As South Africans experience the chilly winter months, our energy needs and consumption patterns change, which has an impact on solar panel performance and efficiency. It is important to understand how these energy needs and behaviours shift through the different seasons to implement practical steps to maximise solar systems at this time of year.
Understanding Winter Solar Performance
There are many factors that affect solar panel performance in winter, including reduced daylight hours and the angle of the sun in the sky. Regardless of geographic location, the simple fact that the sun is just not up for as long in winter as it is in summer has the biggest impact on solar systems. Additionally, with the sun being lower in the sky in winter, this impacts when it starts hitting solar panels at optimum angles, and increase the chance of shading.
Interestingly, cooler temperatures can actually enhance solar efficiency. For instance, solar panels at the coast perform better relative to those in hot areas like the Karoo, due to the cool sea breeze. Solar panels rely on light, not heat. For example, in Europe and the Alps there are solar panels in the snow which work just as well, even though it’s minus five degrees!
Adapting to seasonal energy needs
It might seem obvious, but it is also crucial to understand how energy needs shift from season to season. In winter, with shorter days we use lights more in the mornings and evenings. Heating needs increase, with oil and bar heaters, electric blankets, and more frequent kettle use. Geysers also work harder to maintain temperatures in colder ambient conditions meaning it must be on for longer periods to reach and maintain a temperature. Location, too, plays a part in seasonality impact, if you live in Cape Town, for example, you are likely to use tumble dryers more because of high winter rainfall, while Johannesburg remains sunny almost every day.
Practical tips for optimising solar efficiency in winter
So how can we optimise our solar efficiency and mitigate the impact of season changes
on our systems?
- Shift loads to sunlight hours: Use high-power electric appliances when solar
panels are generating the most (in the middle of the day):- Run washing machines and dishwashers at lower temperatures and during
sunlight hours. - Wash on sunny days to avoid using the tumble dryer.
- Cook evening meals during the day (using a slow cooker on low power rather
than the stove or oven during the evening). - Turn off appliances and lights when not in use.
- Run washing machines and dishwashers at lower temperatures and during
- Install timers on geysers: Set geysers to operate during the day when ambient temperatures are higher, reducing the need for constant heating. Utilise a geyser blanket to maintain efficiency.
- Utilise solar technology: Versofy’s SOLAR’s app is a great tool as it takes weather conditions and historical usage into account. For example, it knows that if it is going to be a sunny day tomorrow, you can drain the battery more today (and use less from Eskom). The app applies technology that takes the myriad of variables into account, so that you don’t need to.
- Increase solar capacity: Installing more solar panels and batteries can assist with resilience to cloud cover and rain in areas like the Cape during winter. We encourage more panelling in these areas, and now is a good time to upgrade, as panel prices are at an all-time low due to the high levels of demand.
