The urgency of reducing carbon emissions increases with every passing month. If the world is to achieve its climate goals, every viable avenue for carbon emission reductions must be deployed. Carbon capture and storage (CCS) is one avenue that is proven, versatile, affordable and essential.
CCS involves separating carbon dioxide (CO2) from other gases coming out of a power plant or other industrial facility before it is released to the atmosphere, and then permanently storing or using the captured CO2. Most often, the media and policymakers tend to think of CCS in the context of power production. However, acknowledgment is growing that the capture and storage of CO2 emissions from industrial sources is an attractive opportunity for emissions reduction that is often easier and cheaper than capture from power plants.
Industrial sources account for around 25 percent of global CO2 emissions, and those emissions (PDF) are expected to grow by over 50 percent by 2050. The International Energy Agency (IEA) has projected that in order to limit global temperature increase to less than 2 degrees C, almost half (45 percent) of the CO2 captured and stored between 2015 and 2050 would come from industrial sources (PDF).
Actually, much of the progress that has been made on CCS is associated with industrial sources. Of the 22 large-scale CCS facilities in operation or under construction globally (see graphic above), 19 capture CO2 from industrial sources. Most of those include facilities where the CO2 is already separated as part of the production process (natural gas processing and fertilizer production) and is relatively inexpensive to capture. Nineteen industrial facilities have a CO2 capture capacity of about 35 million tonnes per year.
Fossil fuel use is an essential element of the production process in a number of industries, including iron and steel, cement, and chemical production. However, unlike power generation, it is not feasible to substitute renewable energy sources for fossil fuels in these production processes in order to reduce CO2 emissions. In addition, for a number of industrial activities, CO2 emissions do not come from burning fossil fuels, but rather are an unavoidable byproduct of a chemical process used to generate a specific product such as cement. In these cases, CCS is the only large-scale technology available that can provide deep reductions in CO2 emissions.
While industrial sources represent a significant percentage of global CO2 emissions, challenges are associated with the widespread deployment of capture technologies. Much of the governmental and public attention on reducing CO2 emissions has focused on the power sector, reducing the sense of urgency for the development of cost-effective approaches in industrial sectors. In addition, the products of the industrial sector often compete in a global market with tight profit margins, making manufacturers sensitive to changes in production costs. Finally, emissions are scattered over many industries with widely divergent characteristics.
The concentration of CO2 associated with industrial process gases varies significantly across industries. For example, nearly pure CO2 streams are generated in bioethanol and fertilizer production, whereas CO2 concentrations associated with cement production and blast furnace steel manufacture are similar to those found in coal-fired power production (less than 20 percent). Consequently, the energy (and cost) required to separate CO2 also varies, increasing rapidly as the concentration of CO2 decreases.
Industrial capture applications can be segregated into three basic categories:
- Processes in which separation of CO2 is an inherent component of normal business operations (natural gas processing, bio-ethanol production, ammonia/fertilizer production).
- Processes in which CO2 is present at high concentrations, allowing relatively inexpensive separation (hydrogen production in oil refining applications and direct reduced iron steel production).
- Processes that generate a large amount of CO2, but for which capture costs are high, and no current requirements or incentives for carbon reductions exist (blast furnace iron and steel production, cement production, petroleum refining, and pulp and paper production).
For the first two categories, CO2 capture is relatively mature, and many commercial technologies have been proven at scale. For the latter category, CO2 capture is more challenging. Lower concentrations of CO2 in the gas streams of these sectors necessitate the use of capture approaches that are more energy intensive and thus more expensive. (More details about the various options can be found in the table below.)
Ongoing research and development activity is targeting capture cost reductions, especially for low-concentration gas streams.
Large-scale integrated projects are clustered in sectors with high-concentration gas streams, whereas for sectors with low-concentration gas streams capture activity is focused on pilot and laboratory/bench scale development.
The high CO2 concentration industrial sectors represent low-hanging fruit in the widespread deployment of CCS, and achievement of emissions reduction goals. Costs are relatively low, and emissions are significant. By targeting these high CO2 concentration facilities, progress can be made in ensuring that the industrial sector is a robust and sustainable component of a low-carbon global economy.
The original article appeared in Green Biz on May 25 2017. To read the original article, please visit Green Biz website here.