Integrated assessment of CCS in the German power plant sector with special emphasis on the competition with renewable energy technologies

The study presents the results of an integrated assessment of carbon capture and storage (CCS) in the power plant sector in Germany, with special emphasis on the competition with renewable energy technologies. Assessment dimensions comprise technical, economic and environmental aspects, long-term scenario analysis, the role of stakeholders and public acceptance and regulatory issues. The results lead to the overall conclusion that there might not necessarily be a need to focus additionally on CCS in the power plant sector. Even in case of ambitious climate protection targets, current energy policy priorities (expansion of renewable energies and combined heat and power plants as well as enhanced energy productivity) result in a limited demand for CCS. In case that the large energy saving potential aimed for can only partly be implemented, the rising gap in CO₂ reduction could only be closed by setting up a CCS-maximum strategy. In this case, up to 22% (41 GW) of the totally installed load in 2050 could be based on CCS. Assuming a more realistic scenario variant applying CCS to only 20 GW or lower would not be sufficient to reach the envisaged climate targets in the electricity sector. Furthermore, the growing public opposition against CO₂ storage projects appears as a key barrier, supplemented by major uncertainties concerning the estimation of storage potentials, the long-term cost development as well as the environmental burdens which abound when applying a life-cycle approach. However, recently, alternative applications are being increasingly considered?Cthat is the capture of CO₂ at industrial point sources and biomass based energy production (electricity, heat and fuels) where assessment studies for exploring the potentials, limits and requirements for commercial use are missing so far. Globally, CCS at power plants might be an important climate protection technology: coal-consuming countries such as China and India are increasingly moving centre stage into the debate. Here, similar investigations on the development and the integration of both, CCS and renewable energies, into the individual energy system structures of such countries would be reasonable.     

CO2 Capture in Pulp and Paper Mills: CO2 Balances and Preliminary Cost Assessment

This paper investigates overall CO₂ balances of combined heat and power (CHP) plants with CO₂ capture and storage (CCS) in Kraft pulp and paper mills. The CHP plants use biomass-based fuels and feature advanced gasification and combined cycle technology. Results from simple process simulations of the considered CHP plants are presented. Based on those results and taking into account the major direct and indirect changes in CO₂ emissions, the study shows that implementing CCS leads to steep emission reductions. Furthermore, a preliminary cost assessment is carried out to analyse the CO₂ mitigation cost and its dependence on the distance that the CO₂ must be transported to injection sites.     

Pinch analysis approach to carbon-constrained planningfor sustainable power generation

A graphical pinch-based methodology for planning retrofits for carbon capture and storage (CCS) in the power generation sector is presented in this work. CCS is widely seen as one of the essential interim technologies to mitigate greenhouse gas emissions, while still being able to utilize fossil fuels, which are relatively inexpensive and reliable in comparison to inherently low-carbon renewable resources. However, retrofitting power plants for CCS entails major capital costs as well as a reduction of thermal efficiency and power output. Thus, it is essential for planning purposes to implement the minimal extent of CCS retrofit that meets the sectoral carbon footprint targets. At the same time, it is necessary to plan for additional power generation capacity or efficiency enhancements to compensate for energy losses resulting from CCS retrofits. The simple graphical approach used in this paper is designed to determine such targets, and shares the same intuitive, insight-driven characteristics of pinch analysis techniques. A case study is shown to illustrate the methodology.     

CO2收集封存战略及其对我国远期减缓CO2排放的潜在作用

碳收集封存(CCS)已被广泛地认为是一种潜在的、可供选择的CO₂减排方案,以稳定大气中CO₂浓度、减缓气候变化.本文介绍了CCS的3大环节：碳的捕获、运输与储存,对不同捕获技术及其技术经济参数进行分析评价,介绍了不同碳地质储存的机理、潜力与成本, 以及CCS的应用对全球减缓碳排放的作用.更新中国MARKAL模型,加入各种可能的CCS技术,特别是考虑CCS的煤间接液化以及多联产技术,以同时考虑石油安全与CO₂减排.通过设置不同的情景,应用中国MARKAL模型研究了CCS对我国远期（到2050年）减缓CO₂排放的潜在作用,结果表明,CCS技术的应用不仅可能减少我国的碳排放,降低边际碳减排成本（碳减排率50%时,下降率达45%）,减轻高减排率时对核电的高度依赖,还可能使我国更长时间地清洁利用煤炭资源（在C70情景下,2050年煤在一次能源消费中的比例可从10%增到30%）.我国应重视对CCS技术的研发以及示范项目的建设.     

Valuing power plant flexibility with CCS: the case of post-combustion capture retrofits

An important development in recent years has been increased interest in retrofitting CO₂ capture at existing power plants. In parallel, it has also been suggested that flexible operation of power plants with CO₂ capture could be important in at least some jurisdictions. It is likely that retrofitted power plants could have significant ??built-in?? flexibility, but this potential is often not considered in studies of the economic performance of power plants with CO₂ capture. This paper makes a contribution to filling this gap by developing methods for first order screening analysis of flexible operation of power plants with CO₂ capture and applying them to the case study example of an appropriately integrated retrofit of post-combustion capture at a coal-fired power plant. The quantitative analysis suggests that rich solvent storage could be an attractive option on a short-run basis for some fuel, CO₂ and electricity price combinations. Results from first order analysis can then be used to determine which operating modes should (and shouldn??t) be included in further, more detailed design studies.     

Embedding CCS infrastructure into the European electricity system: a policy coordination problem

Carbon dioxide capture and storage (CCS) has recently been receiving increasing recognition in policy debates. Various aspects of possible regulatory frameworks for its implementation are beginning to be discussed in Europe. One of the issues associated with the wide use of CCS is that it requires the establishment of a carbon dioxide (CO₂) transport network, which could result in the spatial restructuring of power generation and transmission systems. This poses a significant coordination problem necessitating public planning and regulation. This paper provides a survey over multiple research strands on CCS, particularly energy system modeling and spatial optimization, pertaining to the efficient installment of CCS-related infrastructure throughout Europe. It integrates existing findings and highlights the factors that determine policy coordination needs for a potential wide implementation of CCS in the next decades.     

Biomass-based negative emission technology options with combined heat and power generation

Biomass-based combined heat and power (CHP) generation with different carbon capture approaches is investigated in this study. Only direct carbon dioxide (CO₂) emissions are considered. The selected processes are (i) a circulating fluidized bed boiler for wood chips connected to an extraction/condensation steam cycle CHP plant without carbon capture; (ii) plant (i), but with post-combustion CO₂ capture; (iii) chemical looping combustion (CLC) of solid biomass connected to the steam cycle CHP plant; (iv) rotary kiln slow pyrolysis of biomass for biochar soil storage and direct combustion of volatiles supplying the steam cycle CHP plant with the CO₂ from volatiles combustion escaping to the atmosphere; (v) case (iv) with additional post-combustion CO₂ capture; and (vi) case (iv) with CLC of volatiles. Reasonable assumptions based on literature data are taken for the performance effects of the CO₂ capture systems and the six process options are compared. CO₂ compression to pipeline pressure is considered. The results show that both bioenergy with carbon capture and storage (BECCS) and biochar qualify as negative emission technologies (NETs) and that there is an energy-based performance advantage of BECCS over biochar because of the unreleased fuel energy in the biochar case. Additional aspects of biomass fuels (ash content and ash melting behavior) and sustainable soil management (nutrient cycles) for biomass production should be quantitatively considered in more detailed future assessments, as there may be certain biomass fuels, and environmental and economic settings where biochar application to soils is indicated rather than the full conversion of the biomass to energy and CO₂.

     

Promising synergies to address water, sequestration, legal, and public acceptance issues associated with large-scale implementation of CO2 sequestration

Stabilization of CO₂ atmospheric concentrations requires practical strategies to address the challenges posed by the continued use of coal for baseload-electricity production. Over the next two decades, CO₂ capture and sequestration (CCS) demonstration projects would need to increase several orders of magnitude across the globe in both size and scale. This task has several potential barriers which will have to be accounted for. These barriers include those that have been known for a number of years including safety of subsurface sequestration, pore-space competition with emerging activities like shale gas production, legal and regulatory frameworks, and public acceptance and technical communication. In addition water management is a new challenge that should be actively and carefully considered across all CCS operations. A review of the new insights gained on these previously and newly identified challenges, since the IPCC special report on CCS, is presented in this paper. While somewhat daunting in scope, some of these challenges can be addressed more easily by recognizing the potential advantageous synergies that can be exploited when these challenges are dealt with in combination. For example, active management of water resources, including brine in deep subsurface formations, can provide the additional cooling-water required by the CO₂ capture retrofitting process while simultaneously reducing sequestration leakage risk and furthering efforts toward public acceptance. This comprehensive assessment indicates that water, sequestration, legal, and public acceptance challenges ought to be researched individually, but must also be examined collectively to exploit the promising synergies identified herein. Exploitation of these synergies provides the best possibilities for successful large-scale implementation of CCS.     

Flexible options to provide energy for capturing carbon dioxide in coal-fired power plants under the Clean Development Mechanism

Mitigation and Adaptation Strategies for Global Change - Operators of coal-fired power plants with carbon dioxide capture and storage (CCS) can provide energy for carbon dioxide (CO2) capture by...     

基于生命周期评价的钢铁厂碱渣固碳技术比较研究

本研究以3种钢铁厂碱渣直接法固碳技术为研究对象,该技术将钢渣进行碳酸化处理,可快速永久地将CO2固化储存在钢渣中,气固相反应可分别在高压釜、泥浆反应器和超重力旋转床的水溶液中一步完成,并将其分别定义为T1、T2、T3.通过Umberto软件建立生命周期模型,对3种技术的资源环境影响进行评估.结果表明,T1的环境影响最高,其次为T3,T2的环境影响最小.技术评价显示,T3在技术效率、资源消耗、环境影响方面具有较好的综合效益.敏感性分析表明,加热效率的敏感性系数分别为0.97、0.97和0.46.转换率与温室气体排放的关系分别呈上升、倒U型和下降的变化趋势.提高加热效率、合理利用热源及选择合适的技术效率,将有利于技术优化,减少技术的环境影响,提高固碳效率.     

Interdisciplinary studies on the technical and economic feasibility of deep underground coal gasification with CO<Subscript>2</Subscript> storage in bulgaria

This paper presents the outcome of a feasibility study on underground coal gasification (UCG) combined with direct carbon dioxide (CO₂) capture and storage (CCS) at a selected site in Bulgaria with deep coal seams (>1,200 m). A series of state-of-the-art geological, geo-mechanical, hydrogeological and computational models supported by experimental tests and techno-economical assessments have been developed for the evaluation of UCG-CCS schemes. Research efforts have been focused on the development of site selection requirements for UCG-CCS, estimation of CO₂ storage volumes, review of the practical engineering requirements for developing a commercial UCG-CCS storage site, consideration of drilling and completion issues, and assessments of economic feasibility and environmental impacts of the scheme. In addition, the risks of subsidence and groundwater contamination have been assessed in order to pave the way for a full-scale trial and commercial applications. The current research confirms that cleaner and cheaper energy with reduced emissions can be achieved and the economics are competitive in the future European energy market. However the current research has established that rigorous design and monitor schemes are essential for productivity and safety and the minimisation of the potential environmental impacts. A platform has been established serving to inform policy-makers and aiding strategies devised to alleviate local and global impacts on climate change, while ensuring that energy resources are optimally harnessed.     

Development of a hybrid photo-bioreactor and nanoparticle adsorbent system for the removal of CO2 , and selected organic and metal co-pollutants

Fossil fuel combustion and many industrial processes generate gaseous emissions that contain a number of toxic organic pollutants and carbon dioxide (CO₂) which contribute to climate change and atmospheric pollution. There is a need for green and sustainable solutions to remove air pollutants, as opposed to conventional techniques which can be expensive, consume additional energy and generate further waste. We developed a novel integrated bioreactor combined with recyclable iron oxide nano/micro-particle adsorption interfaces, to remove CO_2, and undesired organic air pollutants using natural particles, while generating oxygen. This semi-continuous bench-scale photo-bioreactor was shown to successfully clean up simulated emission streams of up to 45% CO₂ with a conversion rate of approximately 4% CO₂ per hour, generating a steady supply of oxygen (6 mmol/hr), while nanoparticles effectively remove several undesired organic by-products. We also showed algal waste of the bioreactor can be used for mercury remediation. We estimated the potential CO₂ emissions that could be captured from our new method for three industrial cases in which, coal, oil and natural gas were used. With a 30% carbon capture system, the reduction of CO₂ was estimated to decrease by about 420,000, 320,000 and 240,000 metric tonnes, respectively for a typical 500 MW power plant. The cost analysis we conducted showed potential to scale-up, and the entire system is recyclable and sustainable. We further discuss the implications of usage of this complete system, or as individual units, that could provide a hybrid option to existing industrial setups.     

The oxycoal process with cryogenic oxygen supply

Due to its large reserves, coal is expected to continue to play an important role in the future. However, specific and absolute CO₂ emissions are among the highest when burning coal for power generation. Therefore, the capture of CO₂ from power plants may contribute significantly in reducing global CO₂ emissions. This review deals with the oxyfuel process, where pure oxygen is used for burning coal, resulting in a flue gas with high CO₂ concentrations. After further conditioning, the highly concentrated CO₂ is compressed and transported in the liquid state to, for example, geological storages. The enormous oxygen demand is generated in an air-separation unit by a cryogenic process, which is the only available state-of-the-art technology. The generation of oxygen and the purification and liquefaction of the CO₂-enriched flue gas consumes significant auxiliary power. Therefore, the overall net efficiency is expected to be lowered by 8 to 12 percentage points, corresponding to a 21 to 36% increase in fuel consumption. Oxygen combustion is associated with higher temperatures compared with conventional air combustion. Both the fuel properties as well as limitations of steam and metal temperatures of the various heat exchanger sections of the steam generator require a moderation of the temperatures during combustion and in the subsequent heat-transfer sections. This is done by means of flue gas recirculation. The interdependencies among fuel properties, the amount and the temperature of the recycled flue gas, and the resulting oxygen concentration in the combustion atmosphere are investigated. Expected effects of the modified flue gas composition in comparison with the air-fired case are studied theoretically and experimentally. The different atmosphere resulting from oxygen-fired combustion gives rise to various questions related to firing, in particular, with regard to the combustion mechanism, pollutant reduction, the risk of corrosion, and the properties of the fly ash or the deposits that form. In particular, detailed nitrogen and sulphur chemistry was investigated by combustion tests in a laboratory-scale facility. Oxidant staging, in order to reduce NO formation, turned out to work with similar effectiveness as for conventional air combustion. With regard to sulphur, a considerable increase in the SO₂ concentration was found, as expected. However, the H₂S concentration in the combustion atmosphere increased as well. Further results were achieved with a pilot-scale test facility, where acid dew points were measured and deposition probes were exposed to the combustion environment. Besides CO₂ and water vapour, the flue gas contains impurities like sulphur species, nitrogen oxides, argon, nitrogen, and oxygen. The CO₂ liquefaction is strongly affected by these impurities in terms of the auxiliary power requirement and the CO₂ capture rate. Furthermore, the impurity of the liquefied CO₂ is affected as well. Since the requirements on the liquid CO₂ with regard to geological storage or enhanced oil recovery are currently undefined, the effects of possible flue gas treatment and the design of the liquefaction plant are studied over a wide range.     

Fighting sustainability challenges on two fronts: Material efficiency and the emerging carbon capture and storage technologies

Technological and regulatory responses to large-scale environmental threats, such as depletion of the natural resources and climate change, tend to focus on one issue at time. Emerging carbon capture and storage (CCS) technologies that are in different stages of development offer a case that demonstrates this dilemma. This article approximates the implications of two emerging CCS applications on existing steel mill’s CO₂ emissions and its use of material resources. The evaluated applications are based on the mineralization method and the comparative case represents two versions of a geological CCS method. The results of the evaluation indicate that if technical bottleneck issues related to CO₂ sequestration with mineralization can be solved, it can be possible to achieve a similar CO₂ reduction performance with mineralization-based CCS applications as with more conventional CCS applications. If the CO₂ capturing potential of mineralization-based applications could be taken into use, it could also enable the significant improvement of material efficiency of industrial operations. Urgent problem hampering the development of mineralization-based CCS applications is that the policy regimes related to CCS especially in the European Union (EU) do not recognize mineralization as a CCS method. Article suggests that the focus in the future evaluations and in policy should not be directed only on CO₂ sequestration capacity of CCS applications. Similarly important is to consider their implications on material efficiency. Article also outlines modifications to the EU’s CCS policy in terms of the formal terminology.     

Equal Opportunity for Biomass in Greenhouse Gas Accounting of CO2 Capture and Storage: A Step Towards More Cost-Effective Climate Change Mitigation Regimes

Carbon dioxide capture and permanent storage (CCS) is one of the most frequently discussed technologies with the potential to mitigate climate change. The natural target for CCS has been the carbon dioxide (CO₂) emissions from fossil energy sources. However, CCS has also been suggested in combination with biomass during recent years. Given that the impact on the earth's radiative balance is the same whether CO₂ emissions of a fossil or a biomass origin are captured and stored away from the atmosphere, we argue that an equal reward should be given for the CCS, independent of the origin of the CO₂. The guidelines that provide assistance for the national greenhouse gas (GHG) accounting under the Kyoto Protocol have not considered CCS from biomass (biotic CCS) and it appears that it is not possible to receive emission credits for biotic CCS under the first commitment period of the Kyoto Protocol, i.e., 2008–2012. We argue that it would be unwise to exclude this GHG mitigation alternative from the competition with other GHG mitigation options. We also propose a feasible approach as to how emission credits for biotic CCS could be included within a future accounting framework.     

Obstacles for CCS deployment: an analysis of discrepancies of perceptions

The potential for CO₂ emission reductions through carbon capture and storage (CCS) is depending on investments that can bring the technology from the current R&D through to commercial applications. The intermediate step in this development is demonstration plants that can prove the technical, economic, social, and ecological feasibility of CCS technologies. Based on a CCS stakeholder questionnaire survey and a literature review, we critically analyse discrepancies regarding perceptions of deployment obstacles and experiences from early demonstration plants. The analysis identifies discrepancies between CCS policies versus important deployment considerations and CCS stakeholder policy demands. The discrepancy gap is emphasised by lessons from restructured, postponed, and cancelled CCS projects. To bridge this cognitive gap towards proving CCS through demonstration activities, the article highlights policy implications of establishing a broad understanding of deployment obstacles. Attention to these obstacles is important for policymakers and industry in channelling efforts to demonstrating CCS, hence validating the current focus on CCS as a key abatement potential. Under present conditions, the findings question the robustness of current CCS abatement potential estimates and deployment goals as established by policymakers and in scenarios.     

Biomass-based carbon capture and utilization in kraft pulp mills

Corporate image, European Emission Trading System and Environmental Regulations, encourage pulp industry to reduce carbon dioxide (CO₂) emissions. Kraft pulp mills produce CO₂ mainly in combustion processes. The largest sources are the recovery boiler, the biomass boiler, and the lime kiln. Due to utilizing mostly biomass-based fuels, the CO₂ is largely biogenic. Capture and storage of CO₂ (CCS) could offer pulp and paper industry the possibility to act as site for negative CO₂ emissions. In addition, captured biogenic CO₂ can be used as a raw material for bioproducts. Possibilities for CO₂ utilization include tall oil manufacturing, lignin extraction, and production of precipitated calcium carbonate (PCC), depending on local conditions and mill-specific details. In this study, total biomass-based CO₂ capture and storage potential (BECCS) and potential to implement capture and utilization of biomass-based CO₂ (BECCU) in kraft pulp mills were estimated by analyzing the impacts of the processes on the operation of two modern reference mills, a Nordic softwood kraft pulp mill with integrated paper production and a Southern eucalyptus kraft pulp mill. CO₂ capture is energy-intensive, and thus the effects on the energy balances of the mills were estimated. When papermaking is integrated in the mill operations, energy adequacy can be a limiting factor for carbon capture implementation. Global carbon capture potential was estimated based on pulp production data. Kraft pulp mills have notable CO₂ capture potential, while the on-site utilization potential using currently available technologies is lower. The future of these processes depends on technology development, desire to reuse CO₂, and prospective changes in legislation.

     

Microalgae: a promising tool for carbon sequestration

Increasing trends in global warming already evident, the likelihood of further rise continuing, and their impacts give urgency to addressing carbon sequestration technologies more coherently and effectively. Carbon dioxide (CO₂) is responsible for over half the warming potential of all greenhouse gases (GHG), due to the dependence of world economies on fossil fuels. The processes involving CO₂ capture and storage (CCS) are gaining attention as an alternative for reducing CO₂ concentration in the ambient air. However, these technologies are considered as short-term solutions, as there are still concerns about the environmental sustainability of these processes. A promising technology could be the biological capture of CO₂ using microalgae due to its unmatched advantages over higher plants and ocean fertilization. Microalgae are phototrophic microorganisms with simple nutritional requirements, and comprising the major primary producers on this planet. Specific pathways include autotrophic production via both open pond or closed photobioreactor (PBR) systems. Photosynthetic efficiency of microalgae ranged from 10?C20 % in comparison with 1?C2 % of most terrestrial plants. Some algal species, during their exponential growth, can double their biomass in periods as short as 3.5 hours. Moreover, advantage of being tolerant of high concentration of CO₂ (flue gas), low light intensity requirements, environmentally sustainable, and co-producing added value products put these as the favoured organisms. Advantages of microalgae in comparison with other sequestration methodologies are discussed, which includes the cultivation systems, the key process parameters, wastewater treatment, harvesting and the novel bio-products produced by microalgal biomass.     

Negative emissions of carbon dioxide through chemical-looping combustion (CLC) and gasification (CLG) using oxygen carriers based on manganese and iron

Carbon capture and storage (CCS) is an economically attractive strategy for avoiding carbon dioxide (CO₂) emissions from, e.g., power plants to the atmosphere. The combination of CCS and biomass combustion would result in a reduction of atmospheric CO₂, or net negative emissions, as plant growth is a form of sequestration of atmospheric carbon. Carbon capture can be achieved in a variety of ways, one of which is chemical looping. Chemical-looping combustion (CLC) and chemical looping gasification (CLG) are two promising technologies for conversion of biomass to heat and power or syngas/methane with carbon capture. There have been significant advances made with respect to CLC in the last two decades for all types of fuel, with much less research on the gasification technology. CLG offers some interesting opportunities for production of biofuels together with carbon capture and may have several advantages with respect to the bench mark indirect gasification process or dual-bed fluidized bed (DFBG) in this respect. In CLG, an oxygen carrier is used as a bed material instead of sand, which is common in indirect gasification, and this could have several advantages: (i) all generated CO₂ is present together with the syngas or methane in the fuel reactor outlet stream, thus in a concentrated stream, viable for separation and capture; (ii) the air reactor (or combustion chamber) should largely be free from trace impurities, thus preventing corrosion and fouling in this reactor; and (iii) the highly oxidizing conditions in the fuel reactor together with solid oxide surfaces should be advantageous with respect to limiting formation of tar species. In this study, two manganese ores and an iron-based waste material, LD slag, were investigated with respect to performance in these chemical-looping technologies. The materials were also impregnated with alkali (K) in order to gauge possible catalytic effects and also to establish a better understanding of the general behavior of oxygen carriers with alkali, an important component in biomass and biomass waste streams and often a precursor for high-temperature corrosion. The viability of the oxygen carriers was investigated using a synthetic biogas in a batch fluidized bed reactor. The conversion of CO, H₂, CH₄, and C₂H₄ was investigated in the temperature interval 800–950 °C. The reactivity, or oxygen transfer rate, was highest for the manganese ores, followed by the LD slag. The conversion of C₂H₄ was generally high but could largely be attributed to thermal decomposition. The K-impregnated samples showed enhanced reactivity during combustion conditions, and the Mangagran-K sample was able to achieve full conversion of benzene. The interaction of the solid material with alkali showed widely different behavior. The two manganese ores retained almost all alkali after redox testing, albeit exhibiting different migration patterns inside the particles. LD slag lost most alkali to the gas phase during testing, although some remained, possibly explaining a small difference in reactivity. In summary, the CLC and CLG processes could clearly be interesting for production of heat, power, or biofuel with negative CO₂ emissions. Manganese ores are most promising from this study, as they could absorb alkali, giving a better conversion and perhaps also inhibiting or limiting corrosion mechanisms in a combustor or gasifier.

     

Carbon capture and storage deployment rates: needs and feasibility

Carbon capture and storage (CCS) may become a key technology to limit human-induced global warming, but many uncertainties prevail, including the necessary technological development, costs, legal ramifications, and siting. As such, an important question is the scale of carbon dioxide abatement we require from CCS to meet future climate targets, and whether they appear reasonable. For a number of energy technology and efficiency improvement scenarios, we use a simple climate model to assess the necessary contribution from CCS to ‘fill the gap’ between scenarios’ carbon dioxide emissions levels and the levels needed to meet alternative climate targets. The need for CCS depends on early or delayed action to curb emissions and the characteristics of the assumed energy scenario. To meet a 2.5°C target a large contribution and fast deployment rates for CCS are required. The required deployment rates are much faster than those seen in the deployment of renewable energy technologies as well as nuclear power the last decades, and may not be feasible. This indicates that more contributions are needed from other low-carbon energy technologies and improved energy efficiency, or substitution of coal for gas in the first half of the century. In addition the limited availability of coal and gas by end of the century and resulting limited scope for CCS implies that meeting the 2.5°C target would require significant contributions from one or more of the following options: CCS linked to oil use, biomass energy based CCS (BECCS), and CCS linked to industrial processes.