Rapid expansion of offshore wind development worldwide is posing operation and maintenance challenges as turbines are installed in increasingly remote locations, harsh environments and deeper waters. This demands that Service Operation Vessels (SOVs) are equipped with flexible solutions for secure transfer of maintenance crews in difficult operating conditions, according to Vestdavit.
And this requirement has resulted in an increasing level of orders for the leading Norwegian supplier of boat-handling systems on the strength of its innovative capability to develop versatile davits for heavy-duty workboats able to safely transport personnel and equipment in variable sea states, with deliveries to the likes of Norwind Offshore, Esvagt and Rem Offshore.
According to research firm Rystad Energy, investments in global offshore wind are set to more than double over this decade from $46bn in 2021 to $102bn by 2030, when 265 gigawatts (GW) of capacity are due to be installed, with manufacturing and installation of wind turbines accounting for 50% of total capital expenditure.
Wind ramp-up worldwide
Europe is leading the way as the largest offshore wind region with 8500 turbines expected to be operational by 2030, based on projected investments of $53bn by countries including the UK, Spain, Norway, Denmark and Poland.
In Asia, China is rapidly ramping up wind farm development with 14 projects brought online last year and another 14 with total capacity of 6.3GW currently under construction, while Taiwan is developing 2.4GW of capacity, according to the latest Global Offshore Wind Report from the World Forum Offshore Wind, prepared by research firm Westwood.
In the Americas, leasing activity is increasing off the US with a particular focus on floating offshore wind development in deeper waters, backed by official funding to realise the full potential of this renewable resource.
As well as an increase in project volume, offshore wind farms are expanding both in scale and the size of turbines (15-22MW), with the number of turbines now exceeding 100 for several projects.
This, combined with potential turbine reliability issues due to rapid technological evolution of new models every few years, raises the requirement for regular maintenance of multiple turbines across an extensive wind farm to ensure continued uptime. The use of floating wind technologies with additional components such as mooring lines, dynamic cables and active ballast systems adds to these maintenance challenges.
Operational cost factor
At the same time, wind farm owners need to minimise operation and maintenance costs, and maximise turbine reliability and project revenue over a typical project lifetime of 20-25 years.
“Consequently, there is a requirement for SOV operators to be able to provide safe and efficient deployment of work crews and equipment to perform effective maintenance on several turbines simultaneously across a wide sea area within a tight operational window,” explains Vestdavit Managing Director Rolf Andreas Wigand.
The current fleet of 32 SOVs operating on offshore wind farms worldwide is forecast to increase to nearly 100 such vessels by 2030, according to an earlier report issued by WindEurope and the Polish Wind Energy Association.
Demand for SOVs has increased annually by 20% since 2016, according to Spinergie analysis, with these vessels having advantages over Crew Transfer Vessels (CTVs) as they are able to operate year-round in harsh weather conditions for high activity at wind farm sites, can travel longer distances and have sufficient accommodation for a large number of personnel onboard to facilitate prolonged stays offshore.
Furthermore, Clarksons’ latest Offshore Wind Support Vessel Report also highlights there is a shortage of CTVs that has resulted in higher dayrates amid increased crewing and maintenance costs for such vessels.
SOV fleet capacity limitations
Given fleet capacity limitations and logistical challenges for wind farms far out at sea, SOV operators are increasingly utilising advanced davit systems capable of deploying from a single vessel several heavy-duty workboats carrying crews and equipment for servicing of multiple turbines.
An SOV can serve as a self-supporting mother vessel for many service engineers while being stationed over an extended period a long distance from shore, with some wind farms located over 100km offshore. This results in savings in cost and energy used for maintenance, a need for fewer SOVs, reduction of non-operational downtime and increased turbine availability.
As a result, Norwegian wind farm support vessel contractor Norwind Offshore is seeing increasing demand from offshore operators for high-capacity support vessels that typically carry around 60 technicians onboard who can be deployed rapidly in daughter craft launched from davits for wind farm maintenance, according to COO Roy Ove Standal.
“This has the advantage of being able to transport the required number of service personnel to perform maintenance on a large number of turbines within a relatively short time-frame,” he explains.
“The operator can therefore reach several windmill installations significantly faster than by having to position the mother vessel next to each installation and then use a W2W gangway. This means active use of the workboat/davit solution can provide enhanced operational efficiency, providing weather conditions allow it.”
Increasing uptake of workboat davits
Given the operational benefits of using workboats, there is increasing update of davits by wind support vessel operators including Norwind Offshore that has taken delivery of several davits from Vestdavit for its fleet.
Similarly, Danish shipowner Esvagt has earlier ordered from Vestdavit two large FF-30000 dual-point workboat davits, with heavyweight lifting capacity of 30,000kg, to deploy its Safe Transfer Boats on a newbuild battery hybrid SOV lined up to work at Ørsted’s Hornsea 2 – currently the world’s largest offshore wind farm with 165 turbines – off the UK’s east coast after scheduled delivery in late 2024.
Esvagt states its STBs offer “a safe, effective and flexible transfer solution”, with over 130,300 such boat transfers in the offshore wind segment to date.
Based on its strong track record of deliveries of robust davits to the global naval and coastguard sectors over the past 40 years, Vestdavit has developed innovative boat-handling solutions for the offshore wind market with high regularity and reliable operation in challenging sea conditions for safe launch and recovery of daughter craft.
Bolstering wind market position
These include docking head technology with an anti-pendulation device to counter swing loads for optimal stability during boat launch and recovery, incorporated for example in a PAP-15000 davit with painter boom supplied by Vestdavit for a pair of newbuild Commissioning Service Operation Vessels (CSOVs) earlier contracted by Rem Offshore at Norwegian shipbuilder Vard.
Vestdavit has bolstered its market position in offshore wind after both gaining new customers and winning repeat orders with existing customers – with davit orders from this segment accounting for Nkr100m, or 30%, of record sales last year – and its systems are now being used by around 80% of all offshore wind vessel operators.
“We continue to see a steady uptick in offshore wind orders going forward, driven by the global expansion of wind farm projects and the need for SOVs to maximise the cost-efficiency of maintenance operations,” Wigand concludes.
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