Energy from the Sun

Imagine powering your bedroom lights or your television with light from the SUN! Watch this video to see how it’s done:

Source: U.S. Department of Energy | Energy 101: Solar PV

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All right, we all know that the sun's energy creates heat and light, but it can also be converted to make electricity and lots of it. One technology is called solar photovoltaics, or PV, for short. You've probably seen PV panels around for years, but recent advancements have greatly improved their efficiency and electrical output. Enough energy from the Sun hits the earth every hour to power the planet for an entire year. Here's how it works. You see 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. Take a closer look, and you can see the panel is made up of several individual cells, each with a positive and a negative layer which create an electric field. It works something like a battery, so the photons strike the cell, and their energy frees some electrons in the semiconductor material. The electrons create an electric current, which is harnessed by wires connected to the positive and negative sides of the cell. The electricity created is multiplied by the number of cells in each panel and the number of panels in each solar array. Combined a solar array can make a lot of electricity for your home or business. This rooftop solar array powers this home. And the array on top of this warehouse creates enough electricity for about a thousand homes. Ok, there are some obvious advantages to solar PV technology. It produces clean energy, it has no emissions, no moving parts, it doesn't make any noise, and it doesn't need water or fossil fuels to produce power. And it can be located right where the power is needed – in the middle of nowhere, or it can be tied into the power grid. Solar PV is growing fast, and it can play a big role in America's clean energy economy, anywhere the Sun shines.

Think about the following questions as you watch:

  • How expensive is energy from the Sun?
  • Electrons are tiny charged pieces in a solar panel. When the sunlight hits the solar panel, what begins to happen to the electrons?
  • What is a circuit?

Find a partner and discuss your answers.