Erin HillDefinition/description English 202C3/24/15

How Solar Panels Work to Generate Electricity

Introduction: Climate change is upon us. As a result our world is facing negative consequences and these consequences will only worsen if actions to protect our environment are not taken. One way to combat climate change is through renewable energies. One technology that is able to generate renewable energy is solar panels. A solar panel is an instrument that converts energy from the suns rays into usable electricity. The electricity generated can be used onsite at a home or business or can be transferred back to the electrical grid.

Figure 1: Diagram of how solar panels work to generate electricity. http://wattpatrol.com/solar-panels/

How it works:

PV cells Solar panels are made out of individual photovoltaic (PV) cells. Photovoltaic comes from photo meaning light and voltaic meaning electricity. A group of these PV cells makes a solar panel and multiple panels are called a solar panel array. PV cells consist two layers of silicon, one positive layer, p silicon, and one negative layer, n silicon, with a semiconductor material in between. A thin layer of glass then covers these layers. For optimal exposure the panels should be placed on the south facing side of the building at an angle where they will receive the most direct sunlight.

When the suns rays hit the PV cells on the solar panel the photons or energy particles from light knock off some electrons from the atoms of the silicon. These free electrons are negatively charged and are attracted to the positive side of the PV cell. The cycling of these electrons from negative to positive generates a current, more specifically a DC or direct current. This DC current is gathered from wiring through out the PV cells, collected and channeled through a wire. This process can best be represented in figure 2 on the right.

Figure 2: Diagram of how PV cells in a solar panels works https://colline.co/solar-panels-for-home-diagram/

Inverter The created DC current from the PV cells then travels to an inverter. The inverter is a device that converts the DC current into AC, alternating current. AC current allows the eclectic current to flow both ways through the wire. The DC current must be converted to AC in order to be able to be used to power items such as light bulb onsite or be able to be sent over long distances. AC can also be converted to higher voltages more easily.

Use of Electricity After the DC current is converted to AC by the inverter the electrical current will then connect to the circuit breaker panel and utility meter for the home or business. The electric current can now be used to power lights and appliances onsite. The utility meter monitors how much electricity is being generated and consume. Any excess electricity that is not used onsite will be sent to the power gird. This power grid is run by a utility company and is what regularly supplies non-reusable energy to households and businesses. An advantage of solar panels that are connected to the grid, or grid tied, is that during times of no sunlight a house our business can still receive electricity if needed. Also if the solar panels are producing more electricity than needed it will send it back to the grid. Home and business owners can receive payment for the excess electrically they send back to the grid, this in turn helps cut down on electric bills.

AlternativesSolar panels can also operate as an off gird system. Off grids is where the excess energy generated will get stored onsite instead of being set to the utility power gird. After the solar panels create the DC current the electricity can be stored in a battery on site. The battery can then harness the electricity and store it until the home or business needs it. In this system a home or business runs independently from the regular power grid.

Solar panels also do not have to be stationary or bounded on the side of a building. Solar panel arrays may be in open fields on the ground close to the complex receiving the energy. Also some more complex solar panel arrays are computerized to automatically rotate and angle the position of the panel towards the path of the most direct sunlight.

Conclusion Renewable energies are the new frontier and can help combat climate change. Renewables release zero emissions and are less environmentally damaging. Solar panels are a source of a clean energy that can be installed on homes and businesses to supply electricity. When the suns ray hits the solar panels PV cells, photons from light knock of the elections from the atoms of the silicon. The exchange of electrons from negative to positive generates an electrical current. An inverter then converts the DC current to an AC current. The AC currently then travels to the home or businesses circuit board where it can than be used to run appliances when needed. A unity meter measures the amount of electricity being generate and consumed, any excess electricity will be set back to the grid.

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