Clean air, clean ships

According to BV, the marine industry needs to look at new ways of reducing the environmental impact from ships as public opinion becomes ever more focused on ‘green’ issues. Several new projects are in the pipeline with the goal of an environmental friendly passenger ship, with no marine emissions and very low emissions to air. The question of discharge to the seas is well under control now, with respect to treatment of black and grey water and control of discharge of waste materials. Tackling air emissions is rather more complex, although IMO is introducing new regulatory instruments for NOx, SOx and soon also CO₂.

Engine makers have families of dual-fuel engines that can burn fuel or LNG and BV says it was the first to class dual fuel vessels and has both rules and experience in this field. The issues that now need to be resolved are how to apply a technology which works on gas carriers to the more regulated and sensitive area of passenger vessels.

According to Bruno Dabouis, vice president of the BV marine division, there is considerable synergy between these two sectors at extreme ends of the shipping industry. One offers entertainment, comfort and luxury to its clients, the other enjoys considerable importance in bringing energy to our countries. They share a common concern: energy efficiency and reduction of air emissions.

Natural gas is, potentially, the common denominator, as the gas industry could bring to the cruise and ferry industries the clean natural gas they need to further fuel their move towards higher standards of environmental friendliness. “Bureau Veritas is pleased to serve both industries with a specific focus on technological innovations,” says Dabouis.

Passengers want to sail on clean ships, and cruise and ferry companies want to give them clean ships. That’s why all eyes are on LNG as a fuel. It is clean, SOx emissions are virtually eliminated and the NOx and CO₂ emissions are reduced by about 80% and 20% respectively. And at today’s oil prices, LNG is relatively cheap.

So will we see a sudden swap to LNG fuel for passenger ships? Definitely there is a market for LNG-fuelled ferries, and more designs are on the table. These vessels can operate on fixed routes and solving the LNG supply problem is relatively simple. For large cruise ships it is a different problem. They need to maintain global autonomy, and until there is a global LNG bunkering network we will not see big cruise ships fuelled exclusively by LNG. However, LNG as a fuel for passenger ships is a real possibility for both main propulsion and power generation when in ECAs and in port, with the engines burning conventional fuels on the open seas.

SOLAS for the time being does not authorise the use of low flash point fuel. IMO is working on development of a new code and has already issued interim guidelines, but only a few national authorities have implemented them. So the only existing LNG projects are those operating in national waters or between two countries applying these interim guidelines.

At present BV considers that there is a lack of global distribution of LNG in ports used by passenger ships, and logistical problems related to bunkering. A further major issue for passenger ships that want to use LNG as a secondary fuel is finding sufficient space onboard suitably located for LNG storage. It may be above or below deck, in independent type B tanks for large capacity cold storage or type C pressurised tanks for limited capacity, such as for short sea shipping. Location to guard against risks of collision and grounding and protection against LNG spillages is important.

For small capacities of LNG, non-fixed tanks located onboard the ship may be considered, such as containerised tanks. Such solution could be considered for fuelling large cruise ships during their stay in ports. Bunkering from land based LNG storage facility may also be considered for ships in port. When larger capacities are involved, use of dedicated bunker ships is a strong possibility; alternatively, bunkering from LNG terminals could be considered, subject to relevant agreements and satisfactory safety analysis being in place.

Technical solutions to install gas fuel engines in passenger vessels are in place, but there are still issues, including regulatory ones, to address. Bureau Veritas has recently updated NR 529 “Safety of gas-fuelled ships” and is working together with shipyards, operators and engine manufacturers to use LNG fuelled solutions to deliver what passengers and owners want. Clean air.