The Netherlands is a beautiful country for solar energy. Especially in idyllic Zeeland, the yield can get considerably high. 30 knots is not uncommon and clouds get blown away easily. The Solar Monkey software includes all these factors into yield calculation. Every now and then the yield is higher than 1 kWh/Wp. But what does this mean? Is that actually possible?

In the Netherlands and surrounding countries, the average irradiance is 1,000 kWh per m2 per year. This coincidentally corresponds to the standard test condition: ‘Watt peak’. Because these numbers are the same in the Netherlands, the performance factor is often confused with kWh/Wp. This makes sense because an average system in the Netherlands often scores between 0.8 and 0.9 kWh/Wp. In the capital of Zeeland, Middelburg, the average irradiance is more than 1,100 kWh per m2 per year. This is higher than the standard test condition, so the kWh/Wp can also exceed 1.

sun irradiation Europe
Foto 1: average irradiance per m2 per year in Europe

If a system has a higher yield than 1 kWh/Wp, this does not mean the performance is higher than 100 per cent. kWh/Wp is not the performance factor. The good news: if you have a system in the Netherlands which yield more than 1 kWh/Wp, then you have a very good system!

Take Spain, for example. There, the average irradiance is 1,800 kWh per m2 per year. As a result, the average kWh/Wp in Spain is just under 1.8. The confusion between kWh/Wp and the performance factor, therefore, does not arise there.

Quite complicated matter isn’t? At Solar Monkey we also had to think about this for a long time. All that knowledge and expertise is incorporated in our calculation models, so that you can benefit from it. Not using our software yet? We are happy to help you get started. Request a demo here and get the first three credits for free!

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