Introduction to Solar PV Systems
Basic System Components
The three main components to a solar power system are solar panels to absorb the suns energy, an inverter to convert that energy, and mounting system to safely secure the panels. Other items you will need are switches, cables, meters and connectors. There are also a huge range of optional products available, designed to optimise a PV system such as batteries, optimisers, surge protection devices, monitoring devices and more.
How Does Solar PV Work?
Solar PV panels convert solar energy into an electrical current. When installed, they should be mounted at an optimum angle and direction to optimise the amount of sun that hits them. Both residential and industrial properties make for the perfect location to install. Sometimes even vast land can make for the perfect opportunity for ground mounted solar. When the panels are installed, they collect the suns energy, as direct current (DC) and then a solar inverter converts this to alternating current (AC), which can then be utilised as electricity.
How much energy will it generate?
The amount of energy will depend on where the system is installed in the country with the amount of annual sunshine varying depending upon the latitude and other environmental issues. The table below gives examples of energy generation for each kWp of PV panels installed.
Size of system
The amount of energy generated is directly related to the size of the system and is calculated by multiplying the size of the system as defined in kWp by the annual generation figures from the table above. e.g. a 5kWp residential system in Johannesburg should generate 5 times 1871kWh = 9355kWh per year. The exact generation will depend on how close to north facing it is, how close to the optimum inclination of 30 degrees and any obstructions that might cause some shading.
What To Consider Before Installing A System
Is the location suitable for a PV install?
You will need to make sure that you have the space, whether the system is ground mounted or roof mounted. Remember sky lights, chimneys, and hips on the roof will all impact how many solar panel you can install on that roof.
Is the roof structurally sound, and will installing PV compromise the integrity?
It goes without saying that solar should never be installed on a roof that in structurally unsound, or if installing solar would make it unsound. It is also not advised to install on a roof that has asbestos. If in doubt, you should source an expert to survey.
How suitable is the property in terms of positioning?
To make the most of the sun in South Africa, it is best to install on roofs that face north. You can also mount facing north west or north east however this is less effective.
What is the optimum angle to install on?
This is measured on a case by case basis, depending on the location. To be most efficient, solar panels should be mounted tiled at an angle of between 25 and 35 degrees. Panels should never be installed lying flat.
Is the installation suitable for self-consumption using batteries or grid back up?
When it comes to utilising energy the best way possible, many are looking to battery products, either to supplement their own self consumption, or as a reliable source of energy in the event of a grid failure. Any system using a battery source needs to be of a certain size in order to benefit the user. Some smaller systems would not be able to support an integrated battery.
What are the main incentives for home and business owners?
First and foremost, the owner will be saving on their electricity bill. It is estimated that electricity suppliers will be steadily increasing their prices as demand grows, with the potential for demand being higher than supply. Utilising energy generated is a great was to save.
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