Box Ships: countdown to low sulphur cap

As 2020 approaches, container ship operators are eyeing up scrubbers and LNG.

Container ship operators are often at the forefront of adopting green technology. They have been among the biggest adopters of liquified natural gas (LNG) as a solution to the upcoming sulphur mandates and tightening NOx emissions. Using LNG as bunker fuel brings its own challenges in terms of accommodating the fuel tank in the ship design, locating and operating the fuel gas handling system, and the engine for main propulsion.

With short- and medium-term measures for greenhouse gas emissions kicking in, container ships, which are among the fastest merchant ships around, are once again considering the prospect of newbuilds being a lot slower to boost efficiency and satisfy the Energy Efficiency Design Index (EEDI) mandates of the International Maritime Organization (IMO).

In 2008, when oil prices touched US$100 a barrel, the worldwide container fleet dropped its speed from 21-22 knots to 17-18 knots. Since speed has a cubic relation to fuel consumption, the corresponding fuel savings were so large that additional ships could be deployed to take care of delays in cargo delivery. That experience may well encourage newbuild container ships to lower speeds to fulfil IMO mandates on EEDI.

Another environmental concern relates to biofouling and spreading invasive species through ballast water. With awareness growing across countries and regions about this issue, ships may have to prove they are not carrying invasive species. Container ships operating on a tight schedule may be hard-pressed to clean the fouling and novel ways of cleaning may be needed.

With the low sulphur deadline fast approaching, the existing fleet of container ships faces the dilemma of whether to go for scrubber retrofits or alternative fuels. Despite the cost of scrubbers, container ships undergoing scrubber retrofits spiked mid-year. July recorded 350,000 TEU of capacity in yards for these retrofits.

Evergreen Line, one of the largest container shipping firms, announced it is installing scrubbers on 139 of its ships. Earlier, the Taiwan-based company that operates nearly 150 container ships had announced it would install scrubbers on 20 of its newbuilds, indicating its preferred strategy for meeting the 2020 sulphur cap. A company spokesperson was quoted saying scrubbers, or exhaust gas cleaning systems, may cost up to US$5M, but with oil prices going up and container traffic expected to pick up next year, the continued use of traditional low-cost, high-sulphur fuel will pay off eventually.

The safeguard for scrubbers is against oil prices. Volatility was observed in the markets and the spread between high sulphur and low sulphur oils fluctuated through the year although forward markets for low sulphur did not indicate a significant price difference.

State-owned Shipping Corporation of India (SCI) announced it is not going to install scrubbers on its ships. Citing its belief that the price differential between the two oil grades does not warrant the high cost of scrubbers, the company also said there were significant technical challenges in installing scrubbers.

SCI runs a fleet of 63 ships, of which five are VLCCs and five container ships. SCI chairman and managing director Anoop Kumar Sharma has been quoted in the Indian media as saying the company was considering installing scrubbers but decided there is no payback period. By October the company will start transitioning to low sulphur fuel, he said.

Yards are reporting delays and the promise that scrubbers can be easily installed is not bearing out. IMO estimates that only 4% of ships will be fitted with scrubbers. However, it appears that percentage will be higher for container ships.

Containerships milestone

Meanwhile, July saw a milestone being crossed in using LNG as fuel in shipping. On 4 July, Containerships completed the first ever LNG simultaneous (SIMOPS) bunkering operations. The bunkering was carried out on LNG-powered Containerships Nord in the Port of Rotterdam, which became the first container carrier performing SIMOPS in Europe by means of ship-to-ship bunkering.

Containerships worked closely with Shell, its bunker supplier, the Port of Rotterdam and with the RST Terminal. The vessel received approximately 200 tonnes of LNG.

Containerships says “This unprecedented achievement paves the way for this procedure to be performed on other LNG-powered vessels, including the recently delivered Containerships Polar, sister ship of Containerships Nord. Thanks to SIMOPS, the ship’s stay in the port can be reduced significantly and operational delays avoided. Therefore, transit times can be reduced, offering CMA CGM Group customers a highly reliable and fast connection between northern Europe and the Baltics.”

CMA CGM is set to take delivery of 20 LNG-powered vessels by 2022, including nine 22,000-TEU ships scheduled to be delivered from 2020.

The LNG bunker tank needs to be twice as large as a distillate tank and the fuel gas handling system presents its own challenges. Space is a major issue when converting a non-LNG powered ship as well as in newbuilds, says TGE Marine Gas Engineering sales engineer Jörg Müller.

TGE Marine counts among its successes the LNG fuel gas system it installed in a series of six container ships built at a Chinese shipyard, of which three are in operation. More ships installing the TGE marine gas system are under construction or booked for retrofits.

Worldwide, almost all LNG fuel tanks are IMO type C tanks. Membrane tanks widely used in LNG cargo carriers have been proposed, too.

While membrane tanks are integral to the ship hull and subjected to loads on the hull, independent tanks are self-supporting and not integral to the ship structure. Among the independent tanks are Type C tanks designed as vessels for vapour pressure, following pressure vessel codes.

Mr Müller explains that the membrane tank has better space utilisation but limited vapour pressure capabilities. This means the Type C tank can take more boil-off gas, he says, adding this may be importance if the ship is waiting or in anchorage. Made of stainless or nickel steel, the Type C tank of TGE Marine has a submerged motor-driven pump or a deep well pump, like in a gas carrier.

Mr Müller says a high potential market segment for conversion is the worldwide fleet of container vessels which will stay in service for many decades. For this market, ahead of the Nor-Shipping 2019 exhibition in Oslo, TGE Marine introduced a tri-lobe design for a Type C fuel gas tank. This tank has been designed to fit in one container bay of a mid or large container vessel, following the ship structure. Three cylinder sections are designed in a horizontal transversal arrangement to form three lobes into a single tank. “The focus of this design is to gain volume efficiency while retaining the benefits of the Type C tank, which are pressure holding capability and ease of operation,” adds Mr Müller.

Depending on the ship size, this tank can contain up to 7,000 m³ of LNG. This tank will be tailor made, prefabricated and delivered to the conversion shipyard ready for installation. The related fuel gas handling system will be provided on skids for easy and fast installation. The prefabrication of these modules limits costly dockyard time. “The owner or the shipyard is increasingly asking for prefabricated structures. In the past, companies supplied loose parts and the shipyards did all the construction work. Now shipyards are asking prefabricated skids and units for easier equipment installation,” he adds.

Another trend Mr Müller is seeing is that owners want a high degree of automation in the fuel gas system because they do not want to employ a dedicated gas engineer. “The fuel gas system [including in retrofits] needs to be run without dedicated staff. This means not just providing equipment to the yard but training the crew, providing quick service and spare parts,” he adds.

Addressing biofouling

Meanwhile, the IMO-executed GloFouling Partnerships project to address bioinvasions by organisms, which can build up on ships’ hulls and other marine structures, started its activities this year. This project is a collaboration between the Global Environment Facility, the United Nations Development Programme and IMO. Twelve lead partnering countries (Brazil, Ecuador, Fiji, Indonesia, Jordan, Madagascar, Mauritius, Mexico, Peru, the Philippines, Sri Lanka and Tonga), four regional organisations, IOC-UNESCO, the World Ocean Council and numerous strategic partners have signed up to the project.

The IMO biofouling guidelines may become mandates because of the increased focus on invasive species, says Laurance Langdon, general manager of HullWiper, which is an invited participant in the project. “The main driving locations on invasive species include Australia, New Zealand, Hawaii and California. In some of the ports, if you cannot prove that you are coming with a clean ship as far as biofouling and the threat of invasive species is concerned, you will not be allowed to berth,” says Mr Langdon.

In October, a biofouling conference in Melbourne will take this further. The five-year project may culminate in mandates, he adds. “IMO’s intention is to study the guidelines from 2011-12, strengthen and ratify them. They want a global standard where all countries are managing the risk of invasive species,” says Mr Langdon. Invasive species have had disastrous impacts on the ecosystem of countries leading to billions of dollars in losses.

As IMO develops the GloFouling project, they are issuing guidelines for ports, member states and shipowners. A biofouling management book could be carried on every ship.

Biofouling has a performance impact on the ship, too. A 1% drag on a ship means an increase of 3% to 5% in fuel consumption.

Mr Langdon says there are various levels of fouling: soft, hard, micro, macro and so on. Once the fouling becomes hard, it can penetrate into the performance coating. Removing the fouling at that stage may rip off the paint and repainting may be necessary.

With today’s technology and resources, cleaning need not require the ship to be removed from charter or drydocking. Underwater robots can clean the vessel while the ship is in port for cargo.

A container ship that typically has port stays of a few hours can be cleaned in phases: one part in one port and another in a different port. The fouling removed is collected and discharged in an environmentally safe way, says Mr Langdon.

Source: Rivierra