W2Power is the first practical solution for combined extraction of Wind & Wave energy off-shore. It combines state-of-the-art offshore wind turbines and an innovative, robust wave energy conversion technology on a single, light-weight floating platform. It opens a new market in the renewable energy business.
In Europe, off-shore wind energy will soon need to address areas beyond the shallow, congested southern North Sea if the goals set by policy makers and industry are to be reached. Most other seas with good wind are much deeper, making fixed foundations uneconomic. Moreover, areas such as the northern UK, Irish and French waters as well as those around the Iberian peninsula and Norway have a wave climate that presents design challenges and is an additional cost driver for wind. And around the world, few countries have extensive shallow, protected seas available for wind development. W2Power turns these challenges into business opportunities by enabling conversion of the wave resource on and at the same time being a simple floating wind solution that can be easily mass-manufactured and installed using proven technologies and existing yards.
No commercial floating wind power plants exist. Over the next couple of years, several more demonstration units are likely to be launched. They all face severe design/cost challenges as described above and none offer access to the wave energy resource, which is large enough on its own equalling all the EU’s electricity demand. For the UK, wave energy has a practical development potential that has been estimated to be able to supply more than 40% of power demand if technologies are commercialised. Furthermore, spar-buoy floating wind supports such as the only prototype operating today require sites more than 100 m deep for assembly, making them costly or impractical beyond areas with very deep fjords. Semi-submersibles, proven in offshore oil & gas, can be scaled down to serve as wind turbine supports, but face severe cost-efficiency challenges due to the much lower revenue density in wind than in oil & gas.
Much more than a downscaled oil & gas floater, W2Power is designed from first principles as a true hybrid wind & wave energy conversion plant. Two corners of the triangle support one wind turbine each, and the third corner houses the wave energy power take-off using a Pelton turbine, standard in hydropower applications, driven by three lines of wave-actuated hydraulic pumps mounted on the platform’s sides.
Accommodating two 3.6 MW standard offshore wind turbines like the Siemens 3.6-107 (107 m rotor diameter, hub height 80-85 m), the Shanghai Electric , or the previous GE 3.6 SL, the platform will be rated at more than 10 MW total in areas with a strong wave climate. More importantly, the ability to extract power from the waves in periods of low wind offers unparallelled regularity and extended baseline power with optimal use of the off-shore farm’s power transmission capacity.
There is substantial upside potential: As larger offshore turbines are proven (Areva’s M5000 is “only” 116 m rotor diameter, the same as Shanghai’s 3.6), the patented W2Power platform design allows extending the distance between WT towers without adding proportionally to platform weight and cost. Thus, much more than 10 MW could be produced per platform.
The wave conversion technology is also protected by patents worldwide and is the result of extensive R&D and scale-up of wave driven seawater pumps. Pelagic Power AS, based in Norway’s technology hub Trondheim, was founded in 2005. By supporting its previously free floating (= pelagic) wave pumps on a platform, the company is leveraging its wave technology and at the same time creating the world’s first wave power enabled floating wind turbine.
W2Power features many other innovative design elements adding to its potential. Throughout, the philosophy is to use forces acting on the platform to stabilise it whenever possible. By using counter-rotating wind turbines, the sideways forces can be effectively neutralised. The thrust and the gyro-force from the WT’s also contribute to stabilize the platform. The mooring design allows the platform to yaw, eliminating the need for individual turbine yawing.
W2Power can be assembled in ports or yards and towed offshore, reducing both costs and logistics complexity and reducing environmental load on wind farm sites. Using fully the benefits of modern sensor technology for structural health and fatigue monitoring and fatigue prediction, very lightweight innovative construction is foreseen in the final commercial product using the most cost efficient fabrication techniques are foreseen.
Since its first announcement at All-Energy 2009, the W2Power technology has entered into the validation and engineering stage. Working with leading R&D and industry development partners in a concerted effort, Pelagic Power AS intends to make the new solution be available for wind farm developers when deep-water markets are expected to be opened by 2015.