The Western Canadian Sedimentary Basin is considered a world-class site for underground storage of CO₂.
Photo: ©istockphoto.com/dgmata

The challenge now is to demonstrate that capture technologies are effective on a large scale. A number of large demonstration projects have been announced recently in Canada, such as Saskatchewan’s SaskPower’s Boundary Dam project and Alberta’s TransAlta’s Project Pioneer, Shell’s Quest project, the Swan Hills Synfuels project and Enhance Energy’s Alberta Carbon Trunk Line. Together, the governments of Canada, Alberta and Saskatchewan have contributed more than $3 billion for these CCS projects.

There are many different issues involved in carbon storage. According to the IPCC’s 2005 report, there is a substantial global capacity for storing CO₂ underground. In Canada particularly, geological storage is by far the best option. Potential sites include depleted oil and gas reservoirs, deep unmineable coal beds, salt caverns, and deep saline formations. Saline formations are porous sedimentary rocks deep underground, saturated with salt water. The IPCC considers that they “have by far the largest capacity for CO₂ storage and are much more widespread than the other types of formations.”

Detailed knowledge of these storage opportunities in Canada and elsewhere will be needed in order to deploy CCS at the necessary scale. Assessments are needed to determine the location and nature of potential storage reservoirs as well as their storage capacity. The critical importance of undertaking such assessments has been recognized by several international bodies, such as the IEA and the Carbon Sequestration Leadership Forum, which have recommended that governments take urgent measures to “define, map and evaluate the storage capacity for CO₂ on a resource basis” within their national borders. 

In response to these recommendations, Natural Resources Canada, through the Geological Survey of Canada, launched a major project in 2009 that will identify all major sources of CO₂ and all major potential geological storage formations in Canada. Where feasible, the storage capacity of these formations will be estimated. The data will be integrated with similar information from the United States and Mexico and form the basis for a comprehensive carbon storage atlas for North America. This atlas, which will be available in print and online, is scheduled to be completed in 2012.

Storage must be one of the first considerations in any CCS project, since capture and transport are dependent on the size and location of secure storage sites. In addition to geological storage, there are other potential options that are less feasible at the moment, according to the IPCC. Mineral fixation is currently too expensive and environmentally problematic. Ocean storage technologies are in their infancy, leading to uncertainty as to the permanence of the storage and impact on ocean ecosystems.

There are some potential risks of geological storage to humans and ecosystems, according to the IPCC. Although these risks are minimal for well-chosen storage sites, leakage of CO₂, for example, could affect groundwater quality and organic and mineral resources. Avoiding or mitigating these impacts requires the selection of the best site, along with appropriate monitoring and verification programmes that provide early warning if the storage site is not functioning as anticipated. 

Monitoring is necessary to fill in knowledge gaps about the process, part of which is being able to mitigate and address problems. The data from these projects are promising so far, as they indicate that CO₂ can safely be injected and stored underground under the right conditions.

CCS is a particularly attractive option for Canada. Not only is Canada rich in fossil fuel resources on which several key sectors depend, but its geography holds vast potential for CO₂ storage. Realistically, Canada will still rely on fossil fuels for some time, but CCS is key to reducing our greenhouse gas emissions, in conjunction with investments in renewable energy, renewable fuels and energy efficiency. Indeed, coal-fired power plants and other large industrial emitters, which are strongly dependent on fossil fuels, are known as the biggest sources of carbon dioxide emissions (60 percent of global emissions, according to the IPCC).

The IEA estimates that global deployment of CCS could cumulatively store about 145 gigatonnes of CO₂ emissions between 2010 and 2050, but this calculation is conditional on some 3,400 projects being in place by the end of that period. According to the Global Carbon Capture and Storage Institute, there are currently seven commercial, fully-integrated CCS projects in the world, including Weyburn-Midale, which in total store almost 10 million tonnes of CO₂ per year.

With ongoing work and dedication of its stakeholders, Canada is well positioned as a leader in the development of carbon capture and storage technology.

TO LEARN MORE:

CanmetENERGY: Carbon capture and storage

CO2 Capture and Storage Technology Network

CO2 Capture and Storage Roadmap

Intergovernmental Panel on Climate Change