A study to measure the loads on two turbines at Sheringham Shoal offshore wind farm should help project operator, Scira, optimise its operations and maintenance (O&M) programme. Dutch research institute ECN began work on the project in January.
"Once we know the loads – or force – on the blades, we can calculate the load on other turbine components," explained Haico van der Heijden, business development manager for ECN Wind Energy, speaking with Windpower Offshore. Armed with this information, Scira will be in a better position to determine the expected lifespan of components, and to plan O&M work accordingly.
The project for Scira at Sheringham Shoal is exactly the type of work ECN’s wind division wants to undertake, now that it has adopted a new business strategy. Already a well-known name in offshore wind consultancy and as a provider of turbine layout software, ECN announced last month that it will widen its service offering. It will seek to become a "global leader in innovative solutions" that contribute directly to reducing the cost of offshore wind energy. It wants to achieve this market position by 2016.
Another offshore wind client is RWE, which recently collaborated with ECN on the design and installation of a meteorological mast in Dutch waters. The met mast has been operating in Dutch waters for about nine months and was fully functional from day one, notes van der Heijden. The success of this project is thanks, in part, to ECN’s experience in met mast instrumentation, says van der Heijden.
The institute makes sure its equipment and procedures work properly at its own test site, which features five met masts and is located in an area with wind speeds of 8m/s.
Managing wake effects
Assisting offshore wind operators to increase electricity output by actively managing wake effects is another priority for ECN. With this in mind, it has designed a control system that allows an operator to "steer the wake through the wind farm," explains van der Heijden. "If you do this cleverly, you can increase a wind farm’s output and simultaneously cut the loads on many turbines."
This innovative control system has yet to be bought for an existing offshore wind project, but is due to be deployed at the 129MW Luchterduinen project, being developed by Eneco and Mitsubishi.
Meanwhile, an improvement to ECN’s market-leading project design software, FarmFlow, has been announced. It now includes a code specifically created "for computing unsteady turbulent wakes". This allows developers to design their sites to minimise wakes, while also limiting distance between turbines in order to keep cabling and O&M costs as low as possible.