Energy Payback Time: When does a solar plant contribute to climate protection?

21 September 2021

Before a solar plant can produce sustainable electricity, a lot of energy goes into the production of the solar panels. The question is: When does a photovoltaic systems start contributing to climate protection?

The answer lies within the so-called Energy Payback Time. The Energy Payback Time describes how long it takes for the energy system to produce the same amount that was required to manufacture the energy system in the first place. The higher the incoming solar radiation, the faster you can get the energy needed for the manufacturing process back. In addition, the grid quality and the electricity mix also play a role in the Energy Payback Time.

Now the Fraunhofer Institute for Solar Energy Systems ISE has determined the Energy Payback Time for roof-based solar systems. The study found that the Energy Payback Time for solar roof systems ranges from a minimum of 0.44 years in India and a maximum of 1.42 years in Canada. In Europe, the Energy Payback Time lies between 1 and 1.3 years. With 1.05 years, Sicily comes in first amongst the European countries. With a lifespan of 20 years, such a system can thus produce around 20 times the amount of energy that was needed to produce it.

The study was published in the Photovoltaics Report (PV Report) and looked at monocrystalline solar modules with an efficiency of 19.9% ​​that were produced in China. But how would the Energy Payback Time change if the modules were produced in the EU? According to the institute based in Freiburg, the Energy Payback Time would decrease from 1.05 to 0.97 years for a roof-top solar system in Sicily, and from 1.28 to 1.16 years for the average for the EU.

You can find the full report here:

Photovoltaic Report by the Fraunhofer Institute for Solar Energy Systems ISE

Image by Aron Visuals on Unsplash

Watch now: Installation of the solar plant for the first 5-star eco hotel of Uganda

Join us and take a look behind the scenes and see exclusive footage from the construction of the solar plant for the first 5-star eco hotel in Uganda, the Aquarius Kigo Resort. You will also learn about interesting details and background information, such as why the angle of the solar panels matters, and what the tourists from all around the world travel to Uganda for.


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The 28 kW plant is a great success and reliably delivers affordable green energy. As a result, we’re saving a significant amount of CO2 and strengthen the local economy of the region with sustainable energy.

Enjoy watching!