Impact of German Energiewende on Transmission Lines in the Central European Region

The impacts of renewable energy production and German nuclear phase-out on the
electricity transmission systems in Central Europe is investigated with focus on the
disparity between the growth of renewable production and the pace at which new
electricity transmission lines have been built, especially in Germany. This imbalance
endangers the system stability and reliability in the whole region. The assessment of
these impacts on the transmission grid is analysed by the direct current load flow model
ELMOD. Two scenarios for the year 2025 are evaluated from different perspectives. The
distribution of loads in the grids is shown. Hourly patterns are analysed. Geographical
decomposition is made, and problematic regions are identified. The high solar or wind
power generation decrease the periods of very low transmission load and increase the
mid- and high load on the transmission lines. High solar feed-in has less detrimental
impacts on the transmission grid than high wind feed-in. High wind feed-in burdens the
transmission lines in the north-south direction in Germany and water-pump-storage
areas in Austria.