Ocean Going Vessels Going Green

by Lorenz Bauer (Lee Enterprises Consulting/Biofuels Digest) Currently over 866 million tons per year of CO2, or 2.4% of the world’s total, come from maritime sources. A report to the European Parliament predicts that maritime emission will account for up to 17% of total global greenhouse gas produced by 2050. In the US market, ships used a 150,000 billion BTU of power, corresponding to about 2 billion gallons of ethanol in 2012. These emissions must be curtailed to achieve the global greenhouse gas reduction targets set in recent international agreements.

The importance of maritime emissions have led to a global effort to find approaches to reduce them that include changes in ship design and propulsion systems. This effort has also included testing a wide variety of biofuels. Yet the question of how biofuels and other renewables fit into this reduction effort remains to be determined.

Are Biofuels Useful In Maritime Applications?

New emission standards have opened the door to serious shifts to new maritime technologies and fuels. Environmental regulations limiting SOx and NOx emissions within 200 miles of coastlines are forcing a short term shift away from the currently used heavy fuel oil to alternatives. This shift may be reversed when more ships are retrofitted with emission control devices. These devices will add to the cost of the continued use of heavy fuel oil. There is an increase in the maritime shipping of liquid natural gas and methanol which is funding construction of new port infrastructure capable of handling these materials. Concerns about global warming are also effecting corporate and government strategies.

Biofuels face some significant obstacles as a maritime fuel replacement. Heavy fuel oil is traditionally 20-30% less expensive than gasoline or diesel fuels. The energy density of biofuels is often significantly lower than current fuels. The volumes required are also an issue. Fueling a single large ship for about 10 days of sailing requires over 350,000 gallons of fuel. This presents significant issues when evaluating new fuel sources. Large quantities of fuel are required which necessitates a demonstration scale plant. In addition, the shipping industry is under stress with several major Asian operators in or near bankruptcy which is limiting the source of funding of new initiatives.

Short haul sea shipping, port ships and ferries are where most alternative fuels are likely to be used.

The Maersk Group has a corporate goal to reduce CO2 emissions by 60% from 2007 levels. They are playing a key role in testing biofuels and other alternatives in larger ships and have a dedicated container ship for the purpose of testing biofuels provided from a wide variety of sources.

The first use of biofuels will likely be as blends with other more available and less costly fuels. The increasing adoption of liquefied natural gas, methane and maritime diesel provides easier blending opportunities for biofuel.

Given the current price of biofuels relative to fossil fuels, it is likely that mandates or subsidies will be required to support their initial use.

There has been a significant effort to identify future fuels for the maritime industry. Many alternative fuels have been tested on actual operating ships including: liquefied natural gas, methanol, Bio-diesel, glycerin, algae, and wood based fuels. Some of these fuels are not drop in replacements for current ships and will modifications to existing ships or construction of ships with new fuel and power systems. Others will only be available in selected ports. This limitation can be addressed by constructing flexible power systems capable of operation with one of several fuel sources for the ships not clearly dedicated to a single type of cargo and/or route. The volumes required for shipping are challenging for biomass conversion technologies and currently, none of the possible alternatives are available in the quantities required. It is likely that the fuels will be introduced into the fuel supply pool as blend stocks.

Drop-in biodiesel fuels that blend with maritime diesels and heavy oil fuels are very attractive since no changes in existing propulsion systems and infrastructure are needed. They are essentially free of sulfur and aromatics. The main limits on their use are cost and availability.

There are several different materials that are commonly thought of as biodiesel. Fatty acid methyl esters FAME are traditionally called biodiesels. They have significant advantages in small boat and recreational applications because they are non-toxic and biodegradable.

Renewable diesel is produced by hydroprocessing natural oils. Eni provided biodiesel prepared using their Ecofining^TM process for an Italian navy’s offshore patrol vessel Foscari. Another process, catalytic hydrothermolysis conversion (CHCD), was used to prepare diesel by isomerization of hydrothermal extracted plant oils. This fuel was successfully tested by the US Navy.

Lloyd’s Register was involved in a two year program to test the suitability of biodiesel for use in powering marine engines. The feasibility test took place onboard the Maersk Line container ship, Maersk Kalmar. The results of the test were positive, however, the high costs and low availability led to the conclusion that for the near term biodiesel was not economic alternative to other approaches to lowering emissions.

Glycerin is a by-product of FAME biodiesel production which is generated at levels exceeding market demand in scenarios which maximize FAME use. Several groups have been working on demonstrating its use in marine applications.

In 2013 Maersk announced financial support of two projects aimed at developing lignin based fuels. To date there have been no reports of progress. In 2015 the Port of Frederikshavn and Steeper energy, along with Aalborg University have entered into a partnership to establish the world’s first biomass-based plant to produce a sustainable marine fuel from wood.

Goodfuels Marine and Boskail recently reported the successful demonstration of UPM’s wood-based fuel for use in an operating ship. The feed is derived from Toll oil which is a minor component of the wood. It is similar to hydro processed vegetable oil derived renewable diesel. It does not use the more abundant Lignin.

Testing by the US Navy showed no adverse effects from using a 50/50 blend of a Solazyme algal biofuel with marine diesel. Algae derived fuel contains almost no sulfur so the SOx exhaust emissions are practically zero.

The success of subsidized commercial sugar to chemical conversion technology has led to growth of an industry based on fermentation and biological synthesis. The same fuels being used for land and air applications can be used in maritime engines. The Navy tested Synthetic Iso-Paraffin (SIP) Direct-sugar-to-Hydrocarbon (DSHC) fuels made by converting sugars to a pure paraffin molecule. Bio-butanol and butanol diesel blends have been tested in smaller marine crafts. Recently a 12 1/2 % butanol fuel blend was granted regulatory approval and is being marketed by Gulf Marine Fuels for recreational and small craft at a cost of about $5 gallon or $1500 per ton. While these feeds are technical is capable of powering the engines, their costs and low availability make their use in the near future problematical. READ MORE