Sustainable, reliable and renewable, solar energy is everywhere. In fact, the sun delivers enough energy to our planet every hour to satisfy global energy needs for an entire year.
The sun is a constant, reliable source of energy that we are only now starting to harness. But things are quickly changing. A 2017 report from the International Energy Agency found that solar is the fastest-growing source of power in the world.
How does solar energy work? What are the advantages of using a solar energy system?
What are Solar Panels Made Of?
Most solar panels are photovoltaic and consist of many solar cells made of silicon. Cells are constructed with a positive layer and a negative layer. Together, they create an electric field – just like a battery.
How Do Solar Panels Produce Electricity?
Photovoltaic solar panels generate direct current (DC) electricity. Whenever photons hit a solar cell, electrons are knocked loose from their atoms. This creates an electric current, as long as the conductors are attached to the positive and negative sides of a cell.
As electrons flow through the circuit, they generate electricity.
The U.S. electrical power grid uses alternative current (AC) electricity, so an inverter is needed to get DC electricity into the AC grid.
In addition to the panels, a solar system consists of an inverter, electricity net meter and electricity production meter, which are all connected. The electrical loads will first consume the power produced by your system. Whenever the system produces more electricity than you need, you’ll send power back to the electrical grid.
That’s one of the advantages of solar – you can get paid for the energy you produce.
How Much Power Will My Panels Generate?
Multiple cells are needed to create a solar panel, and multiple panels can be wired together to create a solar array. The more panels you have, the more energy you can generate.
The amount of electricity your system produces will also depend on the efficiency of the solar cells in the panel and the amount of sunlight the panel receives.
Solar panels are have become significantly more efficient over the last five decades. Today, a solar panel that’s 65″ x 39″ is 18.7% efficient and can produce 320 watts of power. That’s enough to power 5-1/3, 60-watt lightbulbs.
Panels come in a variety of wattage ratings.
To get a better idea of who much electricity is generated, let’s look at how much sun the roof gets on your home. The average roof in the U.S. gets about 4 hours of usable sun per day. Let’s say that you have a 250-watt solar panel on your roof. In four hours, that panel would produce 1 kWh (1,000 watts) per day, per 250-watt panel (250 watts x 4 hours).
Each 250-watt panel will produce about 30 kWh per month.
How Much Will It Cost?
The cost of a solar energy system varies depending on your energy needs and location. The average U.S. homeowner spent between $2.71 and $3.57 per watt to install solar. The average gross cost to install a solar system – before tax credits – was $18,840.
These costs don’t take into account the incentives that may be available. A 30% federal investment tax credit is available in the U.S. until 2029, which can reduce the cost of solar substantially.