Gordon N. Keating

Greening Coal: Breakthroughs and Challenges in Carbon Capture and Storage

Like it or not, coal is here to stay, for the next few decades at least. Continued use of coal in this age of growing greenhouse gas controls will require removing carbon dioxide from the coal waste stream. We already remove toxicants such as sulfur dioxide and mercury, and the removal of CO₂ is the next step in reducing the environmental impacts of using coal as an energy source (i.e., greening coal). This paper outlines some of the complexities encountered in capturing CO₂ from coal, transporting it large distances through pipelines, and storing it safely underground.

The cross-scale science of CO2 capture and storage: from pore scale to regional scale

We describe state-of-the-art science and technology related to modeling of CO2 capture and storage (CCS) at four different process scales: pore, reservoir, site, and region scale. We present novel research at each scale to demonstrate why each scale is important for a comprehensive understanding of CCS. Further, we illustrate research linking adjacent process scales, such that critical information is passed from one process scale to the next adjacent scale. We demonstrate this cross-scale approach using real world CO2 capture and storage data, including a scenario managing CO2 emissions from a large U.S. electric utility. At the pore scale, we present a new method for incorporating pore-scale surface tension effects into a relative permeability model of CO2-brine multiphase flow at the reservoir scale. We benchmark a reduced complexity model for site-scale analysis against a rigorous physics-based reservoir simulator, and include new system level considerations including local site-scale pipeline routing analysis (i.e., reservoir to site scale). We also include costs associated with brine production and treatment at the site scale, a significant issue often overlooked in CCS studies. All models that comprise our total system include parameter uncertainty which leads to results that have ranges of probability. Results suggest that research at one scale is able to inform models at adjacent process scales, and that these scale connections can inform policy makers and utility managers of overall system behavior including the impacts of uncertainty.

Mesoscale Carbon Sequestration Site Screening and CCS Infrastructure Analysis

We explore carbon capture and sequestration (CCS) at the meso-scale, a level of study between regional carbon accounting and highly detailed reservoir models for individual sites. We develop an approach to CO(2) sequestration site screening for industries or energy development policies that involves identification of appropriate sequestration basin, analysis of geologic formations, definition of surface sites, design of infrastructure, and analysis of CO(2) transport and storage costs. Our case study involves carbon management for potential oil shale development in the Piceance-Uinta Basin, CO and UT. This study uses new capabilities of the CO(2)-PENS model for site screening, including reservoir capacity, injectivity, and cost calculations for simple reservoirs at multiple sites. We couple this with a model of optimized source-sink-network infrastructure (SimCCS) to design pipeline networks and minimize CCS cost for a given industry or region. The CLEAR(uff) dynamical assessment model calculates the CO(2) source term for various oil production levels. Nine sites in a 13,300 km(2) area have the capacity to store 6.5 GtCO(2), corresponding to shale-oil production of 1.3 Mbbl/day for 50 years (about 1/4 of U.S. crude oil production). Our results highlight the complex, nonlinear relationship between the spatial deployment of CCS infrastructure and the oil-shale production rate.

Effects of shallow basaltic intrusion into pyroclastic deposits, Grants Ridge, New Mexico, USA

Abstract A localized aureole up to 10 m wide developed around a 150-m-wide, 2.6 Ma basaltic plug at Grants Ridge, New Mexico. The plug intruded into nonwelded, pumice-rich compositionally homogenous tuff and volcaniclastic sediments of similar age (3.3 Ma). Color variation (pinkish to orange), strong local contact welding, brecciation, partial melting, and stoping characterize the host rock within the contact zone. Despite the high-temperature basaltic intrusion, there is no indication of extensive fluid-driven convective heat transfer and pervasive hydrothermal circulation and alteration of the country rock. The proportion of volcanic glass, loss on ignition (LOI), fluorine, iron, and some trace and rare earth element contents in the host rocks are somewhat depleted at the contact of the intrusion. Conversely, the degree of devitrification and the potassium content are higher along the contact. Vapor-phase expulsion of elemental species as complexes of fluoride, chloride, hydroxide, sulfide, and carbon dioxide may have been responsible for the minor depletion of the elements during the devitrification of silicic glass at near-solidus temperature related to the basaltic intrusion. The results of finite-difference numerical modeling of the intrusion as a dry, conduction-dominated system agree well with geochemical and mineralogical data. Contact welding of the host rocks apparently occurred at temperatures >700°C under a density-driven lateral load of approximately 1 MPa, corresponding to the observed depth below the former ground surface of ∼100 m. Other physical changes in the first 10 m of host rock, represented by partial devitrification and color changes, apparently occurred at temperatures of 500–600°C, which probably persisted for up to 55 years after the emplacement of the basaltic plug. Devitrification is generally enhanced by the presence of aqueous fluids; however, the abundance of volcanic glass within a short distance (∼10 m) from the plug is consistent with our inference that the plug intruded into a dry (unsaturated) environment.

Collective intelligence of the artificial life community on its own successes, failures, and future

We describe a novel Internet-based method for building consensus and clarifying conflicts in large stakeholder groups facing complex issues, and we use the method to survey and map the scientific and organizational perspectives of the artificial life community during the Seventh International Conference on Artificial Life (summer 2000). The issues addressed in this survey included artificial lifes main successes, main failures, main open scientific questions, and main strategies for the future, as well as the benefits and pitfalls of creating a professional society for artificial life. By illuminating the artificial life communitys collective perspective on these issues, this survey illustrates the value of such methods of harnessing the collective intelligence of large stakeholder groups.

Multiphase modeling of contact metamorphic systems and application to transitional geomagnetic fields

We present a numerical model that improves our capability to simulate multiphase, non-isothermal flow in variably saturated porous and fractured media at magmatic temperatures and shallow crustal pressures. Simulations of heat and fluid flow in variably saturated host rock near a magmatic intrusion provide insight into contact metamorphic processes, including dryout, condensation, and resaturation effects and implications for host-rock alteration. The numerical code, an enhanced version of FEHM, uses a finite-element/finite-volume technique incorporating implicit Newton–Raphson iteration to solve non-linear conservation equations for mass and energy, using thermodynamic properties of water and air in the ranges 10°C≤T≤1500°C, 0.00123≤P≤1000 MPa and 10°C≤T≤1500°C, 0.00123≤P≤22 MPa, respectively. The study area is located at Paiute Ridge, eastern Nevada Test Site, Nevada, USA, where hypabyssal mafic intrusions were emplaced at about 8.5–8.6 Ma (Ar/Ar age estimate) and cooled contemporaneously with part of a geomagnetic field reversal, inferred from paleomagnetic data from over 100 sites in intrusions and remagnetized host ash-flow tuffs. We used a radial model of heat flow and multiphase pore fluid flow adjacent to a 1200°C intrusion to characterize the thermal evolution of the contact metamorphic system. For likely initial pore saturations of 0.4–0.6, an expanding dryout zone near the intrusion and a condensation zone of enhanced saturation (S≤0.8) extends 150–400 m from the intrusion. Host-rock temperatures reach 800°C near the contact and cool below 100°C within 2000 yr after emplacement, two to four times faster than predicted by a simple conduction model. The thermal history of the system is very sensitive to initial saturation. The multiphase thermal model allows bounds to be placed on the rate of change of the transitional part of the geomagnetic field during the field reversal recorded at Paiute Ridge. We assume that magnetization acquisition took place during the life of the thermal system that developed in the intrusions and contact rocks and that the paleomagnetic data provide a quasi-continuous record of the transitional part of the reversal. Sites in intrusions and thermally annealed ash-flow tuffs reveal subtle yet systematic variations in paleomagnetic directions. We combine the directional data with robust thermal (temperature/time) models to estimate the rate of change of the geomagnetic field. Modeled times of 140–290 yr and 215–440 yr for the duration of magnetization acquisition at two different sites correspond to estimated rates of change of 0.06–0.13°/yr for the field during the transitional part of the reversal.

Proximal stratigraphy and syn-eruptive faulting in rhyolitic Grants Ridge Tuff, New Mexico, USA

Abstract Proximal deposits of the 3.3 Ma Grants Ridge Tuff, part of a 5-km 3 topaz rhyolite sequence, are composed of basal pyroclastic flow, surge, and fallout deposits, a thick central ignimbrite, and upper surge and fallout deposits. Large lithic blocks (≤2 m) of underlying sedimentary and granitic bedrock that are present in lower pyroclastic flow and fallout deposits indicate that the eruptive sequence began with explosive, conduit-excavating eruptions. The massive, nonwelded central ignimbrite displays evidence for postemplacement deformation. The upper pyroclastic surge deposits are dominated by fine ash, some beds containing accretionary lapilli, soft-sediment deformation features, and mud-coated lithic lapilli, indicating an explosive, hydromagmatic component to these later eruptions. The upper fall and surge deposits are overlain by fluvially reworked volcaniclastic deposits that truncate the primary section with a relatively planar surface. The proximal, upper pyroclastic surge and Plinian fall deposits are preserved only in small grabens (5–8 m deep and wide), where they subsided into the ignimbrite and were protected from reworking. The pyroclastic surge and fall deposits within the grabens are offset by numerous small normal faults. The offset on some faults decreases upward through the section, indicating that the faulting process may have been syn-eruptive. Several graben-bounding faults extend downward into the ignimbrite, but the uppermost, fluvially reworked tephra layers are not cut by these faults. The faulting mechanism may have been related to settling and compaction of the 60 m thick, valley-filling ignimbrite along the axis of the paleovalley. Draping surge contacts against the graben faults and brittle and soft-style disruption of the upper pyroclastic surge beds indicate that subsidence was ongoing during the emplacement of the upper eruptive sequence. Seismicity accompanying the late-stage hydromagmatic explosions may have contributed to the abrupt settling and compaction of the ignimbrite.

Metrics of Success for Enterprise Geographic Information Systems (EGIS)

ABSTRACT An enterprise geographic information system (EGIS) addresses the institutional challenge of providing common infrastructure to share geospatial data and associated services. We propose a comprehensive definition and conceptual framework for EGIS, and we apply this framework to analyze and assess the success of a prototype EGIS implementation. We define EGIS as institutional GIS capability with three attributes: (1) integrated components (common infrastructure); (2) services (shared data, analysis, modeling, and visualization capabilities); and (3) institutional management (administration and leadership). Further distillation yields nine specific implementation requirements: (1) common networked infrastructure; (2) high reliability and availability; (3) spatial data warehouse; (4) documentation of data and services; (5) coordination of dataflow and workflow; (6) coordination of personnel roles and responsibilities; (7) formalized management; (8) institutional financing; and (9) institutional leadership. We tested the hypothesis that a project-based GIS could be used as a prototype EGIS for a large institution. Evaluation of the Cerro Grande Rehabilitation Project GIS (CGRP-GIS), study system, yielded a comprehensive taxonomy of direct metrics (e.g., server downtime) and indirect metrics (e.g., increases in productivity) for evaluating EGIS. Some elements of the CGRP-GIS did not scale well to EGIS (e.g., management, financing, and leadership), since projects allocate resources primarily to achieve project goals, whereas EGIS allocates resources to long-term infrastructure. An EGIS, constructed on a solid conceptual framework, holds tremendous potential to advance sharing of geospatial data and associated services; to better allocate institutional and project resources; and to aid in problem solving, communication, and decision making.