Exhibition & Conference

13-16 September 2021

Singapore EXPO, Singapore

Technical Programme

Aditya Aggarwal

Director - Global Gas Solutions

American Bureau of Shipping (ABS)

09:15 - 09:45

Wednesday, 18 September 2019

T1.3 The Beginning of a New Era for Ethane Carriers

Recent rapid growth in U.S. natural gas production has not only created a tectonic shift in the world natural gas markets but also impacted the natural gas plant liquids (NGPL) sector. Ethane is separated from the natural gas stream along with other hydrocarbon liquids such as propane, butane, iso-butane and natural gasoline and is a critical feedstock for the petrochemical industry. Surplus shale-based ethane production in the U.S. offers an opportunity for consumers in the east such as China to gain access to this stockpile.

Traditionally, Ethylene was traded in parcel sizes of around 20,000 m3 and transported in handful of gas carriers with pressurized tanks. In the early days of ethane export from the US, dedicated vessels of up to 37,000 m3 were considered large for such trades and potentially a risky venture. However, the success story of ethane import to India via the six 87,000 m3 Very Large Ethane Carriers (VLEC) for Reliance Industries marked a significant transformation in the gas sector and helped recognize the potential to further expand the market size by exporting U.S. ethane to feed new ethane crackers in China.

This paper will provide an overview of the evolution of VLEC market and focus on the development of the next generation of VLEC designs. Carriage of ethane using conventional technology and vessel design poses new challenges that need to be resolved. The higher density and higher temperature ethane cargo requires reinforcement of the existing membrane cargo containment system and imposes restrictions on partial filling of the cargo tanks due to severe sloshing loads. Additionally, the revised IGC Code only allows the use of ethane as fuel upon successfully demonstrating equivalent level of safety as that achieved through the prescriptive requirements for the use of natural gas as fuel. The acceptance to using ethane as fuel requires compliance with the classification and statutory requirements along with an agreement with the flag state. This paper will provide the layout of an approval roadmap in general on the basis of risk assessment for using ethane as fuel.

Foreign flag VLECs that are needed to export the U.S. ethane also require the Certificate of Compliance from the US Coast Guard. Due to complex interplay of requirements of the code and approval from the regulators, the approval process of newbuilding projects can introduce uncertainties such as delivery schedule and costs. This paper will also focus on providing guidance on successful collaboration with the US coast guard.

Multi-cargo capability on the VLECs hold a significant promise to not only reducing contractual risk for ship owners but also lowering the total supply chain costs for the charters.