Assessment of the CO2 capture potential from irreplaceable industrial sources

The industrial sector represents approximately 20% of total US CO2 emissions.1 These emissions can be further categorized as direct (accountable on-site, e.g., stationary combustion), indirect (assigned to electricity purchased for power) and process (CO2 liberated as a reaction by-product). For example, steel and cement production both involve processes that directly emit CO2 as a by-product (via the oxidation of metallurgical coke and conversion of calcium carbonate to lime, respectively). While climate change mitigation efforts have the potential to reduce direct and indirect emissions through the adoption of best practice technologies and low-carbon energy sources, process emissions will remain largely unaffected in the absence of radical advances in engineering. As materials like glass, iron, cement and ammonia constitute the irreplaceable fabric of society and have few green analogs, CO2 emissions from these, as from other irreplaceable industrial processes, are projected to increase unabated. With capture technologies in place, these emissions can be diverted instead to viable CO2 reuse and sequestration opportunities, such as enhanced oil recovery (EOR), food processing, refrigeration, and fertilizer production.2 To assess the capture potential of irreplaceable industry, we first geo-reference these sources alongside all current and potential future CO2 sinks, with the goal of making economically sound linkages between source and markets of comparable scale.3 This entails a cost analysis of on-site capture plus additional transport (freight versus pipeline, hazmat fees, etc.) and compression costs. Geographic information systems (GIS) mapping is used to define the most cost-effective mechanisms for CO2 delivery. Further, additional sources of revenue offset (CO2 waste valorization and potential allowance trading) are incorporated to develop a more complete assessment of economic viability. As these costs are inventoried, the financial incentive gap necessary to compel the targeted source-sink pairings to move forward is calculated. Capture costs fell under a wide range, from $89 per tonne to a low of approximately $28 per tonne. Using $40 per tonne CO2 resale as a reference, our results indicate that the most viable industries for installing CO2 capture technologies are ammonia, ethanol, glass, and petrochemicals. Not surprisingly, many of these industries all ready take advantage of these low CO2 capture costs and consequently represent a large portion of the US merchant CO2 market. When revenue from CO2 resale is incorporated, larger contributors to the industrial emission profile like cement and iron and steel fall under the viability threshold. Finally, incentive based policy (like the current California cap and trade program) pushes even more industries toward carbon neutrality and some cases (ammonia, iron and steel, and petrochemicals) become carbon-negative. It should be emphasized that this analysis is a “lowest-hanging fruit” assessment, whereby lowest possible costs are reported based on plant character (CO2 purity) and source-sink transport logistics. An overall assessment by industry is less optimistic and reveals that those industries with prohibitive capture costs are not substantially aided by waste revenue and policy offsets; thus, the most important variable to reducing economic barriers to capture is the relative purity of CO2. This effort will develop a current economic assessment of moving irreplaceable industry toward carbon-neutrality. Though these industrial process emissions represent a smaller portion of total annual CO2 emissions, these opportunities may serve as a driver for learning and public acceptance, with future applicability to the assessment of carbon-neutrality in other sectors