If you learned something new in this video, consider giving us a thumbs up, and if you want to continue down your path for knowledge, subscribe to our channel.