On a sunny day, approximately 1,000 watts of energy strikes every square meter of the Earth’s surface that is exposed to it. The attraction of getting your own electricity for free has long been a tantalizing prospect. This is especially enticing as increasing costs of electricity, government incentives, and affordable solar panels have made this energy source a more popular prospect for homes and business.
We’ve all seen banks of solar panels on roofs of buildings and houses. But how do they work?
Photovoltaic (PV) Technology
Photovoltaic panels are by far the most common type of solar panel in use today. This type of panel uses the electrical properties of certain kinds of semiconductor materials to generate electricity whenever the panels are exposed to sunlight. Because they generate electricity directly, they have no moving parts and require very little maintenance. Recent advances in photovoltaic cells have brought their costs down, making them more competitive.
How PV Cells Work
Each PV solar panel is an array of flat elements called cells. These cells consist of two very thin layers of silicon: a layer of n-type silicon, which is electron-rich, and a layer of p-type silicon, which is electron-poor. When a photon of light strikes the silicon-rich layer, it can knock one of those electrons lose. This creates a difference in charge between the two layers. If you connect the two layers together by attaching contacts to them, those electrons are free to move toward the silicon-poor layer, creating an electric current.
Inverters
Because PV systems make electricity directly from sunlight, a steady source of energy, the electricity they generate is direct current (DC) instead of the alternating current (AC) that almost all devices and appliances require. To do this, almost all commercial PV solar panels include devices called inverters. These devices are often placed at the end of a row (sometimes called a “string”) of panels, but recently some panel manufacturers place an inverter on every panel.
Some panel manufacturers also build live monitoring into their inverters, allowing them to closely monitor the system’s performance, even anticipating problems before they arise.
Filling in the Gaps
Obviously, PV panels cannot generate power when there is no sunlight, whether at night or because of inclement weather.
● Storage
When the panels are generating a lot of power, the system can divert some of that power to a storage device. The storage device is most often a bank of batteries similar to the high-density batteries used in electric cars, but other storage methods are available. This storage device can then discharge that power when it’s needed.
When the panels are generating a lot of power, the system can divert some of that power to a storage device. The storage device is most often a bank of batteries similar to the high-density batteries used in electric cars, but other storage methods are available. This storage device can then discharge that power when it’s needed.
● Electrical Grid
Solar installations can include a connection to the local power grid, allowing you to pull in more power when you need it. Although this means you still depend on the grid for power, your bill will still be a great deal lower than it would with no solar power at all.
Solar installations can include a connection to the local power grid, allowing you to pull in more power when you need it. Although this means you still depend on the grid for power, your bill will still be a great deal lower than it would with no solar power at all.
Selling Power Back
Because the amount of power an array of solar panels generates varies throughout the day, it may be generating more power than you actually need. If this occurs, your local utility company will be paying you for electricity. Rates that local utilities will pay, and whether they will pay at all, depends on where you are.
The Future
Solar won’t be replacing more mainstream sources anytime soon, but its simplicity and promise of self-reliance together, with advancing technology, mean its share of the energy supply will only grow.
Author Bio: David Olson is a writer, content strategist, and eBook author. He specializes in the latest developments in technology and how they help companies communicate with evolving consumer bases worldwide.
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