How Do Solar Panels Work?

Your Guide to Understanding Solar Technology

Solar energy is the single most abundant source available on Earth. Did you know that there is over 173,000 terawatts of solar energy at any given time? If we were to attempt to use harness all available rays, there would be enough to serve over 10,000 times the amount the world uses. 

 Not only is it abundantly available, solar-generated electricity is one of the most affordable and environmentally friendly forms of electricity available. Solar panels are only one part of a complete photovoltaic (aka PV) system, also called a solar power system. 

What are solar panels made of? 

Solar panels are made up of solar cells. These cells are created out of silicon, which work like a semiconductor. There are two different main types of solar panels:  monocrystalline and polycrystalline. The former is made out of a single silicon crystal, thus the name, while the latter is made up of many crystals pieced together. 

Quick pros and cons: 
  • Monocrystalline solar panels cost more but have a higher efficiency rating (meaning they generate more electricity at any given time) 
  •  Although polycrystalline solar panels cost less, they are less efficient, especially in low-light conditions, and oftentimes have shorter life spans. Because they are less efficient, you often need more panels to generate the same amount of electricity as monocrystalline options. 

How Do Solar Panels Generate Electricity?

When light hits your PV solar panels, electrons inside the panels begin to move and vibrate at a higher rate. As the panels absorb sunlight, this energy creates an electric charge between components in the panels.

The top layer of silicon is suffused with phosphorus to create a negative charge.  The bottom layer of the solar panel is infused with boron, which has a positive charge. Sun rays beam down onto the panel and knock electrons free at the junction between the two silicon layers.  Then, metal plates on the sides of the cell collect those electrons and feed the energy into wires, where it acts like any other source of DC voltage. 

At this point the electricity is sent to either a solar battery or a solar inverter. The inverter transforms the initial current into usable AC electricity that powers your home. 

What Factors Affect Solar Electricity Production?

Residential solar systems can be impacted in a few ways. 

Rooftop shade

If your rooftop is shaded for a portion of the day, that will render your panels unable to produce as much energy as they could under direct light. The amount of sunlight hitting your roof is a direct correlation to the amount of electricity you will be able to generate in that space.  If you are unable to trim trees or there are other buildings shading your roof for hours or an entire portion of the day, rooftop solar might not be your best option.

Seasons and Temperature

Solar panels do not require perfect conditions to produce energy. Although a clear sunny day will generate more electricity than a cloudy one, the weather might impact solar panels differently than you might think. 

Solar panels are more efficient in cold weather. Similar to other electronics, when their components heat up, the panel will generate less voltage and therefore produce less electricity. This doesn’t necessarily mean that solar panels produce more electricity in the winter than in the summer.  Clear, sunny days are more common in the warmer summer months. The sun is usually out for more hours of the day as well. Even if your panels may be slightly less efficient in warmer weather they will produce more electricity in summer than winter.

It is important to focus on the overall picture. While a hot summer day might lead to lower efficiency rates, if the sun is shining for longer hours, there is more opportunity to generate electricity.

Roof Tilt
You should consider the direction your home is facing. The roof pitch can have a significant effect on how well a rooftop solar system works. Pitches around 30 degrees usually work best.
Similar to roof tilt, the solar Azimuth angle is the compass direction that the sunlight hits your rooftop. At high Noon, the sun will come from the North to hit our roofs here in Australia. The wrong Azimuth angle will reduce the energy output of a solar system panel by up to 1/3. In general, a lot of homes use an Azimuth of 0 which faces the equator. 

If you have any further questions about solar panels or how they work, our experts at Westside energy are here to assist you with your green energy needs. 

Go Solar today!