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How Do Solar Panels Work?​

Solar energy is an invaluable natural resource that’s essential to the clean energy transition and could significantly reduce the amount of fossil fuel burned for electricity. The amount of sunlight that hits the earth’s surface in just an hour and a half is enough to meet the entire planet’s energy needs for a full year

Solar panels allow you to take advantage of all that energy and turn it into usable electricity for your home. If you’re interested in residential solar panels but don’t know much about how they work, Cascadia Solar is here to help. Keep reading for an overview of solar photovoltaic (PV) panels and how they produce electricity for homes.

Solar Panels Use the Photovoltaic Effect to Generate Electricity

Certain materials, called semiconductors, generate an electrical current when they’re exposed to sunlight. This phenomenon is called the photovoltaic effect and it’s what allows solar panels to generate electricity.

Here’s a basic overview of how the photovoltaic effect works:

Sunlight Hits the Material:

When sunlight shines on a semiconductor, it loosens the electrons, which are tiny particles inside atoms that carry an electrical charge.

Electrons Start Moving:

These freed electrons move through the material, creating a flow of electrical current.

Electricity is Generated:

This flow of electrons can be captured and directed to power electrical devices, stored in batteries, or sent to the electric grid.

Components of a Solar Energy System

To generate solar energy, you need solar panels. But solar panels are only one piece of the puzzle. Solar energy systems consist of several components that allow you to generate and utilize solar energy.

Outline of solar PV system
  • Solar Panels – Solar panels (also called solar modules) are the most visible part of your solar energy system. They’re installed on your roof where they absorb sunlight and generate direct current (DC) electricity. 
  • Solar Inverter – A solar inverter converts the DC electricity into alternating current (AC) electricity, which is what most houses and the electric grid use. That solar conversion of the sunlight can happen in a single inverter on a wall of your house, or small inverters under the array (microinverters). 
  • Power optimizers – Module Level Power Electronics (MLPE) like DC-DC Power Optimizers or microinverters are mounted directly under each solar panel.  These electronics mitigate losses by optimizing the voltage and current of each solar panel depending on shading and temperature. MLPE also allows for rapid shutdown, and monitoring of each solar panel – making it easier to detect and pinpoint an issue in the system.  
  • Disconnect – All grid-tied solar panel systems have an automatic and manual safety switch. The automatic switch shuts the system down immediately during a power outage. This is required by the utility for safety reasons. The manual switch can be used to turn the system off if necessary for maintenance or during an emergency. 
  • Solar Batteries – A solar battery is an optional addition to your solar energy system. Batteries store the electricity generated by your solar panels and can be used to power your home during a power outage. 
  • Bi-Directional Utility Meter – In Washington State, solar customers can sell the excess electricity their solar panels generate back to the electric grid in exchange for credits on their electric bills. When you install solar panels, you’ll get a new, bi-directional meter (also called a net meter) to keep track of the electricity you send to the grid.

In most grid-tied solar energy systems, the power is routed to a disconnect after it has been converted to AC electricity and then to the electrical system of your house, typically via a breaker in your main electrical panel. Larger systems and battery systems can require different methods of connecting to your electrical service. We’ll figure out the most appropriate interconnection method for your particular electrical service.

Understanding Net Metering

Labeled diagram of how solar net metering works

Net metering is the term used to describe how the utility credits you for your solar production that goes back to the grid.  Any time your solar system is producing more power than your house is using, the excess will flow back to the grid and be recorded on your bi-directional net meter.  Any kWh credits that accumulate in excess of your usage in a particular month will be banked for offsetting later electrical bills. For each kWh that goes to the grid, you are credited with a kWh to use later. In our service area, your credits roll over month to month but not year to year—your account will be reset annually at the end of March. Your solar project manager will design a system based on your annual usage so that you are not leaving credits on the table.  

Right now, Washington State utilities are required to buy back power from their solar customers at the full retail rate of electricity. But changes could be on the horizon. Nearby states, including California, have recently made drastic changes to their net metering policies that reduce incentives for solar customers. It’s possible that Washington will adopt similar changes in the coming years, and we encourage you to go solar now to lock in the best net metering agreement before it’s reduced.

Have questions? We are always here to help! Call 360-531-6163 or contact us to talk to a solar consultant.