Future Research Directions in Carbon Dioxide Removal

Calls for more research into carbon dioxide removal (CDR) technologies and carbon capture applications are coming from many quarters (Amann and Hartmann, 2019; Landau, 2018; Nekuda, 2019; Bipartisan Policy Center report, 2019; Budinis et al, 2016). We need to build on the National Academies of Sciences, Engineering, and Medicine report that recommended financial support for a detailed portfolio of NETs R&D totaling $1 billion annually (NAS, 2019) and the 10-year, $10.7 billion R&D commercial readiness innovation program from the think tank Energy Futures Initiative (Bipartisan Policy Center, 2019).

We need quantitative approaches that will help us to further refine research priorities. Future research would benefit from metrics that assess the critical dimensions of viability, scalability, and cost. Improved rigor will contribute to the robusticity of conclusions. We also need more research to vet promising new directions. Most importantly we need to refine a portfolio approach that hones our understanding of how differing CDR technologies work together. We need reliable estimates of negative emission potentials, we also need to evaluate their common effects on global carbon pools while minimizing negative side effects (Amann and Hartmann, 2019). This involves research that will help us to strategically place these technologies both conceptually and geographically to maximize CDR capacities. To increase the efficacy of co-deployment we need a better understanding of how these technologies interact and compete. We specifically need to determine how to deploy those CDR technologies which use the same environmental compartment. We need a better understanding of co-deployment combinations that maximize CO2 uptake potential. We need to optimize mitigation strategies by developing theoretical frameworks that consider the interactions between technologies, society, and political power. We also need to pay special attention to the effects on food production, ecosystems, and the full slate of SDGs.

The potential of microalgae to sequester carbon warrants more research. Based on the research of Singh and Dhar, (2019), we should explore the prospects of successful commercial deployment may through unsophisticated innovations that reduce costs through an integrated biorefinery set-up wherein every valuable component is extracted, processed, and valorized. Research involving bioprospecting suitable microalgae and genetically engineered microalgae may also deliver results. Although microalgae have massive water requirements further research into lower-cost biofilm-based attached cultivation could yield a less energy-intensive and more easily scaled approach (Kesaano and Sims, 2014; Wang et al., 2017). Attached culture can also simplify harvesting (Wang et al., 2017). Other research microalgae research directions may include flocculation as a low-cost alternative to the more expensive centrifugation (Singh and Dhar, 2019) and specifically efforts to overcome the toxicity of cationic chemical flocculants and polymeric flocculants (Ryan, 2009; Zhou et al., 2012).

Although enhanced weathering seems to be an ideal method of sequestering CO2, more field testing is required as there is still much that we do not know and many variables to consider. The Global Roadmap Study of CO2U Technologies (2016, Lux Research), calls for research to improve catalysis for CO2 reduction and to improve electrolysis to produce H2. Future research should also focus on methods of optimizing the CO2 conversion rate, minimizing the energy consumption of CDR technologies and pairing such technologies with renewable sources of energy.

Examining CDR technologies from the perspective of Life Cycle Assessment (LCA) may prove beneficial (Goglio et al. 2019; Realmonte et al, 2019). LCA is a cradle-to-grave or cradle-to-cradle analysis technique to assess environmental impacts associated with all the stages of a product’s life. All these research efforts would benefit from greater collaborations between research institutes, start-ups, governments and corporations.

While it is important to improve these technologies and reduce their costs, the real issue preventing the deployment of CDR is the absence of public awareness and political will. So, in addition to technical and economic considerations, we need to develop a better understanding of the social and political conditions that will make it possible to scale CDR. This means we need to increase research into social tipping points (STP) and social tipping interventions (STI). To help scale CDR technologies we also need to provide governments with policy instruments, regulatory frameworks and configure financial incentives like carbon pricing.

For references go to CDR Resources. See also Glossary of Terminology Related to CDR.

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