Electricity demand for individual flats, townhouses and houses are likely to continue to increase because of the ever-increasing population in the country. We have seen over the years Eskom not being able to supply this demand. Solar and wind power may not be the total answer but can do a lot towards reducing the cost of electricity and being a source of power when Eskom is not delivering power.
While wind power only has the advantage of being available when wind is available and is more suitable to coastal areas where wind is more generally available; Solar is suitable for the entire country, with South Africa having more than double the sun energy that a country like Germany has, and in many inland areas there are over 300 days of sun a year. Solar panels provide a source of electricity when it’s sunny but not in heavy, cloudy weather or in the dark. During the day, it becomes a source of electricity and can be used to charge batteries and supply loads.
As the adoption of PV solar solutions around the world grows, three types of systems can be considered: Off-grid, Grid-tied, and Hybrid. We will discuss Hybrid in next month’s newsletter. Let’s look at these system types;
Off-grid solar solution is exactly that, off the grid completely. This is where the installation is designed to make the user independent off of Eskom’s grid. There is no connection to the utility, and you are reliant on the power generated by your Solar PV solution, battery backup and optionally a generator. It is successfully being used in isolated areas such as farms and small holdings (plots). The power created by the Solar PV system is in the form of DC power which feeds through an inverter to charge the batteries or convert it to AC power for powering AC loads. When the PV Solar is unavailable the inverter uses the batteries’ DC power to convert and supply the AC loads. When the power in the battery bank becomes depleted and there is no power available from the PV solar system the generator will kick in to provide power.
In a Grid-tied PV system setup your property is still connected to the utility grid and power is generated by the Solar PV system in the form of DC that is converted to AC by the inverter and then used directly in your property. Here the system is used to supplement the supply from Eskom and to reduce overall cost of electricity supply. In the event of no power being produced by the Solar PV System, power is drawn from the grid. These systems make the most financial sense and are mostly used by companies wanting to cut their daytime electrical bills. This is also great for residential properties where all your daytime power will be fed by the sun and only your nighttime loads will be fed by Eskom. In certain municipalities they allow excess power generated by your PV Solar system to be fed back into the grid at agreed rates offered by the municipality. Municipalities have very strict rules with these installations since it is directly connected onto their grid and syncs to it, therefor any product connected onto the grid must be NRS097 approved and you must comply to their installation standards. If feeding power back into the grid there is a process that must be followed, and you must have written permission from the municipalities before you are allowed to feed power back. As mentioned, grid-tie systems are less expensive than off-grid systems making it more affordable since there are no batteries involved. This type of system will reduce your electricity bill, but you will still draw power from the grid at night.
It is essential that your installer is fully trained, familiar and experienced with each of the different types of installations and products used in your system. Our installers are qualified red seal electricians with wireman’s license that comply to SANS 10142-1 standards. We are also PV Greencard approved installers and support the PV Greencard program, ensuring safe and quality PV Solar installations in and around South Africa.