Sean T. McCoy

Life cycle inventory of CO2 in an enhanced oil recovery system.

Enhanced oil recovery (EOR) has been identified as a method of sequestering CO(2) recovered from power plants. In CO(2)-flood EOR, CO(2) is injected into an oil reservoir to reduce oil viscosity, reduce interfacial tension, and cause oil swelling which improves oil recovery. Previous studies suggest that substantial amounts of CO(2) from power plants could be sequestered in EOR projects, thus reducing the amount of CO(2) emitted into the atmosphere. This claim, however, ignores the fact that oil, a carbon rich fuel, is produced and 93% of the carbon in petroleum is refined into combustible products ultimately emitted into the atmosphere. In this study we analyze the net life cycle CO(2)emissions in an EOR system. This study assesses the overall life cycle emissions associated with sequestration via CO(2)-flood EOR under a number of different scenarios and explores the impact of various methods for allocating CO(2) system emissions and the benefits of sequestration.

Implications of compensating property owners for geologic sequestration of CO2.

Geologic sequestration (GS) of carbon dioxide (CO2) is contingent upon securing the legal right to use deep subsurface pore space. Under the assumption that compensation might be required to use pore space for GS, we examine the cost of acquiring the rights to sequester 160-million metric tons of CO2 (the 30-year emissions output for an 800 megawatt power plant operating with a 60% capacity factor and at 90% capture efficiency) using a probabilistic model to simulate the temporal-spatial distribution of subsurface CO2 plumes in several brine-filled sandstones in Pennsylvania and Ohio. For comparison, the Frio Sandstone in the Texas Gulf Coast and the Mt. Simon Sandstone in Illinois were also analyzed. The predicted median values of CO2 plume footprints range from 4500 km(2) to 11,000 km(2) for the Ohio and Pennsylvania sandstones compared to 320 km(2) and 300 km(2) for the thicker Frio and Mt. Simon Sandstones, respectively. We use these footprints to bound the cost to use pore space in Pennsylvania and Ohio and, alternatively, the cost of piping CO2 from Pennsylvania and Ohio to the Mt. Simon or Frio Sandstones for sequestration. The results suggest that pore space acquisition costs could be significant and that using thin local formations for sequestration may be more expensive than piping CO2 to thicker formations at distant sites.

Spatial stochastic modeling of sedimentary formations to assess CO2 storage potential.

Carbon capture and sequestration (CCS) is a technology that provides a near-term solution to reduce anthropogenic CO2 emissions to the atmosphere and reduce our impact on the climate system. Assessments of carbon sequestration resources that have been made for North America using existing methodologies likely underestimate uncertainty and variability in the reservoir parameters. This paper describes a geostatistical model developed to estimate the CO2 storage resource in sedimentary formations. The proposed stochastic model accounts for the spatial distribution of reservoir properties and is implemented in a case study of the Oriskany Formation of the Appalachian sedimentary basin. Results indicate that the CO2 storage resource for the Pennsylvania part of the Oriskany Formation has substantial spatial variation due to heterogeneity of formation properties and basin geology leading to significant uncertainty in the storage assessment. The Oriskany Formation sequestration resource estimate in Pennsylvania calculated with the effective efficiency factor, E=5%, ranges from 0.15 to 1.01 gigatonnes (Gt) with a mean value of 0.52 Gt of CO2 (E=5%). The methodology is generalizable to other sedimentary formations in which site-specific trend analyses and statistical models are developed to estimate the CO2 sequestration storage capacity and its uncertainty. More precise CO2 storage resource estimates will provide better recommendations for government and industry leaders and inform their decisions on which greenhouse gas mitigation measures are best fit for their regions.

Implications of Ammonia Emissions from Post-Combustion Carbon Capture for Airborne Particulate Matter

Amine scrubbing, a mature post-combustion carbon capture and storage (CCS) technology, could increase ambient concentrations of fine particulate matter (PM2.5) due to its ammonia emissions. To capture 2.0 Gt CO2/year, for example, it could emit 32 Gg NH3/year in the United States given current design targets or 15 times higher (480 Gg NH3/year) at rates typical of current pilot plants. Employing a chemical transport model, we found that the latter emission rate would cause an increase of 2.0 μg PM2.5/m(3) in nonattainment areas during wintertime, which would be troublesome for PM2.5-burdened areas, and much lower increases during other seasons. Wintertime PM2.5 increases in nonattainment areas were fairly linear at a rate of 3.4 μg PM2.5/m(3) per 1 Tg NH3, allowing these results to be applied to other CCS emissions scenarios. The PM2.5 impacts are modestly uncertain (±20%) depending on future emissions of SO2, NOx, and NH3. The public health costs of CCS NH3 emissions were valued at

Near-term deployment of carbon capture and sequestration from biorefineries in the United States

31-68 per tonne CO2 captured, comparable to the social cost of carbon itself. Because the costs of solvent loss to CCS operators are lower than the social costs of CCS ammonia, there is a regulatory interest to limit ammonia emissions from CCS.

An engineering-economic model of pipeline transport of CO2 with application to carbon capture and storage

Significance Carbon dioxide removal through the permanent sequestration of biogenic CO2 is a critical technique for climate change mitigation, but most bioenergy with carbon capture and sequestration (CCS) technologies are technically immature or commercially unavailable. In contrast, examples of CCS of biogenic CO2 resulting from fermentation emissions already exist at scale. Here, we evaluate low-cost, commercially ready sequestration opportunities for existing biorefineries in the United States. We find that existing and proposed financial incentives suggest a substantial near-term opportunity to catalyze the growth of CCS infrastructure, improve the impacts of conventional biofuels, support development of carbon-negative biofuels, and satisfy low-carbon fuel policies. Capture and permanent geologic sequestration of biogenic CO2 emissions may provide critical flexibility in ambitious climate change mitigation. However, most bioenergy with carbon capture and sequestration (BECCS) technologies are technically immature or commercially unavailable. Here, we evaluate low-cost, commercially ready CO2 capture opportunities for existing ethanol biorefineries in the United States. The analysis combines process engineering, spatial optimization, and lifecycle assessment to consider the technical, economic, and institutional feasibility of near-term carbon capture and sequestration (CCS). Our modeling framework evaluates least cost source–sink relationships and aggregation opportunities for pipeline transport, which can cost-effectively transport small CO2 volumes to suitable sequestration sites; 216 existing US biorefineries emit 45 Mt CO2 annually from fermentation, of which 60% could be captured and compressed for pipeline transport for under

The Economics of CO2 Transport by Pipeline and Storage in Saline Aquifers and Oil Reservoirs

25/tCO2. A sequestration credit, analogous to existing CCS tax credits, of

Variability and Uncertainty in the Cost of Saline Formation Storage

60/tCO2 could incent 30 Mt of sequestration and 6,900 km of pipeline infrastructure across the United States. Similarly, a carbon abatement credit, analogous to existing tradeable CO2 credits, of

Regulating the geological sequestration of CO2.

90/tCO2 can incent 38 Mt of abatement. Aggregation of CO2 sources enables cost-effective long-distance pipeline transport to distant sequestration sites. Financial incentives under the low-carbon fuel standard in California and recent revisions to existing federal tax credits suggest a substantial near-term opportunity to permanently sequester biogenic CO2. This financial opportunity could catalyze the growth of carbon capture, transport, and sequestration; improve the lifecycle impacts of conventional biofuels; support development of carbon-negative fuels; and help fulfill the mandates of low-carbon fuel policies across the United States.