Pacific Maritime Magazine - Marine Business for the Operations Sector

LNG Marine Fuel in the Pacific Northwest: Addressing Challenges, Developing Solutions

 

The Northwest Shearwater, built by Kawasaki Heavy Industries in 1991, has a capacity of 33.5 million gallons of LNG. Photo courtesy of BP p.l.c.

Liquefied Natural Gas (LNG) is attracting much interest as it gains momentum as a viable marine fuel source. In the Pacific Northwest this development has been particularly prominent, with four separate LNG marine fueling projects in consideration in the Puget Sound area of Washington State – one of the highest such LNG marine fueling concentrations in the United States. Allied with this growth in Puget Sound is the especially strong focus on LNG in nearby British Columbia, Canada with 16 LNG projects planned, including both LNG export facilities and LNG marine fueling operations. The Coast Guard Sector in Seattle, Washington is charged with the responsibility of overseeing the safe operation of LNG marine fueling operations in the Puget Sound area – a significant challenge given the relative newness of LNG marine fueling in the United States for general use, and the immediate need to develop appropriate standards and policies.

Given the often widespread lack of awareness of LNG's characteristics, it is valuable to begin any discussion by first understanding the properties of LNG. Natural gas is a colorless, odorless, and non-corrosive gas composed primarily of methane. Natural gas has been a part of the infrastructure of the United States for decades. Although uncommon in marine use, according to the US Energy Information Administration, in 2009 approximately 61 percent of US households used natural gas to heat their homes. It is typically transported in gas form across land via underground pipelines. However, in order to transport large quantities of natural gas, especially by water, it is advantageous to reduce its volume through liquefaction.

The liquefaction of the gas occurs around -260 degrees Fahrenheit, and reduces its volume to 1/600 of that of the gas. This is essentially the equivalent of a ping pong ball compared to a beach ball.

The boiling point of LNG is -259 degrees Fahrenheit and its flammable range is narrow, only 5-15% by volume.

Like any fuel, LNG carries safety and environmental concerns. One of the greatest, but misplaced, concerns about LNG is that it is highly explosive. Natural gas, when liquefied, is not actually explosive. The vapor, natural gas, will explode, but it must be in its flammable range of 5%-15% normally in an enclosed space. When in its gaseous state, safe handling procedures for natural gas have been used with success. More than 100 LNG production, storage, and fueling facilities currently operate in the United States. Of note: There currently have been no fatal LNG accidents in marine use.

Escaping methane represents both an explosive risk and an environmental concern. "Methane slip" occurs when non-combusted LNG escapes into the atmosphere through the engine exhaust or through the fuel supply chain. Methane is a major component of LNG and methane slip could allow greenhouse gases into the atmosphere. To mitigate this risk, LNG engine manufacturers have designed their engines to greatly reduce methane slip; for example on the LNG-fueled passenger cruise ferry Viking Grace, the Wartsila main propulsion engines have been designed to achieve zero methane slip.

Despite potential concerns, heightened interest in LNG has developed in the maritime community. The transportation of LNG by gas carriers began in 1959 when the Methane Pioneer conducted a transatlantic voyage from the US to the UK. At the time there was limited capacity in LNG marine terminals and import/export facilities. The rapid growth of LNG supplies from new exploration fields in the United States and Canada has now made LNG significantly more available, with favorable pricing compared to traditional petroleum products. The large number (16) of potential LNG export facilities in British Columbia, Canada noted earlier is testament to the rapid growth of LNG – Canada has no current LNG export facilities.

LNG is developing rapidly as a fuel for vessels. There are multiple drivers for this change. The International Maritime Organization (IMO) now mandates compliance with low sulfur, SOx and NOx for operation in Emissions Control Areas (ECA). On January 1st, 2015, vessels of greater than 400GT are required to operate in ECAs with 0.1% sulfur content fuel or less. This is an effort to reduce the carbon emissions and air pollution from ships. The North American ECA includes all of North America within 200nm of the coast as well as other parts of the world.

LNG is advantageous as it meets these requirements and reduces carbon emissions by approximately 20 percent while also reducing SOx and NOx emissions. The IMO has already developed standards to limit SOx and NOx emissions in addition to those limiting carbon emissions. LNG is a prominent option to meet these standards.

Other drivers include the considerable domestic US and Canada natural gas reserves and a willingness to reduce dependence on oil. Money though, cannot be underestimated as a catalyst for change: LNG has an approximate 40 percent price advantage over diesel based marine fuels.

While the demand for LNG vessels in the United States is relatively new, LNG-fueled vessels have been constructed and operated in Norway since 2000, and are widely used in Scandinavia. These vessels have operated without incident, prompting the British Columbia ferries, Washington State Ferries, and Staten Island Ferries to adopt projects for LNG-fueled ferries. The use of LNG is not just limited to ferries. Other corporations and businesses are looking toward LNG as a means to reduce fuel costs and emissions.

While considerable progress is being made to make the liquefaction, storage, transport and handling of LNG for marine use more efficient and reliable, there remain complexities to address in the use of LNG as ship fuel. The current Coast Guard regulations of 33 CFR 127 for LNG marine facilities are for those serving as import or export facilities for LNG cargo vessels. These vessels store LNG on a much larger scale than vessels using LNG solely for fuel. Compare the various size vessels and tank trucks in the table below. A Small LNG Cargo Vessel has a capacity of approximately 36.5 million gallons. A typical ferry fueled by LNG will have a capacity for approximately 50,000 gallons - only 0.14 percent of the cargo carrying capacity of the small LNG cargo vessel. The current regulations intended for large LNG import/export facilities are not fully appropriate for LNG bunkering facilities serving LNG-fueled vessels with low LNG fuel tank carrying capacity.

To address this difference in carrying capacity and regulatory intent, the US Coast Guard is developing new policies for LNG fuel transfers and LNG bunkering operations for smaller capacity operations. Local policies developed by Coast Guard Captains of the Ports (COTPs) will then address any gaps or local needs. Both national and local policies will be used to evaluate proposed LNG marine bunkering facilities. Once the facility has been evaluated, the COTP will issue a Letter of Recommendation to pertinent local federal, state and local agencies if satisfactory.

For LNG-fueled vessels, a Design Basis Agreement process is used to develop appropriate requirements for LNG-fueled vessel installations. This process, developed by the Coast Guard Office of Design and Engineering Standards (CG-ENG), is presented in USCG CG-521 Policy Letter 01-12 "Equivalency Determination - Design Criteria for Natural Gas Fuel Systems." This policy letter establishes design criteria for natural gas fuel systems in conjunction with the International Maritime Organization (IMO) Resolution MSC.285(86), "Interim Guidelines on Safety for Natural Gas-fuelled Engine Installations in Ships." The Coast Guard Policy Letter provides a level of safety that is at least equivalent to that provided for traditional fuel systems by using existing regulations and other relevant standards.

The bunkering (fueling) of LNG-fueled vessels and the fuel transfer processes used also require new policies, currently under development by Coast Guard Headquarters. These policies will provide tools to evaluate a variety of LNG fuel bunkering options. For example, communications, operations, maneuvering and mooring evolutions, emergencies, and mariner training all must be addressed and confirmed. Industry standards such as Oil Companies International Marine Forum (OCIMF) and Society of International Gas Tanker & Terminal Operators (SIGTTO) can also be used to provide guidelines for LNG transfers. The Swedish Marine Technology Forum also provides LNG Ship-to Ship bunkering procedures which can assist in the development of US LNG fuel policy and regulations.

In the Puget Sound area, USCG Sector Puget Sound is currently reviewing four LNG fueling projects, one of the highest concentrations of LNG fueling programs nationally. Washington State Ferries is investigating converting up to six ferries to LNG fueling, or alternatively building a new LNG-fueled ferry. The WSF LNG conversion project would convert Issaquah class vessels by mounting two LNG tanks (total capacity of 50,000 gallons) on the uppermost deck. The vessels would be refueled by LNG tank trucks. This proposal is currently presented in the Federal Register notice for public comment.

Puget Sound Energy (PSE) is developing in the Port of Tacoma, Washington an LNG fueling facility. This natural gas facility would be intended for LNG liquefaction, storage and bunkering. It would provide LNG as a marine fuel to local vessels and could also potentially provide regional natural gas system peak support to gas customers. The project is schedule to be finished in 2018.

Vessels operating inside the green boundaries of the North American Emissions Control Area as adopted by the IMO must use low sulfur fuel. Illustration courtesy of the US EPA.

Especially prominent is the conversion of two ORCA Class Roll On/Roll Off containerships by Totem Ocean Trailer Express to LNG fuel. Serving a dedicated cargo run of Tacoma, Washington to Anchorage, Alaska, these vessels will be converted by 2016. They will be fueled ultimately by the nearby PSE LNG facility, but in the interim could be served by a new LNG bunker barge, a fourth LNG fuel project for the Pacific Northwest.

The use of natural gas is growing rapidly both ashore and at sea. The Coast Guard is meeting this challenge through leadership by partnership. We are using our experience with IMO and other international forums to advantage to integrate proven technologies and safety practices. We are also able to flexibly apply existing domestic regulation tools, such as embodied in the Design Basis Agreement process. Finally, we are working with industry to finalize national and local facility policies. Together, these collaborative efforts will safely facilitate the growth and use of LNG as a marine fuel.

 
 

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