Dutch Company Launches Large-Scale Deepwater Wind Turbine in Italy
Placing wind farms far from the coast addresses controversial questions of negative visual impact that often prevent siting of onshore farms. At the same time, winds offshore are stronger and of better quality than onshore, where they suffer from turbulence from contours in the landscape and large man-made structures.? Until now, the only wind farms built offshore have been in shallow waters, typically around 20 metres in depth and often close to the coast.? However, Dutch firm Blue H Technologies BV has come up with a solution, adapted from the oil and gas industry, that allows wind farms to be built in much deeper water, far from the coast, opening up tremendous new possibilities for the wind industry to harvest wind from sea areas that had not been accessible previously.Neal Bastick, Chief Executive Officer, Blue H Technologies BV, The Netherlands
Blue H has adapted the concept of submerged tension-legged platforms developed by the oil industry and designed a platform stable enough to support a tower and wind turbine in most foreseeable weather conditions, while keeping the cost of construction, installation and maintenance at economic levels.
Large-Scale Floating PrototypeAs proof of concept, Blue H is testing a large-scale prototype Submerged Deepwater Platform (SDP) in waters 108 metres deep at a distance of 10.6 nautical miles (19.6 kilometres) from the coast in Southern Italy. Blue H’s SPD consists of a hollow steel body, which provides the buoyancy. This is held ‘semi-submerged’ under water by chains which connect the buoyant body to a steel counterweight filled with gravel lying on the sea bottom. With the buoyant body held semi-submerged in the water, the necessary uplifting force is created, which keeps the chains under constant tension. Design of the SDP ensures that the uplifting force is always larger than all other forces acting on the platform, such as the weight of the tower and wind energy converter, and the force of the wind and waves, thus ensuring the stability of the platform and preventing any dangerous inclination or oscillation.
Wind Turbines in Deep Water
This SDP foundation type is called ‘soft–soft’ foundation because of its dynamic behaviour; specifically, the soft–soft foundation attenuates horizontal forces by slow movements in the same direction. One offshore wind energy converter is mounted on top of each SDP. Obviously the height of the tower, its weight, and the weight of the wind energy converter determine the size of the SDP. The tower and the turbine on top are assembled onshore and then towed out and positioned offshore in deep waters (50–200 metres deep).
This SDP foundation type is called ‘soft–soft’ foundation because of its dynamic behaviour; specifically, the soft–soft foundation attenuates horizontal forces by slow movements in the same direction. One offshore wind energy converter is mounted on top of each SDP. Obviously the height of the tower, its weight, and the weight of the wind energy converter determine the size of the SDP. The tower and the turbine on top are assembled onshore and then towed out and positioned offshore in deep waters (50–200 metres deep).
Economic Advantage of Floating Platforms
With their goal of ultimately providing power to the grid at prices competitive with all other forms of power, Blue H offshore wind farms will install wind energy converters of the highest power rating to increase the economic feasibility of these projects. Costs of conventional shallow water offshore wind energy foundations increase significantly with water depth. In comparison, the cost of Blue H’s SDP increases only marginally as water depth increases. Therefore, the SDP developed by Blue H provides a cost-effective solution for deepwater offshore wind energy applications.
With their goal of ultimately providing power to the grid at prices competitive with all other forms of power, Blue H offshore wind farms will install wind energy converters of the highest power rating to increase the economic feasibility of these projects. Costs of conventional shallow water offshore wind energy foundations increase significantly with water depth. In comparison, the cost of Blue H’s SDP increases only marginally as water depth increases. Therefore, the SDP developed by Blue H provides a cost-effective solution for deepwater offshore wind energy applications.
The Prototype SDPThe primary purpose of the prototype is to test the assembly, transportation and positioning methods. The secondary purpose is to test performance under actual marine conditions and to monitor local wind conditions, information required to develop an accurate forecast of the future profitability of the first wind farm planned nearby.
Onshore Wind Turbines
Conventional turbines developed for onshore use typically have a rated capacity between 1 and 3MW. Turbines greater than 3MW in rated capacity are difficult to install onshore, because of the problems of transporting blades which are often in excess of 50 metres in length. Onshore wind turbines are very heavy, as weight is not a major problem because the tower rests on the ground or is embedded in the ocean floor. Nearly all onshore turbines have three blades, which rotate at lower speed than two-bladers, and therefore generate less noise, which is an important consideration when wind farms are situated close to residential areas.
Conventional turbines developed for onshore use typically have a rated capacity between 1 and 3MW. Turbines greater than 3MW in rated capacity are difficult to install onshore, because of the problems of transporting blades which are often in excess of 50 metres in length. Onshore wind turbines are very heavy, as weight is not a major problem because the tower rests on the ground or is embedded in the ocean floor. Nearly all onshore turbines have three blades, which rotate at lower speed than two-bladers, and therefore generate less noise, which is an important consideration when wind farms are situated close to residential areas.
Offshore Shallow Water Wind Turbines
Wind turbines installed offshore, which are typically adaptations of three-bladed heavy onshore technology and designs, can be larger than 3MW as the logistical problems are manageable, thus reducing the cost per megawatt. REpower is testing two 5MW wind turbines fixed to the seabed in 44 metres of water in the Beatrice Field in the North Sea off Scotland. These are currently the largest wind turbines in operation in the world, with an overall weight of more than 2,000 tonnes.
Wind turbines installed offshore, which are typically adaptations of three-bladed heavy onshore technology and designs, can be larger than 3MW as the logistical problems are manageable, thus reducing the cost per megawatt. REpower is testing two 5MW wind turbines fixed to the seabed in 44 metres of water in the Beatrice Field in the North Sea off Scotland. These are currently the largest wind turbines in operation in the world, with an overall weight of more than 2,000 tonnes.
Blue H’s Deepwater Wind TurbineIn contrast to fixed foundation offshore turbines, with a floating construction there is a great advantage in using lighter weight wind turbines than those used onshore; this is because all the weight above the water line needs to be counterbalanced by the buoyancy generated by the size and displacement of the platform below the water line. Obviously a lighter structure, such as that used by Blue H, uses less steel overall, which implies a lower total cost for each unit. In addition, Blue H uses two blades for its offshore turbines, which are obviously lighter than three blades, and are easier to install and replace.
Future Developments
Initially Blue H will combine proven marine technology for the platform (i.e. the SDP) together with proven onshore two-bladed wind energy converter (WEC) technology. The WEC will be fully adapted for the sea (i.e. waterproofing the nacelle, adding a crane on board to simplify maintenance operations, including a sophisticated anti-corrosion system) in a process called ‘marinisation’. Blue H’s first commercial marinised WEC will have a rated capacity of 2MW, but with little additional effort subsequent units will be upgraded up to 3.5MW rated capacity. The first commercially operating ‘Wectop’ will be installed in the sea in the summer of 2008 and will be in a position to generate electricity for the grid shortly thereafter, once the cable is laid.
Initially Blue H will combine proven marine technology for the platform (i.e. the SDP) together with proven onshore two-bladed wind energy converter (WEC) technology. The WEC will be fully adapted for the sea (i.e. waterproofing the nacelle, adding a crane on board to simplify maintenance operations, including a sophisticated anti-corrosion system) in a process called ‘marinisation’. Blue H’s first commercial marinised WEC will have a rated capacity of 2MW, but with little additional effort subsequent units will be upgraded up to 3.5MW rated capacity. The first commercially operating ‘Wectop’ will be installed in the sea in the summer of 2008 and will be in a position to generate electricity for the grid shortly thereafter, once the cable is laid.
Long-Term Research
In parallel, Blue H is embarking on some extensive long-term research work in what it calls, Project Diwet (Deepwater Innovative Wind Energy Technology), where the ‘next generation’ technology will be developed. Blue H intends to research and ultimately build a fully operational 3.5+ MW test unit designed from the outset solely for offshore use, with a view to using these design concepts to later develop a much larger unit. The key objective of the Diwet® series is to create an offshore deepwater wind energy unit that is extremely lightweight, but at the same time very reliable, and very easy to service/maintain. The overall structure of the new unit has already been designed, and the main components identified. Blue H is already in advanced discussions with several companies, leaders in their fields, to develop the specific components and subsystems required by the new Diwet unit.
In parallel, Blue H is embarking on some extensive long-term research work in what it calls, Project Diwet (Deepwater Innovative Wind Energy Technology), where the ‘next generation’ technology will be developed. Blue H intends to research and ultimately build a fully operational 3.5+ MW test unit designed from the outset solely for offshore use, with a view to using these design concepts to later develop a much larger unit. The key objective of the Diwet® series is to create an offshore deepwater wind energy unit that is extremely lightweight, but at the same time very reliable, and very easy to service/maintain. The overall structure of the new unit has already been designed, and the main components identified. Blue H is already in advanced discussions with several companies, leaders in their fields, to develop the specific components and subsystems required by the new Diwet unit.
Manufacturing
In cooperation with its technical partners, Blue H intends to manufacture key components of its units in a limited number of strategic locations, with the final assembly of the units taking place in various shipyards near the final destination of the units.
In cooperation with its technical partners, Blue H intends to manufacture key components of its units in a limited number of strategic locations, with the final assembly of the units taking place in various shipyards near the final destination of the units.
Current Offshore Wind MarketOffshore wind energy installations, currently at just over 1,000MW, account for only 1.5% of the overall installed worldwide capacity (approx 91,000MW at the end of December 2007). These installations are concentrated in the North and Baltic Seas, where shallow waters (in the range of 10 to 30 metres) are found far away from the coast. At these depths, the towers are basically embedded in the sea floor using a monopile or a multi-legged structure. These techniques are expensive to apply in deeper waters as costs rise very quickly.
Offshore Wind Market Potential
On the other hand the offshore wind energy potential around the world is enormous. This is the basis for many forecasts predicting that offshore wind energy production will grow very quickly in the coming years, and may reach a third of all wind energy produced by 2020.
On the other hand the offshore wind energy potential around the world is enormous. This is the basis for many forecasts predicting that offshore wind energy production will grow very quickly in the coming years, and may reach a third of all wind energy produced by 2020.
For these forecasts to become reality, offshore facilities will need to be built in seas other than the North and Baltic Seas in deeper waters, therefore using a different technology from the conventional technology used to date. Several solutions are under study involving floating platform concepts, but Blue H is at the forefront of these developments with its SDP concept and with its prototype in the water. It expects that the cost of electricity produced using its technology will ultimately be competitive with the cost of electricity produced by onshore installations.
Blue H Active in European and US Waters
In parallel with refining its SDP technology and developing integrated units, specifically conceived to be installed offshore, Blue H is actively working on developing sites in deep waters in the Mediterranean and in the Atlantic off both the European and North American coasts, in areas close to population centres.
In parallel with refining its SDP technology and developing integrated units, specifically conceived to be installed offshore, Blue H is actively working on developing sites in deep waters in the Mediterranean and in the Atlantic off both the European and North American coasts, in areas close to population centres.
Biography
Neal Bastick (BSc Combined Honours) joined Blue H in 2005 as the last of its founding members with the objective of structuring and building a strong international business around the significant technical strengths already in the company, particularly those of his business partner, Martin Jakubowski, Blue H’s Technology Architect.
Neal Bastick (BSc Combined Honours) joined Blue H in 2005 as the last of its founding members with the objective of structuring and building a strong international business around the significant technical strengths already in the company, particularly those of his business partner, Martin Jakubowski, Blue H’s Technology Architect.
