A series of direct current (DC) transmission corridors designed to transport 10-18GW of wind-generated electricity from north to south Germany has been proposed by the country’s four electricity transmission system operators (TSOs).
The four DC channels would involve laying 1,800-2,400km of new cables. The proposal represents one of the most controversial elements of the TSOs’ draft network development plan 2012 (NDP 2012), unveiled at the end of May.
Construction of the DC channels is not guaranteed, since there is considerable political and public concern about the costs of network expansion. The draft NDP is open to public consultation until 10 July, after which a second draft will be presented to energy regulator, the Bundesnetzagentur (BNA). Agreement on a ‘masterplan’ should be reached by the end of the year. However, annual revisions to the NDP are scheduled, increasing the likelihood of ongoing debate.
"As long as the potential for wind energy onshore, with its significantly lower cost and lower transport needs, is not exhausted there will be resistance," predicts Holger Krawinkel, energy expert at the association of consumer protection centres, Verband der Verbraucherzentrale.
The draft NDP considers network investment over the next ten years, based on three scenarios. The lead scenario "B" assumes offshore wind capacity of 13GW in 2022 and 28GW in 2032, with onshore capacity of 47.5GW in 2022 and 64.5GW in 2032. The pessimistic scenario "A" pitches offshore wind at 9.7GW in 2022. The optimistic scenario "C" is based on the individual plans of Germany's 16 federal states and puts offshore wind at 16.7GW in 2022.
Forecast costs range from €19–27bn, or an average €1.9-2.7bn/ year. Not all of this is attributable to Germany’s official policy of transitioning toward renewable-based electricity generation, known as "Energiewende". About €7bn is linked to earlier initiatives designed to facilitate European electricity trading and network modernisation.