FEEDER SYSTEM: “Feeder to serve for the match”
HBB Hanseatic Break Bulk is a marine logistics company acting as an independent shipbroker and Heavy Lift Agency based in Hamburg, Germany. An integrated part of HBB’s business is to develop coastal concept studies for transportation of Offshore Wind foundations and components.
Foundation installation likely to become bottleneck
The installation part of Offshore Wind turbines, blades and towers above water level has matured greatly in the past years. Between 2016-2018, the next so-called 2nd generation installation ships will enter the market and those additional Wind Turbine Installation vessels (WTIVs) are seen to be even more efficient for installing turbines. As much as that is good news for the wind turbine parts, it is somewhat surprising that those installation ships do not necessarily meet the hoisting capacity and deck space requirement to accommodate the demand of the next generation of XL and XXL monopile foundations.
Monopiles have become by far the most popular foundation type used nowadays for turbine sizes up to 5-7 MW and water depths of up to 30 meters. Especially, over the past 12-18 months with the wind farm planned further offshore there has been increasing interest in XL and XXL monopile foundation studies,. Those future piles range between 9-11m in diameter and weigh between 1,000-1,200 (XL) and 1,200-1,500t (XXL) per piece.
Only 3 installation ships capable for XXL moves
A comparative study made by Dutch civil engineering contractor Ballast Nedam indicates that there are 54 vessels available for wind turbine foundation installation with a hoisting capacity of more than 400t. The study further found that only 13 vessels qualify for lifting and installing the latest version of monopiles weighing up to 1,000t. Another seven vessels are capable of handling piles up to 1,200t and only 3 installation vessels can install piles of the XXL nature up to 1,500t.
The mature problem that is still very immanent in the majority of all sourcing concepts is the fact, that highly specialized wind farm jack-up installation ships, get dragged away from their dedication during a project and are (mis)used for feedering and transportation of foundation components from the marshalling ports back to the construction site offshore.
Soon, provided the next construction race in the North Sea is to commence in 2016-2018, experts foresee a bottleneck in supply of specialized installation tonnage for foundation components. With the industry, moving forward and further offshoreadditional wind farms will start to become bigger and bigger with installation ships working longer and longer on the same project.
Feeder the way out
Those equipment and component supply runs, therefore need to get addressed and be done by dedicated ships that are faster, less fuel consuming and lower emissions, and that are better fitted for transportation than their installation counterparts are. The type of ships that install turbines and foundations should not necessarily be the same, but present itself as a good wingman for the installation ship. For deep-sea cable installation jobs, such concepts are already applied, with the aim to reduce the time of the costly cable laying vessels, cables get pre-spooled onto barges for shipping the cables offshore.
Two ways to utilise HLV as feeder tonnage
One way of bringing further lifting power for foundations, Pre-Piling activities and TP installation into supply, would be to use multifunctional dynamic positioned Heavy Lift Crane Vessels (HLCVs).
HLCVs can effectively be utilised for a variety of services during a wind farm project, such as:
• Transport and installation of Transition Pieces (TPs)
• Transport and installation of Pre-Piles
• Transport of wind turbine components from port to jack-up site (DP2 feedering)
• Serve as accommodation vessels
• Act as ‘Wave breaker’
• Service vessel for grouting, scrubbing works, bubble curtains
• Service vessel for service and postinstallation maintenance works
But moreover HLCV have the crane capabilities not only ready for feeding Monopolies, Transition Pieces and Jackets to the foundation installation ship but eventually install them themselves ‘merry-go-round’ and integrate all offshore activities from production quayside to final position on the seabed. Additionally, due to their higher freeboard levels, those ships are capable to operate much longer during a project cycle even in harsh weather conditions. The temporary downside of DP2-fitted HLCV is, that there are only three ships currently available on the market.
15 additional vessels in the lane after short pit stop requirement
Which brings us to the second and new aspect of a feeder concept. This article shall create awareness that there are a fair number of additional Heavy Lift crane vessels (HLCVs) available, which are constructed and designed as non-DP vessels that could however be converted within a 3-6 month period, into DP2 ships.
All major global Heavy Lift shipping Companies, are holding suitable vessels in their fleet portfolios, that can be converted into DP2 vessels. The author identified 15 potential conversion candidate vessels that are being operated by four different ship owners. The vessels are comparable in their lifting capacities and sizes (all up to or above 1400t lifting capacity).
Easily 10 if not all of these units could change their core business from a transportation focus to transportinstallation mode within a short time frame, helping the distressed transport freight market to improve in rate levels due to the reduced supply in that market and helping the Offshore Wind sector to save costs by avoiding the utilisation of pure WTIVs for foundation installation.
To achieve that, however, we need to see more cooperation between foundation/TP manufacturers, Classification Societies, marine warranty companies and vessel operators in optimising contracts, resources and standards across the industries if we are to see the efficiencies the industry demands.
Daily costs underline the need to new concepts
A comparison of daily hire costs that occur for the different ship types highlights the dilemma further. According to a branch expert, a fairly standard jack-up installation ship, runs today at an average daily hire rate between EUR 80-100.000/day. That average is equivalent to at least 2 Heavy Lift Crane Vessels (HLCV) per day. An existing DP2 fitted HLCV, with single crane capacities up to 1.000t (in multi hook lift up to 2.000t), runs today on an average hire of EUR 35-50.000/day, which still looks like a bargain compared to the daily costs of an installation jack-up platform. Non DP-fitted HLCV vessels require a DP conversion to operate in offshore sites. This would cost roughly €10-15M per vessel or system (in case of portable devices), which, over a depreciation of 10 years, will put them back to the aforementioned hire levels of the existing ships.
Focusing on the conversion process itself, the following technical and commercial points need to be taken into consideration. None of these aspects present a serious challenge that cannot be solved from either the market or by anin-house development:
• Ships need to be fitted with DP2 or better (permanent or portable plug and play)
• Ships require (at least) passive heave compensation
• There needs to be a fair amount of equivalent types of ships that are comparable and interchangeable from their characteristics and capabilities to ensure safe planning and to avoid new bottlenecks or island solutions.
With distance further away from shore, the advantages of the feeder system grows
The water depths of the offshore wind parks of the future will increase, their sizes and the distances away from shore will increase, which will soon become the driver to push down costs per Kilowatt to an acceptable level.
By utilising crane DP feeder vessels in the offshore wind industry to install foundation parts, following additional savings could be achieved:
• Avoidance of marshalling ports for foundation parts, saves handling and storage costs
• Floating Heavy Lift crane vessels are independent from time consuming mooring or jacking operations
• Reduce risks, as handling is limited to one time at production site and once at installation site
• Reduce down time of the installation ship, and consequently total hire days by avoiding unnecessary jacking operation to change from transport cycle to installation mode
• Reduction in port costs as smaller Heavy Lift feeders have less GT compared to huge jack-up ships
• Prevention of CO2 emissions as smaller transport vessels burn less fuel and are even faster
• Advance the completion times of wind parks and get the park connected earlier, with WTIVs concentrating on turbine installation only
• Enhance predictability and planning accuracy with the possibility to continue working on projects also in rough weather conditions
• Ability to look at other markets than Northern Europe for installing wind parks as the supply concept with Heavy lift vessels is exportable and depth independent.
Indisputably, the time is now to start saving costs, reduce emissions, and make foundation installation more efficient, by looking at different foundation feeder concepts. All that will have an ultimate influence on the overall electricity costs for all of us (end-users)!
With thanks to the author André Milschus, Managing Director of HBB Hanseatic Break Bulk GmbH, Hamburg