The 6.XM series was developed specially for offshore use. When producing energy far off the coast, there are several specific challenges to overcome: as the sites are located far out at sea, are difficult to reach and subject to potentially extreme wind and weather conditions, the quality and reliability of the turbines are even more critical to success than usually.
Ormonde wind farm, an offshore wind farm in the Irish Sea, is located ten kilometres west of Barrow-in-Furness in Great Britain. Thirty 5M wind turbines with a hub height of 90 metres and a rotor diameter of 126 metres are installed at a water depth of 17 to 30 metres over an area of 8.7 square kilometres. The wind farm has been generating electricity since the summer of 2011.
The Senvion offshore team is clearly proud of how the project has progressed. Ormonde wind farm is continuously producing more and more output. In the fiscal year 2013/14, the figure was around 570 million kilowatt hours – enough to supply more than 450,000 people with electricity for one year.1
In the history of the international offshore industry, Senvion has made pioneering achievements. We were the first to introduce a 5-megawatt-class turbine onto the market. In 2010, we commissioned the first German offshore wind farm, with six 5M turbines at the Alpha Ventus wind farm, 45 kilometres north of the island of Borkum. Our Senvion 6.2M126 turbine is the most powerful series-manufactured offshore turbine in the world.
All in all, we at Senvion have experience from well over 100 installed offshore-turbines in the multi-megawatt class with a total operating life of 350 years – thus, more than any other provider.
The Smart Tower function allows 6MW turbines to use monopiles as a foundation structure, which significantly improves economic efficiency depending on the condition of the seabed.
The 6.2M152, which was developed on the basis of the 6.2M126, has a 152 metres rotor diameter and a certified service life of 25 years. It will make a key contribution to reducing the power generation costs of offshore wind.
Last year, following anomalies in the rotor bearings, we introduced a technical upgrade to the existing design in the form of enhanced, direct injection of lubricant and adapted the rotor bearing design for the next generation of the turbines. With regular adaptations, we can ensure that existing turbines generate the highest possible yield.
As many full-load hours as possible
Of course, other areas of the company are also looking to the future. The question of how as many full-load hours as possible can be produced with a turbine is one that all operators ask themselves. A setscrew is the pitch system that takes the turbine out of the wind when it is too strong. Thus, if it is possible to predict the wind as accurately as possible, then the wind turbine can be pitched out of the wind at the best possible time, but most importantly at the last possible moment. This is the specific aim of a current Senvion research project called “Triple I Blade Control – Intelligent, Integrated, Individual”. The key to success is the LIDAR sensor (“Light Detection and Ranging”).
This is a method of optical distance and speed measurement as well as of remote measurement of atmospheric parameters. It is very similar to the radar. However, instead of radio waves – as in the case of the radar – laser beams are used. These are intended to enable forecasting of future wind conditions up to 50 metres ahead of the turbine. Although Triple I Blade Control is still a long way off, this project is in line with our commitment to developing the leading-edge technology of tomorrow through applied research.
For the future, the Senvion offshore team is already dealing with the question of what the electricity market will look like in 2020 in order to have the right product ready in time. It is clear here that we are building on our proven concepts and linking technical enhancement with customer wishes and the requirements of the respective site. We are sticking with our offshore activities, despite the tense situation of the industry during the past two years, because we firmly believe in the potential of this market. We have set the right course for future growth with our products and positioning.
1 Calculation based on a three-person household with mean electricity consumption of 3,800 kilowatt hours (kWh) per year.