Owners are increasingly converting vessels' power systems to ensure they pay their way and are more environmentally friendly
While activity is starting to pick up in the offshore sector, oversupply remains a problem. A vessel that does not get chartered is a drain on the balance sheet and even those that do need to maximise cost efficiencies and meet strict emissions requirements.
Fitting a battery or energy storage system (ESS) to provide hybrid power is an increasingly popular means of achieving significant savings on fuel costs, as well as cutting down on emissions.
British Columbia-based Corvus Energy, whose lithium ion-based ESSs have been approved by class societies DNV GL, Lloyd’s Register and ABS, has commented: “With emissions limits becoming more stringent and fuel costs on the rise, operators of OSVs are looking to fuel efficiency measures to help them avoid costly alternatives.
“Further, with an increasing number of customers and regulators mandating emissions control, OSV operators look to hybrid propulsion for a competitive shot at new charters.”
The first OSV to be fitted with such a system in order to replace a generator was Eidesvik Offshore’s Viking Princess, which Wärtsilä retrofitted with a Corvus Orca ESS in 2017. At the time, Wärtsilä said the ESS could result in fuel savings of up to 30% and a reduction of CO2 emissions by up to 18% a year.
Wärtsilä was also engaged to assist in another first, retrofitting North Sea Shipping AS’ North Sea Giant with an ESS to make it the world’s first hybrid offshore vessel with a dynamic positioning (DP) class of DP3. The Finnish company is certainly confident in the future of the technology, noting on its website that it believes battery capacity will increase tenfold to twentyfold in the next 10 years and that “pretty much all short sea challenges can be solved on battery operation, charged from a clean source”.
Seacor Marine is another pioneer in this area, having earlier this year contracted Corvus to install ESSs on four of its PSVs operating in the Gulf of Mexico.
Corvus sees this as a growing trend – it experienced a 350% rise in orders from the oil and gas sector during 2017 and observed that the total market for ESS installations on PSVs grew by 217%.
Retrofitting an ESS can be especially beneficial for DP-equipped vessels. A non-hybrid vessel utilising DP will normally use two or more engines at a time to provide backup power, resulting in a low engine load that is inefficient and can result in increased emissions. Using an ESS to provide this backup power instead means that the operational engine can be used closer to optimal load.
Corvus Energy estimates a PSV fitted with its Orca ESS could see running hours reduced by 10-30%, fuel consumption reduced by 15-20%, CO2 emissions reduced by 15-20% and NOx emissions reduced by 25-35% .A Corvus spokesperson told OSJ that in the past 12 months they have converted 21 offshore vessels equipped with DP to use their Orca ESS system.
OSV operator SolstadFarstad has already converted two vessels, Far Sun and Far Searcher, to operate on hybrid power and in May contracted Westcon Power & Automation to carry out conversion work on two more, Normand Server and Normand Supporter.
SolstadFarstad’s COO Tor Inge Dale said that the company hybridised these vessels at the client’s request, which provides financial support for projects that aim to reduce NOx emissions.
SolstadFarstad’s hybridisation was supported by Norway’s NOx fund, which launched a programme in September 2017 whereby PSVs on long-term contracts in Norway could apply for a fixed payment of Nkr5M towards retrofitting battery systems, with additional support of Nkr4 per kWh of charged shore power over a period of one year. A total of NKr100M was made available under the scheme, which had a deadline of 30 June 2018.
Mr Dale noted that SolstadFarstad is planning further conversions of vessels and that, depending on client willingness to invest in the technology, he anticipates the number of hybrid-powered vessels to increase in coming years.
In an opinion piece for OSJ, Chevalier Floatels owner Marcel Roelofs recently called for charterers to bear in mind carbon footprint when selecting a vessel. He is not alone in this line of thinking. Equinor – formerly Statoil – has a fleet of 40-50 vessels active on the Norwegian shelf on an average day and already prioritises vessels with technology installed to reduce fuel consumption and emissions when chartering. In an article on the company’s website Equinor’s marine manager Frida Eklöf Monstad singles out battery operation and shore power as being effective at reducing emissions, saying “ships that exploit these opportunities are therefore prioritised when contracts are awarded”.
With IMO’s 2020 sulphur cap just around the corner, reducing emissions is on everyone’s mind, whether builder, owner or operator. Even if not swayed by the environmental and cost efficiencies of hybrid power, owners may have no choice but to march to the beat of the environmental drum if charterers view greener ships more preferentially.
Old vessels, new tricks
Conversion can also refer to the complete repurposing of a vessel, although figuring out what to do with a fleet of redundant and unchartered OSVs has been something of a conundrum.
Norwegian start-up Seatres Power sees a novel use for OSVs to be converted into ocean-going mobile power plants. Seatres’ design specification is based around converting an Ulstein 745 class PSV into a SeaKraft power-ship, which would moor up at off-the-grid locations, such as remote communities or projects, to meet short- or long-term power demands.
Each SeaKraft would be fitted with between six and eight heavy fuel oil or diesel generators, with exhaust emissions management able to meet IMO’s tier 3 (diesel) standards. The design can provide up to 60MW to produce up to 500GWh annually per unit.
Using such a vessel would provide the benefit of an all-inclusive self-propelled unit, with generators, high voltage distribution, fuel storage, accommodation, power management and grid connection all handled on board.
Cryo-Shipping, another Norwegian company, is working on converting PSVs into small-scale LNG tankers, using DP systems for safe, efficient at-sea bunkering. Meanwhile Dreifa Energy, registered in the British Virgin Islands but with offices in Norway and the UK, is splitting the floating storage and regasification unit concept into floating storage units converted from older LNG tankers and a floating regasification unit converted from the PSV Blue Betria, for which it received approval in principle from DNV GL in late 2017 .
OSJ and its sister titles have reported on many other actual and proposed applications for old OSVs, including as dredgers, walk-to-work vessels and decommissioning vessels. So it seems there is life in these old dogs yet.