At CWind, we are passionate about innovating for the future of the offshore wind industry, through engineering solutions that make a positive difference.
We have a dedicated, in-house innovation team, comprised of people from across all areas of our business.
Their main aim is to develop improvements in technology, assets and services that will deliver competitive advantages for our clients.
INTRODUCING THE WORLD’S FIRST HYBRID SES CTV
The CWind Hybrid SES is the world’s first hybrid propulsion surface effect ship, offering a step change in operational capability, performance and efficiency in wind farm O&M and construction activities.
CWind is committed to investing in innovation and new technology, in partnership with ESNA, to create a design for the future of CTVs.
The hybrid surface effect ship (SES) CTV has many advantages over traditional CTVs including:
> Reduced emissions
> Significant fuel savings
> Boosted battery performance
> Sustainable green technology for the future
CWind Delivering the World’s First Hybrid SES
There is an industry wide push to develop and adopt new technologies to reduce CO2 emissions, fuel consumption and costs of offshore vessels. Not only does this benefit economically, but also reflects the responsibility the offshore sector has in addressing climate change, one of the challenges that the UK Government has identified. For CWind, striving to achieve these key industrial and client drivers led to exploring the possibility of creating a new CTV that not only delivers lower CO2 levels, but will perform at higher sea state, at increased operational limits and offering better transit comfort as wind farms sites are beginning to be located further off shore. This CTV shall support our clients in achieving their green objectives, when working on their projects.
CWind partnered with ESNA, a naval engineering company that specialises in surface effect vessel development, to deliver a faster and fuel efficient CTV that can operate in higher sea states by using air cushion motion damping, otherwise known as a surface effect ship (SES).
Developing a Greener, more Fuel Efficient CTV
Achieving faster long distance travel, while reducing CO2 was key in the vessel’s development, the team explored both hybrid diesel/electric and hybrid diesel/hydrogen options. Electric propulsion does work best over shorter distances but, despite technological innovation that have reduced battery weight, it was not enough to counteract the weight of a larger battery needed to travel greater distances. Therefore diesel is needed to supplement the electric pack. At this point hydrogen technology is not sufficiently developed to offer a suitable solution, however the vessel may be retrofitted with fuel cells when the technology matures. The hybrid diesel/hydrogen was unable to deliver the CO2 saving to make it viable at this time, whereas the hybrid diesel/electric option can deliver the speed and distance while achieving a lower CO2 value.
The SES vessel was then modelled and tested at the Stadt Towing Tank facility in Norway, where they were able to verify the design as effective in increased sea states. The surface effect vessel design delivered improved sea-keeping and motion keeping performance, demonstrating a 2.0m Hs transfer height, as well as encompassing the characteristic of the SES hull form, to deliver improved fuel efficiency and associated reduction in CO2.
Improving Comfort and Safety
Alongside the improved heave compensation that improves comfort for all passengers and crew, the vessel is also fully air-conditioned, with personalised seating for passengers and crew.
In addition the bridge is ergonomically designed, and has enhanced visibility, for safer transfer of technicians and crew.
CWind has now commissioned the boat builder AMC, to deliver the new Hydrid SES by April 2020. Once in service it will offer a step change in operational capability, performance and efficiency in support of offshore wind farm O&M and construction activities.
TRL (Technology readiness level) Scale
DESIGNING THE NEXT GENERATION OF CTV FENDERS
The fender which has already been in trialled on a CTV, has proven to be very effective at maintain a constant and safe contact with the wind turbine.
The new fender will deliver:
> Safer conditions for crew transfer to a wind turbine
> Reducing the possibility of CTV slips or heaves
> Reduction in lost O&M days on the turbine and lower transfer efficiency as the vessel is able to operate in higher sea states.
> Ability to transfer crews in conditions CTV’s with standard fenders are unable to operate
CTV Fender – Maximising Transfer Safety and Efficiency
Transferring technicians from a CTV to the turbine in an increased sea state, is a known risk activity that can lead to unreliability as well as potential injury.
The transfer operation is dependent on a creating a friction hinge between the rubber on the CTV’s fender and the metal bumper bar of the foundation, applying bollard push to maintain the friction hinge. Issues occur when the friction levels are decreased on the hinge and the CTV slips or heaves, resulting in unsafe conditions for technicians to transfer safely, lost O&M days on the turbine and lower transfer efficiency.
In Field Fender Trails
This new fender design was trialled in field on CWind’s MPC Alliance over four sets of trials, initially in flat calm and up to the last trial in Hs 1.4m with 40 knots wind over the beam.
Results have been conclusive with the fender performing better than the conventional design in all respects, with no compromises. In rougher conditions (Hs 1.5m +, 25knots wind on the beam) the new fender had reduced movement to the point where the vessel would be able to safely transfer personnel.
Interestingly the normal CTV assigned to this field had remained in port that day due to the conditions being unsuitable.
Redesigning the CTV Fender
The key to improving the transfer efficiency is through improving performance in higher sea states, increasing reliability and reducing the possibility of slipping. CWind’s innovation team explored several engineering concepts to address this challenge. The team initially manufactured a non-mechanical cup to increase the contact area with the bumper bar and therefore increase the friction between the two.
Whilst it initially worked, extended tests and robustness assessments showed an unacceptable increase in wear, leading to a degrading of the interface with the foundation and causing increased, sudden movements which could have created a safety risk. Developing the solution further, the design evolved to increasing local force on the bumper through the fender rather than by the thrust of the vessel. A hydraulic mechanism for the bumper was designed and prototyped that applied compressive force when in contact with the landing area.
TRL (Technology readiness level) Scale
SOLVING THE CORROSION CHALLENGE
The C-Ling® solution:
> Will minimise corrosion within the internal structure of the foundation by preventing the exchange of water
> Reinstates the intended corrosion prevention strategy for the foundation
> Has been pre-engineered so that it is suitable for all sites
> Is a dynamic self-sealing solution that adapts to the changing environment
> Requires no ongoing maintenance
> Has been engineered, to be installed using a single tower team from the lower working platform. Minimising the risk to personnel, structures and facilities
> Utilises a patent pending, pressure differential to create a perfect, water tight seal
> Can prevent the transfer of acidic water and anodic material to the environment
Solving Turbine Corrosion Problems
Cable entry points within monopiles have been a challenge for the industry over the last decade. Economies achieved by losing the cable J tubes have been threatened by poor cable protection seals; over 90% have failed, causing unexpected and significant corrosion, leading to dramatic annual losses of steel in the primary steel structure. Corrosion remains a problem as the existing cable protection systems cannot maintain a sealed, deoxygenated environment. This leads to operational issues as a turbine’s expected life expectancy of 25 years is being dramatically reduced, in some cases by up to 15 years, a 60% loss which would prevent any life extension options on the wind farm.
The current industry approach to treating the problem is based around well utilised oil and gas techniques, using zinc & aluminium anodes. This has environmental issues with leaching of hazardous chemicals in to the sea which is something that is increasingly being seen as an unacceptable cost to the environment. In addition, commercially it is expensive to install and maintain, given that there are multiple smaller sites per turbine, rather than a single platform as is more often the case in the oil and gas industry.
C-Ling® the cleaner, greener corrosion solution
In an attempt to find a cleaner solution, CWind formed a partnership with AIS to develop its C-Ling® technology, aimed at providing an innovative and economic product to prolong the life of the turbine foundation without compromising the environment.
C-Ling® works by resealing the turbine foundation with a robust seal, which uses the power of nature to maintain integrity in the dynamic environment and adapt to the changing conditions.
C-Ling® is unique in the market, using a hydrophilic sealant that can self-seal to equalise water pressure differentials, and therefore stopping the transfer of water and anodic material entering the environment.
The benefits are not only positive to the environment, but to the primary structure itself in sealing the foundation with minimal effort. The C-Ling® system is currently being utilised on a 12 month trial at Blyth which will be completed in March 2020.
TRL (Technology readiness level) Scale
C-CLEAN TRIALS – REDUCING MAINTENANCE TIMES
This will reduce subsequent maintenance time needed to keep the turbine clean, while maintain a safe transfer zone.
The key benefits of the C-Clean are:
> Easily fitted to existing turbines
> Highly efficient and effective way of removing marine growth
> Removes marine growth without manual intervention
> Maintains a safer transfer bar for crew transfers
Why is it important to clean the turbine landing point?
Successful transfer of technicians and crew to the ladders on the turbine, is reliant on a stable contact with the CTV, which is achieve by creating a friction hinge between the CTV’s rubber bumper and the turbine landing point. The build-up of the organic matter, slime, reduces friction between the CTV’s fender and the structure, and so impacts the ability of the CTV to maintain the hinge. This ultimately can result in the CTV slipping, with a potential risk for injury.
Current cleaning techniques rely upon maintenance using pressure washers, or manually scrapping marine growth from the metal. Not only does this require a CTV, two persons and the fuel burn associated with it, the results are very short lived with primary propagation, the slime, returning quickly within just 24-48 hours.
What is C-Clean?
C-Clean, developed by the CWind’s innovation team, is a circular unit which is clipped around the landing tube of the wind turbine. The unit is designed to rise and fall using wave motion to remove marine growth without any manual intervention, a simple but highly effective means the elimination of marine growth is constant. Construction material is sufficiently soft to be engineered to not be a hazard to the structure.
C-Clean Trials Update
CWind has installed the first C-Clean unit on a cleaned, boat landing post of the ORE Catapult demonstration wind turbine.
To compare its performance, two bumper bars were cleaned by hand and C-Clean was fitted to just one of the bars. Initial result are good, with a noticeable difference between the marine growth on the bumper bar without the unit compared to the cleaner post with the C-Clean unit. The unit will continue to be monitored to check its performance.
TRL (Technology readiness level) Scale
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