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Mitigating climate change - Solutions and strategies in carbon capture and storage

by Jeff Walker on
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Carbon capture and storage (CCS) needs to be more widely adopted if it is to assist with mitigating climate change. Since International Standards would help to spread this technology, the first steps are being taken towards CCS standardization.

We, humans, are “a dirty bunch”. Our normal activities expel carbon dioxide (CO2) into the atmosphere. From exhaling breath to the cars we drive, and from heating our homes to the industries that employ us, daily living produces large amounts of CO2. The resulting greenhouse gases (GHG) trap heat in our atmosphere, warming it and disturbing the Earth’s climate.

But the problem is not with the air we exhale or most small-scale emissions, since trees and other plants convert CO2 into breathable oxygen. The problem is large-scale production emitting CO2 into the atmosphere at levels far beyond Earth’s capacity to convert it.

According to the United States Greenhouse Gas Inventory (2006), the top five sources of CO2 emissions were : fossil fuel combustion ; non-energy use of fuels ; iron and steel production ; cement manufacturing ; and natural gas systems. Too much CO2 in the atmosphere has been linked to climate change.

pipeline

CO2 pipeline as it enters the facility at Weyburn.

While the impact of human activities on the world’s climate is a contentious and heavily debated subject, the fourth assessment report of the Intergovernmental Panel on Climate Change (IPCC) warned, “ Warming of the climate system is unequivocal ”, and, “ Most of the observed increase in global average temperatures since the mid-20th century is very likely due to the observed increase in anthropogenic (man-made) greenhouse gas concentrations.”

The expected impacts from climate warming are severe and include extreme heat, drought, extreme storms, rising sea levels and the spread of disease. Stabilizing the climate will require significant reductions of GHGs. The problem is that conventional sources of energy, including coal, are expected to be the main sources of energy until well into this century.

According to sources such as the World Resources Institute and International Energy Agency, atmospheric CO2 can only be stabilized by deploying a range of measures. These include significant increases in energy efficiency and conservation, wider reliance on renewable energy and the use of carbon capture and storage (CCS).

Simply put

CCS is a process designed to capture CO2 emissions from large facilities such as coal, oil and gas power stations and other industrial operations before the CO2 enters the atmosphere. It is then transported through pipelines or other means, and permanently stored in deep, secure underground formations.

To capture CO2, three main methods are used :

  • Post-combustion capture, the most common method, which uses solvent to separate CO2 from other gases in the flue stack
  • Pre-combustion capture, in which carbon and hydrogen in the fossil fuel energy source are separated prior to combustion
  • Oxyfuel combustion, in which a fossil fuel is burnt in the presence of pure oxygen.

To transport the captured CO2, conventional pipelines (similar to oil and natural gas pipelines) are used. CO2 can also be transported by ship, road or rail.

For storage, the CO2 is injected into onshore or offshore underground geological areas such as saline formations and depleted hydrocarbon reservoirs. It is trapped underground by overlying impermeable cap-rock and other chemical and physical means.

The evidence suggests CCS is safe. According to a 2009 report from the Carbon Sequestration Council of the United States, CCS can be carried out safely if it is done properly. Norwegian, Canadian and Algerian CCS projects (see box) have not detected any CO2 leakage or groundwater contamination.

The benefits of standards

Proponents are currently using different guidelines and best practices to design, develop and operate CCS projects. This often requires extensive and protracted consultation with a variety of stakeholders and, even then, there can be problems gaining public acceptance.

CCS standardization would provide public credibility and facilitate the wider deployment of appropriate and safe operations. CCS-specific standards could help to address the unique requirements of these projects and provide assurances that projects have adhered to internationally accepted practices for safety and environmental integrity.

Based on and developed using worldwide experience and expertise, international CCS standards would recognize that some projects may cross multiple jurisdictions.

Also, many jurisdictions that would benefit from the rapid implementation of CCS do not necessarily have the comprehensive expertise required to produce their own CCS standards.

Harmonized international CCS standards would benefit everyone : it would address a key need and support the spread of CCS as a way of mitigating climate change.

At first glance, International Standards and new fields of study such as CCS might seem to be incompatible. After all, are not standards about rigid rules to ensure things are always done in a certain way, while new fields of study are dynamic with changing norms and practices ?

In reality, there are different kinds of standards for different situations, and standards developers need to use the appropriate forms for the situation. However, it will be important to ensure that standards do not impede innovation.

The first steps

To support the deployment of CCS, many jurisdictions have released, or are developing, CCS regulations. For example, in the USA, Environmental Protection Agency CCS rules relate to injection wells and greenhouse gas reporting ; the European Union has its Directive on CCS ; and in Canada, a number of provinces are developing frameworks and regulations related to the transportation and storage of CO2. When regulations are proposed, standards are often part of the process.

Standards have indeed been initiated. In North America, CSA Group is working with IPAC-CO2 to develop an accredited bi-national Canada-US standard on the geological storage of CO2. To be published in 2012, this covers characterizing and selecting storage sites, injection-well development, monitoring and verification, expectations for post-injection closure, and risk management. It will be offered as a seed document for developing ISO standards.

In 2011, ISO approved the formation of ISO technical committee ISO/TC 265, Carbon capture and storage (CCS) based on a proposal from Canada which recognized the benefits of International Standards and the advantage of developing appropriate standards when they can do the most good. ISO/TC 265 is chaired by Sandra Lock of Canada. The Standards Council of Canada holds the ISO/TC 265 Secretariat in a twinning relationship with the Standardization Administration of China.

Commercially speaking

CCS technology is in commercial use : in Canada, the Weyburn-Midale CO2 Project has injected over 25 million tonnes of CO2 into depleted oil fields (equal to removing more than six million cars from the road for a year) ; in Norway, the Sleipner Project has stored almost 15 million tonnes of CO2 in a saline aquifer ; and in Algeria, the Salah CCS Project has injected over three million tonnes of CO2 into a deep saline formation.

Although many other projects are underway or planned, CCS is still not widespread. The reasons for this include high cost, concerns about health and safety, lack of carbon pricing, doubts about its efficacy and public uncertainty. Another major obstacle is the lack of clarity about the rules and requirements project operators must follow.

Jeff Walker
Jeff Walker
Jeff Walker
Senior Project Manager, Sustainability Programme
CSA Group