Progress in offshore wind power moving forward at a rate of knots

Germany is now looking offshore in order to retain its leadership position in wind power and to assure the the future growth of its wind sector. The North Sea and the Baltic Sea are the next frontiers of development.

Heather Johnstone, Senior Editor

The honour of having the largest wind energy market in the world goes to Germany, with an installed capacity of 22 247 MW by the end of 2007. Wind power producing 39.5 billion kWh of electricity last year, representing 7.2 per cent of the country’s power consumption. These are impressive figures, and clearly the German wind power industry is in rude health. However, these figures mask a growing problem.

According to the Federal Wind Energy Association, there are close to 20 000 wind turbines rotating on Germany soil, which currently generate more electricity than hydroelectric power plants, even though hydropower has been exploited for more than 150 years. However, locations for wind turbines are becoming scarcer after 20 years of expansion on land.

Wind farms are not licensed for construction in landscape reserves and bird sanctuaries or in the direct proximity of houses and villages. Instead Germany’s states have allocated certain areas to wind farming, but importantly these areas are beginning to run out and new construction on land has fallen off since 2002. Furthermore, many believe that Germany’s onshore wind potential is close to being fully exploited.

Thus, if Germany wanted to retain its leadership position in wind power, it needed to look elsewhere. The obvious answer was to venture beyond the coast. In late 2006, the German government put the wheels in motion to achieve exactly this, with the removal of one of the biggest stumbling blocks facing offshore wind explotation, namely grid access.

Grid access assured

In the Bundesrat, the upper house of the German parliament, on the 24 November 2006, Germany’s federal states approved with a overwhelming majority the introduction of an historic piece of legislation, namely the Infrastructure Planning Acceleration Act, which in one fell swoop gave the green light to the full exploitation of offshore wind that many in the wind industry had been waiting a long time for.

The new grid connection regulation essentially ensures that the costs involved in connecting offshore wind farms to the mainland grid are paid for by transmission system operators (TSOs), rather than by individual wind farm developers. Thus, TSO’s are obliged to cover the cost of connecting offshore wind parks to the grid. Since many proposed wind parks are at a distance of more than 20 km from the coast, grid connection would normally represent a substantial part of the project’s capital cost à‚— it is estimated this could enable future operators to save at least one-fifth of their investment costs.

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Thus, for offshore wind farms this legislation significantly improves the profitability of projects and creates conditions similar to those regulating the connection of land-based power plants to the grid. It is predicted that this legislation could result in Germany having an offshore capacity of 1500 MW by the end of 2011.

It is also hoped that the law will also speed up arrangements for grid connection between the coast and the nearest transmission line. The intention is to channel the cables underground, and that connections to offshore wind parks will be shared by a number of projects, avoiding the situation where each development consortium has to arrange its own link.

The law does, however, only apply to the construction of offshore turbines, which have begun building before the end of 2011, so it remains to be seen how quickly the TSOs install these new grid connections.

Having said that there are some that have responded very quickly. In September 2007, E.ON Netz, the grid operating business of E.ON, announced that it had commissioned ABB to build a 400 MW high voltage direct current (HVDC) substation costing €300 million ($461 million) in preparation to connect offshore north of Borkum.

Offshore wind received another piece of good news when Sigmar Gabriel, the minister for the Federal Ministry of the Environment Nature Conservation and Nuclear Safety announced that there would be an increase in the feed-in tariffs for offshore wind power, rising from the current level from €0.09 per kWh to between €0.11-0.15 per kWh. The decision to raise the feed-in tariff was to reflect the sharply increased prices in raw materials, such as steel and copper, which have risen by 100-200 per cent in the last three years. The new tariff levels have yet to be finalized.

Since the parliamentary decision was taken, planning, measuring and construction have bloomed on the German Baltic and North Sea coasts. Entire cities have positioned themselves to entice wind energy businesses, rig constructors and installers to their harbours and industrial zones. According to the Federal Ministry of the Environment Nature Conservation and Nuclear Safety, the exploitation of offshore wind energy is “one of the largest economic activity and innovation programmes in the coastal states.”

The government and the Bundestag (the lower house of the German parliament) are moving to implement projects to catch up with delayed development in this sector compared with other countries such as Denmark and the UK.

However, the construction of offshore wind farms in waters 20-40 metres deep is technically, economically and ecologically challenging, and therefore associated with unknowns.

Thus, the Ministry for the Environment Nature Conservation and Nuclear Safety agreed with wind turbine manufacturers, energy utilities and the German Offshore Wind Energy Foundation to set up a test offshore wind farm at the Borkum West site in the North Sea, with the first turbines beginning operation later this year.

First offshore test rig

In the summer of 2005, the Offshore Wind Energy Foundation bought the licenses for the Borkum West wind farm with government funds. The test field lies in the area of Borkum West.

The Alpha Ventus project is focused on research projects. The Federal Environment Ministry is providing financing in the region of €50 million for a broad- based research programme over a period of five years.

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The research, which is led by the Institute for Solar Energy Technology (ISET) of the University of Kassel, will focus on the integration of wind energy into the power grid, currents through the wind park, pressure from wind and waves, the further development and adjustment of wind turbine components to offshore conditions and the development of new wind park control systems.

In addition to looking at technological problems, researchers from several institutes will conduct ecological research examining how fish and birds at sea deal with the wind turbines. Furthermore, industry will also be investing €175 million in the test site.

On 30 January 2007, the first symbolic groundbreaking ceremony for the laying of cables on the North Sea island of Norderney took place; through these underground cables electricity from the first German offshore wind farm will start to flow. Twelve wind turbines in the five-megawatt class will rotate about 45 km north of Borkum in the North Sea where water is 30 metres deep.

The operator consortium, comprising the energy utilities EWE, Vattenfall and E.ON Energy, has already commissioned the building of six turbines each from Multibrid in Bremer-haven and Repower in Hamburg. This will be the first time that the Multibrid M5000 has been used offshore.

When the wind blows

Back in 2002, as part of its earlier strategy on wind energy use at sea the government decided to construct three research platforms in the North and Baltic Seas.

Fino 1 measuring station, which began operation in 2003, is one of them. It is located approximately 45 kilometres north of Borkum at a depth of 28 metres, and is in the vicinity of the Borkum West offshore wind test site. Average marine winds have been measured at 43 km/hour and at their peak, reach 65 km/hour. Wind speed analyses from the Fino 1 show that it is very rare for the wind to ever stop blowing completely on the open sea, and for this reason, a wind turbine at sea can generate twice as much power as the same equipment on land.

Commercial offshore developments

Currently there are 18 wind farms at sea and four wind farms in the coastal regions of the North and Baltic Seas have now been approved.

There are several commercial offshore wind energy projects expected to go ahead between 2009 and 2010. One of the most ambitious is the sandbank 24. It is being developed by the Oldenburg-based company Projekt and international financial investor Greenoak.

The pilot phase, comprising 80 wind energy turbines of the 5 MW class, was approved by the Bundesamt fàƒ¼r Seeschifffahrt und Hydrographie (German Shipping Authority) on 23 August 2004. The project can be increased in further development stages to a total of 980 wind turbines.

The grid connection in the form of a high-voltage direct current transmission system consists of approximately 190 kilometres of undersea line up to the coast near Bàƒ¼sum and approximately 50 kilometres of land line up to the grid in-feed point in Brunsbàƒ¼ttel.

Offshore wind forecast

In fact, substantial growth in the German offshore wind industry is expected to materialize from 2008 onwards, with offshore installations in the North Sea and the Baltic Sea being the next frontier for development. The Berlin government has set a target for the installation of up to 5000 wind turbines at sea by 2025.

This number of turbines would be expected to supply 15 per cent of the Germany’s demand for power. And just five years later – 2030 – Germany’s bid for domination in the world wind market could see offshore turbines meeting as much as a quarter of her power needs.

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