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Floating wind turbines an opportunity for india, floating wind turbines potential, commercial scale floating wind turbines,

Add Japan to the list of countries setting up innovative wind farms. On Wednesday, Japan’s first floating wind turbine began operation about half a mile off the coat of the Nagasaki prefecture. The 100-kilowatt turbine will be replaced with a 2-megawatt turbine next summer, once data regarding performance and maintenance is collected.

After the 2011 Fukushima nuclear power plant disaster and subsequent multi-reactor shutdown, government officials are looking for safer, cleaner forms of energy. Wind energy is clearly one of those. And given that all of Japan’s wind farms held up fine to last year’s earthquake and tsunami, it’s no wonder the country is turning more to wind.

Clean Technica (

* First floating wind turbine - video

Classification services provider ABS has certified the design, fabrication and installation of the first commercial-sized floating turbine, located off the coast of Portugal. source

Floating wind turbines are to be the initial focus of a new agreement between Britain and the United States this week as international talks convene in London to accelerate the deployment of clean energy technologies,” : DECC

may 2012

Let us just see what the UK thinks about floating offshore wind energy potential.

The UK benefits from a third of Europe’s offshore wind potential, has more installed offshore wind than any other country, the biggest pipeline of projects and is rated year after year by Ernst & Young as the most attractive market among investors.

Exploiting this economically, particularly in deeper waters off the west of the country, will require significant technology developments to build large offshore wind arrays. Much of the deeper waters between 60 and 100 metres are too deep for fixed structures but benefit from consistently higher wind speeds.

Makes a lot of sense for Indian conditions too. 

Floating wind technologies could therefore open up new areas off the coast of the UK. This will ultimately increase the potential of this sector, particularly post 2020 as the available shallow water sites are developed, and will help to meet our decarbonisation and energy security targets.

This is long term planning. After they fully utilise the shallow waters. However India may choose floating offshore wind energy if the cost becomes less than 

Offshore wind energy itself. 

However I am interested in knowing the cost of floating offshore wind energy as compared on shore wind energy in India and the cost of transmission of power.

On shore, setting up evacuation facilities and transmission lines are the prerogative of the government as it is pretty expensive.

So, one would be interested in knowing the cost of transmission of power for offshore floating wind mills. source

* The Japanese Environment Ministry plans to start its first trial operation of an offshore floating wind turbine for power generation later this month in may / june 2012 off Kabashima island--one of the Goto Islands--in Nagasaki Prefecture.

Offshore wind turbines have several advantages over land-based turbines including better efficiency and no problems with noise or low-frequency dangers to residents.

The ministry aims to introduce the power generation method on a large scale as a sustainable energy source, officials said.

The trial turbine is a small 100-kilowatt model with three 11-meter blades. The turbine is hollow, allowing it to float, while ballast keeps it upright and wires anchor it to the seafloor.

Another type of offshore turbine is fixed directly to the seabed with support pillars. more

The DECC noted that U.S. Department of Energy (DOE) Secretary Steven Chu recently unveiled a six-year, $180 million offshore wind initiative that will fund four demonstration projects. Meanwhile, the U.K.'s Energy Technologies Institute (ETI) is putting together a £25 million ($40 million) offshore wind floating system demonstration project. The goal is to have an offshore wind turbine capable of cranking out 5 to 7 megawatts of power by 2016.

"Selection of the organisation to deliver the project is ongoing and an announcement on who will be carrying out the project on behalf of the ETI is expected early next year," the DECC said. "The ETI is also currently investigating various sites that could host the demonstrator and has announced that it is working with WaveHub, 16 kilometres north east of St Ives off the Cornish coast to carry out a site feasibility study."

As far as we know, Principle Power's 2-MW turbine called WindFloat is the deep-water turbine project that's farthest along. Late last year it became the first offshore wind turbine to be installed without the use of lift vessels-and the first floating wind turbine platform in the open waters of the Atlantic Ocean-when it was towed out to sea and put in place about 215 miles off the coast of Agucadoura, Portugal. source
If the floating wind turbines have lesser capital cost than offshore wind energy, it is a good opportunity for India.  India has long coast line of over 7000 kms and floating wind energy using floating wind turbines can be come a great source of energy.
Watch Altaeros Energies’ floating wind turbine in actionLast October, Glass and Rein were awarded the ConocoPhillips 2011 Energy Prize, a joint initiative between the oil and gas company and Penn State created to recognize new ideas and original, actionable solutions to improve the way the U.S. develops and uses energy. Glass, CEO of Altaeros Energies and inventor of the turbine, and Rein, the company’s co-founder, received a total of $125,000 to further the development of their concept officially called the Aerostat Platform for Rapid Deployment Airborne Wind TurbineAlain Goubau also is co-founder. source and video

* Ultra-large floating vertical-axis wind turbine (VAWT) designs, with the target of carving 20% out of the forecast cost of energy (CoE) of deep-water installations

Government-owned Sandia is concentrating its initial efforts on rotors, focusing on the Darrieus “egg beater” design and H- and V-shaped blade concepts, while other key technological components of offshore VAWTs, such as drivetrains, floating foundations, and mooring and anchoring solutions, are to be studied in follow-on research and development (R&D) projects.

“HAWTs [horizontal-axis wind turbines] emerged as predominant technology for land-based wind over the past 15 years, primarily due to advantages in rotor costs at the 1-5MW machine scale,” says Josh Paquette, co-principal investigator, along with Matt Barone, on the project.

“And as we have moved offshore, we have taken these designs and marinised them, but our question is whether this will continue to make economic sense in far-offshore and deep-water locations.

“It might be that the turbine itself could represent a little more of the total cost of a floating turbine, but bring down the other costs.

“Our project will investigate at the 10-20MW scale, where the VAWT architecture is a potentially transformational technology.”

VAWTs are seen as solving a number of the central engineering challenges posed by trying to install HAWTs on floating foundations at sea, not least that the “ominidirectionality” of vertical-axis rotors means the turbine can harness wind from any direction without costly yaw or pitch systems.

Also, VAWTs make operation and maintenance more straightforward, as the drivetrain and generator are closer to foundation level and so more easily accessible.

Paquette hopes that the project will reinvigorate VAWT research, after progress on many promising rotor concepts and related technologies stalled in the 1990s, when three-bladed horizontal axis rotors became the default design.

“Historically, VAWTs have had their challenges — longer total blade lengths were a cost issue back in the 1980s when VAWTs were first being developed, they suffered from ‘torque ripple’ [a phenomenon where torque is exerted at two places around the rotor], structural resonance was a problem, finding a workable braking system and so on,” he says. “But their theoretical performance was higher than horizontal machines by a little less than 5%, and they can assimilate gusts and direction changes in the wind instantaneously and without complicated control systems.

Yes these are futuristic. Not immediate. But it is important for us to make the future as well as the present.

*Siemens has purchased a MaXccess system following successful trials 

of the transfer and access technology at the Hywind floating wind demonstration project off Norway.

The first-ever deal will "improve the safe transfer of service specialists onto offshore wind turbines," said Siemens, which will apply the system on a wind project up to 30km offshore to increase experience and identify futher optimisation.


The system was designed by Osbit Power and tested off Norway by a strategic alliance that also included Siemens, Statoil and Fred Olsen Windcarrier.

“Our approach to safety is driven by our Zero Harm policy and we never compromise on this. Thanks to the innovative design which Osbit Power has developed, the hazards normally associated with the transfer phase have been reduced,” said Richard Luijendijk, director Siemens Energy Service Renewables UK & Ireland. 

Sea trials of MaXccess showed that reliable access in 1.9 metre significant wave height conditions can be achieved with this first version of the system and under the local conditions where it has been tested. 

I dont see any reason why India cant pursue this technology of Hywind floating wind. 

Except for funding. 

“By proactively engaging with emerging companies such as Osbit Power, we once again prove that we are at the forefront of the innovation in offshore wind, and continue to strive for excellence and safety in all service operations,” said Ken Soerensen, head of Service Offshore Wind Business of Siemens Energy. source 

“Vertical-axis machines have very definite benefits [over HAWT designs] at very small scale and for very large floating turbines where you can use the buoyancy [of the moored foundation] to support the rotor and not have to use the bearing [a failure-prone component],” says Paquette.

A floating wind turbine is an offshore wind turbine mounted on a floating structure that allows the turbine to generate electricity in water depths where bottom-mounted towers are not feasible. The electricity generated is sent to shore through undersea cables. 

Offshore wind turbines are being used in a number of countries. Offshore winds tend to flow at higher speeds than onshore winds, thus allowing turbines to produce more electricity.

Instead of relying on physical foundations like bottom-fixed turbines, floating platforms are attached to the seabed by mooring lines.  This means that they can be viably deployed in much deeper water.

There are three main types of floating wind platforms.

Spar buoy � It is a ballast-stabilized design which has a long, cylindrical tank with ballast and a center of gravity below the center of mass.

Tension leg platform - The tension leg platform (TLP) has additional buoyancy in the tank and uses taut-leg mooring lines to stabilize the turbine.

Shallow draft barge -  The shallow draft barge (SDB) has a tank which floats on the surface of the water and has a large waterplane area.

The spar buoy and shallow draft barge designs use a catenary mooring system, which loosely moors the turbine tank to the seafloor to prevent drifting.  Catenary mooring systems are less costly than taut-leg moorings, but require either a large waterplane area or low center of gravity in order to provide necessary stability.  Loose mooring lines also subject the turbine system to greater motions than taut-leg moorings, increasing the complexity of system integration.  Taut-leg mooring systems are more complex than catenary systems, however taut mooring lines are beneficial, especially in deeper water, because shorter lengths of mooring line are needed, and taut lines produce a more stable platform.

Blue H

In December of 2007, Dutch Company Blue H Technologies launched the world�s first floating turbine off the coast of Southern Italy.

Dutch Blue H Technologies has devised a Submerged Deepwater Platform(SDP). It�s a modified form a Tension Leg Platform. SDP�s are made of a buoyant hollow body that is �semi-submerged� in water by chains or tethers, which are in turn connected to a counterweight on the sea bed � thus creating the necessary uplifting force to keeps the chains constantly tensioned.

During 2008, Blue H installed this prototype wind energy unit 11.5 nautical miles off the Southern Italian coast in deepwater. After 6 months at sea, the unit was decommissioned early in 2009.

In 2008, Blue H also started engineering its second proof of concept,  a tension legged platform for a 2MW floating wind turbine which it intends to complete in 2012 and install in its Tricase wind farm.

The 2 MW unit will be followed by the deployment of final proof of concept: a larger pre-production floating turbine in 2014, combining Blue H�s platform with a 3rd party offshore turbine.

In order to promote its deep water floating technology, Blue H pioneered and developed by itself one deepwater 90MW site, the Tricase wind farm, which is close to securing its final permit.


Hywind is the world�s first full-scale floating wind turbine. This 2.3MW floating offshore wind turbine is developed by Norwegian energy company Statoil ASA.

The turbine itself was manufactured by Siemens. Technip built the floater and was responsible for the installation work offshore. Nexans Norway laid the submarine power line. This comes ashore near Skudeneshavn at the southern end of Karm�y, where local grid operator Haugaland Kraft operates a receiving station.


For the first time ever, a floating megawatt-class wind turbine is delivering electricity.

Although the Hywind turbine has been generating electricity to the Norwegian grid since late September 2009, its main objective is to test the impact of wind and waves on the structure over a two-year period.  The results have so far been promising and indicate the long-term viability of this type of floating turbine technology.


In the U.S., technology company Principle Power has devised WindFloat. It�s an integrated system consisting of a semi-submersible floating platform capable of supporting commercial offshore horizontal axis wind turbines. The system utilizes drag embedment anchors and a conventional catenary mooring and is designed to accommodate any multi-megawatt offshore turbine.

The innovative features of the WindFloat dampen wave and turbine induced motion, enabling wind turbines to be sited in previously inaccessible locations where water depth exceeds 50m and wind resources are superior. Further, economic efficiency is maximized by reducing the need for offshore heavylift operations during final assembly deployment and commissioning. Multiple projects are in development for the installation of commercial Windfloat units in both European and US offshore wind farms.

Windfloat foundation has three advantages. Its static and dynamic facillity provides sufficiently low pitch performance enabling use of commercial offshore wind turbines. The design of the windfloat enables the structure to be fully assembled onshore and towed to its final location. The mooring system employs conventional components such as chain and polyester lines to minimize cost and complexity. Through the use of pre-laid drag embedded anchors, site preparation and impact is minimized.


HiPRwind is an EU project introducing a new cross-sectoral approach to the development of very large offshore wind turbines. Focused on floating systems, this 5-year pan-European R&D effort will develop and test new solutions for enabling offshore wind technologies at an industrial scale. The project is designed with an "open architecture, shared access" approach in that the consortium of 19 partners will work together, in a collaborative way, to develop enabling structural and component technology solutions for very large wind power installations in medium to deep waters. 

The project will address critical issues of offshore wind technology such as the need for extreme reliability, remote maintenance and grid integration with particular emphasis on floating wind turbines, where economic and technical weight and size limitations of wind turbines and support structures can be overcome.

HiPRWind will develop and test novel, cost effective approaches to floating offshore wind turbines at a lower 1-MW scale.


A French consortium Nass & Wind has confirmed it will be installing a full-scale demonstration model of its WinFlo floating turbine off the coast of Southern Brittany, near Lorient port. Winflow is an integrated floating wind turbine on an innovative semi-submersible platform. It has an innovative anchoring system, suitable for all seabed types. This is suited to depths in excess of 50m. This project is piloted by Nass & Wind Industrie, bringing together six industrial and scientific partners: Nass & Wind Industrie, DCNS, SAIPEM, In Vivo Environment, IFREMER and ENSIETA.

The machine will be manufactured in pre series, and marketed from 2015 onwards. The budget for this project is over �35 million.


Technip, in association with N�nuphar, Converteam and EDF Energies nouvelles is launching the Vertiwind project to test a pre-industrial prototype of a vertical-axis offshore floating wind turbine. The partners of the project are Seal Engineering, ISITV, IFP Energies nouvelles, Arts et M�tiers, Bureau Veritas, Oceanide.         

Land-based testing of a 0.5-scale prototype is currently underway at the �Carrieres� site, in Boulonnais.  Once this phase is complete, testing will commence at sea.


The WindSea concept is based on a semi submersible platforms with three columns and three turbines. The platform is self orientating towards wind. The mooring lines are connected to a detachable turret and cable for power transmission is guided through the turret to the seabed.

Following the completion of a two-year design phase, there are plans to build a WindSea prototype in 2012.  


wind power concept that is fixed using a Spar-type float and anchored to the seabed by a taut anchorage system - allowing it to face in different directions depending on the direction of the wind.  Last month, the company deployed the prototype off the coast of Norway, with transport to site and a full test program scheduled to start later this spring.

Advantages of floating wind turbines:

A key advantage of using floating wind platforms is that they allow developers access to previously inaccessible waters where there is stronger yet less turbulent winds � helping to reduce the overall cost of wind energy.

Another benefit is that floating platforms can generally be commissioned and assembled at the quayside, without the need for heavy-lift jackup or dynamic positioning (DP) vessels, further reducing the cost and risk of deployment activities.

Design Standards for floating wind turbine structures:

Existing standards are in practice restricted to bottom-fixed structures only:




With regard to use for design of floaters, shortcomings of these standards exist with respect to:


Station keeping

Site conditions (related to LF floater motions)

Floater-specific structural components (tendons, mooring lines, anchors)

Accidental loads

ALS design in intact and damaged condition

Other: Simulation periods, higher order responses, safety level...

Safety level for floating support structures:

The target safety level of the existing standards is taken as equal to the safety level for wind turbines on land as given in IEC61400-1, i.e. normal safety class

Cost-benefit analyses would likely show a need to go up one safety class, from normal to high, at least for some structural components

The DNV guideline for floating wind turbine structures recommends design of station keeping system to high safety class

Target safety level is likely to depend on the number of turbines in the wind farm

Special issues to be considered relative to current requirements in existing codes:

Adequate representation of wind in low frequency range

Adequate representation of dynamics may require more thorough/improved representation of simultaneous wind, waves and current

Gust events based on gust periods in excess of 12 sec must be defined; must cover expected events and reflect frequencies encountered for dynamics of floaters

For floaters which can be excited by swell, the JONSWAP wave spectrum is insufficient and an alternative power spectral density model must be applied

For tension leg platforms, water level and seismicity may be of significant importance

Special issues to be considered relative to current practice for bottom-fixed structures:

Simulation periods to be increased from standard 10 min to 3 to 6 hrs

Purpose: Capture effects of nonlinearities, second-order effects, slowly varying responses

Challenge: Wind is not stationary over 3- to 6-hr time scales

Loads associated with station keeping system include permanent loads

Pretension of tendons (permanent load)

Pretension of mooring lines (permanent load)

Ship impact loads (from maximum expected service vessel) need more thorough documentation than for bottom-fixed structures

Larger consequences of ship collision

Motion of two bodies with different motion characteristics

Reliability-based calibration of partial safety factor requirements for design of structural components not covered by DNV-OS-J101

Examples: tendons, mooring lines

Existing design standards from other industries may be capitalized on:

DNV-OS-C101 and DNV-OS-C105 for tendons

DNV-OS-E301 for mooring lines

Difficulties because of different definition of characteristic loads

Shortcomings because of rotor-filtrated wind loads are not covered by existing standards

Need for data to define a representative set of design situations for safety factor calibrations

Load and response data for various structural components

Model scale data

Data from analytical models

Sufficient floating stability is an absolute requirement

In operation phase and in temporary phases

In intact as well as in damaged condition

Additional compartmentalization is usually not required for unmanned structures

The need for a collision ring in the splash zone depends on


Substructure material (concrete/steel/composites)

Size of service vessel and resistance against ship impacts

Location and design of manholes and hatches to be carried out with a view to avoid water ingress

Dropped objects and ship collisions may pose threats to stability

Station keeping:

Catenary or taut systems of chain, wire or fibre ropes

Tendon systems of metal or composites for restrained systems such as TLPs

Dynamic positioning

Various issues for Catenary and taut moorings:

Mooring system is vital for keeping wind turbine in position such that it can produce electricity and maintain transfer of electricity to receiver

Optimization of mooring systems may lead to non-redundant systems where a mooring failure may lead to loss of position and conflict with adjacent wind turbines

Sufficient yaw stiffness of the floater must be ensured

Various issues for tendon systems:

Systems with only one tendon will be compliant in roll and pitch

Floaters with restrained modes will typically experience responses in three ranges of frequencies

High frequency, wave frequency, low frequency

More complex to analyse than other structures

Terminations are critical components, regardless of whether tendon is metallic or composite

Needs for information:

Load/response data for various structural components


Mooring lines

Structural components in floater


Analysis models

Model tests

Full scale measurements

Wind data for definition of new gust events

Wind data in low frequency range

Ship impact load data

Data for accidental loads and frequencies of accidental events causing damage of wind turbine structure

Specifications of offshore floating wind turbines:

Nominal Power Output: 10MW

Design and Velocity: 13.25m/s

Tip Speed Ratio: 7, 6 (max. blade tip velocity: 90m/s)

Rotational Speed: Variable 5-12.2 rpm

Turbine Diameter: 140.5 meter

Number of Turbines Blades: 3

Tower: Lattice tower with 4 legs

Maximum wave height: 30 meter

Hub height: 101 meter

Turbine Position: Upwind of the tower

Generator: Direct driven PM generator

Water Depth: 60 meter

Design Loads: According to IEC 61400-3:2009. Design Class IB

Control System: Variable speed + pitch

3MW floating wind turbine construction costs:

3 MW Rated Wind Turbine Cost: Nacelle & Blades ~ $4.5M ($1.5M/MW)

3 MW Wind Turbine Tower & Buoy (Steel) ~ 500 tons ~ $1.5M ($3K/ton)

8 Gravity Anchors 150 tons each in Water; 2 per side; 225 tons each in Air ~ 2,000 tons of Granite in Air ~ $100K

8 Steel Mooring Lines & Connectors; 2 per side ~ 2 tons of Steel ~ $100K

Assembly Costs at a Coastal Facility or Floating Barge ~ Costs of Assembly of Onshore Wind Turbine

Installation of 8 Gravity Anchors by Boat Equipped with 250 ton Crane

Total Construction Costs of Floater and Mooring System ~ 1.7M ~ 0.6M/MW

Tow Out & Installation Costs ~ 1-2 Days ~ $50K/Day ~ $100K Total

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  • Nitin
    Nitin -

    Swedish Offshore wind finds support

    Three European countries expressed support for a Swedish companyslarge-scale offshore wind power project that is trying to tap the European Commissions 4.5-billion euro ($6.48 billion) clean energy fund.

    Hexicon Corp. has earlier sought support from Sweden, Malta, and Cyprus for the financing of its offshore wind technology, which puts together turbines and other applications for wind and wave power on a floating platform.


  • solar1234
    solar1234 -

    I have been advocating OFF SHORE WIND FARMS  in India since a decade and no action even for a pilot plant and you are talking of Floating wind turbines ! Let us be realistic.

    Dr.A.Jagadeesh  Nellore(AP),India
    Wind Energy Expert

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