Here on Earth we have access to one of the most plentiful sources of power known to man – the sun. But how does solar power work?
Around 70% of light from the sun makes its way to Earth – the rest is reflected back into space. Now we’ve learned to convert this energy into electricity using solar photovoltaic (or solar PV) panels.
Solar panels are made up of many solar ‘cells’. Each cell contains two thin layers of silicon on top of one another. The top layer has been treated so that the atoms within it are unstable and have too many electrons, while the bottom layer has been treated so that there are fewer atoms, with plenty of space for them to move around. Only after the cells are exposed to sunlight can the atoms move from the top layer to the bottom layer.
Once light hits the top layer, the electrons become ‘excited’ and start moving towards the bottom layer. Once the electrons are moving in the same direction, electricity is created, and this is harnessed by two metal contacts placed on either side of the silicone, which creates a circuit.
The electricity created by solar power is known as direct current, whereas the electricity we use on a day-to-day basis is alternating current, so before the solar energy can be used it must first go through an inverter. After this, the energy can be used in the same way as power supplied by electricity companies is used.
Solar energy can be harnessed in lots of different ways – from small solar panel installations on top of domestic roofs to massive ‘solar gardens’ in fields and deserts.
The best news is that there’s plenty of power to go around. In 2002, the earth absorbed more energy from the sun in a single hour than the world used in one year.