As solar power technology gets cheaper and cheaper, it also gets more and more affordable, which means that not only private homes but also large-scale utilities are shifting to solar power. And with the overall state of our mother Earth and our precious climate, the switch from conventional to renewable energy sources, especially solar ones, has accelerated significantly.
Now, it most probably does not come as a surprise, that solar power needs sun to do any good. There is in fact a direct linear correlation between the amount of sun rays (radiation) reaching a solar panel and the energy that this very solar panel produces.
Solar radiation is however not the same as temperature, which is why you will find plenty of large-scale solar power parks, as well as consumer-scale house solar panels, in the colder areas on earth, e.g. Northern Europe. As long as the clouds do not stand in the way, your solar panels will keep on producing electricity, even in wintertime – if they’re snow-free. And even with clouds above our heads, solar panels, depending on their type, will still produce approx. 10-25% of their nominal (maximum) power output.
What affects solar radiation?
Is there anything that affects solar radiation? Yes, there is. Besides the cloud coverage, solar radiation depends on the time of the day and time of the year (both indicating where the sun is located on the sky, at what angle it hits your solar panel and whether or not anything, such as a building, mountain or tree is casting a shadow on it) – so the more clouds or shadow the more limited solar radiation; early morning and late afternoon hours mean also smaller energy production and finally, the more up north you are the lower the position of the sun during winter months in the northern hemisphere, hence again the more limited energy output.
Add to this sand being blown from desert areas, like for instance Sahara sand, which, on rare occasions, affects solar energy production in Europe and can decrease the power output with e.g. 10% in Germany.
Temperature
What about the temperature? Well, extremely high temperatures, like the ones we’ve seen in e.g.: the state of Minnesota (US) and in many parts of Southern and Central Europe back in July 2019, decrease the efficiency of solar panels and hence also the amount of electrical energy produced. This has to do with the physics of what is going on in a solar panel.
Without going into details, as each solar panel manufacturer may have a slightly different technical specification for their panels, solar panel efficiency, i.e. the percentage of the solar energy that can actually be converted into electricity, decreases with temperature increase. The typical testing temperature for solar modules is 25°C / 77°F.
Bear in mind that it’s the temperature of the panel and not the ambient one. Temperatures higher than this can reduce output efficiency by 10-25%. Now, add this the fact that, when the ambient temperature is for example 25°C, on a sunny day, this can easily mean 40-45°C on the solar panel itself – which is again what matters when we speak about efficiencies.
Future of solar energy
What does this mean for the future of solar energy? With global temperatures constantly rising – what effect will this have on the development of solar power around the world? Any thoughts?
Will a further, drastic drop in production costs of solar panels counter-balance the potentially lower efficiency, due to higher ambient temperature?
No matter what, the good news is that there are ways to make a fairly precise analysis of historical power production from a given solar panel type in a given geographical location. This analysis will answer the question of what your new solar farm would have produced if it was already in operation in the past.
Equally, a similar analysis of the future power production, that you can expect from the solar panel, is also possible. Both are available at ConWX and both will give you a very good picture of what to expect from your solar farm – during a heat wave, in colder winter months, with blue skies or heavy rain clouds. With access to multiple, high-resolution Numerical Weather Prediction (NWP) models, ConWX data specialists, meteorologists, and mathematicians have mastered the understanding of big weather, wind, and solar data.
It’s ALL in the data and we can read it!
