Experts predict that by 2016 one-fourth of all maritime fuel will be liquid natural gas (LNG). This constitutes a 3% increase from 2006 levels. What is propelling this spike in LNG for maritime propulsion? Several factors, not the least of which is the substantial economic and environmental benefits of converting from Compressed Natural Gas (CNG) to LNG, are contributing to this “sea- change”. LNG has been used as a vehicle for storing exported natural gas for some time, but has begun to be viewed as a more cost-effective way to propel ships.
The Cost-Benefit Rationale
Upfront building costs of natural gas-powered ships are higher than those of conventional ships (approximately 25%), according to LSU economist Loren Scott. But those costs are offset by a considerable savings in maintenance costs (40%) and lower fuel costs (LNG costs approximately $1 per gallon), which coupled with LNG’s substantially lower greenhouse emissions makes using it attractive fiscally and opens possibilities to ship operators in markets with more stringent emissions regulations.
LNG burns more efficiently (producing more heat than oil). Beyond these direct savings, LNG puts less stress on engine components, thereby extending their life. To capitalize on these gains, shipbuilders will have to incur costs associated with converting their current operational infrastructure, e.g., ship fuel stations, as well as engines. But for forward-thinking company Harvey Gulf which is currently building the first-of-its-kind U.S. LNG refueling facility at Port Fourchon (at a cost of $400 million), the long-term gains justify the short-term investment.
Who Stands To Gain from Using LNG to Propel Vessels?
Another pioneer in the sphere, Turkish shipbuilder Sanmar has recently completed two exclusively LNG- powered tugboats – the first of their kind. Most tugs run on marine diesel and are virtual seagoing smokestacks. Sanmar estimates their LNG-powered tubs emit 26% less CO2 and as much as 90% less NOx, with nearly no particulate emissions (a critical advantage in countries with strict NOx emissions [e.g., Norway]).
The tugboats are powered by two Rolls-Royce engines, which produce 4,572 hp at 1,000 RPM (more than sufficient torque) and those engines are also 20% more efficient at powering their azimuth thrusters (the rotating propellers that make them fleet on their feet.) As an added benefit, Rolls-Royce reports that its LNG engines require far less maintenance than diesel engines.
“Most of the world’s tug fleets operate close to shore, where emissions regulations are most stringent,” said Neil Gilliver, president of Rolls-Royce merchant. “As LNG becomes more widely available, I have no doubt that many major ports will soon opt for this clean, lower cost and smoke-free fuel to power their tugs.”
Dana Madama is the Online Marketing Manager at eMaint Enterprises, located in Marlton, NJ, which provides CMMS and EAM solutions for all of your maintenance and asset management needs.