A group of researchers have investigated the influence of the regulatory framework on supporting the expansion of ground-mounted PV plants close to transport routes as railways, highway and federal roads in Germany. Their analysis showed that most of the PV systems installed next to these routes are located on what was once agricultural land.
October 28, 2024
Emiliano Bellini
New research conducted by scientists from the Helmholtz-Centre for Environmental Research Leipzig has shown that more than 39% of Germany’s operational PV plants corresponding to approximately 6.9 GW are located within 500 m of a transport route such as a railway, a highway, or a federal road.
“In Germany, areas covered by PV plants next to transport routes are mostly agricultural areas with all levels of yield potential,” the research’s corresponding author, David Manske, told pv magazine. “The German legislator is in a position to ease this point of conflict by excluding areas above a selected threshold value of yield potential in line with existing potential studies.”
In the study “The development of ground-mounted photovoltaic systems next to transport routes,” published in Renewable and Sustainable Energy Reviews, the research team explained the main goal of their work was to assess if the regulatory changes introduced in 2023 by the amendment of the country’s renewable energy law, the so-called EEG, have impacted the expansion of PV plants next to transport routes.
Their initial hypothesis is that, in particular, five new provisions contained in the new EEG version released in 2023, which make it easier to build PV plants close to transport routes, will have an influence on the expansion of these projects and increase land use conflicts.
The group used geospatial data from the Manske & Schmiedt dataset created by the same Helmholtz-Centre for Environmental Research Leipzig and PV system data from the German Federal Network Agency’s Core Energy Market Data Register, with the latter providing information on 8,965 PV plants totaling 17.18 GW and occupying a total surface of 27,000 ha as of April April 20, 2023.
It also utilized the Digital Basic Landscape Model (BasisDLM) to collect data on the transport routes and the Corine Land Cover (CLC) dataset was used to measure the land type occupied by ground-mounted PV systems. It also used the so-called Soil Quality Rating for Cropland in Germany dataset to estimate the quality of arable land affected by PV systems.
Through their analysis, the academics found that, on average, there are 0.12 ha of PV plants within the mandatory 500-m strip for every km of road or railway track and 0.16 ha for every km of railway, as well as 0.1 ha for every km of federal road and 0.21 ha for every km of federal highway.
“The area data for ground-mounted PV plants indicate that more and more hectares of PV plants are being erected next to transport routes since the first monitored plant was installed in 1988,” they highlighted, adding that, previous to the new rules, the strips alongside transport routes could not be wider than 200 m, while until 2020 this limit was set at 100 m. “In 2021, 82 ha of PV plants were installed within the newly subsidized 110-200-m strip, which increased in 2022 to 125 ha.”
The researchers also found that about 71% of the PV plants installed next to transport routes are located on what was once agricultural land. “The PV plants examined in this study are located on former agricultural land cover soil that is of high quality (1407 ha), very low quality (1130 ha as of April 2023), low quality (1110 ha), and medium soil quality (1057 ha),” the research group emphasized. “Good soil quality does not seem to be an exclusion criterion for the installation of PV plants.”
The scientists said that policymakers may contribute to reducing land use conflicts by excluding areas “above a selected threshold value of yield potential in line with existing potential studies.”
The research project is part of the EE-Monitor initiative which is intended to provide a scientifically sound basis for a social debate on the nature-friendly expansion of renewable energies in Germany, while supporting the identification of undesirable developments and positive trends in the expansion of renewable energy.
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