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These plans constitute Germany's first electricity network development plan (NDP 2012), which was rubber-stamped by federal energy regulator the Bundesnetzagentur (BNA) last month.

NDP 2012 comprises 51 grid upgrade measures, including several projects that will be of major importance to the transmission of wind-generated electricity.

One is the west-coast cable project, an alternating current (AC) line comprising five links running from Brunsbuttel to the Danish border. There are also four new direct current (DC) links vital for wind transmission (see map). One, the Combined Grid Solution, will service offshore wind in the Baltic Sea, while the other three are vital for the transmission of onshore wind generation: Corridor A will run from Emden in the north west to Philippsburg in the south west; Corridor C, the longest, is a north-south corridor comprising two parts, one running from Brunsbuettel to Grossgartach, and one from Wilster to Grafenrheinfeld; Corridor D will run from Bad Lauchstadt in central Germany to Meitingen in Bavaria.

The current lack of major north-south links in Germany has led to an excess of wind-generated electricity in the north of the country being routed to the south via neighbouring Poland and Czech Republic, putting a strain on their transmission systems ).

However, the final approved version of NDP 2012 contained 24 fewer upgrade measures than earlier drafts of the document. Robert Habeck, the minister responsible for the transformation to widespread renewables use in the northern German state of Schleswig-Holstein, questioned the regulator's decision.

Missing link

Habeck said that the east-coast cable proposed in the draft NDP, but excluded from the final version, is needed to accommodate wind energy expansion in the east Holstein region. Already wind output in the region is curtailed due to a lack of transmission capacity, he said. Habeck added that this could not wait for the next NDP due in 2013, but rather must be decided quickly.

BNA's culling of 24 measures brought the anticipated cost of NDP 2012 down by EUR5 billion, from EUR20 billion to EUR15 billion. After a steady barrage of complaints in 2012 about the costs of switching to a wind and renewables-based energy system, this cost-reduction was announced as good news by BNA president Jochen Homann, who said the amount was considerably less than what the transmission system operators had originally proposed.

Overestimated

The NDP claimed that Germany's four transmission system operators had overestimated transmission needs in their initial scenarios, drawn up in 2011, which fed into the first NDP draft published in May 2012. Their initial estimate was that strengthening and optimising 4,400 kilometres and new build of 1,700 kilometres would be needed over the coming ten years, as well as another 2,100 kilometres of high-voltage direct-current corridors, at an investment of EUR20 billion.

Although the final NDP 2012 still makes it clear that swift completion of some new grid projects is vital, 24 of the total 74 network projects in the initial NDP draft have been placed on the back burner. One of the four high-voltage direct-current overall transmissions systems has also been laid aside for the time being, deemed non-urgent and possibly not necessary.

The NDP is to be updated every year. It could be altered significantly as issues in the coming years are factored in, such as curtailing the output of wind stations during high wind periods to avoid network overload and developments in electricity storage technologies.

The effects of planned rapid expansion of wind energy in southern Germany, where growth has been slow until now, may also have an impact.

These events may speed development of some of the sidelined measures, but demand management may soon become widespread in Germany, reducing network loads and the need for cable-strengthening.

For example, a regulation is planned that will reward Germany's industrial heavy electricity users, such as aluminium smelters, for making their processes more flexible and altering power demand in response to market signals. This is expected to be implemented this year.

The drawing up of national ten-year NDPs is required under the European Commission's third internal market package of measures of 2011. The NDP took on special significance for Germany after the Fukushima nuclear disaster in Japan in March 2011, which prompted the federal government to implement a nuclear phase-out strategy and decide on the "Energiewende" policy - the switch to increasing reliance on renewables in electricity and energy supply - with all the changes in electricity network connections and upgrades that this would require.