Photovoltaic (PV) materials and devices convert sunlight into electrical energy. A single PV device is known as a cell. An individual PV cell is usually small, typically producing about 1 or 2 watts of power. To boost the power output of PV cells, they are connected together in chains to form larger units known as modules or panels. Modules can be used individually, or several can be connected to form arrays. One or more arrays is then connected to the electrical grid as part of a complete PV system. Because of this modular structure, PV systems can be built to meet almost any electric power need, small or large.
The full Solar PV Energy System
Solar PV modules and arrays are just one part of a PV system. Systems also include mounting structures that point panels toward the sun, along with the components that take the direct-current (DC) electricity produced by modules and convert it to the alternating-current (AC) electricity used to power all of the appliances in your home.
Solar PV modules are where the electricity gets generated, but are only one of the many parts in a complete Solar PV system. In order for the generated electricity to be useful in a home or business, a number of other technologies must be in place. These Include the Mounting Structures, Inverters and Storage (Battery Systems).
Dantata Solar Ltd has set up partnerships with the best suppliers for these structures whilst working on increasing local content in its project proposals, e.g. for the mounting structures, to ensure that solar PV systems become even more affordable in Nigeria.
Mounting Structures
PV arrays must be mounted on a stable, durable structure that can support the array and withstand wind, rain, hail, and corrosion over decades. tilt the PV array at a fixed angle determined by the local latitude, orientation of the structure, and electrical load requirements. are pointed due south and inclined at an angle equal to the local latitude. Rack mounting is currently the most common method because it is robust, versatile, and easy to construct and install. More sophisticated and less expensive methods continue to be developed.
In areas with lower irradiation levels, especially in the northern hemisphere, or to get the highest performance some of these mounting structures have inbuilt tracking mechanisms to automatically move panels to change the tilt of the panels to track the best irradiation levels and to follow the sun across the sky, which provides more energy and higher returns on investment. Due to this, two-axis trackers allow for modules to remain pointed directly at the sun throughout the day. Naturally, tracking involves more up-front costs and sophisticated systems are more expensive and require more maintenance. These are however not necessary for ground mounted solar PV system in most areas in Nigeria as the irradiation levels are quite good.
Inverters
Inverters are the next critical component of a solar power system. They are used to convert the direct current (DC) electricity generated by solar modules into alternating current (AC) electricity, which is used for local transmission of electricity, as well as most appliances in our homes.
PV systems either have one inverter that converts the electricity generated by all of the modules, or micro-inverters that are attached to each individual module. A single inverter is generally less expensive and can be more easily cooled and serviced when needed. The micro-inverter allows for independent operation of each panel, which is useful if some modules might be shaded, for example. It is expected that inverters will need to be replaced at least once in the 25-year lifetime of a PV array.
Advanced inverters, or "smart inverters," allow for two-way communication between the inverter and the electrical utility. This can help balance supply and demand either automatically or via remote communication with utility operators. Allowing utilities to have this insight into (and possible control of) supply and demand allows them to reduce costs, ensure grid stability, and reduce the likelihood of power outages.
Storage
Batteries allow for the storage of solar energy, so we can use it to power our homes at night or when weather elements keep sunlight from reaching PV panels. Not only can they be used in homes, but batteries are playing an increasingly important role for utilities. As customers feed solar energy back into the grid, batteries can store it so it can be returned to customers at a later time. The increased use of batteries will help modernize and stabilize our country's electric grid.