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Electrical machinery and equipment need a lot of power and the sun has plenty of energy to give, so what’s stopping us? By installing just a few solar panels, you can work with electricity at almost no cost. And you’re doing both our society and the environment a favour by working without carbon emissions, noise, fumes or air pollution. But those solar panels, do they really deliver enough power in the winter months? Spoiler alert: the answer in most cases is ‘YES’.
During autumn and winter, darkness can stick around for quite a long time and that’s not ideal for solar power. But it turns out that in practice, solar panels still does their job. The best example of this is actually quite simple, but at the same time essential for the winter workplace: a light source. You can hire a trailer-mounted 4x60W LED solar lighting tower from Boels, for example. It gets its power entirely from the sun and therefore has the ECO label for sustainable machines and tools.
The solar lighting tower has three solar panels, each providing 305W of power for the four 60W lamps, which is enough to light up almost 5,000 square metres of construction site. There is also a battery on board, of course, to store the captured solar energy so that work can continue as usual during the evening and night. In fact, dimmed to the lowest setting, the solar lighting tower can illuminate the site all year round without recharging. A solar-powered lighting tower saves on average 1.3kg of carbon-dioxide an hour compared to fossil fuel alternatives. That’s more than 11,000 kg of CO2 in one year!
Especially on very sunny days with freezing cold temperatures, solar panels work at their best because the solar cells conduct electricity better at lower temperatures
How to prevent lower yields?
Those CO2 savings sound so good that you could easily forget to ask about the downsides of solar power. After all, it is obvious that cold, cloudy and dark days produce a lot less solar power. But funnily enough, this is only partly true. Especially on very sunny days with freezing cold temperatures, solar panels work at their best because the solar cells conduct electricity better at lower temperatures. The reverse is also true: too much solar radiation on a hot, tropical day actually produces proportionally poorer efficiency.
So solar panels don’t depend on heat, but on getting sufficient light. And that doesn’t necessarily have to be full sun! A solar panel also captures a lot of light (=energy) on cloudy days. And usually that’s (more than) enough to keep the light on during the evening and at night.
The real efficiency killer, though, is shade. So always make sure that trees, other buildings, but also scaffolding, cranes and so on don’t cast their shadows on the solar panels all day long. Finally, direction is also important. A southern orientation works best; panels facing south-east and south-west can reduce the efficiency by 20-30 per cent.
Why solar panels don’t need much cleaning
Another concern is dirt and debris from falling autumn leaves, snow and ice. The solution is actually a simple one: solar panels have a self-cleaning film layer and are normally placed at an angle of about 35 degrees to capture the best sunlight. That angle is enough to ensure that leaves, snow and ice can slide off relatively easily, and a good downpour will wash away any remaining dirt. Only things like dried-up bird droppings may need to be cleaned by hand. Having self-cleaning film layer means that the of (aggressive) cleaning agents is not recommended and you are better of using pure water or osmosis water.
In short, solar energy also has a bright future on the building site. It’s no wonder that you see more and more solar panels on the roofs of site huts and contractor units, as well as fully or partially electrified machines and equipment at work.