An 89.2 m PSV is proving a catalyst for change in Western Australia, placing Siem Offshore at the vanguard of environmentally aware operations, writes Mark Pointon
Australia is on target to become one of the world’s largest producers of liquefied natural gas (LNG). There are currently extensive major developments either in production or planned, supported by an extensive network of companies and vessels.
Of these, Siem Thiima is unusual in being able to operate on either conventional marine diesel fuel (MDO) or LNG. Working within a 50-strong fleet of offshore oil and gas vessels for Woodside Energy, Siem Thiima is the only duel-fuelled LNG vessel in operation and a first for an OSV in Australia.
The rationale in bringing the Siem Thiima to Australia was part of an overall strategy driven by environmental concerns, upcoming global regulation changes and commercial considerations.
With the potential for an over-supplied market and a weak pricing structure, Australian LNG producers, of which Woodside Energy is one of the largest, recognised that an opportunity existed for its use as a marine fuel.
A key driver for this development was IMO’s proposal to reduce the sulphur content of marine fuels from the current 3.5% to 0.5% by January 2020.
There are many different fuel and technological options available to meet both IMO’s requirements and other proposed environmental legislation associated with the 2016 Paris agreement on climate change. Among these, LNG has been shown to substantially reduce exhaust emissions to levels lower than the Marpol requirements. Sulphur oxides and ozone-damaging particulates are almost zero. Nitrogen oxide is reduced by 90% and carbon dioxide is reduced by 25%.
Platform supply vessel (PSV) Siem Thiima was built by Remontowa shipbuilding in Gdansk, Poland and was delivered in November 2016. It was awarded a charter contract, as a duel-fuel (LNG/MGO) PSV in April 2016.
“This contract represents a significant milestone in terms of the commitment to Australia and the Asia Pacific region for Siem Offshore, and [is] a significant step towards sustainable transportation on behalf of Woodside, given the environmental benefits of LNG as the primary fuel source,” Siem Offshore said in a statement.
This sentiment was mirrored by former Woodside Energy chief operating officer Mike Utsler who said, “We’re thrilled to be the first company to bring one of these vessels to the southern hemisphere. Australia is on track to become the world’s largest producer of LNG, so it makes perfect sense to build duel-fuel capabilities for our marine fleets here.”
On 23 February 2017, Siem Thiima was successfully refuelled by EVOL LNG at the King Bay Supply base near Dampier. The company, an industry leader in the safe handling of LNG in the Australian power generation, transportation and industrial markets, designed and fabricated the LNG bunkering system for Woodside; it is fully compliant with the international bunkering standard, ISO 18683:2015
Siem Thiima is classed with DNV GL with a gas-fuelled notation. The Wärtsilä duel-fuel engines can operate on natural gas or MDO. This fuel flexibility reduces operational expenses, offers compliance with the most stringent emission standards, and ensures full redundancy to enable uninterrupted operation. Siem Offshore Australia marine manager Charlie Baker explained that crew can switch seamlessly between fuel sources. This is particularly useful if the vessel is in port and not running all engines, or must operate longer than expected between bunkering stops.
He explained that “Siem Offshore’s primary activity is the ownership and operation of one of the world’s most modern fleet of OSVs. The Siem Thiima is environmentally friendly and focused on improving fuel economy.”
High-end technical features assure the vessel is fit for multiple tasks besides safe supply duties, such as fire fighting, oil recovery and standby/rescue operations, while all the while reducing the NOx, SOx and CO2 footprint.
“Significant efforts have been made to assure a tailored combination of LNG operation and optimal hull shape for future cost benefit in the demanding OSV market,” noted Mr Baker.
The Siem Thiima is fitted with a 230 m3 cylindrical Type C LNG bunker tank situated adjacent to the four engines. One of the design challenges was its positioning and placement of this unit. When combined with its cold box encasement, air lock system and gas monitoring system - required to comply with the International Code of Safety for ships using gases or other low-flashpoint fuels (IGF Code) - the resulting compartment required approximately three times as much space as a conventional marine gas oil tank containing the same energy equivalent amount of fuel.
Mr Baker indicated that during the charter period, the Thiima had undertaken LNG bunkering operations twice monthly at Karratha. He explained that the LNG fuel was loaded at a temperature of -162 degrees centigrade and that the operating pressure of the fuel tank was maintained between 3 and 7 Bar.
Operationally, Siem Thiima has been working primarily between the King Bay supply base and the offshore facilities at Goodwin, Rankin, OHKA, Angel, Nganhurra and Ngujima-yin.
An analysis of vessel utilisation in 2018 shows that the vessel has spent the majority of its time at sea. The emission figures returned are very impressive: the duel-fuel emissions of NOx and SOx were significantly lower when compared to similar vessels operating on conventional fuels alone.
To ensure environmental and crew welfare, all crew with designated safety duties are given Basic training that complies with IGF and STCW code requirements. In addition, Advanced training is given to masters, engineer officers and all personnel with immediate responsibility.
The Siem Thiima is playing a key role in demonstrating the capability and efficiency of LNG as a marine fuel in Australia. DNV-GL Singapore’s plans for the future include developing a “green corridor” along the route of the existing Australia to Northern Asia iron ore trade.
Supported by Perth-based LNG Marine Fuel Institute, the “green corridor’ initiative is a collaborative joint investment project between a group of companies that includes BHP, Rio Tinto, Woodside, shipping companies and classification societies, to assess the commercial viability of LNG as a marine fuel in the Australia to China bulk iron ore trade.
Sources close to the project have indicated that it is highly likely that it will lead to the building of a fleet of LNG-fuelled iron ore carriers in the near future. The LNG bunkering hub currently under development in the Pilbara, will provide these vessels with enough fuel to undertake the round trip to northern Asia and back to Australia. In addition, Woodside Energy has publicly stated its intention to ultimately extend the use of LNG fuel to all of its offshore vessel logistics fleet.