The German Solar Kapital has used films in three of its solar power plants in Greece. It claims that the payback period of the new solution is relatively short.
German renewable energy developer Solar Kapital recently tested a white film to improve the yield of bifacial solar modules at three of its solar power plants in Greece.
Solar Kapital reports that approximately 2,500 m2 of its films were used at its Lagkadas solar farm. The modules were mounted on single-axis trackers with an inclination of 25 degrees and placed at an average height of 1.5 meters above the ground. Measurements from June 2022 to May 2023 showed a weighted average production increase of 6.4% over the year, although values varied due to radiation intensity.
The company reported that the actual yield of the two inverters during the period was 1,661 kWh per kW. Considering the weather conditions, a 4% lower yield is assumed, in which case the average production yield is 1,730 kWh/kw, which the company considers significant for the region. Solar Kapital said that with a guaranteed feed-in tariff of 0.073 euros ($0.079/kWh), the membrane’s payback period is less than 2.5 years.
Solar Kapital also tested membranes at the Kilkis solar power plant, which is based on two-axis tracking technology. The measurements showed a yield increase of about 2.5% with both inverters at the factory. Taking into account the feed-in tariff of €0.335/kWh and the minimal labor and geotextile needs, the company estimates the membrane’s payback time to be less than a year.
However, the payback time estimates do not take into account the changing costs of electricity production or the possible benefits of reducing the need for grass cutting. The nature of the subsoil is also significant, as installation costs increase on rocky ground.
Over time, the applied geotextile breaks down, and Solar Kapital’s engineers assume that its reflectivity decreases by about 20% annually due to weather and dust. As a result, the additional output of bifacial solar modules is reduced.