EnerSea Marine CNG

EnerSea began its quest to develop a modern CNG marine transport system in 2001 with the development of its VOTRANS (Volume Optimized Transport and Storage system) technology and designs. The VOTRANS system introduced a major breakthrough in the ability to store and deliver compressed natural gas on marine vessels cost effectively. Much more gas can be stored in and delivered from VOTRANS containment systems, and at a correspondingly lower cost, than with previous CNG design approaches.

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EnerSea has undertaken an intensive development program to commercialize this technology through engineering, validation, certification and application efforts. The results of these labors are EnerSea ship and barge-based CNG systems for which ABS has declared “…are ready to move directly into project construction” and that “ABS will approve EnerSea ships and barges built with VOTRANS CNG systems.”

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Application of EnerSea CNG Marine Transport Systems

CNG marine transport can provide ideal solutions for a wide variety of regional applications, including:

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• To markets located beyond pipeline reach and less than about 3000 kms

• For supply sources not large enough to justify the high capital investment required for LNG projects

• To offtake gas directly from offshore production facilities, including in deep and ultra-deep waters

• To replace fuel oil and diesel with natural gas in “stranded” markets

• To offtake the associated gas from oil production fields

• To produce and transport gas from extended oil well tests and early production systems

• To serve as an “all-in-one” gas production host and transport system for remote fields

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Comparison of CNG with LNG Supply Chain

CNG is often compared with LNG, as both are large volume, marine-based gas transport solutions. However, these two technologies typically target different sectors of both supply sources and energy markets. In summary, the major differences include:

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• Capital Investment: CNG projects do not require massively expensive liquefaction and regasification plants. Thus, the overall supply chain project is typically an order of magnitude less expensive.

• Footprint and environmental impact is much less for CNG terminals than for LNG terminals.

• LNG often requires expensive pre-processing of the supply gas to a much higher degree than required for CNG to remove components such as mercury and CO2.

• CNG does not experience “boil off” gas emissions from ships and storage facilities.

• CNG is typically more energy efficient than LNG.

• In summary, CNG targets small-to-medium sized regional gas delivery projects, while LNG must be geared toward large scale, long haul projects.

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Marine CNG – A Unique Project Management Tool

In addition to providing a cost-effective regional gas development solution in itself, CNG marine transport projects also offer several unique and valuable features for flexibility and risk management:

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• Easy Supply and Market Access: The terminals needed for loading and offloading vessels are simple in design, highly cost- effective (especially compared with LNG liquefaction and regasification facilities), and friendly in their physical footprint and environment benefits. Therefore, CNG may access supply sites and sensitive markets more easily than other marine-based solutions, such as LNG.

• Redeployability: Unlike pipelines and LNG projects, the great majority of CNG project capital is redeployable to other applications if needed. This provides a unique risk management solution in case unexpected events occur in the supply chain, including reservoir, market, commercial and political risks.

• Scalability: CNG project capacity is easily scalable by adding vessels to, or redeploying vessels from, the fleet. Therefore, unlike pipelines, upfront investment in capital for speculative capacity is not required, but instead can be employed at the time when such additional capacity may be required. With the above risk management and flexibility features, CNG projects may be able to secure more attractive financing and yield higher “risk-weighted” value to project stakeholders.

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Safety and Environmental Benefits

 

 

• Air quality: CNG delivered to markets to replace fuels such as coal, fuel oil and diesel will significantly reduce CO2 and other emissions; potentially valuable emissions credits may be available in such projects.

• Project emissions:  CNG has no “boil-off” losses; the use of cargo gas for marine fuel also mitigates bunker use and storage in the shipping operation.

• CNG terminals have a modest physical footprint and environmental impact to the terminal area.

• Cargo transfer buoy terminals can be located 5-20 kms from the coast for offshore loading and offloading of CNG vessels in highly sensitive areas.