Bringing together floating production technology expertise and Dutch know-how from electrical cables to shipbuilding has helped Bluewater turn a new tidal energy concept into reality. Elaine Maslin reports.
BlueTEC installed offshore Texel. Image from Damen.
For most in the offshore industry the name Bluewater is associated with floating production units. However, Bluewater, based outside Amsterdam, has been developing another string to its ship-shaped bow and, in fact, it is less unlike floating production than you might think.
The firm, supported by a consortium of fellow Dutch companies, has designed the BlueTEC tidal energy unit, a moored, modular-design floating platform, which supports underwater turbines. The first unit, the Texel platform, was installed in the Wadden Sea offshore the Netherlands earlier this year, producing electricity into the Dutch grid from day one.
It is fitted with a 100kW turbine, which will be upgraded to a T2 (200-300kW) turbine later this year, increasing to two T2s (or 500kW capacity) and in total producing electricity for a 1.5-year trial period.
The project has made rapid progress. It went from a blank sheet of paper in 2006, when Bluewater decided to investigate new potential business streams, to the formation of a project team in 2009, to the start of construction late 2014, and then grid-connection into the water this May.
Allard van Hoeken. Photo from Bluewater.
“If you look back to November 2014, fabrication had not yet started,” says Allard van Hoeken, Head of New Energy at Bluewater. “We only had a drawing. We went from a drawing to a new grid-connected platform in six months, which is unheard of in the tidal energy industry.”
Key to the project’s success has been a willingness to collaborate between a cluster of Dutch firms, each bringing their own expertise – and share of the project funding – to the table: Damen, Acta Marine (Van Oord), Tocardo, TKF, Vryhof, NIOZ Royal Netherlands Institute for Sea Research, and the Dutch Tidal Test Centre. Germany’s Schottel Hydro and UK-based Nylacast are also involved.
While bringing all these companies together for one project posed communications and interface challenges, existing solutions were easier to find by keeping companies within their specialist scope, van Hoeken says. “It’s not all new technology. What’s new is the overall platform concept and putting these bits together with companies that understand the technology and the sea.
The BlueTEC concept. Image from Bluewater.
“A turbine manufacturer cannot yet predict the forces involved very well – there are so many unknowns and everyone knows at sea you get unexpected conditions,” he says. “However everyone has a scope they are comfortable with. That way, there may be elements that might be difficult, like the mooring system or the dynamic power cable in a tidal race and their connections to the platform, but these can be addressed.”
With BlueTEC, the company’s aim was to design a platform and mooring system that could be operated for years in a sustainable way. Equipment needed to be accessible from the surface, and hook-up and hook-off needed to be easy. It also needs to be transported easily to remote locations where Bluewater sees the initial market for such systems, which led to a modular containerized design. It was also designed for using different turbines – some of them allowing change out ability in situ – for flexibility. And it had to be simple and low cost.
The result is a relatively simple and very cost-effective solutions, van Hoeken says. BlueTEC is comprised of container-like modules, like pontoons, for ease of worldwide transport, connection and scalability. The turbines are not the largest units, like some are aiming for; Bluewater believes the smaller units will be more attractive to start with as they are easier to hook-up and off as well as handle generally on- and offshore. Water can pass through the turbines in either direction, so they do not have to swivel with the tide and all the electronics are stored in a dry accessible space within the unit, which can be easily disconnected and taken to a quayside for heavier repairs.
Dutch ship builder Damen got involved by talking with Bluewater at Houston’s Offshore Technology Conference two years ago, says Jeroen van Woerkum, sales manager Benelux, Damen Shipyards.
“This is an interesting market for Damen,” van Woerkum. “When something floats, it is interesting for Damen. And this could grow into very large projects.
“The first step is to learn,” he says. “Damen built the platform as well as research and development to make sure the shape of the platform is sufficient to carry the weight and also the thrust of the water as the tide changes.”
Bluewater started electricity generation gently from Texel after installation in May, gradually building up the operational hours to today’s 24 hours a day, seven days per week operation. As much as possible in the system is being monitored, including loads on the mooring lines. Planning is already underway to switch out the current 100kW 5m-diameter turbine to the 200kW 9.6m-diameter turbine.
Next year will see a second turbine installed on the unit, using a T-bar, building it up to 500kW.
Bluewater would then like to move to a capacity of 2-3MW, adding larger turbines to the T-bar and additional buoyancy, and to do so it will need to move to another deeper site. Bluewater’s ultimate ambition is to design and build tidal farms of 50-500MW.
Ultimately, Bluewater is looking to be operating floating production units, not much unlike FPSOs, instead extracting clean power from the ocean.