How can sunlight charge my phone?
The Sun’s energy warms our planet, drives its winds and ocean currents, and provides the energy for life to flourish. Today it’s used to produce the electricity our society relies on.
Solar energy has become an important resource for powering modern technology, industry, and transport. Today we harvest and store solar energy to power our houses, appliances, and computing technology. It can be used to power our vehicles. Even space-craft can operate on little more than the sun’s rays.
Is there a limit to what can be powered by the Sun? The question isn’t an easy one to answer, but it’s important to first know a thing or two about how energy released by the Sun transforms into an electrical charge here on Earth, so you never run out of power, at the wrong moment.
Roughly one hundred and fifty million kilometers away, our nearest star – the Sun – is busy generating ripples of electromagnetic radiation as light energy. Roughly eight minutes after this light energy leaves the Sun’s atmosphere, a tiny fraction of it bumps into our planet. Some of it is scattered and reflected back into space or absorbed into our atmosphere. But some of it reaches the surface and we can use it to generate electricity.
Some power plants, called solar concentrators, focus sunlight onto containers of salt, which melts and flows through pipes running through boiler rooms. The steam from the heated water can then turn a turbine, which is used to generate electricity. But that’s just one way sunlight generates electrical power.
Plants have evolved clever ways to put sunlight to work, using the tiny charges in chemical reactions between water and carbon dioxide to form glucose, which they use to grow in a process we call photosynthesis. Just like in plants there are some materials that release energy when they absorb light.
Power production based on this kind of technology is called photovoltaics, but you may know these as solar cells.
Materials like silicon are treated with elements such as phosphorus or boron, and arranged into layers. When the sunlight hits it, electrons start moving between these layers. By putting many thousands of these cells together, and connecting them to the power grid or a big battery, solar farms can generate large amounts of electricity.
Sunlight is a clean, efficient, limitless source of electricity that can power just about anything that needs a charge, even the phone in your pocket.