Canada's CO₂ Capture and Storage TRM 
Technology Pathways: Transport Technology

• Transport Systems
• Cost of Transport
• Transport R&D Needs

Transport Systems

After the CO₂ is captured and compressed, it is transported to a storage site in either its gas or liquid phase. Like other gases, it is most convenient and economic to transport CO₂ in its dense phase which could be either a supercritical phase or a liquid phase. The two primary means of moving CO₂ in either phase are by pipeline or tanker transportation.

Pipeline Transportation

Pipelines are a commercially established technology today. They are used around the world for moving large quantities of fluids over great distances. Energy pipelines are in operation in desert regions, in the Arctic, over mountain ranges, under seas and lakes and through densely populated areas. Pipelines crisscross North America carrying natural gas, oil, condensate and water over distances of thousands of kilometres.

CO₂ pipelines are also in commercial use today, most using the technology applied in energy pipelines. Large-diameter lines currently safely move up to 20 to 30 MtCO₂e annually, most of which (22 MtCO₂e/yr) is in the U.S. Both natural sources of CO₂ from New Mexico and Colorado, and industrial emissions (captured using amine scrubbing) are shipped to CO₂-EOR projects in West Texas. Some projects have operated since the 1970's. A separate 330 km pipeline carries 2 MtCO₂e/yr from the Great Plains Synfuels Plant in North Dakota to the Weyburn CO₂ Flood Project in Saskatchewan, the largest operating CO₂-EOR project in Canada. Another short, small-diameter pipeline has been operating in the Joffre-Red Deer area since 1986.

Important components of any pipeline transportation system are local storage facilities (such as depleted oil or gas reservoirs or salt caverns) which are used as surge tanks in gathering and distribution networks. These facilities can be used for temporary storage to help with pipeline system optimization and with delivery balancing. Similar temporary storage facilities would also likely be needed for a CO₂ pipeline system.

Pipelines can be used for multi-product transportation, which often help with the economics of a project. Slurries can be used to transport two phases of product simultaneously, and it is possible that CO₂ could be useful as a diluent when transporting bitumen (however, some technical questions still need answering). Alternatively, slugging or batching the bitumen and liquid CO₂ is another consideration.

Despite the current maturity of the technology available for CO₂ pipeline transportation, some issues persist. For example, the product needs to be free of hydrates or corrosive compounds, which highlights the need for more advanced capture technologies. This issue also indicates the need for industry standards on factors like the temperature and composition of the CO₂ streams, to ensure pipeline quality and integrity. Special attention is required when designing new pipelines through populated areas, such as overpressure protection and leak detection technologies. However, moving CO₂ by pipeline is even safer than the current practice of moving hydrocarbon liquids and petrochemicals by pipeline (because CO₂ is neither flammable nor explosive and it is not considered toxic unless it is present in very high concentrations), and therefore many safety concerns can be dealt with using existing knowledge and experience.

Tanker Transportation

Moving CO₂ overland by tanker is economic if the distance is short, if the volume being transported and frequency of trips are low, and if the customer is willing to pay a high price for CO₂. In most cases tanks would be loaded onto trains or trucks, with rail being more competitive than road transportation, provided the logistics fit the parameters of existing rail systems.

An alternative is to use rail or ships for large-scale transportation, which would mean using liquefied natural gas (LNG) technology in marine tankers today. This option would improve the chances of developing an international market for CO₂. Such a system would provide buffer capacity to handle any local shut downs in CO₂ supply that might occur (for example, the shut down at a power plant or large injection site). However, such a global system would require massive infrastructure investment. This means the option might develop over time (if a sufficiently high enough carbon constraint emerges), but it certainly will not be a starting point for CCS deployment. Transportation of this scale will only occur after CCS proves to be a commercially viable way of reducing GHG emissions on a local scale.

A global market for CO₂ with all the necessary infrastructure is an important long-term concept to consider, no matter how far away from commercialization it might be, because of the potential to capture CO₂ from large source countries or regions like China, India and the E.U., and transport it to large storage and CO₂-EOR opportunities in the Middle East, Russia and elsewhere.

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Cost of Transport

Many factors play into the economics of the transportation options. The cost of pipeline transport depends on the physical geography of the route taken (for example, onshore versus offshore or arctic versus temperate climates) and whether or not the route is heavily populated. Factors that impact the cost of ocean transport include the volumetric capacity of marine tankers and the availability of loading and unloading infrastructure. Both transport options are obviously affected by the distance of the route taken and the volume of product moved.

Pipeline transportation is estimated to cost (CDN) $6/tCO₂ for 650 kilometres transported in a common carrier network with a capacity of 14.5 MtCO₂e/yr (Thambimuthu, 2004). To construct such a pipeline would also entail an additional upfront capital investment. There are no solid estimates of how much overland tanker transportation would cost within Canada (either by truck or train), but it would certainly cost more than pipeline transport considering the volume of CO₂ that needs to be moved. Further, the cost to ship CO₂ from other countries to Canada (for storage in the WCSB for example) would be prohibitively high at this stage and will likely remain that way for some time. Although oceanic tanker transport may be the only option in countries without easy access to geological storage, an investment in this type of infrastructure development is a costly endeavour and would only occur in a world that places a very high value on CO₂ emissions reductions.

Pipeline transportation is not a terribly costly component of a CCS system, especially when compared to the cost of capture and compression. Economies of scale are a big factor in transportation cost, but learning effects are generally quite small because transportation technology is already mature and in commercial use.

Transportation Risks

The risks associated with CO₂ transportation tend to be local (like the capture risks noted previously), such as pipeline ruptures or leaks to the nearby environment. As already noted the risks posed by such events are comparable or even lesser in severity than those of other industrial activities, and these risks are considered manageable using current approaches (IPCC, 2005). The cost of risk management approaches for CCS movement is generally quite small compared to the overall cost of transportation.

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Transport R&D Needs

Practical experience shows that CO₂ transportation by pipeline is an established and commercial technology in most applications, and only incremental improvements are expected in most areas. However, new technology and knowledge is needed in two priority R&D areas.

Gas Characterization

A comprehensive database of CO₂ emissions streams in Canada, which would include CO₂-purity levels and other important information (related to other gases [and trace gases] in the emissions stream), would be a valuable undertaking. A list of end uses for each CO₂ source would help identify whether certain gas streams are best suited for CO₂-EOR, CO₂-ENGR, CO₂-ECBM or other opportunities.

Gas characterization can include developing an understanding of the effects of impurities on the physical state of the CO₂-rich gas streams, and on the physical state of CCS infrastructure like pipelines, compressors and storage tanks. Understanding the reactivity of trace elements like H₂S, SOx, NOx, oxygen, nitrogen and argon would be extremely valuable.

Pipeline Parameters

A second priority is to better understand optimal pipeline parameters for CO₂ transportation, which includes the study of using existing pipelines, or the co-transportation of CO₂ with other products in a dedicated pipeline. The study would include addressing any environmental and safety issues associated with large-scale CO₂ transport, as this would help in setting optimal pipeline parameters, and perhaps even specific codes and standards for building and operating CO₂ pipelines in Canada. As the important technology that links the capture and storage components of CCS, transportation plays an integrating role. Process modelling and process optimization studies on integrated approaches to CCS are an important part of better understanding pipeline parameters.

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