Ship Transport

Large scale transportation of CO2 by ship has been limited to the food and brewing industry to date. These industries transport some 100,000 tonnes of CO₂ per year. This is much less than the amount which would need to be transported for commercial CO2 storage. However, the conditions required for CO2 transport are similar to those of Liquefied Petroleum Gas (LPG) of which large quantities are transported by ship. LPG transport therefore provides extensive information relevant to creating large scale CO2 transport networks.

Current CO2 transport ships carry liquid CO2 at temperatures of -25 to -30C and pressures of between 1.4 to 1.7 MPa. The typical capacity of a ship is 850 to 1,400 tonnes of CO2 which is too small for the large quantity of CO2 that would need to be transported for CO2 storage. However, semi-ref type ships used for LPG transport, which cool LPG to -70C and pressurise it to 0.7 MPa could hold up to 24,000 tonnes of CO2.

As transportation by ship does not allow a continuous flow of CO2 from the industrial source to the storage sink some sort of interim storage facilities would be required (e.g. in harbours). Currently LPG is stored either in large steel tanks at pressure or in underground rock caverns, both of which could be used for intermediate CO2 storage.