Fuelling an industry on LNG - special report

May 3, 2013 - PRLog -- The question of how to counter rising bunker fuel prices and the emergence of an unforgivable regulatory framework on ship emissions has exercised the greatest proportion of thought and debate across industry leaders in recent years. With operating expenditure dominated by the cost of fuelling ships with marine diesel oil (MDO) and other heavy distillates, finding ways to make ships operate more efficiently has pre-occupied the strategic planning of shipping companies the world over.

Whilst concern over fuel prices has gnawed away at the industry, the International Maritime Organisation (IMO) has forged ahead with establishing its drastically low-tolerance stance on ship emissions. With the integration of EEDIs (Energy Efficiency Design Indices) and SEEMPS (Ship Energy Efficiency Management Plans) into the regulatory landscape, attempts to tackle the quantity of CO2 emitted by the worldwide fleet are in full force.

However, whilst energy efficiency management can help ship operators to confront the challenges of rising fuel prices and regulatory limits on CO2 emissions, a unified approach to complying with IMO legislature on SOx, NOx and other particulate emissions has yet to be agreed upon. Whilst exhaust gas cleaning is gathering traction in the debate, it is the emergence of Liquefied Natural Gas (LNG) as an alternative marine fuel that is guiding the industry towards its tripartite solution for lowering fuel costs, reducing CO2 emissions and complying with ECA (Emission Control Area) limits.

The concept of ships being fuelled by LNG is not a new one.  Modern LNG carriers, which have existed for over 40 years, were conventionally built to use their cargo as a propulsion fuel. More recently, the practice has been extended to other vessel types albeit on a minor scale and limited to vessels off the Norwegian coast. As of December 2012, the number of LNG-fuelled vessels worldwide (excluding LNG carriers) stood at 34 with a further 31 on order; these numbers are predominantly represented by offshore support vessels and passenger and car carrying ferries.

In light of the fact that the first LNG-powered ferry sailed in 2000, the international maritime community beyond Norway is yet to fully embrace LNG as a fuel. Lack of progress cannot be blamed on engine manufacturers, who have been forthcoming with their provision of dual-fuel engine types; leading names such as Rolls-Royce, MAN Diesel and Wärtsilä have competed with one another over the last decade to provide LNG propulsion options for a range of vessel types and classes.

However, whilst the end stage of harnessing LNG for marine propulsion has been adequately catered for, long-term and universal solutions for the storage and bunkering of LNG have yet to be found. So how is progress being made to ensure that storage and bunkering infrastructure can complement the technological advances made by engine manufacturers?

Onboard storage

With LNG carriers currently being built to carry up to 266,000 cubic metres of LNG in the case of the Q-Max class, the industry has until now concentrated its efforts on designing fuel tanks for maximum capacity. For vessels that ply their trade transporting alternative commodities or passengers, however, an LNG storage solution that has limited impact on a vessel’s conventional cargo is paramount.

CRYO AB, belonging to Sweden’s Linde Engineering Division, is currently involved in the manufacture of 86 m3 tank units for a series of LNG powered tug boats on order from Norwegian marine services company, Buksér og Berging AS. All aspects of the system are designed for efficiency to ensure that LNG combustion is maximised. The tanks are vertically shaped to ensure minimal footprint and vacuum insulated to minimise LNG evaporation. Two identical tank systems separated by a barrier wall are also included in the compact installation, which meets the criterion of 100 per cent redundancy without the need for a separate tank unit.

For Hamworthy, manufacturer of composite LNG storage and handling systems, the focus has been on designing a system that makes the system both space-efficient and completely redundant, guaranteeing a constant fuel supply. The fuel gas system is fully containable in one fuel tank skid, holding both the LNG fuel tank and tank room, which contains equipment for evaporating LNG, heating of the gas, and pressure holding.

Full redundancy in the system is also achieved without impacting on spatial efficiency. Reidar Strande, Hamworthy Oil & Gas Systems Director LNG, says: “To meet strict maritime requirements the systems are fully redundant, guaranteeing fuel supply under any circumstance. No fuel pumps are necessary. Natural gas will rather be delivered to the engines by differential pressure between tank and engine. Tank pressure is maintained by controlled evaporation of LNG in a closed cycle with the fuel tank.”

Bunkering

A further element in the total infrastructure required for LNG fuelling is the bunkering facility both on board the vessel and ashore. Currently, the lack of LNG bunker facilities outside of Scandinavia is stifling the LNG movement in regions beyond Europe. This stumbling block is something that Jörg Redlin, Director Marketing & LNG Division at Marine Service GmbH, a Hamburg-based marine consultancy, anticipates will take a few years yet to overcome.

“With regard to the multi-million investments needing to be taken for providing LNG fuelled ships with a global infrastructure of not just conventional bunker facilities, we suppose this process to exceed 2015”, says Redlin.

Such an outlook suggests that LNG is an unrealistic option outside of Europe for the foreseeable future. However, innovative solutions to help accelerate a global move to LNG are not in short supply. Marine Service, for one, revealed a world first mobile LNG fuel tank container at the SMM exhibition in Hamburg in September 2012, which it is hoped can help fill the current void in land-based bunkering facilities, particularly outside Europe.

Read more on: http://www.marineoffshoretechnology.net/health-safety-environment/fuelling-industry-lng