BDEW: Overhead lines and more efficient wind farm connections could save Germany tens of billions of euros

Allowing several key transmission lines to be built overhead and better planning the connection of offshore wind farms could significantly reduce Germany’s investment needs for transforming its energy system. The German energy industry association BDEW said.

According to BDEW, decarbonising Germany’s energy sector and reducing the country’s dependence on fossil fuel imports will require €721 billion by 2030, including €131 billion for expanding and modernising the transmission grid. BDEW has identified two areas with significant potential for savings.

These are placing some transmission lines above ground and reducing the investment needed to connect offshore wind farms through better planning. According to estimates by the companies involved, these measures could deliver long-term savings of tens of billions of euros from the mid-2030s.

“For the energy transition to succeed, we must keep costs in focus. It will be more important than ever to make full use of all savings potential in the future,” said BDEW head Kerstin Andreae.

Germany’s network regulator (BNetzA) also recently said that using overhead lines for the necessary expansion of the German grid by 2045 could save up to €35 billion in investment.

Placing some lines above ground

According to BDEW, the underground transmission cables planned for the three routes OstWestLink, NordWestLink and SuedWestLink should instead be built as overhead lines, since planning is still at a very early stage and no connection to offshore lines is planned.

These projects could save tens of billions of euros, significantly reducing charges for consumers. Since all three projects are still at the beginning of the planning process, BDEW says this would not cause any delays.

All other existing grid expansion projects, such as SuedLink, SuedOstLink, NordOstLink, Rhein-Main-Link and others, should continue to be built as underground cables. Underground lines may be an appropriate solution for specific projects, taking into account potential impacts on land and property prices, planning delays, weather and security considerations, and technical constraints, BDEW adds.

Making better use of infrastructure for offshore wind farms

According to BDEW, connecting offshore wind farms to the grid will require substantial investment of €150–180 billion by 2045. This amount could rise further as global prices for some raw materials increase. However, the installed capacity of offshore wind farms and their grid infrastructure is used to its full potential only during part of the year.

The annual number of full-load hours depends heavily on the location of the wind farms and their density. The interaction between individual wind farms, which can result from wake effects caused by neighbouring wind farms, could increase as further expansion takes place.

To maximise the utilisation potential of the wind farms and their connections, the decisive target should be the actual energy generated in TWh, rather than the installed capacity of the farms in GW. BDEW says that a shift from a target in GW to a future target in TWh should be explored without lowering the overall ambition of the expansion plans.

In addition, further optimisation of the layout of offshore areas should be explored to reduce wake effects and maximise energy generation in Germany’s exclusive economic zone. This requires closer cooperation with neighbouring countries such as the Netherlands and Denmark, particularly with regard to developing the area.