Created on 20 September 2014
If you have made the decision or are thinking about making the decision to go solar, then you may be wondering - how does sunlight actually get turned into electricity? You may have other questions too, such as will your solar panels work on cloudy days, and will your panels work at night via moonlight, which, after all, is reflected sunlight? To find out the answer to these questions and a few more, please read on.
Q. How does solar power work?
The sun may be around 93,000,000 million miles away, but it is still a very powerful source of energy, and if you've even been sunburnt, you'll know just how powerful! Solar energy came about thanks to a chance discovery. While studying light, the French scientist Alexandre Edmond Becquerel noticed that when certain materials, such as silicon, absorbed light, they “knocked” electrons loose. From this observation, he perfected the photovoltaic (PV) cell, which was a device containing an electric field that made these “knocked” electrons flow in a certain direction, hence creating an electric current. Modern-day PV cells still use the same principle.
Q. Do solar panels work on cloudy days?
Yes, but less efficiently. The brighter the day, the more light arrives at the PV cells, and the greater the number of electrons that are sent flowing. If the sun is blocked by cloud, less light reaches the cells, and less electricity is produced. On a dull day, a panel will only produce between 10 and 25 percent of the electricity it can produce on a clear day.
Q. Can solar panels work by moonlight?
No, the sunlight reflected by the moon is too weak to generate any solar power. Your system will still power or at least partially power your home at night, as most systems come with a battery that stores some of the electricity generated during the day to be used at night.
Q. How long do solar panels last?
That depends on the manufacturer. Most PV solar panels have a lifespan of around 25 years, but can run for 40 years and beyond.
Q. Is there a need to keep solar panels clean?
Yes, there is. PV cells only work if they receive direct sunlight, so anything that is blocking them will prevent them from generating any electricity. This could be leaves and other natural debris, bird faeces, and of course in winter if your roof is covered in snow, your panels will not work. In general terms, it is probably worth having your solar panels cleaned once every couple of years or so.
Q. How much electricity does a solar panel typically produce?
That depends upon the kind of system you install. As a general rule, each 1kW of solar panels produces 850kWh of power in a year. Therefore, if you have a 4kW system, you will generate 3,400kWh of electricity annually, which is roughly worth about $400, and is enough to power nine big screen plasma TVs for a whole year.
Hopefully, that should have answered some questions you may have had about solar energy. If you wish to get more info, you can visit the Department of Energy Solar Website , which have plenty of information and resources