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While experts in various fields discuss the potential of carbon capture and storage (CCS) technologies, the utilization of carbon dioxide as chemical feedstock is also attracting renewed and rapidly growing interest. These approaches do not compete; rather, they are complementary: CCS aims to capture and store huge quantities of carbon dioxide, while the chemical exploitation of carbon dioxide aims to generate value and develop better and more-efficient processes from a limited part of the waste stream. Provided that the overall carbon footprint for the carbon dioxide-based process chain is competitive with conventional chemical production and that the reaction with the carbon dioxide molecule is enabled by the use of appropriate catalysts, carbon dioxide can be a promising carbon source with practically unlimited availability for a range of industrially relevant products. In addition, it can be used as a versatile processing fluid based on its remarkable physicochemical properties.

Background, aim, and scope One of the most important sources of global carbon dioxide emissions is the combustion of fossil fuels for power generation. Power plants contribute more than 40% of the worldwide anthropogenic CO 2 emissions. Therefore, the increased requirements for climate protection are a great challenge for the power producers. In this context a significant increase in power plant efficiency will contribute to reduce specific CO 2 emissions. Additionally, CO 2 capture and storage (CCS) is receiving considerable attention as a greenhouse gas (GHG) mitigation option. CCS allows continued use of fossil fuels with no or little CO 2 emissions given to the atmosphere. This could approve a moderate transition to a low-carbon energy generation over the next decades. Currently, R&D activities in the field of CCS are mainly concentrated on the development of capture techniques, the geological assessment of CO 2 storage reservoirs, and on economic aspects. Although first studies on material and energy flows caused by CCS are available, a broader environmental analysis is necessary to show the overall environmental impacts of CCS. The objectives in this paper are coal-based power plants with and without CO 2 capture via monoethanolamine (MEA) and the comparison of their environmental effects based on life cycle assessment methodology (LCA). Methods This LCA study examines the environmental and human health effects of power generation of five coal-based steam power plants, which differ in the year of installation (2005, 2010, 2020), the conversion efficiency, and in the ability and efficiency to capture CO 2 . For the removal of CO 2 from combustion and gasification processes in power plants, three main technology concepts exist: (1) precombustion technology, (2) oxyfuel combustion systems, and (3) post-combustion separation. As post-combustion technology shows the highest level of maturity, this study concentrates on this route, focusing on capture using monoethanolamine (MEA). The analysis regards the postcombustion retrofit of coal power plants with MEA to be a general option in 2020. Results Material and energy flows are balanced on the level of single processes as well as for the whole process chains.The life cycle inventory clearly shows decreasing inputs and outputs according to the efficiency increase from 43% to 49% in case of the power plants without CO 2 capture. In case of the MEA plants, all inputs and emissions raise, according to the additional energy consumption, except CO 2 and sulphur dioxide. The strong decrease of SO 2 partly results from the necessary improvement of desulphurisation if MEA wash is used. The influence of up and downstream activities on the results is determined. For the MEA plants, a considerable effect of up and downstream activities on the overall results is observed. Finally, the inventory results are assigned to selected impact categories. Global warming (GWP), human toxicity (HTP), acidification (AP), photooxidant formation (POCP), eutrophication (EP), and primary energ...

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Alkaline water electrolysis (AWE) is a mature hydrogen production technology and there exists a range of economic assessments for available technologies. For advanced AWEs, which may be based on novel polymer-based membrane concepts, it is of prime importance that development comes along with new configurations and technical and economic key process parameters for AWE that might be of interest for further economic assessments. This paper presents an advanced AWE technology referring to three different sites in Europe (Germany, Austria, and Spain). The focus is on financial metrics, the projection of key performance parameters of advanced AWEs, and further financial and tax parameters. For financial analysis from an investor's (business) perspective, a comprehensive assessment of a technology not only comprises cost analysis but also further financial analysis quantifying attractiveness and supply/market flexibility. Therefore, based on cash flow (CF) analysis, a comprehensible set of metrics may comprise levelised cost of energy or, respectively, levelized cost of hydrogen (LCH) for cost assessment, net present value (NPV) for attractiveness analysis, and variable cost (VC) for analysis of market flexibility. The German AWE site turns out to perform best in all three financial metrics (LCH, NPV, and VC). Though there are slight differences in investment cost and operation and maintenance cost projections for the three sites, the major cost impact is due to the electricity cost. Although investment cost is slightly lower and labor cost is significantly lower in Spain, the difference can not outweigh the higher electricity cost compared to Germany. Given the assumption that the electrolysis operators are customers directly and actively participating in power markets, and based on the regulatory framework in the three countries, in this special case electricity cost in Germany is lowest. However, as electricity cost is profoundly influenced by political decisions as well as the implementation of economic instruments for transforming electricity systems toward sustainability, it is hardly possible to further improve electricity price forecasts.