Insight: Carbon Capture and Sequestration Face an Uphill BattleShawn Martin | February 07, 2017
Carbon capture and sequestration (CCS) technology seeks to impact and reduce atmospheric emission of greenhouse gases (GHGs).
Studies by the Society of Petroleum Engineers (SPE) showcase its ability to capture and sequester large volumes of carbon dioxide (CO2) citing field studies by Shell Canada's Quest project where engineers were able to capture and store over one million tonnes of CO2 in its first year in operation. Despite recent progress, large-scale deployment of CCS has several obstacles to overcome and is yet to have a significant impact on emissions of GHGs.
Challenges facing wide-spread adaptation of CCS include economics, storage capacity, and pipeline capacity. These roadblocks throw into question the viability of CCS and its role in climate mitigation.
Economics of CCS implementation are questionable. CCS is likely to have its largest impact by being adopted into electrical power generation sites. The EPA estimates that 2 gigatonnes of atmospheric CO2 emissions originate from fossil fueled electric power generation. They are a central source of CO2 that could play a large role in CCS. However, fitting a CCS system to a gas-fired power plant can increase the cost of electricity by as much as 50%.
The reason for such a large overhead when fitting CCS systems to electrical power generation sites is that their respective flue gas streams are already depleted in CO2 concentrations. They exhaust a high volume, low concentration gas stream that can only by handled by a significantly scaled up CCS system. The systems' large footprint restricts airflow lowering operational efficiency, poses space constraints, and requires significant power to compress the captured gas.
Advocates for CCS have found that these increased costs remain competitive with alternative electrical power generation sources such as wind or solar and that the cost of achieving aggressive goals to reduce CO2 emissions remains unfeasible without a large-scale deployment of CCS.
Models that combat the pitfalls of alternative zero-emission energy sources against fossil fuel power generation sites equipped with CCS find a competitive advantage where the expected reduction in capital costs in second-generation facilities will be economically favorable when compared to excessive deployment of higher efficiency solar cells and energy storage devices that would have an equal impact on atmospheric CO2 concentrations.
In event that CCS can find an economical feasible means of mitigating GHGs there still remains transport issues which will require substantial infrastructure investments. The amount of CO2 to be sequestered is astronomical and greatly exceeds current pipeline capacity, even in the most developed countries.
In the U.S. there exists a combined length of over 4,500 miles of CO2 pipelines compared to an approximate 300,000 miles of transmission lines that accommodates natural gas. The movement would require scaling of pipeline and compression capacity that would mirror the current infrastructure that supports the natural gas industry.
Implementation of large-scale CCS requires substantial upstream investments and produces an end product that far exceeds its economic value. Economics, investments, and infrastructure aside storage capacity is limited and developing a market for the sequestered CO2 requires innovation.
A plausible solution presented by SPE is to integrate sequestered CO2 into enhanced oil recovery methods as well as develop injection wells to handle excess volumes. Completions methods would need to abandon slick-water, a tried and proven fracturing technique, to a certain degree and predominantly use energized fluid treatments, pressurized gases.
The availability of low cost CO2 favors such developments and some formation damages indigenous to water fracturing, including clay swelling may be avoided, but lacking bench-mark data and proven results implementation in any given formation would be approached with hesitation.
CCS is a solution that impacts the global carbon budget by stripping GHGs from exhaust streams, albeit the scale to which it is deployed remains inadequate and its future uncertain. CCS hinges on investments that require long lead-times even as atmospheric concentrations of CO2 continue to rise. A record annual increase of 3.05ppm/yr was observed 2015 by the U.S. National Oceanic and Atmospheric Administration, and the movement towards large-scale CCS development is caught in an uphill battle.