Deep CCS: Moving Beyond 90% Carbon Dioxide Capture

Abstract

The large-scale deployment of carbon capture technologies is expected to play a crucial role in efforts to meet stringent climate targets set forth by the Paris Agreement, but current models rely heavily upon carbon dioxide removal (CDR) strategies for which viability at the gigatonne scale is uncertain. While most 1.5 and 2 °C scenarios project rapid decarbonization of the energy sector facilitated by carbon capture and sequestration (CCS), they generally assume that CCS units can only capture ∼90% of the CO 2 in coal and natural gas combustion flues because this was previously considered the optimal condition for aqueous amine scrubbers. In this Perspective, we discuss a small but growing body of literature that examines the prospect of moving significantly beyond 90% capturea concept we term deep CCS in light of recent developments in materials and process design. The low incremental costs associated with performing varying degrees of deep CCS suggest that this approach is not only feasible but may also alleviate burdens placed upon CDR techniques facing significant barriers to large-scale deployment. We estimate that rapid deployment of deep CCS in deep decarbonization pathways could avoid more than 1 gigatonne of CO 2 globally each year. The principles of deep CCS could also be applied directly to the CDR strategy of employing bioenergy with CCS, which could lead to a significant alleviation of the land and freshwater burden associated with this technology.

A Pathway Towards Net-Zero Emissions in Oil Refineries

“…The net-zero paradigm entails balancing any residual CO 2 emissions with an equivalent amount of permanent CO 2 removal from the atmosphere. Because of large uncertainties in the cost of technologies such as direct air capture (DAC) (Dods et al, 2021), a recent focus in CCS development has been to achieve CO 2 capture rates well above 90% (Feron et al, 2019;Gao et al, 2019;Hirata et al, 2020;Brandl et al, 2021;Danaci et al, 2021). But regardless of the ability to achieve high capture rates, upwards of 30% of a refinery's emissions may remain unaddressed by post-combustion CCS alone.…”

Direct air capture: process technology, techno-economic and socio-political challenges

“…Higher than 90% capture rates can be economical and are technically possible using existing separation processes. [156][157][158] Such an approach could reduce the burden on NETs, like DAC, that are currently proposed to deal with residual emissions.…”

Understanding the complexity of existing fossil fuel power plant decarbonization

“…Deep CCS beyond 90% CO 2 capture could be another technology option for the ''last-mile'' problem in decarbonization. In certain situations, it provides a lower marginal decarbonization cost than direct air capture ll OPEN ACCESS (DAC) (Dods et al, 2021). Coupling biomass with CCS, known as BECCS, is a negative emission technology (NET), which is included in many mitigation pathways.…”