A new concept for transporting compressed natural gas (CNG) is being developed and commercialised jointly by Statoil, Canadian-owned Teekay Shipping and Norway’s Leif Höegh & Co
Allowing natural gas to be shipped from an offshore field to terminals, this solution has been pursued together with Det Norske Veritas in a preliminary project since 2002.
Newly-created Compressed Energy Technology (CETech), owned equally by the three partners, is responsible for marketing the technology and has already sought patents for several solutions.
The planned vessels will be equipped with large horizontal pipes capable of carrying gas under high pressure, with the biggest ships able to load up to 20,000 tonnes of CNG.
“We initially envisage using the technology in the storage system on production and storage ships,” says project manager Per Henning Hanssen in industrial development, who chairs CETech.
He believes that the most relevant application in the short term will be on oil fields with small quantities of associated gas, which could be stored with the aid of the CNG technology.
Natural gas is transported today either under pressure in pipelines or liquefied for shipment in special carriers. Both these methods have their constraints.
Pipelines can be used over relatively short distances, while LNG is primarily attractive for high gas production and long shipping routes.
CNG vessels will be particularly useful where traditional gas field developments are uneconomic because of size and geographical location. Compression also loses less energy than liquefaction.
CNG technology could be a relevant choice for distances from 300 to 2,000 nautical miles and production volumes from 500,000 to three billion standard cubic metres per year.
“We can already see that the technology is attracting interest in the international market,” says Mr Hanssen.