Wind turbines rotating at sea
7 min read

Offshore wind energy: How can we use wind power efficiently?


Pumps for the energy source of the future

Wind energy parks play a decisive role in the transition to sustainable energy supply. What many people don’t realise: These parks could not be operated without the numerous pumps installed to provide cooling and fire protection. With its innovative and reliable pump sets, KSB enables dependable power supply – onshore and offshore.

Germany’s power mix in 2023

Wind power is the most important of green energies

The main benefit of wind power is obvious: green energy, entirely without harmful exhaust gases. In 2023, the share of wind power in the power mix of Germany equalled more than 32 %, which makes it the country’s main energy source. And it will gain even more in significance: The German Federal Government has formulated some fixed expansion goals for the coming years in the Renewable Energy Sources Act (Erneuerbare-Energien-Gesetz, EEG). By 2030, the capacity of wind energy parks is to more than double, reaching 145 gigawatts. Yet, wind energy also brings some major challenges: The space required for wind farms is enormous. The noise of and shadows cast by wind turbines can disturb residents, animals and the landscape. Also, wind energy naturally depends on wind – which means it is not always reliably available. A response to all of these challenges is offshore wind farming.

Offshore wind parks are highly reliable in supplying energy

The term offshore is self-explanatory: Wind parks are located away from the shore, out at sea. In Germany, this would be in the North Sea and Baltic Sea, for example. This brings some decisive benefits: The higher speed of wind at sea enables an energy output that is twice as high as that onshore. Out at sea, the wind is also more consistent than on land, which means that offshore farms can generate energy 90 percent of the year.

Offshore wind farms are of unbelievably large dimensions and require the most innovative of technologies: from gigantic rotor diameters to foundations on the seabed weighing several hundred tonnes. A particularly impressive example is one of the largest wind turbines worldwide with a rotor diameter of 220 m. The pumps for its main cooling circuit are supplied by KSB.

Transformer platforms at sea bundle the electricity generated by the individual turbines and transform it to a higher voltage level to ensure almost loss-free transmission through many hundreds of kilometres of submarine cables on the seabed.

Offshore expansion goals of the German Federal Government in gigawatts

Offshore wind power to be expanded

The German Federal Government has identified offshore wind energy as a key component of energy transition and would like to accelerate its expansion by measures such as the Offshore Wind Energy Act. It entered into force on 1 January 2023 with the aim to make tenders and planning faster and less complicated. One part is the new area development plan for the expansion of offshore wind power, which was published by the Federal Maritime and Hydrographic Agency (Bundesamt für Seeschifffahrt und Hydrographie, BSH) on 20 January 2023. It defines in concrete terms where and by when wind farms are to go live in the North Sea and Baltic Sea. By 2030, offshore farms are to provide almost four times their present output – a highly ambitious aim. In Germany, 28 parks are currently (December 2022) generating wind power at high sea, the majority in the North Sea. This makes Germany second-ranked in Europe.

Pumps play a decisive role in offshore wind parks

Pumps are an essential component of energy generation in wind farms: They are used in many areas – both for the turbines and the transformer platforms. Here, they particularly serve to cool systems such as gear units, generators and transformers. Wind turbines and transformer platforms have got their own coolant circuits. In turbines, these are cooled by an air/liquid heat exchanger making use of the wind. On the transformer platforms, the temperature of the cooling circuits is maintained by seawater, which is supplied by seawater lifting pumps, such as the UPA pump from KSB. Both for turbines and transformer platforms, KSB pumps also ensure the circulation of coolant. Powerful pumps are further needed for fire-fighting systems, for treating seawater and for pressure boosting. In all of these applications it is crucial for the pumps to be reliable even under the most adverse conditions, thus reducing or even eliminating maintenance, repair and life cycle costs.

Pumps in offshore parks have to meet exacting requirements on being robust and reliable, bearing in mind that wind turbines are exposed to extreme conditions. Salty sea air and salt water, strong winds, storms and waves – these are all factors that cause corrosion and wear on components in the long term. Maintenance work will then be required – and this is much more challenging at sea than on land. Wind parks are often difficult to reach, especially in weather conditions that can pose a danger to people. But every minute of standstill means the plant is not economical and is costing money. What is the key to keeping maintenance work down? Reliable technology that is efficient, wear-resistant or even non-wearing. Meeting these criteria, KSB has got a large range of innovative pumps on offer.


KSB pump of the Etaseco RVP type series for offshore operation

KSB's Etaseco and Etaseco RVP for efficient offshore operation

One example of reliable and efficient pumps for offshore parks is the Etaseco type series. KSB has developed this pump to handle the constantly growing amounts of waste heat generated as the output of wind turbines increases. The requirement of minimising maintenance work and life cycle costs is also fully satisfied by the Etaseco type series. A motor and bearing design optimised for operation under adverse conditions reduces the maintenance requirements of the type series to practically zero. The maintenance concept developed for wind power often makes it possible to operate the pumps over the entire service life of the system without having to dismantle them for maintenance purposes. The MTBF (mean time between failures) exceeding 1,300,000 hours is unparalleled and testifies to the outstanding reliability of this type series. With their particularly compact and light-weight design, these pumps are especially suited for use in tight spaces. The main type series Etaseco is employed in the main cooling circuit that requires large flow rates whereas the Etaseco RVP pumps optimised for smaller flow rates are used for cooling the transformers. By the way, selected sizes of Etaseco are certified to the US Standard for Safety for Water Pumps UL 778. Renown manufacturer Nissens Cooling Solutions, for example, installs them in cooling systems intended for export to the USA and Canada.

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