World Oil Outlook - Opec

At first glance, retrofitting scrubbers is an obvious and quick solution to eliminate
SOx emissions. The systems can also help remove nitrogen oxide (NOx) and
particulates (soot), although for this the technology becomes more complex and
expensive. The bulkiness of scrubbers, the confined space available on existing
ships, increased maintenance, corrosion issues when dealing with SOx, as well as
discharge challenges, remain areas of concern and need to be properly addressed.
Nonetheless, especially for large vessels, scrubbing technology is viewed as part of
the solution to comply with future regulations.
Switching to low sulphur gasoil is also an alternative, especially for smaller ships
operating mainly in ECAs. While this will advance the life of the ship’s engine, it
will, however, also increase fuel costs. Moreover, technical upgrades, such as different
injector nozzles and fuel system reconfigurations to cope with lower viscosities
and pour points will have to be fitted.
Biodiesel would also be able to accommodate the IMO requirements. In addition,
it could offer some potential ‘environmental-related’ benefits, such as carbon
credits, and better biodegradability in case of oil spills. However, given the length
of time fuel is often on-board ships and at temperatures suited to microorganisms,
there are concerns that the high levels of humidity could promote bacterial growth
and deterioration. This raises serious concerns in terms of corrosion, filter plugging
and, in the worst case, gel formation inside the entire fuel system. In addition, the
price and availability of marine biofuels may be out of reach for many ship owners.
The current common presumption is that there will be no substantial volumes of
biodiesel in this sector for the foreseeable future.
All this has led to a number of companies and organizations, such as Det Norske
Veritas, MAN, Mitsubishi, Rolls Royce, Wärtsilä and Austal, exploring the LNG option.
LNG is being seen as a new ‘green bunker fuel’ and a convenient way to address
the challenges outlined by the IMO regulations. Supporters of LNG see it as an option
that solves most of the concerns related to the other possibilities being explored.
LNG combustion is virtually soot- and SOx-free, NOx emissions are controllable,
and due to the higher hydrogen content in methane, natural gas-powered ships can
emit up to 25% less CO2, 2 on a tank-to-wheel basis, compared to traditionally powered
ships. Other potential benefits include reduced lubricant oil consumption and
avoiding the need for heavy fuel oil pre-treatment installations. Dedicated LNG
ship engines are designed as four stroke spark ignition versions, or large dual-fuel
two stroke piston engines, which do not represent a major deviation from current
designs and operations. This is an important factor for shipping lines, especially in
the light of staff hiring and/or retraining.
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