The sun , the power plant in the sky, bathes the Earth in ample energy to fulfil all the world's power needs many times over. It doesn't give off carbon dioxide emissions. It won't run out. And it's free! So how can people on Earth turn this bounty of sunbeams into useful electricity?
The sun's light (and all light) contains energy. Usually, when light hits an object the energy turns into heat, like the warmth you feel while sitting in the sun. But when light hits certain materials the energy turns into an electrical current instead, which we can then harness for power.
Old-school solar technology uses large crystals made out of silicon, which produces an electrical current when struck by light. Silicon can do this because the electrons in the crystal get up and move when exposed to light instead of just jiggling in place to make heat. The silicon turns a good portion of light energy into electricity, but it is expensive because big crystals are hard to grow.
The Earth receives and collects solar energy in the atmosphere, oceans, and plant life. Interactions between the sun's energy, the oceans, and the atmosphere, for example, create winds, which can produce electricity when directed through aerodynamically designed wind machines.
The Solar photovoltaic cells convert solar radiation into electricity (photovoltaic literally means "light energy"; "photo" = light, "voltaic" = energy). Individual cells are packaged into modules, like the one shown at the right; groups of modules are called arrays. Photovoltaic arrays act like a battery when the sun is shining, producing a stream of direct current (DC) electricity and sending it into the building or sharing it with the grid.
Solar or photovoltaic (PV) cells are made of semiconducting materials that can convert sunlight directly into electricity. When sunlight strikes the cells, it dislodges and liberates electrons within the material which then move to produce a direct electrical current (DC).1 This is done without any moving parts
The Solar Cell
Solar panels are divided into cell blocks, which are made up of solar cells, the basic component of a solar panel. Each solar or photovoltaic cell creates its own electricity, which then joins the flow of electric current from the other cells and then other panels and on down the line until it passes through the inverter and into your light bulbs.
Solar cells contain a semiconductor material, typically silicon. Sunlight or, more specifically, a photon of light, is absorbed by the solar cell. This absorption creates solar heat which frees electrons in the semiconductor, creating an electric current. This current is created by the way of a p-n junction. That is to say that two thin wafers of silicons one "doped" with another element to be positively charged (p) and the other negatively charged (n) are brought in close contact with each other. As photons react with the n-junction, extra electrons are freed and the electrons tend toward the p-junction, which has extra room or "holes." This creates that electric current. Conductive wires, which run between the p-n junction, guide this electric flow out and along the circuit that eventually delivers electricity to the home.
The Power of the Panel
The electricity created by a single solar cell is rather miniscule, but when joined with the other cells in the panel, you begin to get some notable charge. Then combine one solar panel, which may create anywhere from just a few Watts to a few hundred Watts of electricity, with the other panels in a solar array, and you could have a solar system strong enough to power a home.