Assessing Carbon Capture: Public Policy, Science, and Societal Need

Abstract

From typhoons to wildfires, as the visible impacts of climate change mount, calls for mitigation through carbon drawdown are escalating. Environmentalists and many climatologists are urging steps to enhance biological methods of carbon drawdown and sequestration. Market actors seeing avenues for profit have launched ventures in mechanical–chemical carbon dioxide removal (CDR), seeking government support for their methods. Governments are responding. Given the strong, if often unremarked, momentum of demands for public subsidy of these commercial methods, on what cogent bases can elected leaders make decisions that, first and foremost, meet societal needs? To address this question, we reviewed the scientific and technical literature on CDR, focusing on two methods that have gained most legislative traction: point-source capture and direct air capture–which together we term “industrial carbon removal” (ICR), in contrast to biological methods. We anchored our review in a standard of “collective biophysical need,” which we define as a reduction of the level of atmospheric CO2. For each ICR method, we sought to determine (1) whether it sequesters more CO2 than it emits; (2) its resource usage at scale; and (3) its biophysical impacts. We found that the commercial ICR (C-ICR) methods being incentivized by governments are net CO2 additive: CO2 emissions exceed removals. Further, the literature inadequately addresses the resource usage and biophysical impacts of these methods at climate-significant scale. We concluded that dedicated storage, not sale, of captured CO2 is the only assured way to achieve a reduction of atmospheric CO2. Governments should therefore approach atmospheric carbon reduction as a public service, like water treatment or waste disposal. We offer policy recommendations along this line and call for an analysis tool that aids legislators in applying biophysical considerations to policy choices.

How green is blue hydrogen?

“…In fact, there is no experience at commercial scale with storing carbon dioxide from carbon capture, and most carbon dioxide that is currently captured is used for enhanced oil recovery and is released back to the atmosphere. 44 Further, our analysis does not consider the energy cost and associated greenhouse gas emissions from transporting and storing the captured carbon dioxide. Even without these considerations, though, blue hydrogen has large climatic consequences.…”

Low-cost temperature transition mixtures (TTM) based on ethylene glycol/potassium hydroxide as reversible CO2 sorbents

“…[4][5][6][7] It must be said that all the long-term strategies has still serious drawbacks and, in many cases, considering the entire cycle (including transportation of the absorbed CO2 and its regeneration, among the other factors), current CCUS strategies sequester less CO2 than that they emit it. [8] Anyway, this does not mean that we do not need CCUS strategies, but only that we need better strategies than the existing ones, with optimal capacity, selectivity, recyclability, stability and cost. [9] Generally speaking, the most mature CC technologies take advantage of two chemical reactions, by using aqueous monoethanolamine (MEA) solutions or aqueous alkaline hydroxides and carbonates as sorbents (Scheme 1).…”

Current Developments of Carbon Capture Storage and/or Utilization–Looking for Net-Zero Emissions Defined in the Paris Agreement

“…Figure 2 shows the CO 2 life-cycle considering two pathways: carbon capture and storage (CCS) and carbon capture and utilization (CCU). [12] and Bui et al [13]).…”

“…Figure 2. Analysis of life-cycle of CO 2 with capture and storage, and capture and utilization from main sources pathways (based on Sekera and Lichtenberger[12] and Bui et al[13]). …”