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Exergy-based analyses are useful means for the evaluation and improvement of energy conversion systems. A life cycle assessment (LCA) is coupled with an exergetic analysis in an exergo-environmental analysis. An advanced exergo-environmental analysis quantifies the environmental impacts estimated in the LCA into avoidable/unavoidable parts and into endogenous/exogenous parts, depending on their source. This analysis reveals the potential for improvement of plant components/processes and the component interactions within a system. In this paper, the environmental performance of an advanced zero emission plant (AZEP) with CO2 capture is evaluated based on an advanced exergoenvironmental analysis. The plant uses oxy-fuel technology and incorporates an oxygen-separating mixed conducting membrane (MCM). To evaluate the operation of the system, a similar plant (reference plant) without CO2 capture is used. It has been found that the improvement potential of the AZEP concept is restricted by the relatively low avoidable environmental impact of exergy destruction of several plant components. Moreover, the endogenous environmental impacts are for the majority of the components significant, while the exogenous values are, generally, kept at low levels. Nevertheless, a closer inspection reveals that there are strong interactions among the components of the MCM reactor and the components constituting the CO2 compression unit. Such results are valuable, when the improvement of the environmental performance of the plant is targeted and they can only be obtained through advanced exergy-based methods.

The construction industry is considered as one of the least productive, highest energy consuming, and least digitized industries. The Lean Management (LM) philosophy became a significant way for eliminating non-value-added activities and wastes during a building’s lifecycle. However, studies have shown that philosophies are not efficient by themselves to solve the issues of the construction industry. They need to be supported with the appropriate technologies and tools. Therefore, the integrated use of Building Information Modelling (BIM) with LM or Value Engineering (VE) were proposed in the literature. Nonetheless, it was also seen that BIM can provide more insights and improvements when BIM is integrated with data analysis tools to analyze BIM data. In the literature, the synergies between these concepts are generally addressed pairwise, and there is no comprehensive framework which identifies their relationships. Therefore, this study aims to develop a maturity framework that facilitates the adoption of LM, VE, BIM, and Big Data Analytic (BDA) concepts to address long-standing productivity and digitalization issues in the Architecture, Engineering, and Construction (AEC) industry. Design Science Research (DSR) methodology and its three-cycle view (relevance, rigor, and design cycle) were applied to build the proposed maturity framework. Two interviews were performed to identify and observe research problem in relevance cycle. In the rigor cycle, a comprehensive literature review was performed to create a base for the development of the maturity framework. In addition to the developed base of the framework, lean processes were added to this cycle. In the design cycle, the developed framework was evaluated and validated by five experts through face-to-face interviews. The importance of employer’s requirements to adopt the proposed methodologies, the negative impact of change orders, the importance of pre-construction phases to facilitate value creation and waste elimination, and the usage of common data environment with BIM were identified as the prominent application and adaptation issues.

Electric mobility is beginning to enter East African cities. This paper aims to investigate what policy-level solutions and stakeholder constellations are established in the context of electric mobility (e-mobility) in Dar es Salaam, Kigali, Kisumu and Nairobi and in which ways they attempt to tackle the implementation of electric mobility solutions. The study employs two key methods including content analysis of policy and programmatic documents and interviews based on a purposive sampling approach with stakeholders involved in mobility transitions. The study findings point out that in spite of the growing number of policies (specifically in Rwanda and Kenya) and on-the-ground developments, a set of financial and technical barriers persists. These include high upfront investment costs in vehicles and infrastructure, as well as perceived lack of competitiveness with fossil fuel vehicles that constrain the uptake of e-mobility initiatives. The study further indicates that transport operators and their representative associations are less recognized as major players in the transition, far behind new e-mobility players (start-ups) and public authorities. This study concludes by identifying current gaps that need to be tackled by policymakers and stakeholders in order to implement inclusive electric mobility in East African cities, considering modalities that include transport providers and address their financial constraints.

Abstract Bioenergy systems are expected to expand over the coming decades due to their potential to address energy security and environmental pollution challenges. Nevertheless, any renewable energy project can only survive if approved environmentally superior to its conventional counterparts. Life cycle assessment (LCA) is an internationally standardized and validated methodology to evaluate and quantify the environmental impacts of bioenergy systems. However, due to its methodological scope, the LCA method measures only the environmental consequences of the target products of energy systems. The LCA approach can neither allocate the environmental impacts at the component level nor measure the environmental impacts of intermediate products. These challenges can be substantially resolved by systematically integrating the LCA approach with the thermodynamically-rooted exergy, offering a powerful environmental sustainability assessment tool known as “exergoenvironmental analysis“. Due to the unique methodological and conceptual characteristics of exergoenvironmental analysis in revealing the possibilities and trends for improvement, it has recently received increasing attention to mitigate the environmental impacts of bioenergy systems. Therefore, this review is aimed to thoroughly summarize and critically discuss the evaluation of sustainability aspects of bioenergy systems based on exergoenvironmental analysis. The pros and cons of using exergoenvironmental analysis in bioenergy research are also outlined to identify possible future directions for the field. Overall, exergoenvironmental analysis can offer more detailed information on the environmental consequences of each flow and component of bioenergy production plants, thereby diagnosing the breakthrough points for additional environmental improvements.

Die weltweite Nutzung von Energie aus erneuerbaren Quellen wie Wind, Sonne, Biomasse, Wasser oder Erdwärme steigt kontinuierlich. Eine Vielzahl von Ländern hat im Rahmen ihrer Aktivitäten zum Klimaschutz Ziele für den zukünftigen Ausbau von erneuerbarer Energien verabschiedet. Trotz dieser vielfach ambitionierten Vorgaben und ansteigender installierter Kapazität von erneuerbaren Energien, treten Hindernisse bei der Umsetzung der politischen Ziele zu Tage und deren Erreichen wird gefährdet. Vielfältige Gründe für diese Schwierigkeiten konnten bisher identifiziert werden. Um erfolgreich die Diffusion von erneuerbaren Energietechnologien voranzutreiben und die politischen Zielvorgaben zu erfüllen, müssen die bekannten Hindernisse adressiert und Lösungen gefunden werden. Planungs- und Genehmigungsprozesse als Teil der Entscheidung über die Zulassung erneuerbarer Energieprojekte sind ein Faktor für die erfolgreiche Diffusion dieser neuen Technologien. Ein Element von Planung und Genehmigung sind oftmals Umweltprüfungen. Diese erfordern die Ermittlung und Berücksichtigung der Auswirkungen von erneuerbaren Energieprojekten auf die Umwelt. Das Ziel diese Dissertation ist die Ableitung von Hypothesen zur Rolle von Umweltprüfungen bei der Diffusion von erneuerbaren Energien und zur Notwendigkeit von Innovation bzw. Adaption dieses Instruments. Dieses Ziel wird erreicht durch die Analyse von gesetzlichen Vorgaben sowie der Praxis von Umweltprüfungen im Bereich von erneuerbaren Energien. Dazu werden zwei Fallbeispiele, die Vereinigten Staaten von Amerika sowie Deutschland, untersucht und verglichen. Grundsätzlich kann die Schlussfolgerung gezogen werden, dass Umweltprüfungen in bestimmten Aspekten verändert werden müssen, um den besonderen Herausforderungen bei der Diffusion von erneuerbaren Energien gerecht zu werden. Einige Bereiche der gesetzlichen Vorgaben sowie der Praxis von Umweltprüfungen stellen derzeit Hindernisse dar. Als ein Feld für zukünftige Forschung wird die Charakterisierung sowie empirischer Validierung der Rolle von Umweltprüfungen bei der Diffusion von erneuerbaren Energietechnologien gesehen. Weiterhin ist es nötig, die Prozesse, durch die eine Veränderung von rechtlichen Grundlagen sowie der Praxis von Umweltprüfung erreicht werden können, besser zu verstehen. Dabei ist es von besonderem Interesse zu analysieren, welche Rolle länderübergreifendes Lernen und der Transfer von Erfahrungen haben. The worldwide generation of energy from renewable resources such as wind, sun, biomass, water or ground heat, is constantly growing. Numerous countries have adopted renewable energy goals, often as part of their policies on fighting climate change. However, despite ambitious policy goals and increasing numbers in installed capacity, difficulties in the diffusion of renewable energy technologies occur and are jeopardizing the achievement of the targets. Several aspects have been identified to account for these difficulties in renewable energy diffusion. In order to successfully realize the diffusion of renewable energy technologies and to reach the goals for their future contribution to energy generation, the existing hindrances need to be addressed and solved. Planning and permitting, as the relevant decision-making processes, are one element of successful siting and deployment of renewable energy. Part of these planning and permitting processes often are environmental assessments (EA) requiring the consideration of the effects and impacts of the proposed renewable energy projects on the environment. The goal of this PhD thesis is the generation of hypotheses on the role of EA in the diffusion of renewable energy technologies, and on the need for innovation/adaptation of EA to fit the innovation system of renewable energy technology diffusion. This goal will be pursuit by the analysis of EA systems and EA practice related to renewable energy diffusion. Two cases will be analyzed and compared, namely the United States of America and Germany. In general, the conclusion can be drawn that EA for renewable energy diffusion needs to be improved in certain aspects in order to be able to meet the special requirements of this energy system. Some elements in EA legislation and practice pose certain problems in renewable energy diffusion. One field for further research would be the characterization of the role of environmental EA in renewable energy technology diffusion and its validation by qualitative means. Furthermore, in order to achieve the necessary changes of EA, it is important to enhance the understanding of the processes of change of this instrument. In particular, how cross-national policy learning and transfer of experiences impact the occurrence of such changes needs to be further studied.

The sharing economy is making its way into our everyday lives. One of its business models, car-sharing, has become highly popular. Can it help us increase our sustainability? Besides emissions and vehicle miles traveled, one key aspect in the assessment regards the effect of car-sharing on car ownership. Previous studies investigating this effect have relied almost exclusively on surveys and come to very heterogeneous results, partly suggesting spectacular substitution rates between shared and private cars. This study empirically explores the impact of car-sharing on noncorporate car ownership and car markets in 35 large German cities. The analysis draws on publicly available data for the years 2012, 2013, 2015, and 2017, including, among others, the number of shared cars per operating mode (free-floating and station-based) and the number of cars owned and registered by private individuals (i.e., excluding company cars). We find that one additional station-based car is associated with a reduction of about nine private cars. We do not find a statistically significant relation between car ownership and free-floating car-sharing. Neither type of car-sharing appears to impact the markets for used and new cars significantly. Given the measurable impacts on car ownership levels, this result is surprising and invites future research to study car-sharing’s impact on the dynamics of car markets.

a b s t r a c t This paper represents a unique collaboration between experts in architecture and engineering from around the globe to evaluate the true potential to reduce CO2 emissions from buildings. The result of this experiment in remote collaboration between Europe, USA, Japan and China, was a summary that was generated for the Holcim Forum workshop, "Reduce CO2 - With technology to zero emissions." This covers challenges of reducing emissions from building construction, operation and maintenance while also presenting an array of potential solutions. Here we expand on that work for the benefit of a broader audience.

This paper presents the findings of experimental investigations regarding the influence of 13 different flux enhancing chemicals (FeCl3, polyaluminium chloride, 2 chitosans, 5 synthetic polymers, 2 starches and 2 activated carbons) on respirometric characteristics and nitrification/denitrification performance of membrane bioreactor (MBR) mixed liquor. Flux enhancing chemicals are a promising method to reduce the detrimental effects of fouling phenomena via the modification of mixed liquor characteristics. However, potentially inhibiting effects of these chemicals on mixed liquor biological activity triggered the biokinetic studies (in jar tests) conducted in this work. The tested polyaluminium chloride (PACl) strongly impacted on nitrification (-16%) and denitrification rate (-43%). The biodegradable nature of chitosan was striking in endogenous and exogenous tests. Considering the relatively high costs of this chemical, an application for wastewater treatment does thus not seem to be advisable. Also, addition of one of the tested activated carbons strongly impacted on the oxygen uptake rate (-28%), nitrification (-90%) and denitrification rate (-43%), due to a decrease of pH. Results show that the changes in kLa values were mostly not significant, however, a decrease of 13% in oxygen transfer was found for sludge treated with PACl.