A group of industry experts discuss technologies and fuels for future-proofing offshore vessels, while addressing the potential to repurpose existing vessels through innovative conversions
If you have plans to build an offshore support vessel to serve either the renewables or oil and gas markets, then your ship design needs to burn future fuels or be future-fuel ready.
This was one of the key observations during a wide-ranging panel discussion at a webinar featuring ship designers, builders and a leading offshore energy industry analyst that explored the best technologies for future-proofing vessel designs, optimising efficiency and maximising operability. Not limiting their discussion to newbuilds, the panel also addressed opportunities for repurposing stacked offshore vessels from the oil and gas sector in the renewables sector.
Presenting at Riviera Maritime Media’s Exploring current and future vessel designs in the offshore sector webinar on 17 June were IHS Markit ConstructionVesselBase manager Catherine MacFarlane, OSD-IMT Ship Design & Marine Consultancy sales manager Wijtze van der Leij, ESNA naval architect and co-founder Trygve Espeland and Royal IHC market director offshore renewables Stefan Lettink. Held during Offshore Webinar Week, the event was produced by Offshore Support Journal and Offshore Wind Journal in association with enginebuilder Caterpillar and sponsored by ship designers OSD-IMT and Royal IHC, which also builds vessels.
Ms MacFarlane kicked off the event, making several key observations regarding potential opportunities for newbuilds and repurposing laid-up oil and gas tonnage through conversions.
Noting the flurry of orders for wind turbine installation vessels (WTIVs) in the last 18 months, Ms MacFarlane said IHS Markit sees space for four more newbuilds on top of those already ordered.
“We’ve seen the market really focused on next-generation jack-ups to install the next-generation turbines. We’re looking at the flip side – are there any alternatives to the newbuilds and upgrades to existing vessels that are in planning?” she said. She noted that Heerema Marine Contractors’ semi-submersible deepwater construction vessel Thialf will be deployed for the first commercial turbine installation campaign in 2023. “This is a solution for projects that have seabeds that are unsuitable for jack-up units,” she said. IHS Markit knows this is the case for projects in the Baltic, for example.
“So, there is a potential for an alternative turbine installation method to come into play and open up the market for these types of vessels,” Ms MacFarlane said.
Another trend she noted was the conversion of retired drilling units in China to meet turbine installation demands in that region.
Cold-stacked drill ships: attractive conversions?
Turning to vessels capable of installing foundations outside of mainland China, Ms MacFarlane noted there are 21 such vessels available globally. Of these, nine install foundations only and 12 both foundations and wind turbines, with another 13 on order or under construction.
We have seen the oil and gas monohulls and semis capitalising on the low utilisation in oil and gas markets and transferring their skills and their vessel time into offshore wind. But the question now being asked is, ‘Are these units going to be effective towards mid-decade for the installation of the larger monopiles (and jackets) that we’re starting to see come into the market?’
Ms MacFarlane observed that 24 relatively young, cold-stacked drill ships were potentially good candidates for conversion to offshore wind service, noting the successful refit of Bokalift 2 by Dutch owner Royal Boskalis. Previously serving as Yan and GSF Jack Ryan when owned by Transocean, the 20-year-old drill ship underwent conversion at Dry Docks World in Dubai. Following the addition of about 10,000 tonnes of new steel and a new offshore crane capable of lifting 4,000 tonnes, Bokalift 2 can handle the installation of the latest generation wind turbine foundations, with its first assignment in Taiwan. Bokalift 2 will be operated by BoWei Offshore, a joint venture between Boskalis and Hwa Chi Construction, a Taiwanese marine engineering and construction firm.
“Strong competition among Asian and Chinese shipyards is lowering newbuild prices”
“So, is there an opportunity here in terms of pricing?” asked Ms MacFarlane, noting these floaters have been sold for scrap for prices ranging between US$6.5M up to almost US$12M.
Newbuild WTIVs are costly. Eneti, the former Scorpio Bulkers, is building a Gusto-designed jack-up WTIV for US$330M at South Korea’s Daewoo Shipbuilding and Marine Engineering (DSME). The design leans into the clean energy transition by being ammonia- and LNG-ready, with 4,400 kWh battery power and a shore power connection, lowering CO2 and NOx emissions. Such future proofing is becoming more and more attractive to energy developers that are becoming more focused of their carbon footprints, whether the offshore vessel is being chartered for the offshore renewables or oil and gas.
With delivery in Q3 2024, the WTIV will be employed in Northern Europe or Asia, according to NYSE-listed Eneti, which is eyeing additional newbuilds for the US offshore wind market.
The first wind turbine installation vessel being constructed for the US, the similar-sized jack-up design Charybdis, is being built at a cost of US$500M at Keppel AmFELS in Brownsville, Texas. It will be capable of installing both the largest generation turbines and foundations.
Primarily designed to provide a safe platform to accommodate technicians to maintain and service wind turbines, service operations vessels (SOVs) will be in high demand over the next decade as offshore wind grows exponentially, requiring a 133% increase in the current global fleet.
Based on IHS Markit ConstructionVesselsBase assessments, there will be demand for 63 SOVs in the offshore wind market by 2030. Ms MacFarlane noted the current fleet of SOVs in service – all in Europe – is 27, with another 16 under construction, all to be delivered by 2024.
By the end of 2024, there will be 43 SOVs – one for Taiwan and the rest for Europe – with some of these representing conversions of platform supply vessels (PSVs) or subsea support vessels.
Ms MacFarlane questioned whether there might be opportunity for more conversions of 28 PSVs under construction or being held at shipyards, most of which were ordered between 2013 and 2015. There are another 46 cold-stacked PSVs with a “fair amount of deck space,” she said, of about 800 m2 or more.
“Will this kind of conversion be able to effectively compete against a bespoke SOV in terms of long-term opex contracts, or will we see conversions trying to enter into the capex offshore wind market, trying to pick up some of the shorter-term campaigns for efficiency in cargo transfer?” asked Ms MacFarlane.
As two leading Dutch ship designers in SOVs and other offshore vessels, Mr van der Leij and Mr Lettink delved further into emerging design and technology trends for the market, building on Ms MacFarlane’s observations and analysis.
One of the first points Mr van der Leij wanted to highlight was how alternative fuels will shape future SOV and offshore vessel design. Noting OSD-IMT’s long heritage of designing PSVs, anchor handlers, tugs, research vessels and other workboats, Mr van der Leij said: “One thing all these vessels have in common is that they are burning diesel fuel or fossil fuels, and so (they are) polluting the environment.” By contrast, a recently unveiled design for a mini-SOV will be equipped with three diesel generator sets and battery pack in a diesel-electric hybrid application. “These vessels are always on DP or DP-2, meaning that you will need spinning reserve in case of failure. In this case, this will be done by the battery pack, meaning that you can shut down one or two generator sets, and then increase the load on your generator sets, allowing you to have a better fuel consumption,” he said. Mr van der Leij said this is “the new standard in offshore, especially the offshore renewable sector. So, if you’re looking at current vessel designs, I would say this will be it.”
Mr van der Leji noted OSD-IMT is also progressing a mini-SOV design by participating in studies looking at future fuels, one possibility being methanol (CH3OH).
While most methanol is produced using natural gas, non-fossil e-methanol could be produced by combining hydrogen produced through electrolysis, using renewable energy and captured CO2.
To use methanol, a low-flashpoint fuel, the mini-SOV would need to take in certain safety design elements, including an onboard nitrogen generator for tank blanketing, a fuel preparation space, methanol storage tanks and cofferdams around the tanks. The vessel will be fitted with dual-fuel internal combustion engines and batteries.
Four future fuels
Providing the perspective of a designer and builder, Mr Lettink noted three trends in the current SOV market that are driving design. First is the strong competition among Asian and Chinese shipyards that is lowering newbuild prices. The second is a “more concrete interest” in zero-emission vessel solutions that is being driven by commitments to low-carbon footprint targets. Third is the high cost of wind turbine downtime driving the need for improved efficiency of operations in the field, underpinned by the introduction of decision-support systems.
Looking at zero-emissions solutions and decision-support systems in tandem, Mr Lettink said the main challenge in choosing the right fuel is to find the right balance “between green ambitions on one hand, and the costs on the other hand.” To support owner choices, Royal IHC examined the pros and cons of four alternative fuel options for SOVs: a battery system with offshore charging capability; liquefied hydrogen and fuel cells; methanol with dual-fuel engines; and liquefied organic hydrogen carrier (LOHC) and fuel cells.
Mr Lettink described the battery system with shore power charging capability as “a very clean solution” but noted it comes with “a premium of 20% on the capex. On the other hand, we think it can benefit from low costs per kilowatt hour in the near and far future.”
In the case of liquefied hydrogen, he said it was “100% clean” solution but came with “35% extra costs for the operator,” with a high cost per kilowatt hour and a 35% premium on capex.
For methanol, Mr Lettink noted it would be a more commercially available solution by about 2025, but it is not 100% clean and would require a 10% increase in capex.
As for LOHC, he said this is where Royal IHC saw the most challenges due to its “very low efficiency,” and the complexity of the plants. “We expect this to be quite expensive,” he said, noting the capex was unknown.
More detailed research was conducted by Royal IHC into the battery and hydrogen propulsion options.
For the battery and offshore charging option, the shipbuilder estimated a requirement of 18 MWh of net battery capacity will allow for 16 hours of operations at Hs-2 (significant wave height). Accurate forecasts of workable days are critical to keeping capex costs manageable. “It’s very important to reach the right balance between the added costs and an amount of battery power you need because if you want to add 8% of workable days per year on batteries, it requires an additional 20% of investments in battery capacity,” said Mr Lettink.
In its study of an LH2-powered SOV, Royal IHC estimated a requirement for two fuel tanks totalling more than 400 m3 of hydrogen storage, and with a 5- to 6-MW, fuel cell would be able to operate for 15 days supporting an offshore windfarm.
Beyond future-fuel options, Mr Lettink dove deeper into digitalisation as a means to increasing vessel efficiency by evolving towards autonomous vessel operations. Using a decision support system, “you can optimise the planning and the route of the SOV through the windfarm in terms of time duration or fuel consumption,” he said. Taking the decision support system one step further, he said IHC’s Mission Master brings together input from several IHC digital tools, including its IHC Pathplanner (for optimising the route for lowest fuel consumption), IHC Workability Tool (to simulate the behaviour of the vessel and gangway on site), IHC Gangway and IHC DP System. Data supplied by these systems is fed to IHC’s Mission Master, laying the foundation for an autonomous SOV. “There will still be crew onboard,” noted Mr Lettink, “but some vessel tasks will be taken over the Mission Master” similar to autopilots on airplanes. “So, whereas the decision support system collects and processes the data to make the optimal routes, the Mission Master also makes it possible to execute the mission autonomously,” he added.
“If you want to add 8% of workable days per year on batteries, it requires an additional 20% of investments in battery capacity”
He expects the autonomous SOV will lead to safer and more reliable operations, high uptime for wind turbines, and eventually a reduction in crew.
Mr Espeland discussed ESNA’s use of well-proven surface effect technology in its crew transfer vessel (CTV) designs to minimise hull resistance and reduce vessel motions to improve seakeeping. These characteristics pay off in reduced fuel consumption and increased passenger comfort. “We use the air cushion to motion-dampen the entire vessel,” he explained.
Using SES technology, ESNA is able to incorporate the performance of a larger vessel in a small vessel platform. The ESNA-designed SES Sea Puffin 1 uses its air cushion for motion damping when accessing wind turbines, offering the same wave height for safe transfer as 20- to 22-m catamaran CTVs, he said. Equipped with the same power, Sea Puffin 1 is considerably faster than the catamaran CTV, reaching speeds of 40 knots . Additionally, as it is closer to the size of a daughter craft, Sea Puffin can be deployed using a standard davit from any mothership.
Mr Espeland highlighted some new designs that take the SES technology further, including a mid-range diesel-electric hybrid SES CTV that could serve renewable and oil and gas structures 20- to 40-nautical miles offshore, and a zero-emission hydrogen fuel cell SES vessel.
Addressing the 22-m diesel-electric hybrid SES, Mr Espeland said the vessel has very low fuel consumption: “Typically, we see 30 to 40% savings from a catamaran doing the same job.”
He said the main takeaway for the zero-emission vessel is not the performance but the fuel efficiency, because fuel consumption is low. This translates into a smaller fuel-cell installation and lower hydrogen consumption. Mr Espeland said the main drawback is that hydrogen is very expensive, but because the hydrogen-fuel SES CTV is a very fuel-efficient vessel, the capex becomes more economically feasible.
Polls suggest optimism for first zero-emission SOV
Polls taken during the webinar suggested that delegates are optimistic that the first zero-emission SOV would be ordered in the near future: 47% of respondents said the first zero-emission SOV would be ordered ‘within three years’ and 10% ‘within a year’ – 43% of respondents thought it would be ‘after three years’.
The primary hurdles for zero-emission SOVs appear to be picking the winning carbon-neutral fuel and commercial payback. Asked ‘What is the biggest hurdle for the successful introduction of zero-emission SOVs?’ 39% of voters chose ‘difficult to choose the right zero-emission technology’, while 30% selected ‘windfarm owners do not want to pay a premium’. 25% of respondents chose ‘lack of infrastructure’ and just 7% ‘lack of regulations’.Two binary polls suggested an evolution in the turbine installation market, as suggested by Ms MacFarlane, and a preference for bespoke SOVs.
One poll asked: ‘Do you think turbine installation from a vessel other than a jack-up will become accepted industry practice?’ 72% responded ‘yes’ and 28% ‘no’. In the second poll, 92% of voters said ‘yes’ when asked, ‘Do you think a newbuild SOV, compared to a converted PSV, offers a distinct advantage in terms of operational efficiency?’In a poll assessing the appetite for investment in emerging technology, with the question, ‘How much more are you personally willing to pay for an alternative product that reduces emissions?’, 64% of respondents choose ‘1-25%’, 15% ‘nothing’, 13% ‘25-50%’ and 8% ‘more than 50%’.
To the question, ‘Do you expect there is a market for a cost-effective mini-SOV?’ 59% said ‘yes’, 36% said ‘no’ and 5% said ‘yes, but only when powered by methanol’.And in the final poll question, ‘Which energy carrier do you consider to be the most promising choice for the future?’ 50% of respondents choose ‘hydrogen’, 20% ‘methanol’, 15% ‘ammonia’ and 15% ‘something else.’ No one responding to the poll choose ‘LOHC’, perhaps persuaded by Mr Lettink’s presentation.