Does solar work during load shedding?
As long as it is light, solar modules will be producing power. However, there is a misconception that a solar PV system will prevent load shedding – it’s actually a bit more complicated than this.
Firstly, there are different types of solar PV systems: grid-tied, off-grid (microgrids), and islandable on-grid microgrids. In South Africa, grid-tied solar PV systems are most commonly used, as these are the most affordable and have the best business case.
Unfortunately, grid-tied solar PV systems will generally be programmed to switch off during load shedding. Why is this? It comes down to international safety standards. Solar modules generate DC electricity, but this needs to be converted into AC to be used in buildings. As such, solar inverters are used to convert the electricity.
During a grid outage (such as Eskom’s load shedding), the solar inverters are designed to switch off. This serves as protection for grid personnel that might be working on transmission lines during outages. If buildings continue to generate power during a grid outage and potentially export power to the national grid, it could be fatal for maintenance personnel who are unaware that there is live electricity in the lines when the grid is off.
As such, grid-tied inverters cannot operate in off-grid conditions. However, it is possible to form one’s own “on-grid” microgrid, that essentially fools the inverters into thinking that they are grid-tied, but keeping them off-grid to maintain safety. This requires the use of a generator or battery and specialised control equipment. We have covered the article in depth, in our blog about options for C&I buildings during loadshedding.