How Do Solar Panels Work?
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How Solar Panels Work: A Quick Description
Transitioning to a clean energy future is made possible by programs like Community Solar, which offer a very real opportunity for every day residents to support clean power in a convenient manner. So, how is it that solar panels can actually produce the energy that powers our communities? Looking for a simple answer on how solar panels work? Let us break it down for you.
How Much Energy Does the Sun Actually Produce?
During each and every moment between sunrise and sunset, the sun sends to the earth 1.74 x 1017 watts of energy every moment of every day; that is 1.74 followed by 15 more zeros. The amount of energy that humanity uses on a daily basis is produced by the sun´s rays hitting the earth in just 14.5 seconds. While much of the suns energy is reflected back into the atmosphere due to cloud cover, the star of our solar system provides more than enough energy to power our entire civilization.
But how exactly do solar panels turn the energy found in the rays of sun into electricity that can be used by our homes and businesses?
The Science Behind Solar Panels
In 1839, French physicist Alexander Edmond Becquerel launched the development of solar technology when he discovered the “photovoltaic (PV) effect”. While subsequent development in solar energy technology was slow, in the 1950s, researchers with the Bell Telephone company discovered that silicone gave off an electric charge when it was exposed to sunlight. The original solar panels that hit the market only had a 2 percent efficiency rating and amazingly cost about $16,000 per watt (with inflation counted in). Today, consumers can expect to pay only $4 per watt for solar systems today, which is part of the reason that solar photovoltaic panels to produce almost 500 GW of energy in 2018.
While the science behind how solar panels work might seem difficult to understand, essentially a solar photovoltaic (PV) panel allows photons to separate electrons from atoms. This subsequently creates a flow of direct current (DC) electricity. With the use of an inverter that turns DC electricity into alternating current (AC) electricity, the energy from the sun can be used directly in our homes.
Solar panels are actually made up of solar units called photovoltaic (PV) cells. Most commercially available solar panels include 32, 36, or 48 cells. Inside each PV cell there are two layers of silicone, though other semi-conducting material has been used in PV panels. The two layers of silicone are necessary in order to create an electric field with separated opposite charges.
Solar panel manufacturers thus add other materials to the layers of silicone to create positive or negative charges. Phosphorous is often added to one layer of the silicone to create a negative charge, while boron is what offers a positive charge to the other layer. The opposite charges thus create an electric field at the intersection. When a photon (from sunlight) hits this electrically charged PV cell, electrons are first pushed free and then pushed out of the silicon “sandwich”, thus creating a source of energy.
Necessary Parts of a Solar PV System
Solar photovoltaic panel technology has increased in efficiency in recent years. Today, mono crystalline panels have shown to be more efficient per unit of space than their poly crystalline counterparts. Once the energy from the sun is captured, however, it requires other pieces of technology such as an inverter before it can be used inside our homes and businesses.
Inside the PV cell, metal plates gather the loose electrons that had been knocked loose by the photons from the sun. These plates direct the loose electrons and eventually transmit them to wires where they can easily be transported. The wires from the solar PV panels go directly to an inverter where the DC current produced by the panels is changed into AC current. There are three different types of inverters that are commonly used by in solar energy arrays today.
A centralized inverter (also known as a string inverter) is the least expensive option and connects an entire solar panel array to an electrical panel. Unfortunately, this type of inverter is usually the least efficient as shading on the panels can reduce the amount of energy produced.
Micro-inverters are smaller and installed on each solar panel. That means that if part of a solar panel systems receives periodic shade during the day, the reduced energy production from those panels will not affect the rest of the system.
Power optimizers are a hybrid alternative that incorporate the best of both centralized and micro-inverter technology. These optimizers are installed on each panel, but they don’t directly change the current to AC. Rather, these optimizers enhance the DC current produced by the panels before it is sent to a central inverter. This type of inverter system is by far the most effective and efficient.
Lastly, solar panel systems also require a mounting rack and a performance monitoring system. While many people associate solar panels with rooftop mounting, rooftop solar PV systems often face challenges associated with proper placement. Unless a home is located in an area without shade and with an unobstructed view to the south (where sunlight is more direct), chances are that the energy production will be reduced. Community Solar farms, on the other hand, are purposefully located in areas where the maximum amount of sunlight can be gathered.
While solar panel technology might seem very technical, the science behind this renewable form of energy is essentially straightforward. Recent developments have allowed the solar energy industry to increase efficiency while simultaneously reducing the size and thickness of individual solar panels. In the near future, these efficiency gains could help solar energy to become a greater contributor to the U.S. power grid.
For people whose roof is not suitable for rooftop solar panels, Community Solar projects are one way to enjoy the benefits of a renewable, environmentally friendly energy source that also makes economic sense in the long run. Clearway Community Solar is one company that works to bring communities together through local solar farms while offering them a renewable, environmentally friendly energy source.