Recently a rather ordinary looking Norwegian coast guard cutter came to the port of Hamburg and created something of a stir. This little craft KV Barentshav (also here), seemed unremarkable, but its power plant was unusual. In addition to diesel, it could be powered by Liquified Natural Gas.
It has been a long time since we saw a shift in fuel for ships, from coal to oil. Now it seems we may be seeing the beginnings of another shift. The big drivers are reduced fuel cost and reduced emissions. The Norwegians seem to be the leaders here, but the US Coast Guard is not totally unfamiliar, particularly the M side of the house. the Dec 2011 issue of Marine Safety Engineering (pdf) had an article predicting that predicted that natural gas fuel vessels were coming soon.
This issue highlights another technology that is becoming more important every day, and that is the increased use of liquefied natural gas (LNG). Whereas, we previously considered LNG as a cargo, new MARPOL regulations for reduced emissions are now making it an attractive fuel source. It is extremely clean burning and is much lower cost than similarly clean diesel fuel. Marine Safety Engineers are leading the charge in establishing the appropriate safety standards needed for LNG fueled vessels, which not only includes the vessels themselves, but also bunkering facilities and waterways risk management.
Looking at cost, a study of the possible application of this technology to the marine transportation industry is available here: http://www.cleanskies.org/?publication=natural-gas-for-marine-vessels-u-s-market-opportunities (pdf). The study notes,
Based on the current forecasts, natural gas delivered for production of LNG is now at least 70% less expensive on an energy equivalent basis than marine residual fuel and 85% less expensive than marine distillate fuel. EIA currently projects that this relative price advantage will continue, and even increase, through 2035.
LNG does require approximately twice the volume for the same energy content and the infrastructure for its distribution is still limited. Currently engines designed to burn LNG are built by Wartsila, Rolls-Royce, and Mitsubishi. Some of these engines are duel fuel, burning either LNG or conventional diesel fuel.
- the US has ample supplies of natural gas,
- it may be less than half the cost on a per energy unit basis,
- that its use reduces maintenance costs,
- LNG is more environmentally friendly, and
- the possibility of duel fuel makes this option more practical.
Perhaps the Coast Guard may want to think about powering some of its assets with LNG. When the replacement for the 87 foot WPB is planned, it might be worth a look. They fit the profile of good candidates for LNG since they will normally return to the same base to be refueled. Extending usage to road vehicle and support equipment would amortize the cost of providing the infrastructure and make this option even more attractive.