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The United States is unique in the energy reserves held in shale gas fields, which coproduce natural gas and natural gas liquids. Use of this resource, however, contributes to greenhouse gas emissions and, correspondingly, climate change. We explore how natural gas and natural gas liquids might build bridges toward low-carbon transportation fuels. For example, as petroleum refineries produce less gasoline in response to widespread electrification, natural gas liquids can be converted to fuel. We consider whether the greenhouse gas emissions from production and use of these fuels might be offset through three potential outcomes of converting coproduced natural gas to CO

At COP26, India announced strong climate commitments of reaching net-zero greenhouse gas emissions by 2070. Meeting this target would likely require substantial deployment of CO 2 capture and storage (CCS) to decarbonize existing large-point sources of CO 2 . This study attempts to evaluate opportunities for deployment of CCS in India in the forthcoming decades. A geographic information system-based approach was adopted for mapping existing sources of CO 2 with the sinks. The results show that regionally-appropriate ways of moving towards CCS at scale exist in both the power and industrial sectors. Coupled analysis of these sectors with sinks shows that eight clusters may be developed throughout the country to sequester 403 Mt-CO 2 annually. These clusters are concentrated near Category-I oil basins and the Category-I coalfields (Damodar Valley), which may also create suitable financial incentives by incremental oil and coalbed methane recovery, respectively. Furthermore, a first-order costing analysis evaluates that the cost of avoidance across basins may range from –$31 to $107/t-CO 2 , depending on the type of storage reservoir and the proximity to large-point sources. A total of 12 suitable hubs and clusters were created based on annual emissions above 1 Mt-CO 2 of each large-point source and their proximity with geological sinks. Supplementary material: Frequency distribution of sources based on their distance from the sink in each cluster is available at https://doi.org/10.6084/m9.figshare.c.6189961

Global energy modeling exercises project significant deployment of CO2 capture and storage (CCS) to bridge the gap between India's pledged climate commitments and the 1. 5°C target. Despite advances in laboratory analyses and process modeling, the information on geologic storage potential in India is limited. Prior studies indicate that the vast majority of storage potential exists in saline aquifers (50–300 Gt-CO2); though, this might be overestimated. These estimates also estimate the theoretical potential in coal seams to be 2 while shale basins have not been evaluated as geologic CO2 sinks on a systems level. Based on several recent climate developments and CCS best practices, we suggest revisiting these potential estimates. We demonstrate how revisiting some assumptions might enhance the coal repository available as a sink by a factor of 7–8. We also present proof-of-concept analysis to show that Indian shale reservoirs might have suitable CO2 adsorption capacity. With detailed recommendations for revising these estimates, we present a methodological framework for incorporating the best practices for coal seam and shale basin storage potential. Based on source-sink mapping exercises, we also argue that unconventional basins in India are especially relevant because of their proximity to large point sources of CO2.

Management of coalbed methane (CBM)-produced water is a crucial part of the water–energy nexus, especially as CBM is projected to play a key role as a bridge fuel in major economies. In this paper, we consider one management technique, i.e., desalination of CBM-produced water to generate potable water. We discuss a confluence of geographic, sociotechnical, regulatory, and other circumstances that could make this concept viable for select coal-bearing regions. Having said that, for maximizing benefits, it is prudent to take a synergistic view targeting multiple objectives (water access, health, environmental impacts, and ease of waste management). Thus, we make design recommendations and suggest a system-evaluation framework for making sustainable decisions related to produced-to-potable water systems. For instance, a key question is whether such systems should be centralized or decentralized—and this paper highlights crucial tradeoffs that are present in both the cases.

Coalbed methane (CBM) has emerged as one of India’s important unconventional natural gas sources in the past decade. A number of environmental questions flank the commercial development of CBM and its holistic success, one of which is coproduced water management. Present work aims at assessing the geochemistry of co-produced water samples collected from CBM wells in Jharia coalfield, India. It is found that pH is within accepted limits and the bacterial contamination is minimal. The major ions present in the water samples are sodium and bicarbonate. It is observed that the produced water is generally influenced by a mix of evaporite dissolution and silicate weathering and the samples are oversaturated with respect to calcite and dolomite. Subsequently, an assessment of the energy requirements of membrane-based technologies (such as reverse osmosis and nanofiltration) has been performed. The estimated energy consumption is 0.45–1.40 kWh per cubic meter of water, for differing levels of sodium desir...

India's CO2 emissions have risen at a compounded annual growth rate of 3.1% over the last three decades, primarily from an increase in consumption of fossil fuels . Carbon capture, utilization, and storage (CCUS) is considered one of the most effective strategies to counter these trends by reducing the carbon footprint of existing and upcoming infrastructure. Utilization of captured CO2 (CCU) to produce valuable green chemicals is an economically viable proposition. On the other hand, storage of CO2 (CCS) reduces the carbon footprint by sequestering the captured CO2 in geological formations, which in some cases, facilitates hydrocarbon recovery. This paper showcases how a multifaceted approach of combining CCU and CCS in an economically viable manner is a key factor in the maintaining of sustainable development. We discuss at a systems level, the benefits of the implementation of CCUS for India's energy security, positive path dependency, and resiliency. This is followed by a bottom-up review of the symbiotic relationship between the capture and utilization/storage. We provide an assessment of sustainable CCUS implementation by pairing state-of-the-art technologies in the field of carbon storage/utilization with possible future directions in India. We also suggest pathways for the potential and the impact of India's carbon-intensive sources in different CCUS chains such as markets for large-scale utilization of CO2 in emerging methanol economy. Finally, we provide research and policy recommendations that would facilitate a sustainable collaborative effort across sectors in mitigating the increasing carbon dioxide in the atmosphere.

Various modeling studies analyzing global 2 °C climate stabilization scenarios have projected penetration of CO2 capture and storage (CCS) technologies in India alongside a sizable penetration of renewable energy technologies. The assessments of geological storage potential over India have shown wide variation across regions. This paper examines the locations of large point sources of CO2 emissions in India and matches it with carbon storage locations to minimize the cost of CCS evolving grid. The concept of weighted Euclidean distance and Integrated Environmental Control Model are used to propose suitable pipeline networks for emissions-intensive clusters to optimize the cost of CO2 avoidance. The computational method estimates proximate storage location for each CO2 emitting source taking into account the total storage potential at each location. CCS requirement in India would vary depending on the global climate stabilization target. We examine two targets for India that correspond to 2 °C and well below 2 °C global mitigation regimes. According to our estimates, India could mitigate around 780 Mt CO2 per year below 60 $/t-CO2 (2005 prices) over 30 years, and another 250 Mt CO2 per year for up to 75 $/t-CO2 prices through CCS under these scenarios respectively.

Coal-fired power plants are one of the most important targets with respect to reduction of CO2 emissions. The reasons for this are that coal-fired power plants offer localized large point sources (LPS) of CO2 and that the Indian power sector contributes to roughly half of all-India CO2 emissions. CO2 capture and storage (CCS) can be implemented in these power plants for long-term decarbonisation of the Indian economy. In this paper, two artificial intelligence (AI) techniques—adaptive network based fuzzy inference system (ANFIS) and multi gene genetic programming (MGGP) are used to model Indian coal-fired power plants with CO2 capture. The data set of 75 power plants take the plant size, the capture type, the load and the CO2 emission as the input and the COE and annual CO2 emissions as the output. It is found that MGGP is more suited to these applications with an R2 value of more than 99% between the predicted and actual values, as against the ~96% correlation for the ANFIS approach. MGGP also gives the traditionally expected results in sensitivity analysis, which ANFIS fails to give. Several other parameters in the base plant and CO2 capture unit may be included in similar studies to give a more accurate result. This is because MGGP gives a better perspective toward qualitative data, such as capture type, as compared to ANFIS.

India is a country with rising energy needs. Much of the energy demand is met by coal and there are dynamic links between coal consumption and economic growth. However, the increasing coal use is likely to result in increasing carbon dioxide emissions. India's power sector contributes to about half of the all-India CO 2 emissions. As a result, end-of-the-pipe abatement of CO 2 in the power sector may be one of the prominent mechanisms to reduce India's greenhouse gas (GHG) emissions. Carbon capture and storage (CCS) technology may provide such a means in the Indian coal-fired power plants. This paper initially makes an effort to assess the economic implications of this technology on existing Indian coal-fired power plants. Some characteristic features of Indian power plants are identified with special reference towards CCS deployment. The importance of proximity of coal linkage and sink location from the power plant is established using the studied examples. General trends on the estimates of cost of electricity (COE), emission factor and net plant efficiency are evaluated. Subsequently, the trends in costs are projected for the next three decades for the upcoming plants using CCS. In these predictions, three scenarios of CCS deployment are considered, with varying carbon price range. In a high carbon price scenario (C price of US$ 80/t-CO 2 in 2030), CCS is firmly established as a useful technology for the Indian coal-fired power plants by the year 2050.

In this opinion paper, we contend that in light of recent findings and the expected future of Indian coal business, fugitive methane emissions from coal mining and handling activities may c...

Development of CO2 capture, utilization, and storage (CCUS) platforms has been deemed crucial for achievement of the Paris Agreement goals. Life-cycle assessment (LCA) is an important tool for assessing the efficacy of these technologies in achieving true net-carbon reduction. Critical review of previously published LCA-based evaluations of CCUS technologies reveals that there is an urgent need for more transparent accounting of carbon removal efficiency. Updated methods should incorporate better focus on the CO2 uptake as the primary objective and better differentiate apportionment between “avoided emissions” and true net sequestration. We posit that widespread, uniform application of a standardized ratio metric, carbon return on investment (CROI), will improve the usefulness of LCA to articulate true CO2 sequestration by candidate CCUS platforms. We present two case studies to illustrate the value of this metric for diverse CCS and CCU applications. We also provide several recommendations to make future CROI results as unambiguous as possible and boost their usefulness. These recommendations pertain to conventional LCA concepts, including: choice of functional unit (or declared unit) and system boundaries, application of system expansion, and proper mathematical formulation of the proposed metric. Future work should aim at carrying forward our work on proposed minimum CROI and incorporating the time-value of CO2 fluxes.

India's developmental needs in the near and long-term future will be strongly interlinked with the need to provide steady electricity to its cities and villages. The current fleet of Electricity Generating Units (EGUs) in India is mostly coal-based. These coal-fired power plants lead to a substantial amount of CO2 emissions. Due to international climate obligations, there might be a need to limit the amount of unmitigated CO2 emissions being emitted into the atmosphere. Mitigation of such emissions at coal-fired power plants offers an easily controllable way of reducing such emissions. The mechanisms to reduce emissions in coal-fired power plants may be through installation of super-critical units, repowering the plant with Integrated Gasification Combined Cycle (IGCC) or with use of coal blended with biomass. More radical emission cuts may be obtained by retrofitting the existing plants with CO2 Capture and Storage (CCS), a technology with the ability to reduce the emissions by 80-85% of the current emissions levels. This paper begins with a brief insight into some of the mechanisms to cause emission reductions in coal-fired power plants. It focuses mainly of how retrofitting the power plants with CCS technology will affect the techno-economic of the plant. Three types of plants will be analyzed, viz, Low performance, medium performance and high performance; the categorization being based on the current Indian fleet of EGUs. We analyze five pathways for mitigation, with two focusing on efficiency improvements and three on CCS technology. The results show that overall cost of avoidance for CCS ranges from US$ 59.54 to US$ 85.41 per tonne of CO2. There is a strong incentive for repowering of old plants to supercritical units and their subsequent retrofitting with CO2 capture systems than direct retrofitting of low performance plants.

Coal is the backbone of the Indian power sector with more than 60 % of the net installed electricity capacity being coal-based. Among other fossil fuels, natural gas also contributes significantly to the power sector in India. This contribution may increase in the future with exploration of new reserves of unconventional gases, more stringent climate norms and so on. Concurrently, the global climate change problem also becomes more enhanced if larger dependence on fossil fuels remains. In some scenarios, carbon dioxide (CO2) capture and storage (CCS) with natural gas combined cycle (NGCC) may be a feasible technological alternative. Such a scenario is manifested by some critical factors such as low natural gas prices and high carbon tax, among others. Nevertheless, several parameters remain highly uncertain if CCS is to be introduced in NGCC plants. As a result, modern computational techniques such as soft-computing approaches may be used to generate predictive models for cost and performance in such plants. This paper utilizes one such technique, multi-gene genetic programming (MGGP) to generate predictive models for cost of electricity (with coefficient of determination, R2 > 95 %), CO2 emission factor and net plant efficiency (R2 > 98 %). The sensitivity analysis carried out for these parameters show results which are expected in real situations. Subsequently, the calculation of the CO2 avoidance cost and energy penalty for a hypothetical case is demonstrated. The results show that MGGP can be successfully used in such applications.

India is a major developing country with ambitious developmental goals. Future development is expected to increase energy demands and subsequently greenhouse gas (GHG) emissions. Carbon capture and...

Coal is the backbone of the Indian power sector. The coal-fired power plants remain the largest emitters of carbon dioxide, sulfur dioxide and substantial amounts of nitrogen oxides, which are associated with climate and health impacts. Various CO2 mitigation technologies (carbon capture and storage—CCS) and SO2/NO x mitigation technologies (flue gas desulfurization and selective catalytic reduction) have been employed to reduce the environmental impacts of the coal-fired power plants. Therefore, it is imperative to understand the feasibility of various mitigation technologies employed. This paper attempts to perform environmental life cycle assessment (LCA) of Indian coal-fired power plant with and without CO2, SO2 and NO x mitigation controls. The study develops new normalization factors for India in various damage categories, using the Indian emissions and energy consumption data, coupled with the emissions and particulate emission to come up with a final environmental impact of coal-fired electricity. The results show a large degree of dependence on the perspective of assessment used. The impact of sensitivities of individual substances and the effect of plant efficiency on the final LCA results is also studied.

It is anticipated that achievement of the Paris Climate Agreement goals will require widespread deployment of negative emission technologies (NETs). The most prominent NET is bioenergy with carbon capture and storage (BECCS), which is typically envisioned to use terrestrial crops as feedstock. Several recent studies have focused on aquatic BECCS (A-BECCS), making use of microalgae or macroalgae as feedstock, as possible means of reducing water and land use. However, the high logistical complexity of the A-BECCS supply chain makes it likely that regional biophysical and socio-technical factors will strongly influence its overall favorability. Therefore, this study applies life-cycle assessment (LCA) incorporating a geographic information system (GIS) framework to estimate the environmental impacts of A-BECCS over all stages of its life-cycle. Three candidate locations in the USA are evaluated based on seemingly good proximity to coastal regions and CO2 storage; namely, East Coast, West Coast, and the Gulf of Mexico. Monte Carlo simulation is used to characterize distributions of model outputs, including energy return on investment (EROI) and net global warming potential (GWP). Results reveal that only the Gulf of Mexico configuration has any likelihood of achieving both net energy production (probability of EROI > 1 = 29%) and net CO2 sequestration (probability of GWP 1), but not net negative carbon sequestration. These results call into question the feasibility of the modeled A-BECCS system as an energy-producing NET and offer insights into possible system reconfiguration. For example, anaerobic digestion offers very low EROI and creates multiple carbon-bearing waste streams, which strongly undercuts overall net CO2 sequestration. Finally, it is observed that enhanced oil recovery (EOR) strongly contributes to net-energy production (EROI > 1) in the modeled A-BECCS system, but also strongly undercuts net CO2 sequestration, which is arguably the main goal of any NET. This analysis showcases how geographically-explicit analysis can advance our understanding of biomass-based NETs.

Coal-fired power plants are amongst the largest sources of air pollution in India. These power plants emit a number of gaseous pollutants, including sulphur dioxide (SO2), nitrogen oxides (NO x ) and also particulate matter. Recent international as well as national studies show a rapid increase in SO2 and NO x emissions. Both these gases have harmful impact on human health and hence need to be controlled. Typically, these pollutants are controlled using the wet flue gas desulphurization (FGD) units (for SO2) and hot-side selective catalytic reduction (SCR) units (for NO x )—mostly absent in the coal-fired power plants in India. This paper attempts to understand the plant level implications of using Wet FGD and hot-side SCR systems in Indian coal-fired power plants. The impacts on the technical (efficiency, energy penalty), environmental (emissions, fuel use) and economic (cost of electricity) aspects have been estimated through simulation of a power plant with and without the emission controls. Effect of increasing use of high-sulphur imported coal has also been discussed.

Ever increasing carbon dioxide emissions and the associated climate impacts are major concerns for human civilization today. Fossil-fuel-fired power plants are the leading emitters of CO 2 . Carbon Capture and Storage (CCS) from coal power-plants is one of the most promising technologies for mitigating CO 2 emissions from energy sector. However, CCS technology is highly resource intensive and not yet commercially viable. Thus, it is essential that the impacts of this technology are estimated beforehand. This paper attempts to understand the implications of implementing CCS in Indian coal power plants on the environmental resources. The cases of a new 500 MW sub-critical and a 660 MW super-critical plant, with and without CCS using a variety of capture technologies, have been simulated. The relevant parameters in terms of which the environmental impact shall be gauged are the additional requirement of resources (such as coal, water, chemical agents etc.) and emissions of CO 2 , SO 2 , NO x , HC1 and particulate matter. The influence of different design and operating parameters such as coal properties, boiler efficiency, CO 2 capture levels and CO 2 product pressure, has also been studied.