The German wind power industry
The technology at a glance
Wind energy has been used in many regions of the world for centuries. In recent decades, it has become an important component of sustainable energy supplies. Germany is a pioneer developing the technology and raising capacity levels throughout the world.
The yield from wind turbines relative to the wind speed has increased by a factor of 3. To make optimal use of wind energy, the construction of the turbine towers needs to be as high as possible. The largest German turbines currently have a nominal capacity of 4 to 6 megawatts (MW). Their overall height can reach up to 200 metres with a hub height of around 120 metres, and the individual rotor blades are up to 65 metres long.
In Europe, newly installed turbines have an average nominal capacity of 2 MW.
A wind turbine consists of a nacelle, rotor blades, hub, generator and tower. Depending on the technical design, the turbine can also have a gear unit. In the ongoing development of wind turbines, the focus is on improving serviceability and using high-grade, proven materials to raise the level of turbine utilisation.
The wind drives the rotor blades and these transfer the kinetic energy to a generator. German manufacturers have developed two different systems to efficiently convert wind energy into electricity: generators with gear units and gearless generators. The type of generator deployed depends largely on the useable wind speeds and the location of the turbine.
Most turbines are installed on land (onshore). However, because of the consistent weather conditions and the greater average wind speeds, the German wind industry is increasingly focussing on the use of wind turbines at sea (offshore). For these offshore systems, wind turbines with a capacity of up to five MW are being developed.
Experience with ocean-based projects has already been gained and turbines produced by German manufacturers have been successfully installed in numerous nearshore wind farms off the coasts of Denmark, Sweden, the UK, Ireland and the Netherlands.
The challenges presented by offshore turbines are firstly their construction, then ongoing maintenance during operation. German industry provides technology for manufacturing, installing and servicing offshore wind turbines and their components. The maritime sector is currently developing foundation technologies and logistic concepts.
Rapid growth in Germany and the world
For many years Germany was the world’s largest market for wind turbines. Currently the annual market growth rate is higher in Spain and the US. However, Germany remains the largest manufacturer of wind turbines and components in the world. In Germany, not just design and engineering companies specialise in wind energy but also numerous service providers in the field of maintenance and servicing. New industries, such as tower constructors and rotor blade manufacturers, supply customers around the world with high quality products. In 2006 the German wind energy sector achieved added value amounting to EUR 7.2 billion, of which EUR 5.6 billion was achieved in the manufacture of turbines and components alone. The German Wind Energy Institute (DEWI) estimates that 37 % of the world’s wind turbines and their components are made in Germany. Manufacturers and suppliers of wind turbines have again increased their capacities in 2006 and in some cases were able to increase production in Germany by more than 50 %.
1,208 new wind turbines with a total capacity of 2,233 MW were installed in Germany in 2006. This corresponds to a 23.5 % growth on the previous year. The latest statistics from the German Wind Energy Institute indicate that by the end of 2006, 18,685 wind turbines had been installed in Germany, with a total capacity of 20,622 MW. Thus Germany is still world leader in this sector.
Worldwide, around 15,000 MW wind power capacity were installed in 2006. Last year the front-runner was again the USA with newly installed capacity of around 2,800 MW. There was also strong growth in India, with around 1,500 MW, and China, with 1,000 MW, increasing the total installed wind energy capacity worldwide to approximately 75,000 MW. Many of these wind turbines have been manufactured in Germany or include German components.
Underlying conditions
Government research, development and promotional measures, as well as favourable funding opportunities, accelerated progress in the development of German wind technology during the 1990s. Since April 2000, fixed feed-in tariffs specified by the German Renewable Energy Sources Act (EEG) have offered planning reliability for manufacturers and service providers. Producers of electricity from wind energy receive a guaranteed constant minimum price over a maximum term of 20 years. The amount of the feed-in tariff depends on the location of the wind turbine. Since the guaranteed feed-in tariff for newly installed turbines is lowered every year, this encourages continuous technological development.
In Germany, older wind turbines are now being replaced with a new generation of more powerful and quieter generators. This so-called repowering is subject to a special provision in the EEG Act: The replacement turbines must produce at least three times the previous output in order to qualify for the feed-in tariff.
The German federal government is increasingly focussing on developing offshore wind energy. For this reason it passed a law in 2006, stipulating that grid operators must bear the costs for connecting to offshore wind farms. Offshore wind turbines require greater refunding than turbines on land, since installing and operating offshore wind turbines is much more labour-intensive.
In order to integrate the growing amount of electricity produced by wind energy into the mains grid, which nevertheless fluctuates due to weather conditions, it is necessary to expand the grid and develop storage possibilities.
Outlook
For Germany, studies have established that the more wind power produced, the further wholesale prices fall on the Leipzig Power Exchange. According to scientists, Germany’s wind turbines currently achieve savings in excess of one billion euros per year. Calculable costs for electricity from wind energy are now stabilizing the strongly fluctuating exchange prices for electricity. In the USA, fluctuating fuel prices are hedged with wind power. Production costs for wind-generated power are already comparable with those of new, conventional power stations.
The Global Wind Energy Council (GWEC) estimates that wind energy can meet more than 34 % of the world’s electricity demand by 2050. As major suppliers of climate-friendly electricity for the mains grid, onshore and offshore wind farms play an essential role – along with individual turbines for off-grid users – in international efforts to counter the threat caused by climate change.
In future, research and development will increasingly focus on virtual power plants. These enable renewable energy generation systems to be combined so that all plants can be optimally controlled – both economically and technically – from a central control room. This would mean that any lull in the wind could be balanced out. In Germany, pumped storage power plants with a capacity of 8,000 MW are available for this purpose. However, research into other storage systems is also necessary to ensure 100 % provision from renewable energy. German scientists are currently carrying out intensive research into air pressure storage processes to store surplus wind energy temporarily in salt caverns. The stored air pressure can be quickly converted into electricity. In this way hydropower, solar, wind and bioenergy plants can be operated as a linked network.
Countries like Germany, which have pioneered wind energy, will continue to shape the market in the next few years. For this reason German companies and institutions are investing considerable financial resources and time in training and educating qualified wind energy specialists. In addition to universities and colleges, chambers of trade, vocational training establishments and regional training centres also offer specialist training and further education programmes designed to pass on the expertise that has been acquired over many years.
