Solar is Future: Components

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Typically, a standard photovoltaic system is equipped with these three main components: the PV modules, the inverter and the meter. There are additional components for safety requirements and if desired, additional components are also included for system monitoring and communication.

The PV Module

Individual solar cells for PV systems are first combined into PV modules to provide easily manageable units with a suitable voltage level for various applications. A group of PV modules is called the PV array. The ability of the PV module to convert the sunlight it is exposed to is referred to as its efficiency. In terms of area, a PV module’s efficiency is always slightly less than that of the solar cell itself, because the active cell surface of the PV module is always somewhat smaller than its total surface area. Today, depending on the quality of the solar cell, standard PV modules have an efficiency of approximately 12 – 15 %. That means that 12 – 15 % of the sun’s radiant energy collected by the PV module is converted into electricity. Keep this in mind when planning a solar power system because the lower the efficiency of the PV module, the greater the number of PV modules required to meet a desired power level.

The Inverter: the Heart of your System

The type of power produced by the PV array is direct current, or DC.
This DC power needs to be converted to alternating current, or AC, before it can be utilized by your appliances or fed to the utility grid. The system component that converts the DC power into grid-compliant AC power is called the inverter. Inverters are a very important piece of the solar system. There are safety standards that need to be met for any device that is going to be connected directly to the public utility grid.
It is important that an inverter be certified for use with the utility grid prior to selecting one. Like PV modules, inverters also have an efficiency rating. That efficiency rating measures their ability to convert the DC power fed into them to AC power. No inverter is 100% efficient because it takes some of the energy supplied to complete the actual conversion process. Today, modern inverters have an efficiency of up to 98%. The efficiency is critical because it will determine the amount of sunlight that is actually converted and fed to the grid as AC power, which in turn, affects the amount of credit that is earned. The inverter is responsible for operating the solar power system so that the maximum possible energy production is achieved.

Metering

Most utility companies in the United States have an interconnection program in place. Precisely how the system owner is compensated varies from company to company. However, the one thing they all have in common is the requirement that the power sent to the utility company be metered. Most meters look like any other power meter for home or business use. How the meters are connected to your system will vary depending on how the individual program works. For detailed information on metering requirements in your area, contact your local solar power installer.