Solar PV Systems Have Four Main Components:
1. Solar photovoltaic panels ("solar panels")
3. Racking and mounting system
4. Performance monitoring systems
Solar panels collect and convert the sun’s energy into electricity. They are a key component of a solar panel system. Most commonly available panels today are either poly-crystalline or mono-crystalline solar panels. The key differences between poly- and mono-crystalline panels are in efficiency and cost. Typically, mono-crystalline panels are more efficient (and thus more expensive) than poly-crystalline panels.
The cells in your solar panels collect the sun’s energy and turn it into direct current (DC) electricity. Most homes and businesses, however, use alternating current (AC). Inverters change the DC electricity from your panels into usable AC electricity. There are three basic types of solar inverters.
String (or centralized) Inverter
A single inverter is used to connect your entire array of solar panels to your electrical panel. String inverters are frequently the least expensive inverter option and are a very durable technology that have historically been the most installed inverter type. Multiple strings of panels can be connected to each inverter, though, if the electricity production from one of the panels in a string drops (as may happen due to shading), it can temporarily reduce the performance of that whole string.
If you choose microinverters, one will be installed at each solar panel, which allows each panel to maximize production. If some of your panels are shaded at different times of day or if they aren’t all installed facing the same direction, microinverters will minimize performance issues. The cost of microinverters tends to be higher than the cost of string inverters.
Systems that use power optimizers are a hybrid of micro-inverter and string inverter systems. Like microinverters, power optimizers are installed at each panel. However, instead of converting the DC electricity from the solar panels into AC electricity, the optimizers “condition” the DC electricity before sending it to a centralized inverter. Like microinverters, they perform well when one or more panels are shaded or if panels are installed facing different directions. Power optimizer systems tend to cost more than string inverter systems, but less than microinverter systems.
Rack and Mounting Systems
Racking and mounting systems are used to affix your solar panels either to your roof or to the ground. They also allow you to position your panels at an angle that is best for capturing the sun’s rays.
To perform at their best, solar panels should face south and be installed at an angle between 30 and 45 degrees (depending on how far you are from the equator). Panels facing east or west and at a pitch angle of five degrees or more will still work well but will produce 10 to 20 percent less electricity than those installed under ideal conditions.
There are two types of mounts: fixed mounts, in which the panels remain stationary, and track mounts, which allow panels to “follow” the sun as it moves across the sky during the day (single-axis track mounts) and during the changing seasons (dual-axis track mounts). Track mounts are only suitable for panels installed on the ground.
The Difference Between Fixed vs. Track Mount Systems
Fixed mounts are less expensive and the only option if you are installing your panels on your roof. Track mounts are more costly, but they allow you to increase your panels’ electricity production by 30 percent or more.
Because of their additional cost and increased maintenance, track mounts are best suited to situations where you have limited space and want to maximize the electricity production from a limited number of solar panels.
Performance Monitoring Systems
Performance monitoring systems provide you with detailed information about the performance of your solar panel system. With a monitoring system, you can measure and track the amount of electricity your system produces on an hourly basis.
While some solar installers charge extra for installing a monitoring system, it can provide significant value over the lifetime of your solar panels. Monitoring systems help you identify any performance issues to ensure that you maximize the electricity production (and therefore the financial returns) of your solar panel system.
There are two types of monitoring systems:
On-site monitoring: The monitoring device is physically located on your property and records the amount of electricity produced.
Remote monitoring: Your solar PV system transmits its performance data to a monitoring service that you can access online or with a mobile device.