Environmental Externalities of Geological Carbon Sequestration Effects on Energy Scenarios

Geological carbon sequestration seems one of the promising options to address, in the near term, the global problem of climate change, since carbon sequestration technologies are in principle available today and their costs are expected to be affordable. Whereas extensive technological and economic feasibility studies rightly point out the large potential of this ‘clean fossil fuel’ option, relatively little attention has been paid so far to the detrimental environmental externalities that the sequestering of CO2 underground could entail. This paper assesses what the relevance might be of including these external effects in long-term energy planning and scenario analyses. Our main conclusion is that, while these effects are generally likely to be relatively small, carbon sequestration externalities do matter and influence the nature of future world energy supply and consumption. More importantly, since geological carbon storage (depending on the method employed) may in some cases have substantial external impacts, in terms of both environmental damage and health risks, it is recommended that extensive studies are performed to quantify these effects. This article addresses three main questions: (i) What may energy supply look like if one accounts for large-scale CO2 sequestration in the construction of long-term energy and climate change scenarios; (ii) Suppose one hypothesizes a quantification of the external environmental costs of CO2 sequestration, how do then these supposed costs affect the evolution of the energy system during the 21st century; (iii) Does it matter for these scenarios whether carbon sequestration damage costs are charged directly to consumers or, instead, to electricity producers?Geological carbon storage, External costs, Energy scenarios

Thermal effects on geologic carbon storage

The final publication is available at Springer via http://dx.doi.org/10.1016/j.earscirev.2016.12.011One of the most promising ways to significantly reduce greenhouse gases emissions, while carbon-free energy sources are developed, is Carbon Capture and Storage (CCS). Non-isothermal effects play a major role in all stages of CCS. In this paper, we review the literature on thermal effects related to CCS, which is receiving an increasing interest as a result of the awareness that the comprehension of non-isothermal processes is crucial for a successful deployment of CCS projects. We start by reviewing CO2 transport, which connects the regions where CO2 is captured with suitable geostorage sites. The optimal conditions for CO2 transport, both onshore (through pipelines) and offshore (through pipelines or ships), are such that CO2 stays in liquid state. To minimize costs, CO2 should ideally be injected at the wellhead in similar pressure and temperature conditions as it is delivered by transport. To optimize the injection conditions, coupled wellbore and reservoir simulators that solve the strongly non-linear problem of CO2 pressure, temperature and density within the wellbore and non-isothermal two-phase flow within the storage formation have been developed. CO2 in its way down the injection well heats up due to compression and friction at a lower rate than the geothermal gradient, and thus, reaches the storage formation at a lower temperature than that of the rock. Inside the storage formation, CO2 injection induces temperature changes due to the advection of the cool injected CO2, the Joule-Thomson cooling effect, endothermic water vaporization and exothermic CO2 dissolution. These thermal effects lead to thermo-hydro-mechanical-chemical coupled processes with non-trivial interpretations. These coupled processes also play a relevant role in “Utilization” options that may provide an added value to the injected CO2, such as Enhanced Oil Recovery (EOR), Enhanced Coal Bed Methane (ECBM) and geothermal energy extraction combined with CO2 storage. If the injected CO2 leaks through faults, the caprock or wellbores, strong cooling will occur due to the expansion of CO2 as pressure decreases with depth. Finally, we conclude by identifying research gaps and challenges of thermal effects related to CCS.Peer ReviewedPostprint (author's final draft

Investigation of the influence of polyelectrolytes hydrodynamic properties on the hydrate formation process

One of the most perspective non-traditional sources of hydrocarbon raw materials and energy is gas hydrates (GH), which stimulates their large-scale study in many laboratories and scientific centers around the world. The interest in the GH is related to the possibility of their industrial application. The use of technologies for storage and transportation of natural gas in the form of GH requires fundamental kinetic studies of the hydration process at atmospheric pressure in the presence of chemical impurities (catalysts, surfactants, etc.). During the research, an increase in the rate of gas hydrates formation was discovered at the expense of activated impurities and composite compounds obtained on their basis, which lead to changes in the hydrochemical and hydrodynamical modes of systems. It was established that the process of GH formation occurs due to the binding of methane macromolecules and other chemical impurities, which contribute to increase the number of moles of gaseous methane, due to the flow of exchange processes between the polymer matrix and water soluble salts, as well as a result of the change in the hydrodynamics of the water system. The purpose of this work is to investigate the effect of polyelectrolytes solutions hydrodynamic properties on the GH formation. We used a number of ionenes based on polymeric quaternary ammonium salts, side aliphatic radicals of different lengths contained in the acyl fragment

An Assessment of PIER Electric Grid Research 2003-2014 White Paper

This white paper describes the circumstances in California around the turn of the 21st century that led the California Energy Commission (CEC) to direct additional Public Interest Energy Research funds to address critical electric grid issues, especially those arising from integrating high penetrations of variable renewable generation with the electric grid. It contains an assessment of the beneficial science and technology advances of the resultant portfolio of electric grid research projects administered under the direction of the CEC by a competitively selected contractor, the University of California’s California Institute for Energy and the Environment, from 2003-2014

Carbon Capture and Sequestration: How Much Does this Uncertain Option Affect Near-Term Policy Choices?

One of the main issues in the climate policy agenda, the timing of abatement efforts, hinges on the uncertainties of climate change risks and technological evolution. We use a stochastic optimization framework and jointly explore these two features. First, we embed in the model future potential large-scale availability of Carbon Capture and Storage (CCS) technologies. While non-CCS mitigation that reduces fossil energy use is modelled as exerting inertia on the economic system, mainly due to the durability of the capital in energy systems and to technology lock-in and lock-out phenomena, the implementation of CCS technologies is modelled as implying less resilience of the system to changes in policy directions. Second, climate uncertainty is related in the model to the atmospheric temperature response to an increase in GHGs concentration. Performing different simulation experiments, we find that the environmental target, derived from a cost-benefit analysis, should be more ambitious when CCS is included in the picture. Moreover, the possible future availability of CCS is not a reason to significantly reduce near-term optimal abatement efforts. Finally, the availability of better information on the climate cycle is in general more valuable than better information on the CCS technological option.Climate change, Uncertainty, Sequestration, Cost-benefit analysis

Leveraging Artificial Intelligence and Geomechanical Data for Accurate Shear Stress Prediction in CO2 Sequestration within Saline Aquifers (Smart Proxy Modeling)

This research builds upon the success of a previous project that used a Smart Proxy Model (SPM) to predict pressure and saturation in Carbon Capture and Storage (CCS) operations into saline aquifers. The Smart Proxy Model is a data-driven machine learning model that can replicate the output of a sophisticated numerical simulation model for each time step in a short amount of time, using Artificial Intelligence (AI) and large volumes of subsurface data. This study aims to develop the Smart Proxy Model further by incorporating geomechanical datadriven techniques to predict shear stress by using a neural network, specifically through supervised learning, to construct Smart Proxy Models, which are critical to ensuring the safety and effectiveness of Carbon Capture and Storage operations. By training the Smart Proxy Model with reservoir simulations that incorporate varying geological properties and geomechanical data, we will be able to predict the distribution of shear stress. The ability to accurately predict shear stress is crucial to mitigating the potential risks associated with Carbon Capture and Storage operations. The development of a geomechanical Smart Proxy Model will enable more efficient and reliable subsurface modeling decisions in Carbon Capture and Storage operations, ultimately contributing to the safe and effective storage of CO2 and the global effort to combat climate change

Regional Flow Simulation in Fractured Aquifers Using Stress-Dependent Parameters

A model function relating effective stress to fracture permeability is developed from Hooke's law, implemented in the tensorial form of Darcy's law, and used to evaluate discharge rates and pressure distributions at regional scales. The model takes into account elastic and statistical fracture parameters, and is able to simulate real stress-dependent permeabilities from laboratory to field studies. This modeling approach gains in phenomenology in comparison to the classical ones because the permeability tensors may vary in both strength and principal directions according to effective stresses. Moreover this method allows evaluation of the fracture porosity changes, which are then translated into consolidation of the medium.Comment: 10 pages, 7 figures, submitted to Ground Water 201