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CO2 emissions: making a difference

Sometimes it’s not the grand gestures, but the detail in the day-to-day running of the ship that makes all the difference in the reduction of CO2 emissions

While the Copenhagen conference may have failed to produce any clear guidance on the reduction of emissions for shipping, scrutiny on the industry’s environmental record remains as close as ever. Environmental awareness is far more than the question of what is coming out of the ship’s funnel – although that is, of course, important – and items as diverse as paint, fuel cells and satellites are playing a part in reducing the environmental impact of the industry as a whole.

Hull efficiency

Reducing the friction between the hull and the water is one of the most effective ways of increasing the efficiency of a vessel. In the long term, improved hull design will be responsible for the most change in this area. Given the lifespan of the average vessel, however, it is also important to develop methods to improve the efficiency of existing hull forms. One of the most effective ways of doing so is to encase the hull in a layer of air, or bubbles – a technique that has been known for some time, but that is not generally practical for large-scale use. Danish company DK Group has developed a system that does exactly this, by integrating an air cavity into the midship and box section of the vessel. An air injection system pumps compressed air into the cavity through a system of automated compressors and valves. This creates a layer of air between the vessel and the hull, designed both to minimise the hull/water contact area and minimise air consumption. An automatic control system monitors the volume and pressure of air and maintains the optimal air level in the air cavity. According to figures from DK Group, the system can reduce fuel consumption and related emissions by 15% for tankers and bulkers, 7-9% on an LNG tanker and 7.5% on a containership.

Paint and coatings

While the system can be retrofitted, new developments in antifouling mean that simply repainting a vessel with the right coating can have a similar effect. MOL, for example, has made research into high-performance antifouling paints that improve vessels’ fuel efficiency, one of the key elements of its CO2 reduction technology R&D initiative. According to research carried out by MOL, the drag of seawater over the vessel’s wetted surface accounts for 50% to 80% of all resistance, including wind and wave resistance. By developing a super-slick antifouling paint for ship bottoms, MOL hopes to reduce CO2 emissions by 8% to 12% compared to conventional antifouling paints.

Similar predictions are made by International Paint, which estimates that, over a five-year period, a single VLCC currently coated with a self-polishing copolymer antifouling could reap savings of 9,000 tonnes of fuel if coated with the most modern generation of antifouling, reducing its CO2 emissions by 31,000 tonnes and saving around $3.6 million. In-service experience on a range of vessels has shown savings of up to 9% on fuel usage and CO2 emissions, the company said.

Work with the weather

Even with the most efficient hull design possible, it is still possible to reduce CO2 emissions even further by choosing a route that works with the weather, rather than against it. Similarly, the use of a “just in time” slow steaming route that takes the best advantage of the time available to arrive at port just before the vessel is due rather than the “hurry up and wait” approach, can save large amounts of fuel. The IMO says that fuel savings of up to 2-4% can be made using this method. Rich Brown, VP of products at Applied Weather Technologies, which provides routing services and develops BVS weather-routing software, describes weather routing as “one of the industry’s best-kept secrets,” saying that many owners are not aware of the savings that can be made.

One reason weather routing is likely to be particularly popular with shipoperators is that it is a means of reducing fuel, CO2 emissions and costs at the same time, whereas most CO2 emission-reduction technologies are costly to implement. In fact, it is likely to be the cost savings, as much as the CO2 emission savings, that are the initial selling point, Brown says. “More and more companies are looking to control fuel costs – and many of them are looking to reduce CO2 as well.” He estimates that owners can save between 5-10% on fuel costs with weather routing and reduce CO2 emissions on a California-Asia route, although savings are not as large on north-south routes.

Ship of the future?

Fuel cells, a cleaner and more efficient way of producing energy from existing fuel sources, have often been predicted as the future of electricity generation on land. That concept had now been expanded to ships. During the United Nations Climate Change Conference in Copenhagen (COP15), the offshore supply vessel Viking Lady was docked in central Copenhagen and shown off to the press and COP15 delegates as the “only ship with a fuel cell integrated as part of its power generation”. It was claimed that, compared to a traditional ship, the Viking Lady’s advanced technology enabled her to reduce harmful NOx emissions by 180 tonnes and CO2 emissions are reduced by 20%. The Viking Lady’s LNG-powered engines emit no smoke or sulphur.

Classification society Det Norske Veritas’s chief operating officer Tor Svensen used the vessel as a venue for a press conference announcing the results of a study which points to potential CO2 emission reductions of up to 25% for the existing merchant fleet, which could translate into annual reductions of more than 250 million tonnes of CO2 . He said that the potential for CO2 emission reduction in newbuildings is even higher.

Nuclear ships?

Lloyd’s Register, more controversially, has been looking at the feasibility of nuclear-powered merchant ships. While several nuclear-powered merchant ships have indeed been built and operated in the past – and nuclear-powered icebreakers are still in operation today – the concept has never become mainstream. “The steady increase in the price of fuel oil – and the probable introduction of either a carbon-emissions trading scheme or a related tax – now presents the possibility that nuclear propulsion could be more competitive,” the classification society said in a statement earlier this year. As a result, Lloyd’s Register’s research programme is revisiting the technical challenges of nuclear propulsion for ships, as well as refuelling and waste-disposal issues.

Preventing alien invasion

The spread of pollution and invasive species though ballast water discharge, while not as high profile as CO2 emissions, is one of the most environmentally contentious issues in the shipping industry. According to the IMO “Invasive aquatic species are one of the four greatest threats to the world’s oceans.” The German government estimates that invasive species such as the Chinese mitten crab have caused up to R85 million damage in German waters alone.

The first stage of the Ballast Water Management Convention came into effect last year. Under the Convention, vessels constructed from 2009 onwards which have a ballast capacity of less than 5,000 cubic metres must be fitted with ballast water treatment systems. From 2012, new vessels with a ballast capacity of 5,000 cubic metres or more must be equipped with such systems.

There had been some debate about whether technology was sufficiently advanced to allow implementation of this convention. However, during MEPC 59 in London in July 2009, the IMO determined that sufficient type-approved technologies are currently available for ships constructed in 2010 that there is no need for changes to the existing resolution and, therefore, no changes to Assembly Resolution A.1005(25) are needed.

Tom Mackey, chairman of HydeMarine, said that “ships with smaller volumes of ballast water will be the first ones who must comply with coming regulations. These early adopters are an indication that shipowners and yards now recognise that the IMO BWM Convention will soon be ratified and that newbuildings need to install IMO Type Approved BWT systems”.

Indications are that owners are aware of this need, with Hyde Marine receiving orders for six ballast water treatment systems in a single week, for example. Of these, five were for newbuilding projects on offshore supply vessels and one deep-water survey vessel, and one for retrofit on a marine research vessel.

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