We have just passed midwinter’s day or, more correctly in the southern hemisphere, midwinter’s night, which, for us in the south, is the longest night of the year.
In the highveld, winters are rather pleasant, largely because there is no rain. In fact, there mostly are not even clouds. So, our winter days, generally, have beautiful blue skies and beautiful sunlight. Of course, the sunlight is much weaker than during summer because the sun is further away.
As far as solar energy is concerned, one would receive noticeably less electricity out of a photovoltaic system in winter, although one could almost be guaranteed of solar power for about half a dozen hours a day.
In Pretoria, something that is very noticeable at this time of the year is that the air is unbelievably still. During a number of early mornings and evenings, the air here does not move at all.
I have a large window in my bedroom and a glass sliding door in my lounge, each of which looks out onto trees and shrubs. At times, I look out into the garden and notice that not a single leaf is moving on any tree or plant. It looks amazing, just like a photograph. At times, it looks quite unreal in that absolutely nothing moves.
So, this time of the year is not good for wind power in Pretoria. In fact, Pretoria is not good for wind power at all at any time.
Actually, midwinter, when one needs heaters to warm the house, is not a good time for wind energy anywhere, because midwinter and midsummer are times when air movement is least. Wind mostly occurs at the changing of seasons, like in spring and autumn.
If you are thinking of using renewable energy based on solar and wind power, then you have to remember the limitations of their inherent characteristics. In sunny South Africa, solar is mostly available at lunchtime, but not at breakfast or dinner time. You cannot watch any TV movies in the evening on solar power. In the case of wind, you may or may not get it, much like playing poker.
I am all in favour of solar and wind energy when it is genuinely economically viable. So, to my mind, the main challenge of using solar and wind energy is to find applications which fit in with the cyclical nature of solar and the random nature of wind. For example, considering places like De Aar and Upington, they should be linking solar plants to factories that need their main power for four hours over midday, and none at night, when all the staff are at home.
Further, what would be ideal is if the factory could use electricity at 12 V or 24 V dc power, and not at 220 V or 380 V ac power. Electricity could then be used straight from the solar plant.
But converting the low-voltage dc to high-voltage ac to send electricity to Cape Town is not a good idea. Think about it.
Here is something else to think about: France produces three-quarters of its electricity from nuclear power, while Germany has had a major wind and solar programme going for decades now. Right now, Germany has three times the installed renewable electricity capacity of France’s nuclear capacity, yet produces more carbon dioxide than France. The nuclear power of France is stable, but the wind and solar power of Germany is unstable. In desperation, Germany has started building coal-fired power stations again. The first three new German coal-fired power stations are up and running, with 20 more planned. Interesting that nobody is told about these.
It is silly of the antinuclear green groups to make war over nuclear power. They are desperate to stop nuclear at all costs. They even resort to court cases and smear campaigns. I am personally regularly the target of the smear campaigns, and I receive hate mail and insulting comments. Even physical threats.
Nuclear people are not antisolar and antiwind. We just say: “Don’t kid the public; you can’t run an electric train and steel foundry on solar and wind power.” We also say: “Use the solar and wind in dedicated situations in which their inherent properties make sense.”
The best power of all is brain power. Think about these things.