Photons & Solar Panels
We talk plenty today about solar panels, but not many really grasp how they work — how they create electricity.
In his book, Let It Shine: The 6,000-Year Story of Solar Energy, author John Perlin takes readers back to Albert Einstein in 1905 for perspective on the matter of light: “Einstein showed that light possesses an attribute that earlier scientists had not recognized. Light, he discovered, contains packets of energy, which he called light quanta (now called photons).”
“Photons?” you might ask. “Isn’t that something they use on Star Trek?” Yes, the word was used in the fictional television series. Remember photon torpedoes? If you do, you should also know this word has nothing to do with make-believe.
To begin, we need to understand light, or photons, posts Arizona State University:
“If light is imagined as a flow of particles, the particles are called photons with each photon carrying a discrete packet of energy. For a beam of fixed energy photons, the intensity of the beam depends the number of photons per second. Light can also be described as waves with the distance between waves, the wavelengths, inversely proportional to energy. The low energy radio waves have wavelengths of meters and the high energy x-rays can have wavelength of a millionth of a meter or less.”
So let’s discuss our sun, ultimate provider of light to Earth. The following information list comes from the US Department of Energy:
- Enough energy from the sun hits the earth every hour to power the planet for a year
- Sunlight is made up of tiny packets of energy called photons
- These photons radiate out from the sun, and about 93 million miles later, they collide with a semiconductor on a solar panel here on earth. It all happens at the speed of light
- A solar panel is made up of several individual cells, each with a positive and a negative layer, which create an electric field
Thus, the light with which we see and are warmed is made of photons.
As you might imagine, photons are not something that is seen by the human eye. But this video might help your PV vision.
Few of us are physicists, but this information will hopefully assist in understanding how photovoltaic panels work, as well as the miracle of light.
Energy 101 video via US Department of Energy