Offshore Wind Farms and the Turbine Installation Vessel

[Merchant Marine]

From http://gcaptain.com/maritime/blog/windfarming/

"Offshore wind farming has picked up steam during the last decade, with more & more countries installing these gigantic turbines in their coastal waters. The largest wind farm in the world is located of the coast of Jutland, in the North Sea. An even larger farm has been given the green light for off the coast of Britain.

One of the largest offshore areas in the U.S. with shallow water is off Cape Cod, where a major wind farm has been proposed.

The construction of these farms have given rise to a new class of ship: the Turbine Installation Vessel.

The first purpose built TIV was the TIV Mayflower Resolution, currently known as the TIV Resolution & owned by MPI Offshore. This vessel utilizes both dynamic positioning & jack-up technology.

Equipped with 6 retractable legs, the Resolution will set up on location using DP, then elevated out of the water using the jack-up legs. This provides a stable platform to install the turbine on top of a previously prepared foundation. Once installed, the Resolution lowers back down to the water & moves to the next location, where the process is repeated. She has the capacity to carry 10 wind turbines.

Offshore wind turbines are less obtrusive than turbines on land, as their apparent size and noise is mitigated by distance. Because water has less surface roughness than land (especially deeper water), the average wind speed is usually considerably higher over open water.

Offshore installation is generally more expensive than onshore, depending on the location. Offshore towers are a fair bit taller than onshore towers once the submerged height is included, making the foundation more expensive to build.

Offshore saltwater environments also raise maintenance costs by corroding the towers, but fresh-water locations such as the Great Lakes do not. Repairs and maintenance are usually more costly than on onshore turbines, motivating operators to reduce the number of wind turbines for a given total power by installing the largest available units.

Offshore saltwater wind turbines are outfitted with extensive corrosion protection measures like coatings and cathodic protection, which may not be required in fresh water locations.

Transporting large wind turbine components (tower sections, nacelles, and blades) is much easier over water than on land, because ships and barges can handle large loads more easily than trucks or trains. On land, large goods vehicles must negotiate bends on roadways, which fixes the maximum length of a wind turbine blade that can move from point to point on the road network; no such limitation exists for transport on open water.

Offshore wind turbines will probably continue to be the largest turbines in operation, since the high fixed costs of the installation are spread over more energy production, reducing the average cost. Turbine components (rotor blades, tower sections) can be transported by barge, making large parts easier to transport offshore than on land, where turn clearances and underpass clearances of available roads limit the size of turbine components that can be moved by truck.

Similarly, large construction cranes are difficult to move to remote wind farms on land, but crane vessels easily move over water.

Offshore wind projects must strike a viable balance between technological and economic challenges.

Offshore technology has had to adapt to operate successfully in a more challenging environment. Tough weather conditions, which can limit access for routine maintenance, and the saline environment create the need for more robust turbine parts. This in turn means higher costs, which are not always offset by the higher productivity due to the higher offshore winds.

Continued operational R&D, and policy support that recognizes the value added from renewable energy projects like offshore and onshore wind, will go a long way toward resolving these challenges."

Its only natural that the highly developed offshore industry will play a major role in future energy. Technologies designed for the emplacement of oil platforms are now being used for wave and wind farm emplacement offshore. Jack-Up legs are an old technology first used to anchor drilling barges directly to shallow areas of the seabed.

DP or Dynamic Positioning is a sophisticated combination of GPS, Electric Azimuth Thrusters and computer systems that can hold a vessel in one position with an accuracy measured in a few feet.

As a mariner I would be very glad to see a boost in offshore jobs thanks to renewable energy. With GOM oil jobs being taken over by foreigners it would be a helpful boost to the US Merchant Marine to have a new specialty.

Be sure to go to the actual article for pictures and video of this amazing ship!

[kristopher]

1. Great article - lack of these ships has been the bottleneck for offshore wind.

Kick and recommend

[Yuugal]

2. K&R nt

[drm604]

3. Interesting.

I never realized this was an issue. I guess I'd just assumed that they'd use the same technology as offshore platforms.

[Dead_Parrot]

6. I assume they have been doing

The buggers didn't spring up like mushrooms. ;)



Presumably, having dedicated kit makes it faster and cheaper. Plus, they won't have to scrounging gear off the fossil fuel co's every time - which must be an interesting job...

[Braulio]

9. Fossil fuel co's?

Oil companies seldom own this kind of equipment, they lease or rent it. You never heard of outsourcing? It's used in the oil industry all the time.

[Gregorian]

4. Finally.

It took a melting planet and high fuel prices. Just the amount of fuel we used for seismic petroleum exploration could have been used to install this technology. It's going to be a relief for sure.

[Merchant Marine]

5. Yeah

I just thought it was interesting that the techniques and technology developed by the offshore industry for oil exploration were going to be so useful for renewables as well

[Gregorian]

7. Interesting that you would say that.

I only knew about seismic exploration because of a childhood friend who became a merchant marine at the Palo Alto harbor, and then went on to be captain of one of the seismic ships.

[Braulio]

8. But what's amazing about it?

As you say, this is just old offshore industry technology they use in the Gulf of Mexico. It's no big deal. What I like about these offshore windfarms is their impact on fish, those towers are going to be surrounded by fish. So the key will be to get in close enough without getting hit by the blades, I guess...do they come close to the water surface so we have to worry about it?