How Does It Work?
Figure 1 shows a typical solar photovoltaic (PV) system. The solar panels each have an arrangement of PV cells that, when exposed to sunlight, produce electricity in the form of direct current (DC). This DC power is passed through an inverter, a device that converts the DC power into alternating current (AC), the power we all use for our household lighting and appliances.
The system in Figure 1 is a grid-connected system. In such a system, if you are using less power than what your solar system is producing, excess power is transferred back to the utility grid. Almost every state in the United States has a law that allows renewable energy systems to sell excess power to the utility under the “net-metering” law.
- Solar Modules
Solar modules mounted on the roof or grounds of your property convert sunlight into DC power.
This power is sent to a device called an inverter (or power converter) which converts the DC power from the solar modules to AC power identical to that being sent to you from the utility grid.
- Electrical Panel
Power travels from the inverter to your electrical service panel (your breaker box). The power from the electrical panel will be distributed to any electrical loads in your home.
- Utility Meter
When excess power is produced by the solar, the power will flow into the grid through your electric meter. This will cause your meter to run backwards gaining you a credit with the utility company.
- Utility Grid
The utility grid automatically provides electricity when needed – at night and during the day when your demand exceeds your solar production.
- Net Metering
Net metering legislation states that the utility company must credit you at retail rates (the same rate they would have charged you).
System with Battery Backup
Figure 2 shows a system with battery backup. Using a battery backup allows you to store the electricity produced by your panels and use it when there is a power outage. We can design your battery for a pre-determined “number of days” of storage.