Generating Electricity from Sunlight: How Do Solar Panels Work?
From a flashlight to an international space station, solar panels can transform light into energy to power just about any item, of any size. The benefits are clear – sunlight is free, will never run out and is completely green. But just how do solar panels actually work? We tell you all you need to know about how those futuristic looking panels can generate electricity and power everything from a kettle to an entire skyscraper simply by utilizing sunlight.
Photovoltaic Cells and the Sun’s Energy
The basic explanation is that solar panels use a network of photovoltaic (PV) cells to capture the sun’s energy, which is then converted to electricity and used to power pretty much anything you want. However, that doesn’t really explain the science behind the panels or what all these terms mean. Firstly, let’s look at just what PV cells are. Photovoltaic (from ‘photo’ meaning light and ‘voltaic’ meaning electricity) cells are manufactured from layers of semi-conducting material, usually silicon – this is because stripped down silicon is ideal for the transmission of electrons, which is essentially how solar panels operate.
Sunlight contains photons which are absorbed by the silicon, or other semiconducting material, when they hit the solar panel. The electrons in the silicon’s atoms are then displaced and a number are released, allowing electric fields in the cells to pull the free electrons into a current. The metal contacts on the top and bottom of the PV cell are then able to generate electricity. That’s the science bit but there’s more to a successfully functioning solar panel than that.
Silicon is a particularly shiny material, which would ordinarily reflect the photons rather than absorb them. An anti-reflective coating is therefore applied to the surface to encourage as much absorption as possible – the more photons, the more electricity can be generated. This is also why the panels themselves are generally installed on a roof, preferably south facing in the northern hemisphere and north facing in the southern hemisphere.
DC to AC Inverters Finish the Job
The current that panels generate is direct current (DC) so an inverter converts the solar power to alternating current (AC), which is what your household appliances use. If you are on a net feed-in system, this can be directly used in your home, with any surplus fed back onto the national grid through your electricity meter. On a gross feed-in system, all electricity generated is fed onto the grid, for which you’ll receive a feed-in tariff. An off-grid system stores any excess electricity in a bank of rechargeable batteries.
Solar panels could very well be the future of energy for the globe. Every household and business utilising the free, inexhaustible and green energy from the sun for their power needs is a dream scenario. The technology is there, it just needs to be developed to increase its efficiency, something which is happening in labs across the world right now. The future is bright!