Photovoltaic (PV) systems use solar modules, also known as panels, to turn the sun’s energy into electricity. A single PV cell typically produces 1 or 2 watts of power by itself. PV cells are connected together in chains to boost their power output. These chains of cells are called modules or panels. When several modules are linked together they are called an array. A complete photovoltaic system consists of one or more arrays connected together as well as several other elements which facilitate the transformation and transmission of electricity.
A photovoltaic system requires a durable, stable structure that supports the solar arrays and can withstand wind, hail, rain and corrosion for decades. With these support structures, the PV array is tilted at a fixed angle, according to the electrical load requirements, local latitude and orientation of the system.
This method allows the system to generate the most amount of power depending on which hemisphere and latitude it is located. For example, if the system is located in the northern hemisphere, the modules will be pointed south, with an inclination that is equal to the local latitude. This rack method currently has the most widespread use. This is because of its sturdiness, versatility, and ease of installation.
Ground-based PV systems have a different mounting structure. For this type of system, the structure includes a mechanism which automatically follows the sun across the sky. Panels are usually designed to track from east to west with one-axis trackers. Two-axis trackers point the modules directly at the sun all day. Ground-based systems yield the highest energy returns but have higher upfront and maintenance costs. Still, thanks to continuous improvements over the years, the cost-benefit analysis now favors ground-mounted systems.
Photovoltaic modules convert solar energy into direct current (DC) electricity, which has to be converted into alternating current (AC) electricity in order to be usable by a home. This is done either with an inverter that converts the electricity output of all the modules or by a series of micro inverters which convert the electricity of each module separately. A single inverter is cheaper and easier to maintain, but micro inverters allow the tuning of each individual panel. This can be useful if one panel has a lower output than the rest due to shade.
Homeowners can also purchase smart inverters, which can improve a system’s efficiency by over 20%. Unlike conventional inverters that systematically store power in batteries, smart inverters store it only when necessary. Smart inverters allow two-way communication with the inverter and the utility company. This works well to help the utility company decrease cost by balancing supply and demand. Smart inverters could also ensure grid stability and reduce the likelihood of power outages.
An increasingly important part of a photovoltaic system is the battery. Batteries store electricity during peak hours of production and then distribute the stored electricity during nighttime or poor weather conditions. They can also be used in combination with on-grid systems by storing electricity before it is sold. As battery technology improves, solar systems will become much more stable and efficient.
Which Photovoltaic System Configuration is Right for You?
Homeowners have many options at their disposal, whether they’re looking for low upfront costs, peak efficiency, or low maintenance. Photovoltaic systems can be built to meet almost any power need.