Power plant products |
Hydrogen-powered offshore service vessel
In collaboration with its long-term supplier Windcat Workboats, Vestas is launching a pilot programme to explore how the world’s first hydrogen-powered crew transfer vessel can help reduce carbon emissions from its offshore service operations. The CTV is powered by a dual-fuel solution, so it can be powered by hydrogen in a combination with marine gas oil. The solution will be tested as part of a pilot programme at the Norther Wind Farm, started in July. Running until the end of 2022, the programme will allow Vestas to explore the most scalable approaches to incorporate hydrogen into its operational setup. The goal of the trial will be to collect insights into the opportunities and limitations of hydrogen- powered vessels in daily operations. Christian Venderby, executive VP, Service, at
Vestas commented: “Hard to abate sectors, such as shipping, will be the final frontier in our global journey towards decarbonisation. Hydrogen is a crucial technology to advance this journey, which is why Vestas is eager to test its potential to reduce emissions from our service operations.” Carbon emissions associated with offshore operations currently account for one third of Vestas’ scope 1&2 emissions. The new CTV holds the potential to generate a CO2
saving of 158
tonnes, an estimated saving of 37 % less in carbon emissions compared to a traditional vessel. This saving is expected to be validated during the trial, as well as providing information about how the solution can be scaled up if it proves to make an impact on Vestas’ scope 1&2 emissions. At present, the vessel is projected to be
powered mostly by ‘grey’ hydrogen owing to a lack of available green hydrogen in the amounts needed, a situation that can be resolved once green hydrogen supplies reach the required level of maturity.
“This vessel, developed with our sister company
CMB.TECH, offers the industry a cost-effective solution to significantly reduce emissions from service vessels, which can be applied to any wind farm today. By using dual fuel combustion engines, we can make hydrogen technology operational in the industry and kick- start further development of the technology, regulation, supply chain, etc. Collaborations like these are what is needed to be able to scale this technology further” commented Willem van der Wel, md of Windcat Workboats.
First offering of onsite WTG blade root repairs
Until now blade root damage to older wind turbines could only be repaired at the manufacturing site, an expense which sometimes left operators with no choice but to purchase a new blade or scrap the entire turbine. But a Danish company, CNC Onsite, has developed a portable tool developed to efficiently replace damaged inserts in blade roots. The company claims to be the first to offer economical precision repairs carried out at the wind farm, with several clear benefits in cost and waiting time. Embedded into the blade root during the manufacturing process, the threaded inserts that are critical for joining the blade to the nacelle hub can over time become loose. In older blades, microcracks can form, which allow contaminants such as grease and hydraulic oil to weaken the bonding. This ultimately endangers the structural safety of the blade root, especially when fatigue loading is high. At worst, this can result in the blade breaking away.
With CNC Onsite’s method, the rotor blade is dismounted before repair at the wind farm. The portable automatic machining tool aligned to the blade drills away the faulty inserts from the composite material. Ensuring the cavity matches the exact diameter and shape of the replacement part, an additional, precise drilling process is performed so that the new part can be inserted and then fixed in place using bonding material. “Repairing the blade root inserts onsite can be a complex operation. You need to be able to control several process parameters to ensure you do not do more damage to the blade and it is important to drill exactly in the centre of the existing inserts,” said Søren Kellenberger, sales director and partner, CNC Onsite. The new tool benefits from experience gained
with the company’s existing machine technology, which is used to perform repairs to the yaw ring and tower flanges in line with micrometer tolerances. CNC Onsite has teamed up with We4Ce, a blade rotor and blade root connection specialist, to deliver a complete repair solution focused on high-strength blade roots. “The difficult parts of replacing a threaded insert – also referred to as bushings – are first of all centring the replacement part and secondly the processing technology for the bond. Based on our track record since 2008, we have developed inserts with a design that takes in both. This full solution offers consistent and stronger bond between the insert and the blade,” commented Edo Kuipers, engineering manager and co-owner of We4Ce. The energy transition is increasing demand for blades, so manufacturers are not only running at full capacity producing new blades, but older blade models are often phased out after some five to 10 years, which means a new mould has to be created. Because blades are the most expensive component of a WTG, accounting for some 25 to 30 % of the build cost, replacing them is often not financially feasible. The operator may decide to keep the turbine running at reduced capacity or even decommission it. Issues with threaded inserts are usually detected during maintenance and mostly occur in turbines older than 10 years. The new CNC Onsite blade root repair is estimated to take two to three days, To haul a blade, an oversized load, not only costs many tens of thousands of Euros but also requires detailed planning and approvals, not to mention the downtime costs. Its repair service, says CNC Onsite, will be offered at a fraction of these costs. The full repair service will be available from autumn 2022.
40 | September 2022|
www.modernpowersystems.com
Above: Damage to inserts (credit CNC Onsite)
Above: Repairing threaded inserts of blade root takes a few days
Above: Inserts after repair (credit CNC Onsite)
Above: After the new inserts have been replaced the blade can be reattached to the nacelle with bolt studs.
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