High temperature aquifer thermal energy storage (HT-ATES) can contribute to the integration of renewable energy sources in the energy system, the replacement of fossil fuel-based heat supply and the utilization of surplus heat from industrial sources. However, there is limited understanding on the drivers, barriers and conditions of HT-ATES implementation. The objective of this study is to partly fill this knowledge gap by developing a methodological framework for a quick scan on market potential of HT-ATES. Based on the application of this framework to a case study in the Netherlands, it is concluded that the proposed method is suitable for a pre-feasibility analysis on the HT-ATES market potential. The investigated case study has a planned district heating system with geothermal energy as the heat source. HT-ATES is found to be cost-effective compared to a reference technology, i.e. a natural gas boiler, in the scenarios under existing and more sustainable alternative policies. The lifetime of HT-ATES and the size of heat demand have a strong influence on the market potential.@en

This paper reports the development of a tool to assess the environmental performance of carbon dioxide capture and storage (CCS) chains. The environmental assessment is done for the whole CCS chain. The tool has been designed to produce transparent and traceable results and is easy to work with. The tool is meant for a broad group of stakeholders for assessing CCS chains on their environmental performance. It provides insights into the environmental performance of CCS chains by using a learning-by-doing experience for users. It allows both knowledge sharing and stakeholder engagement so that view points of stakeholders are better understood and decision making on the deployment of CCS can be improved.

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This study performs an assessment of existing LCA literature to obtain insights into potential environmental impacts over the complete life cycle of fossil fuel fired power plants with CCS. CCS results in a net reduction of the GWP of power plants through their life cycle in the order of 65-84% (PC-CCS), 68-87% (IGCC-CCS), 47-80% (NGCC-CCS), and 76-97% (Oxyfuel). The results show a lower performance for NGCCs on GWP, although in absolute terms, the GWP of NGCCs with CCS appears in the same order of magnitude as PC-CCS (76-245gCO₂eq/kWh vs. 79-275gCO₂eq/kWh in PC-CCS). This is due to upstream emissions in NGCC chains. Deploying CCS in PC, IGCC and NGCC results in relative increases in eutrophication and acidification when comparing to power plants without CCS. The limited available LCA literature on oxyfuel with CCS shows this technology as generating the lowest relative increases in the environmental impact categories. For power plants without CCS, direct emissions account as the main contributor to GWP, acidification and eutrophication while for power plants with CCS, indirect emissions appear as the main contributor to GWP, acidification and human toxicity potential. The highly relative importance of emissions occurring upstream (e.g. coal mining, coal transport, MEA production) and downstream (e.g., CO₂ transport, CO₂ storage) when assessing the environmental performance of power plants with CCS implies the need for optimal designs of CCS chains to also include up- and downstream processes.

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In this study, we identify and characterize known and new environmental consequences associated with CO₂ capture from power plants, transport by pipeline and storage in geological formations. We have reviewed (analogous) environmental impact assessment procedures and scientific literature on carbon capture and storage (CCS) options. Analogues include the construction of new power plants, transport of natural gas by pipelines, underground natural gas storage (UGS), natural gas production and enhanced oil recovery (EOR) projects. It is investigated whether crucial knowledge on environmental impacts is lacking that may postpone the implementation of CCS projects. This review shows that the capture of CO₂ from power plants results in a change in the environmental profile of the power plant. This change encompasses both increase and reduction of key atmospheric emissions, being: NO_x, SO ₂, NH₃, particulate matter, Hg, HF and HCl. The largest trade-offs are found for the emission of NO_x and NH₃ when equipping power plants with post-combustion capture. Synergy is expected for SO₂ emissions, which are low for all power plants with CO₂ capture. An increase in water consumption ranging between 32% and 93% and an increase in waste and by-product creation with tens of kilotonnes annually is expected for a large-scale power plant (1 GW_e), but exact flows and composition are uncertain. The cross-media effects of CO₂ capture are found to be uncertain and to a large extent not quantified. For the assessment of the safety of CO₂ transport by pipeline at high pressure an important knowledge gap is the absence of validated release and dispersion models for CO₂ releases. We also highlight factors that result in some (not major) uncertainties when estimating the failure rates for CO ₂ pipelines. Furthermore, uniform CO₂ exposure thresholds, detailed dose-response models and specific CO₂ pipeline regulation are absent. Most gaps in environmental information regarding the CCS chain are identified and characterized for the risk assessment of the underground, non-engineered, part of the storage activity. This uncertainty is considered to be larger for aquifers than for hydrocarbon reservoirs. Failure rates are found to be heavily based on expert opinions and the dose-response models for ecosystems or target species are not yet developed. Integration and validation of various sub-models describing fate and transport of CO₂ in various compartments of the geosphere is at an infant stage. In conclusion, it is not possible to execute a quantitative risk assessment for the non-engineered part of the storage activity with high confidence.

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In this paper we identify and characterize known and new environmental consequences associated with CO2 capture from power plants, transport by pipeline and storage in geological formations (CCS). The DPSIR framework, describing environmental Drivers, Pressures, States, Impacts and Responses, is used to systematically review environmental impact assessment procedures and scientific literature on CCS. Also, it is investigated whether crucial knowledge on environmental impacts is lacking that may postpone the implementation of CCS projects. The findings of this study are that the capture of CO2 from power plants results in a change in the environmental profile of the power plant. This change encompasses trade-offs and synergies in the reduction of key atmospheric emissions, being: NOx, SO2, NH3, particulate matter, Hg, HF and HCl. The largest trade-offs are found for the emission of NOx and NH3 when equipping power plants with post-combustion capture. Synergy is expected for SO2 emissions, which are low for all power plants with CO2 capture. An increase in water consumption ranging between 32% and 93% and an increase in waste and by-product creation with tens of kilotonnes annually is expected for a large-scale power plant (1 GWe), but exact flows and composition are uncertain. The cross-media effects of CO2 capture are found to be uncertain and not quantified. For the assessment of the safety of CO2 transport by pipeline at high pressure an important knowledge gap is the absence of validated release and dispersion models for CO2 releases due to pipeline failures. There is also uncertainty in estimating the failure rates for CO2 pipelines. Furthermore, uniform CO2 exposure thresholds, detailed dose-response models and specific CO2 pipeline regulation are absent. Most gaps in environmental information regarding the CCS chain are identified and characterized for the risk assessment of the underground, non-engineered, part of the storage activity. This uncertainty is considered to be larger for aquifers than for hydrocarbon reservoirs. Failure rates are found to be heavily based on expert opinions and the doseresponse models for ecosystems or target species are not yet developed. Integration and validation of various sub-models describing fate and transport of CO2 in various compartments of the geosphere is at an infant stage. Concluding, it is not possible to execute a quantitative risk assessment for the non-engineered part of the storage activity with high confidence. Finally, several recommendations have been formulated to deal with the knowledge gaps identified in this study.@en

This study quantifies the trade-offs and synergies between climate and air quality policy objectives for the European power and heat (P&H) sector. An overview is presented of the expected performance data of CO2 capture systems implemented at P&H plants, and the expected emission of key air pollutants, being: SO2, NOX, NH3, volatile organic compounds (VOCs) and particulate matter (PM). The CO2 capture systems investigated include: post-combustion, oxyfuel combustion and pre-combustion capture. For all capture systems it was found that SO2, NOx and PM emissions are expected to be reduced or remain equal per unit of primary energy input compared to power plants without CO2 capture. Increase in primary energy input as a result of the energy penalty for CO2 capture may for some technologies and substances result in a net increase of emissions per kWh output. The emission of ammonia may increase by a factor of up to 45 per unit of primary energy input for post-combustion technologies. No data are available about the emission of VOCs from CO2 capture technologies. A simple model was developed and applied to analyse the impact of CO2 capture in the European P&H sector on the emission level of key air pollutants in 2030. Four scenarios were developed: one without CO2 capture and three with one dominantly implemented CO2 capture system, varying between: post-combustion, oxyfuel combustion and pre-combustion. The results showed a reduction in GHG emissions for the scenarios with CO2 capture compared to the baseline scenario between 12% and 20% in the EU 27 region in 2030. NOx emissions were 15% higher in the P&H sector in a scenario with predominantly post-combustion and lower when oxyfuel combustion (-16%) or pre-combustion (-20%) were implemented on a large scale. Large scale implementation of the post-combustion technology in 2030 may also result in significantly higher, i.e. increase by a factor of 28, NH3 emissions compared to scenarios with other CO2 capture options or without capture. SO2 emissions were very low for all scenarios that include large scale implementation of CO2 capture in 2030, i.e. a reduction varying between 27% and 41%. Particulate Matter emissions were found to be lower in the scenarios with CO2 capture. The scenario with implementation of the oxyfuel technology showed the lowest PM emissions followed by the scenario with a significant share allocated to pre-combustion, respectively -59% and -31%. The scenario with post-combustion capture resulted in PM emissions varying between 35% reduction and 26% increase.@en

A systematic assessment, based on an extensive literature review, of the impact of gaps and uncertainties on the results of quantitative risk assessments (QRAs) for CO₂ pipelines is presented. Sources of uncertainties that have been assessed are: failure rates, pipeline pressure, temperature, section length, diameter, orifice size, type and direction of release, meteorological conditions, jet diameter, vapour mass fraction in the release and the dose-effect relationship for CO₂. A sensitivity analysis with these parameters is performed using release, dispersion and impact models. The results show that the knowledge gaps and uncertainties have a large effect on the accuracy of the assessed risks of CO₂ pipelines. In this study it is found that the individual risk contour can vary between 0 and 204m from the pipeline depending on assumptions made. In existing studies this range is found to be between <1m and 7.2km. Mitigating the relevant risks is part of current practice, making them controllable. It is concluded that QRA for CO₂ pipelines can be improved by validation of release and dispersion models for high-pressure CO₂ releases, definition and adoption of a universal dose-effect relationship and development of a good practice guide for QRAs for CO₂ pipelines.

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The main goal of this study is to identify knowledge gaps and uncertainties in Quantitative Risk Assessments (QRA) for CO2 pipelines and to assess to what extent those gaps and uncertainties affect the final outcome of the QRA. The impact of methodological choices and uncertain values for input parameters on the results of QRA's have been assessed through an extensive literature review and by using commercially available release, dispersion and effect models. It is made apparent that over the full life cycle of a QRA knowledge gaps and uncertainties are present that may have large scale impact on the accuracy of assessing risks of CO2 pipelines. These encompass the invalidated release and dispersion models, the currently used failure rates, choosing the type of release to be modeled and the dose-effect relationships assumed. Also recommendations are presented for the improvement of QRA's for CO2 pipelines.@en