You’ve probably seen calculators with solar cells — devices that never need batteries and in some cases, don’t even have an off button. As long as there’s enough light, they seem to work forever. You may also have seen larger solar panels, perhaps on emergency road signs, call boxes, buoys and even in parking lots to power the lights.
Although these larger panels aren’t as common as solar-powered calculators, they’re out there and not that hard to spot if you know where to look. In fact, photovoltaics — which were once used almost exclusively in space, powering satellites’ electrical systems as far back as 1958 — are being used more and more in less exotic ways. The technology continues to pop up in new devices all the time, from sunglasses to electric vehicle charging stations.
The hope for a “solar revolution” has been floating around for decades — the idea that one day we’ll all use free electricity from the sun. This is a seductive promise, because on a bright, sunny day, the sun’s rays give off approximately 1,000 watts of energy per square meter of the planet’s surface. If we could collect all of that energy, we could easily power our homes and offices for free.
In this article, we will examine solar cells to learn how they convert the sun’s energy directly into electricity. In the process, you will learn why we’re getting closer to using the sun’s energy on a daily basis, and why we still have more research to do before the process becomes cost-effective.
Generate cheap, green electricity from sunlight
Solar panel electricity systems, also known as solar photovoltaics (PV), capture the sun’s energy using photovoltaic cells. These cells don’t need direct sunlight to work – they can still generate some electricity on a cloudy day. The cells convert the sunlight into electricity, which can be used to run household appliances and lighting.
The benefits of solar electricity
•Get paid for the electricity you generate. The UK government’s Feed-in Tariffs pay you for the electricity you generate, even if you use it.
•Sell electricity back to the grid. If your system is producing more electricity than you need, you can sell the surplus back to the grid.
•Cut your carbon footprint. Solar electricity is green renewable energy and doesn’t release any harmful carbon dioxide or other pollutants. A typical home solar PV system could save over a tonne of carbon dioxide per year – that’s more than 30 tonnes over its lifetime.
How do solar panels (PV) cells work?
PV cells are made from layers of semi-conducting material, usually silicon. When light shines on the cell it creates an electric field across the layers. The stronger the sunshine, the more electricity is produced. Groups of cells are mounted together in panels or modules that can either be mounted on your roof or on the ground.
The power of a PV cell is measured in kilowatts peak (kWp). That’s the rate at which it generates energy at peak performance in full direct sunlight during the summer. PV cells come in a variety of shapes and sizes. Most PV systems are made up of panels that fit on top of an existing roof, but you can also fit solar tiles.
Solar tiles and slates
Solar tiles are designed to be used in place of ordinary roof tiles. A system made up of solar tiles will typically cost about twice as much as an equivalent panel system. Solar tile systems are not normally as cost-effective as panel systems, and are usually only considered where panels are not considered appropriate for aesthetic or planning reasons.