How Solar Energy Works

Solar energy is a vast, inexhaustible, and clean resource. Solar electricity generation is a great alternative to electricity from fossil fuels, with no pollution and no threats to public health. The energy we get from the sun is tremendous. 18 sunny days on our planet contain the same amount of energy as is stored in all fossil fuels combined. It is an incredible option to convert that abundant amount of energy into electricity solar power systems. These Photovoltaic systems (PV) are usually made up of several solar panels that are able to convert energy into usable electricity

Solar Panels

Solar panels are made up of individual cells that have layers of special semiconductor materials that are arranged in positive and negative layers (similar to the setup of a battery). Light energy from the sun shines on solar panels and hits the layers of semiconductors with photons (what makes up sunlight) in order to create a flow of electrical energy. The energy from the photons frees electrons within the semiconductor material which creates direct current (DC) electricity. Wiring connected to the positive and negative sides of the cell harness that electrical current using wires that are connected to the panel which carry the electricity to an inverter. Here the electricity can be converted into alternating current. Solar panels can link together to provide either all or a portion of the power needed for a home or business to run.

Solar Panel Chart
Rooftop PV solar

Rooftop PV

A photovoltaic (PV) system is usually composed of several solar panels. For a typical home or small business, the solar panels are usually mounted on the roof. After sunlight creates electricity in the form of direct current (DC), it is sent to an inverter that changes the (DC) electricity into alternating current (AC) because our home appliances and lighting are designed for (AC) electricity. This (AC) electricity can then be used in your home or business, sent to the electric grid, or sold to the utility. In hybrid systems, electricity can be used in your home and the excess can be sold to the utility. The choice of using the electricity, selling it, or both options in the hybrid modal depend on the policies available with your utility.

Utility-Scale, Ground Mount PV 

Large utility-scale, ground mount PV systems are installed to provide solar electricity for the electrical grid, similar to a traditional power plant. Once the (DC) electricity is generated, inverters convert the (DC) electricity into usable alternating current (AC) electricity, and then the electricity is sent into a transformer before it heads to a substation. At the substation, electricity is converted into a voltage that is able to meet the requirements of utility grid transmission lines and is either fed onto the electrical grid to serve the needs of local communities, or travels to other regional locations and/or states.

Utility-Scale PV

What Are Solar Panels Made Of?

solar panel layers

Photovoltaic (PV) panels are manufactured as solid panels that are completely sealed so there is almost no risk of hazardous exposure to toxic materials. PV panels are commonly installed in desert and arctic environments and are built to be completely weather tight under all environmental conditions. The top is typically tempered glass and the back plate is permanently sealed on the back side to sandwich in the solar cells that are between the glass and back plate.

As mentioned above, the PV panels themselves are made as a solid, sealed unit and water cannot wash any chemicals off of them (there are no liquids in solar panels). In addition, the chemicals in PV panels do not vaporize off and the panels have a very high melting point that exceeds most typical fires. Some PV panels use silicon in the solar cells. Silicon is a common material found in many soils, sands, and rocks. There is small amounts of solder containing some lead that is used to connect solar cell wires, but as the cell is sealed in the panel, this small amount of solder cannot leave the panel.

Halifax Solar farm

Aerial view of Halifax 20 MW PV system

Typical ground mount, utility scale PV

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