By Prof. Fritz Vahrenholt
(Text translated/edited by P. Gosselin)
After the phase-out of nuclear energy at the end of 2023, the coalition agreement aims to bring forward the phase-out of coal, “Ideally, this already would be achieved by 2030“.
To this end, renewable energies are to take over 80% of electricity generation, which is to increase from 600 TWh (terawatt hours) today to 680-750 TWh (p.56). While concrete generation targets are named for solar energy (quadrupling of today’s capacity to 200 GW) and for off-shore wind energy (also quadrupling to 30 GW), the agreement only speaks of a target for on-shore wind energy of a land take of 2% of the country’s surface area.
If we were to talk about an increase of 30,000 turbines – and this can be assumed if the area doubles from today’s 0.9% of the land area – this would not go down so well in the countryside.
But is the 2% area really accurate? It is just as inaccurate as the figure of 0.9% for today’s land area. This is because the area figures refer in each case to the narrowly defined area covered by the B-Plan. The necessary distances to residential buildings are not included in this area figure. The 0.9% corresponds to 3100 km² today (source: Federal Environment Agency and Competence Centre for Nature Conservation and Energy Transition).
“1,325 square kilometres and thus approximately 42 percent of the areas considered – taking into account the existing installations as of the cut-off date December 31, 2017 – are free for the installation of wind turbines.” This means that there were 28,500 turbines on 1800 km² in 2017 (today there are 30,000 turbines). This is, as I said, the area of the B-plans. This area does not include the necessary distance to residential buildings, which, however, must be covered by planning.
If you divide the number of turbines (28,500) by the area (1800 km²), there are 16 turbines/km², i.e. an average of 62,500 m² per turbine or 250 m by 250 m. This shows that the necessary distance to residential buildings is not sufficient.
6 times the area
If we calculate an average size of 5 turbines per wind farm, the wind farm would cover an average area of 176,000 m² (420 m x 420 m with 4 wind turbines at the edges and 1 in the middle) without distance areas (at a distance of 300 m between the turbines). With a distance of 600 m (which is already questionable from the point of view of emission protection) to the nearest residential area, the park requires an area of 1020 m x 1020 m = 1.04 km². This is six times the area of the B-Plan area, which is merely nestled around the plant configuration.
Even if one takes into account that today 5% of the turbines are located in the forest (where there are no distance restrictions) and in the future perhaps 20% will be built in the forest, the area required would only be reduced to five times the B-Plan area.
In other words, those who demand 2% of the land area with B-plans for wind power plants actually need 10% of the land area.
Now it will be conceded that the size and height of turbines will increase significantly, so that we can expect less than 30,000 turbines. That is correct. But the land consumption will remain in the same order of magnitude, because larger turbines also need a greater distance between each other (5 times the rotor diameter, at 120 m that is 600 m distance).
Moreover, they need a distance of at least 1000 m from residential areas. The output increases, but so does the land consumption. The fact that a multiplication of wind energy does not result in a guaranteed output does not need to be mentioned again here.
Even the windy November showed that wind energy production was often enough close to zero to 5000 MW, and thus less than 10% of the possible output of 60,000 MW. And 3 times zero is zero.
Source: Rolf Schuster.