According to LR, US ethane production capability, as a by-product of total increased US gas production, is under-utilised. The potential exists for annual exports of 1 million tonnes of ethane to provide employment for 0.18 million cubic metres of shipping capacity if shipped to North Europe, a further 0.32 Mn Cu M if shipped to South Asia and a similar amount to China through the Panama Canal. Projects are now underway to produce and move this ethane.
The report looks at the risks and challenges in developing a safe and efficient trade in ethane using larger ships and requiring ethane specific technical solutions.
“The window of opportunity to tie up ethane exports and secure tonnage to serve this trade is now open to feed potential markets in Europe and Asia,” said Tim Protheroe, President, Lloyd’s Register North America Inc.
“Lloyd’s Register has identified the technical risks and best technical pathways to help ensure that near term demand for large VLECs can be met by shipyards and gas containment system suppliers.
Our job is to help anyone looking at trading ethane to make the best commercial decisions based on the best technical insight as well as working with regulatory bodies such as the US Coast Guard and flag administrations to ensure that the risks are understood.”
As explained by LR, one of the critical factors to be addressed is the containment technology used in very large ethane carriers (VLECs) as traders look for the most efficient shipping options.
Leonidas Karistios, Global Gas Technology Manager, Lloyd’s Register, said: “We have been studying the potential for ethane for over a year and we asked the question, ‘What would a safe and efficient 80,000 m3 ethane carrier look like?’. The answer is that to transport larger quantities in a single hull will almost certainly require the adoption of alternatives to Type ‘C’ gas containment systems.”
Historically ethane has been transported in small liquefied ethane/ethylene carriers (LEC) designed and constructed to carry ethylene (boiling point -104°C) as well as ethane and other ‘normal’ LPG cargoes. All these vessels have Type ‘C’ containment systems and it is estimated that the maximum feasible size of a ships with Type ‘C’ cargo tanks is around 40,000m3.
The study evaluates all tank technology options and identifies that, for ethane carriers of 80,000 m3 and over, the adoption of either prismatic type ‘B’ tanks or membrane systems would provide the likely best technical design pathways – based on a ship with three to four tanks.
Lloyd’s Register has been working with major shipyards on variations of tank technology options and with containment designers, such as GTT, to identify technical solutions for large ethane carriers.