Insights

The future of carbon capture will focus on cost reduction

Organisation: Global CCS Institute

The Global CCS Institute publishes a yearly review covering the latest developments of the CCS industry. In the Global Status of CCS: 2014 report the Institute highlights progress made in bringing CCS to market, most notably with the inauguration of the world's first coal-fired power plant with CCS at Boundary Dam in Saskatchewan, Canada. In this Insight, the Institute's Principal Manager for Carbon Capture, Ron Munson, discusses the significance of this development and some of the research priorities that will bring down the capital and operating cost of future CCS processes.

There has been significant progress in large-scale carbon capture operations this past year – especially in the power sector. SaskPower’s Boundary Dam Carbon Capture and Sequestration Demonstration Project, which began capture operations in October, is the world’s first commercial-scale power plant with a fully integrated carbon capture system. Similarly, operations are anticipated to begin at the Kemper County Energy Facility in Mississippi in 2016. Construction has begun on the Petra Nova power plant capture system in Texas and progress continues on several other efforts worldwide. The lessons learned from these early demonstration efforts will provide valuable information for decreasing the cost of design, construction, and operation of future carbon capture facilities. In fact, SaskPower has stated that a capital cost reduction of up to 30% is readily achievable if a project similar to their Boundary Dam effort is undertaken in the future.

As we look to the future of carbon capture technology, it is clear that there needs to be a focus on research and development (R&D) to drive down costs. Three main areas will be targeted: materials, processes, and equipment.

Materials

R&D related to materials will involve the development of higher-performance solvents, sorbents and membranes. For solvents and sorbents, that could mean materials with enhanced separation kinetics. Faster reactions allow for shorter residence times and smaller reaction vessels. Smaller vessels correspond to lower capital costs. In addition, solvents and sorbents that require less energy to strip separated CO2 would result in lower parasitic energy losses and thus decreased costs. For membranes, materials with enhanced permeability and selectivity would have similar impacts on both capital and operating costs.

Processes

Process improvements can also lead to reductions in both capital and operating costs. Heat integration can lead to efficiency improvements in both the capture system and the associated power plant or manufacturing facility (eg boiler feedwater pre-heating). Process intensification involves coupling two or more processes or systems within a single vessel. This can take the form of a hybrid process, such as one that includes both a solvent and a membrane contactor. Another form of process intensification is the combination of CO2 separation and syngas shift in a water gas shift reactor of an integrated gasification combined cycle system. Combining multiple processes into a single reactor reduces capital costs and depending on the process, can also reduce energy requirements.

Equipment

Development activity surrounding equipment for carbon capture is focused on novel designs that allow for size reduction and energy efficient processing. These designs may include features that enhance contacting between the capture medium and flue gases, effectively increasing mass transfer and decreasing the size of sorption equipment. Advanced manufacturing techniques are under development that promote the construction of heat transfer surfaces that are more efficient and allow for greater process integration. Finally, novel equipment designs that take advantage of technologies not previously pursued for gas separation (e.g. rapid expansion of high pressure gases facilitating cryogenic separation) are being investigated. This approach would result in very significant size, and thus capital cost, reduction.

Priorities for the Next Generation of Capture Technologies

Several technologies employing the principles described above are currently under development. Bench-scale efforts have been completed for a variety of second generation technologies, and small pilot-scale (~1 MWe) testing is underway for a limited number of promising approaches. Mike Matuszewski, the Technology Manager for the U.S. Department of Energy’s (DOE) Carbon Capture R&D Program, has stated that the program’s top priority over the next several years is to advance additional second generation technologies through the small and large (~5 – 25 MWe) pilot-scales to be ready for demonstration-scale testing in the 2020 – 2025 time frame. This is a critical step in advancing more cost-effective capture technologies and readying them for widespread future deployment. One of the key elements in advancing these technologies is collaboration between researchers, technology developers, and technology users to facilitate integration of individual technological developments into cost-effective capture systems. This will be the most effective pathway to meeting DOE capture goals of $40/tonne CO2 captured for second generation technologies.

The potential to reduce the cost of carbon capture is significant. R&D to support cost reductions is on-going and effective. However, in order to realise cost reductions at industrial scale, pilot testing of the most promising technologies is critical. Continued funding and support of these development efforts by both government and industry is essential to advance these technologies and move us forward toward achieving GHG mitigation goals.