dcsimg Wind - Ramboll Group


Wind is an important renewable energy source, and there is a steady growth in its usage as an energy source at 20-30% annually. It has become a worldwide success story as the most dynamically growing energy source. In the three years between 2005 and 2008, global wind installations have more than doubled.

Wind is an important renewable energy source, and its usage as an energy source keeps growing steadily at 20-30% annually

Some predict that a global capacity of more than 1,500,000 MW is possible by the year 2020 – which is more than 10 times the capacity we have today. Both onshore and offshore wind farms are included in worldwide strategies for the growth in renewable energy production, and the reduction of CO2 emissions. The UK, US and Germany have proven to be particularly ambitious within this area, and legislation will be contributing to a positive development for wind power in the years to come. As of May 2009, 80 countries around the world are using wind power on a commercial basis.

Oceans of opportunity

Currently only 1GW of the global wind energy is produced offshore, a figure equivalent to 1% of the wind energy produced worldwide - this is however expected to increase 50 times over by 2020. The advantages of placing wind farms at sea are numerous. They are able to produce up to 50% more electricity than onshore wind turbines, due to higher and steadier wind speeds across the open water. Other advantages include greatly reduced visual impact, less turbulence, and lower noise constraints – allowing higher rotor speeds and leading to the production of more wind energy. 

Being positioned at sea means that these wind farms can then be placed relatively close to areas with a high population density, such as the Greater Gabbard Wind Farm, located 26km off the Suffolk coast of England. We have acted as lead designers for this project which is currently the world's largest wind farm under construction.

Handling the specific challenges of the sea

Despite the obvious advantages, designing offshore wind farms is not as straight forward as one might think. Due to their position out at sea, offshore wind farms are much more complex to design, construct and maintain than those on land. But according to Søren Juel Petersen, Director for Business Development of Ramboll's offshore wind department in Denmark, the future lies in offshore wind power. Ramboll has designed more than 60% of the world's offshore wind turbine foundations, basing our work on our 35 years’ experience with structural support design for oil and gas platforms at sea. Our ability to deal with the challenges of the sea environment in this connection has successfully been adapted to wind farms.

The wind turbine foundations penetrate 40-50 metres into the sea bottom, extend from the bottom trough the entire water depth and 20 metres above the water level of the sea

Individually designed foundations

The wind turbine foundations penetrate 40-50 metres into the sea bottom, extend from the bottom through the entire water depth and 20 metres above the water level of the sea. In some cases, this means that they have to be 90 metres high, almost equivalent to the height of Big Ben in London. Including the wind turbine itself, the height may well reach the 190 metres of the tower Turning Torso in Malmö, Sweden. Taking this into account, it is clear that the stability of the foundation is very important. These foundations have to be individually designed to match the specific conditions at its location, as water depths and soil conditions can vary greatly over an wind farm area of several hundreds square kilometres.

Extreme conditions

Because of their 'open' placement out at sea, the foundations will have to resist extreme wind loads, wave loads, fatigue and ship impact. Due to Ramboll's experience, advanced analyses and several design innovations we are able to adapt our designs to the specific circumstances. This saves our clients considerable amounts as our foundation designs are lighter – and less material means lower prices, increasing the competitiveness of wind power against other energy forms.


Learn more

Scottish and Southern
World's largest wind farm
You can read more about the world's largest wind farm under construction, Greater Gabbard wind farm, here.
Scottish and Southern website
Ramboll provides multidisciplinary consultancy services in all areas of wind farm projects – from development to commissioning
Wind services
Here, you can read more about our expertise in wind and the services we offer within this area.
Offshore wind energy


Søren Juel Petersen
Søren Juel Petersen
Global Market Director
T+45 5161 8760