How Green Is Your Vessel?

By Katy A. Smith 11-20-2012 03:56:00

It’s not easy designing ships that are fuel-efficient, emission-compliant and reasonably priced. Today’s naval architects are more than up to the task.

By Kathy Smith

What drives naval architecture today is the same force that seems to drive everything else in the maritime business: the push to go green. As shipowners work to adhere to the growing number of changing regulations on everything from the disposal of ballast water to the mandate for a lower carbon footprint, naval architects are being challenged to create new designs in keeping with the requirement for more fuel-efficient, environmentally-friendly vessels. "Clearly the focus on emissions has been driven in part by some of the customer base,” says John Waterhouse of Elliott Bay Design Group in Seattle, which provides services to clients from single-boat owners to large corporations like Norwegian Cruise Line. He adds that shipowners are also looking at a wide variety of energy-saving initiatives such as recycled materials, LED light bulbs and variable-speed motors.

Outside-the-Box Thinking

Waterhouse is a firm believer in looking outside the marine industry to see what can be used or adapted from other sectors, for example, using items from the building industry or the on- and off-road trucking markets. Even equipment being built for the railroad industry may help develop some of the emission-control technologies that will be used on the water one day. Durk Nijdam from New York-based D2G Maritime, a company experienced in European shipbuilding and sustainable green technology, agrees: “We have to start looking outside the box. We can get much farther ahead by using other techniques, technologies and materials that are not really common in the industry.” He is already busy applying green technologies from Europe to America’s Marine Highway program.

Building more fuel-efficient vessels also means weighing the cost of carrying cargo for longer periods of time versus the additional fuel burn. Some naval architects say ships are slowing down as owners realize speed can be costly. For green fuel alternatives, much of the focus right now is on LNG, but it’s currently still an expensive alternative. Darrel Harvey of Alan C. McClure Associates, a 30-year-old naval architecture and marine engineering firm in Houston, notes: “Compressed natural gas or CNG, which is the same as LNG but not cooled or compressed as far, is what we’re going to see as the big push in the not-too-distant future. The nice thing about it is you don’t have all the cooling requirements, the bleeding, and the cryogenic tanks to store the gas in. You can just put the compressed natural gas in a properly designed and constructed pressure vessel and take the gas out as you need it.”

SOx and particulate matter emissions could be practically eliminated and NOx emissions reduced by 90 percent in gas-fuelled, lean-burn, 4-stroke engines, says a comprehensive report titled “Technology Outlook 2020” written by DNV Research and Innovation in Norway. The report goes on to say that LNG-fuelled ships cost 10-20 percent more than their diesel-fuelled counterparts. CO2 emissions could be reduced by as much as 25 percent using natural gas, but unburned methane is a definite environmental problem. Storage costs, especially on longer hauls, and the limited availability of LNG in some ports are also a concern; however, bunkering terminals are predicted to increase.

As the next tier of emission-control guidelines from the IMO dictates, the options for treatment of exhaust gases will include using either costly low-sulfur fuel or scrubbers. Jonathan Parrott, Vice President at Seattle-based Jensen Maritime Consultants, celebrating 50 years in business, indicates some scrubbers are as big as some of the silencers on these engines. “You’re talking about a three-foot-diameter by 10-foot-long tube that, on some of these smaller boats, is going to be very difficult to put in. Still, we have to look ahead for that type of technology.” In fact, Wärtsilä is in the process of developing its first commercial marine scrubber for short-sea carrier Containerships Ltd. Oy of Finland, to be delivered this August.

Start Your Engines!

Another factor to consider in the green equation is engine performance. Worn bearings and out-of-balance machines can contribute to considerable lost energy over time. “Misalignment can sap four to five percent of a machine’s energy on average and in some cases up to 10 percent, depending on the degree of misalignment,” says Rich Merhige, President of Advanced Mechanical Enterprises in Florida, a mechanical engineering firm that focuses on vibration analysis and laser alignment services in the marine industry. The company is currently using a sophisticated new tool developed by Windrock Inc. specifically for diesel engine diagnostics, using vibration and ultrasonics. The Windrock system provides valuable information about the condition of the engine so that it can be tuned to optimize performance.

Hybrid propulsion systems are also a green alternative but are not widely used as of yet. Robert Allan Ltd., located in Vancouver, B.C. and in business since 1930, recently partnered with Seattle-based Foss Maritime in the development of the world’s first hybrid tug, which is now working in the Port of Los Angeles and Long Beach. It was a very successful project but ultimately subsidized by the port and the State of California – an option not available for most shipowners. “Those who are taking the first steps are paying a significant premium,” Robert G. Allan says. “The majority of the savings will be in reduced maintenance on the machinery on those vessels, but the additional cost of putting these complex systems into harbor vessels is significant.”

The Hull Factor

When it comes to hull design for greener ships, naval architects can now predict hull resistance with more advanced tools than before so that hulls can function at optimum efficiency across the broadest range of conditions. Kenneth Humphreys of New Orleans-based Mino Marine, experts in offshore liftboat design, says Ship Constructor is one of the popular 3D modeling software systems. Other key software programs include Finite Element Analysis, which helps designers evaluate the structure in detail and reduce redundancies, hull weight, and construction costs. Computational Fluid Dynamics allows naval architects to accurately simulate fluid flow and perform comparative analyses faster than before and with a greater degree of engineering certainty.

Scott McClure of Alan C. McClure Associates adds, “The other part of that is to work on hull form efficiencies for the same speed to reduce fuel consumption and power demand. There has also been quite a bit of work done on coatings to eliminate or highly reduce marine growth as well.” Advanced Mechanical Enterprises’ Merhige cautions, however, that the combination of lighter scantlings with higher engine power can make vessels more prone to vibration and alignment problems.

With 3D CAD design continuing to evolve, naval architects are able to get a better feel early on for the volume, weight and performance of a ship. However, this adds another element to the decision-making process for the shipowner. At the start of a project they may know what kind of engine they’re going to use, but they may not know what kinds of pumps or HVAC systems they want. Essentially, the 3D-modelling aspect of design is now pushing the customer to make those decisions earlier. Simulation modeling is also more in demand. “On a passenger vessel,” says Elliott Bay’s Waterhouse, “we have the tools now for simulating the evacuation of a ship.” Wind tunnels and simulators are also helping ship operators be confident about coming into and out of ports, and fire modeling is also becoming more prevalent.

Looking Ahead

DNV’s “Technology Outlook 2020” report elaborates on other technologies being used or considered in the unending search for green solutions: Skykites, for example, are easily installed but are wind-dependent and may conflict with cargo-handling and equipment. Renewable biofuels like biodiesel and crude plant oil have reduced emissions but are hard on piping, and fuel instability is a concern. Using nuclear power is a far-off possibility since storing and handling radioactive waste would be problematic, among other societal issues. Marine fuel cells are characterized by limited lifetime use and slower power response, while batteries can provide excellent power storage but require long periods to charge.

Guido Perla, owner of Guido Perla & Associates in Seattle with European, Asian, and Latin American subsidiaries, points out that “Diesel/electric is a proven technology that has been around a long time. With the use of properly sized batteries, we can enhance efficiency and operation through reduced emissions and fuel usage.” Perla suggests that eventually a source of energy will be found that will (1) occupy a physical space equal to or smaller than what a gallon of fuel oil uses, (2) have the same or better calorific value, and (3) be priced competitively. Therefore the best investment for operators is to start applying and understanding the use of electricity to propel vessels, as that will keep them on the forefront of technology.

John Korpi, General Manager of Dalian FKAB Marine Engineering in Shanghai, reports China has carefully been studying green technology development in Europe and has held many green ship conferences during the past year. Last August a LNG-fuelled tugboat modified by China Natural Gas was successfully tested in Wuhan, a reflection of China’s national campaign for greener waterways.

As technologies and tools change, naval architects must follow suit. They not only have to look at designing a ship for today but for its future mission profile. Jensen Maritime’s Parrott says, “It doesn’t pay to have blinders on. You always want to look at the potential down the road.” Discussions and innovations will no doubt continue toward further advances in green technologies for the maritime industry. As well, the human factor in the equation cannot be forgotten. Robert Allan adds, and it’s as good a summation as any: “At the end of the day, the guy with his hand on the throttle is the most important influencer of fuel consumption and emissions.” – MarEx



Kathy Smith is a writer and virtual assistant based in Victoria, British Columbia. This is her first appearance in The Maritime Executive.

The opinions expressed herein are the author's and not necessarily those of The Maritime Executive.