A solar power system uses a variety of components that work together to generate electricity. These include panels that convert sunlight into direct current (DC) electricity, an inverter that changes DC to alternating current electricity used in homes, and batteries to store energy at night.
Additional components include racking systems that mount the solar array, combiners and disconnects, fuses, breakers, meters and wiring.
Solar Panels
Solar panels convert sunlight into electricity to power your home or business. Solar panel systems require little maintenance beyond an occasional inspection and cleaning. For homeowners, solar energy reduces utility bills and is eligible for tax credits and rebates. Businesses are able to sell excess electricity back to the grid through a process called net metering, further reducing energy costs.
A solar panel is a group of silicon solar cells that are connected together and covered by an aluminum frame. Each solar cell generates a small amount of electricity. Individual solar panels are grouped into large solar arrays or “solar farms” to supply larger amounts of electricity to commercial or residential buildings.
When a solar system is operational, the DC electricity from the solar panels is passed through an inverter to convert it to AC electricity that can be used throughout your home or building. This power can also be sold back to the grid through an electric meter.
Electrical Panel
A PV solar panel array is the source of electricity for your home. Its output depends on solar irradiance which varies throughout the day and year.
Electrical panels can be connected in parallel or in series. In parallel wiring, the negative (-) wires of each solar panel connect to each other and then to a common positive (+) terminal that attaches to the battery and regulator. This method amplifies the voltage without losing power.
In a series wiring system, the panels have to be of the same power rating and characteristics. Otherwise, the voltage will drop.
Most PV systems use an electric meter that records the flow of electricity in and out of your house. This is the basis of net metering, which lets you offset your utility bills with rooftop solar. The energy that is generated but not used is sent back to the grid, which stores it for future use.
Inverter
Inverters convert DC electricity into AC (Alternating Current) power that can be used to run appliances. They can be central inverters or microinverters.
Solar cells produce DC electricity, but the grid and your appliances use AC power. The inverter takes the DC power produced by your solar panels and turns it into the power you need to use in your home.
All standard residential inverters offer production monitoring, but some are capable of monitoring each panel and making individual adjustments to maximize efficiency. This is known as “self-optimizing” and comes at an extra cost.
Some inverters also allow you to set phantom loads, like low-power night lights and clocks, to be always on rather than flashing on and off. This helps reduce the amount of power your solar system draws from the grid during peak demand. It may also help you stagger your energy usage, so you can save on battery costs. However, this feature will increase your upfront installation cost.
Batteries
Unlike a generator, solar batteries don’t require refueling. They work with your solar panels to provide backup power in case of a grid outage, and are now more affordable than ever with rebates and tax credits available for both the system and battery. Energy enters your solar battery as DC electricity and is stored there until you need it, at which point the inverter converts the battery’s output into AC for use in your home.
Batteries are rated for their capacity and voltage, and it is important to properly size them to match your energy consumption. Lithium-ion batteries are the most common because of their lightweight, high efficiency and long lifespans. Other options include flow batteries (not a great fit for residential solar) and lead-acid storage. Some solar batteries have built-in inverters, while others require an external one. The most advanced systems are designed to invert less frequently for better performance and longevity. This is known as round-trip efficiency.
