An all-too-frequent question that we get from tenants in buildings with new grid-tied solar installations is: “Our building has solar – why do we still have load shedding during the day when the sun is shining?”
The short answer is that solar panels are not a load shedding solution on their own.
That is, a grid-tied solar installation without an integrated battery and/or generator does not help with daytime load shedding, no matter how bright the day. When the grid is off, the solar is too.
A non-technical explanation is that the load, or demand, in residential buildings is intermittent. Stoves, kettles, water heaters and fridges go on and off at random times through the day. Likewise, the supply, if it is solely solar panels, is also intermittent. The sun shines brightly until it does not, and when a cloud passes over, electricity production drops dramatically.
When intermittent demand meets intermittent supply there will be frequent gaps. Without something to fill the gap, normally electricity from the grid, the entire system will trip. During load shedding, it is electricity from a battery or a generator which must fill the gap.
There is a further, slightly more technical, explanation. All appliances in South Africa run on an electrical frequency of 50 Hz. Solar panels require the grid, a battery, or a generator to provide a reference frequency to produce power at that frequency. They cannot do it in isolation.
So, the only way that solar panels can also be a load shedding solution is if it they are coupled with a suitably sized battery or a generator, or both.
Installing solar panels, with or without battery and generator integration, can be a complicated and costly endeavour. Not only that, but the system needs to be monitored, inspected, maintained, and cleaned if it is to work optimally over its 20- to 25-year life. Decentral Energy will design, build, supply and run solar installations for residential buildings, taking the pain (and risk) out of the owners’ hands.
