Grid integration of intermittent renewable energy sources using price-responsive plug-in electric vehicles

Plug-in electric vehicles (PEVs) are expected to balance the fluctuation of re-newable energy sources (RES). To investigate the contribution of PEVs, the availability of mobile battery storage and the control mechanism for load man-agement are crucial. This study therefore combined the following: a stochastic model to determine mobility behavior, an optimization model to minimize vehicle charging costs and an agent-based electricity market equilibrium model to esti-mate variable electricity prices. The variable electricity prices are calculated based on marginal generation costs. Hence, because of the merit order effect, the electricity prices provide incentives to consume electricity when the supply of renewable generation is high. Depending on the price signals and mobility behavior, PEVs calculate a cost minimizing charging schedule and therefore balance the fluctuation of RES. The analysis shows that it is possible to limit the peak load using the applied control mechanism. The contribution of PEVs to improving the integration of intermittent renewable power generation into the grid depends on the characteristic of the RES generation profile. For the Ger-man 2030 scenario used here, the negative residual load was reduced by 15 to 22 percent and the additional consumption of negative residual load was be-tween 34 and 52 percent. --Plug-in electric vehicles,demand-side management,variable prices,intermittent generation

Vehicle-to-grid regulation based on a dynamic simulation of mobility behavior

This study establishes a new approach to analyzing the economic impacts of vehicle-to-grid (V2G) regulation by simulating the restrictions arising from un-predictable mobility requests by vehicle users. A case study for Germany using average daily values (in the following also called the "static" approach) and a dynamic simulation including different mobility use patterns are presented. Comparing the dynamic approach with the static approach reveals a significant difference in the power a vehicle can offer for regulation and provides insights into the necessary size of vehicle pools and the possible adaptations required in the regulation market to render V2G feasible. In a first step, the regulation of primary, secondary and tertiary control is ana-lyzed based on previous static methods used to investigate V2G and data from the four German regulation areas. It is shown that negative secondary control is economically the most beneficial for electric vehicles because it offers the high-est potential for charging with 'low-priced' energy from negative regulation. In a second step, a new method based on a Monte Carlo simulation using stochastic mobility behavior is applied to look at the negative secondary control market in more detail. Our simulation indicates that taking dynamic driving behavior into account results in a 40% reduction of the power available for regulation. Be-cause of the high value of power in the regulation market this finding has a strong impact on the resulting revenues. Further, we demonstrate that, for the data used, a pool size of 10,000 vehicles seems reasonable to balance the var-iation in driving behavior of each individual. In the case of the German regula-tion market, which uses monthly bids, a daily or hourly bid period is recom-mended. This adaptation would be necessary to provide individual regulation assuming that the vehicles are primarily used for mobility reasons and cannot deliver the same amount of power every hour of the week. --

Optimizing the charge profile: Considering users' driving profiles

PHEVs are discussed controversially. On the one hand, the evolutionary approach of a hybrid vehicle helps the consumer to adopt to electric driving, using the range extender when driving longer distances. On the other hand, PHEVs have a more complex propulsion system and a potentially low emission impact due to a low electric driving share. These factors, however, strongly depend on the consumers' driving and charging behavior. Therefore, this paper simulates realistic driving based on the national German travel survey. Firstly, battery profiles are modeled using further information about parking locations, charging scenarios, as well as different battery sizes. Secondly, total costs of different alternative vehicles are calculated and minimized varying the battery size. According to the simulation, PHEVs are less expensive and thus important for market adoption. High electric driving shares of more than 80% allow fair emission reductions. And for the few longer trips, PHEVs can use the fall-back option of the internal combustion engine. PHEVs thus do not require an oversized battery and are thus more economical. In the early market, PHEVs will be equipped with smaller batteries; and with higher market share, require customization of the battery size for different customer segments and vehicle types. --

On the design of a European bioeconomy that optimally contributes to sustainable development

The inevitability for a change in humankind's resource and fossil energy consumption is demonstrated by global crises such as the climate change, disturbances of natural cycles, and the loss of biodiversity. The sun provides sufficient energy to generate electricity and by photosynthesis, solar radiation is converted into energy chemically bound in biomolecules, which provide building blocks for the production of various materials, chemicals, or fuels. The bioeconomy puts biomass at the center of an economy that attempts to cover resource and energy demand by renewable materials to address the global challenges. However, the finiteness of the terrestrial surface limits renewables, requiring a prioritization of use. The Sustainable Development Goals (SDGs) provide a common ground for global peace, prosperity, improved health and education, reduced inequality, and spur economic growth while tackling climate change and biodiversity loss, making it the most comprehensive framework for defining objectives in the design of the bioeconomy. Against this background, this dissertation is particularly dedicated to the design of bioeconomic value chains based on agroforestry residues in the European Union, considering economic, environmental, and social objectives to optimally exploit the potential to contribute to a sustainable development. All objectives are matched to SDGs to unveil congruencies, conflicts and trade-offs between different goals, and to provide aggregated insights and courses of action in the agroforestry residue-based bioeconomy to politics, the scientific community, and corporate decision-makers. The availability of agroforestry residue volumes and their current uses is the first major concern of a bioeconomy aligned with the SDGs to be assessed in this work. Key findings are that the most promising agricultural residue in the EU is wheat straw, followed by maize stover, barley straw, and rapeseed straw, which together account for about 80% of EU’s cereals and oil crops residues. In forestry, waste bark from the two coniferous species, spruce and pine, are most promising with the highest supplies in Scandinavia and central EU. The time-series-based forecast model predicts a total increase of the bioeconomic potential of the prioritized agricultural feedstocks from 113 Mt in 2017 to 127 Mt in 2030. The forecast indicates the largest increase of all investigated crops for corn stover at up to 20% until 2030, while rapeseed straw production is forecasted to decrease in many regions. To take environmental and social aspects into account on a regional level, along with international competitiveness, this dissertation develops a multi-criteria strategic network design model for the planning of bioeconomic value chains. The environmental and social objectives are derived by means of Life Cycle Assessment and Social Life Cycle Assessment, respectively. The developed set of 35 economic, environmental, and social objective functions allows for the consideration of 16 of the 17 SDGs. The model is applied for the planning of a second-generation bioethanol production network based on agricultural residues in the EU. Single-criteria optimization shows that sustainably available agroforestry residues could substitute up to 22% of the petrol demand in the EU in 2018 under optimal production networks for certain objectives (i.a., global warming). For environmental objectives, the decision to substitute petrol or edible crops-based ethanol has the highest impact. The greenhouse gas benefits could amount to up to 59 Mt CO2 eq., conforming to about 1.35% of the EU’s 2018 total emissions. However, global warming optimization leads to opportunity costs for other objectives. While for ecosystem quality, for example, the achieved value reaches 50% of its optimum, other categories like land use and water consumption could even be net deteriorated by optimizing global warming. For objectives such as land use, only 19% of the total agroforestry residues is used to substitute 100% of the edible crops-based ethanol, which would free up 11.7 billion m2 crop land. Social objectives lead to large and labor-intensive production networks distributed all over the EU. Depending on the social objective, the value creation slightly shifts regionally. To optimize local employment, the network relocates to regions with high unemployment rates, such as Spain, Italy, and parts of France. Economically strong metropolitan regions are at a disadvantage in favor of weaker regions of Central and Eastern EU when optimizing economic development. At best, up to 140,000 new jobs could be created in the EU while 12,000 jobs could be lost due to substitution of reference products. In terms of network extend, most socially and environmentally optimal production networks are similar, although the substitution decision has little impact for social objectives. This means that interesting trade-offs between social and environmental objectives can be found with only minor sacrifices. Economically optimal networks are much smaller and more centralized than environmental ones, and lead to costs of about 0.75 €/l second-generation ethanol. Environmental optimization results in cost between 0.88 €/l to 2.00 €/l, which implies that large-scale bioethanol production is not economically feasible with today’s oil prices and taxes. While the single-criteria optimization reveals conflicts within and between the environment, social, and economic dimensions, Pareto optimization is conducted to unveil trade-offs between conflicting goals. Significant environmental and social benefits can often be realized with only small economic detriments, and vice versa, economic profitability can substantially be improved at low environmental opportunity cost. Furthermore, the applied Pareto optimization shows that the endpoints human health and ecosystem quality are suitable aggregators of environmental impact categories, wherefore they could serve as representative of the environmental dimension in decision-making. Nonetheless, a transparent consideration of a broad range of impacts and knowledge about the categories’ contributions remains indispensable to reveal possible negative consequences of a decision. In a final step, the objective functions are matched to SDGs, and opportunity cost between the objective functions are calculated to unveil congruencies and conflicts between different goals. The assessment of relationships between the different SDGs supports the perception that different aspects of sustainability are not equally directed. Sustainability, expressed by the SDGs, is rather case-specific and varies between a multitude of interdependent social, environmental, and economic criteria. Decision-makers, whether at the corporate level pursuing one or more business objectives or at the policy level, using the SDGs as a framework, should be aware of the reciprocities between the different criteria. The dissertation shows that the European bioeconomy has a great potential to contribute to sustainable development. Multi-criteria optimization models enable sound trade-off decisions that are aligned to the SDGs

Evaluation of European electric vehicle support schemes

Electric vehicles can reduce carbon dioxide emissions, increase energy efficiency, and help to reduce the dependency on oil imports. However, today's technical and economic challenges are preventing mass-market adoption. In order to create an early market and support economies of scale in production, some European countries have already established support schemes. This research study aims to provide an overview of the existing support schemes in Europe and to assess them using four criteria: effectiveness, efficiency, practicability, and political acceptance. The study concludes with an impact analysis of today's economic support schemes which considers the total costs of ownership. While one-time support schemes help to reduce the large initial investments for EVs, recurring instruments are often more effective and efficient but also smaller in volume. The comparison of the different regional incentive schemes reveals that EVs today are only economically attractive in Denmark and Norway, but at relatively high prices. Thus, regulators need to increase the volume and efficiency of the support schemes, establish high scoring instruments, and align these on a European scale. In addition, non-monetary support, e.g. free-parking, can help to overcome technical or smaller economic hurdles. --

Optimizing plug-in electric vehicle charging in interaction with a small office building

This paper considers the integration of plug-in electric vehicles (PEVs) in micro-grids. Extending a theoretical framework for mobile storage connection, the economic analysis here turns to the interactions of commuters and their driving behavior with office buildings. An illustrative example for a real office building is reported. The chosen system includes solar thermal, photovoltaic, combined heat and power generation as well as an array of plug-in electric vehicles with a combined aggregated capaci-ty of 864 kWh. With the benefit-sharing mechanism proposed here and idea-lized circumstances, estimated cost savings of 5% are possible. Different pricing schemes were applied which include flat rates, demand charges, as well as hourly variable final customer tariffs and their effects on the operation of intermittent storage were revealed and examined in detail. Because the plug-in electric vehicle connection coincides with peak heat and electricity loads as well as solar radiation, it is possible to shift energy demand as desired in order to realize cost savings. --Battery storage,building management systems,dispersed storage and generation,electric vehicles,load management,microgrid,optimization methods,power system economics,road vehicle electric propulsion

Invest in fast-charging infrastructure or in longer battery ranges? A cost-efficiency comparison for Germany

To reach ambitious CO₂ mitigation targets, the transport sector has to become nearly emission-free and the most promising option for passenger cars are battery electric vehicles (BEV) powered using renewable energy. Despite their important benefits, BEV still face technological barriers, mainly their limited battery range and the limited availability of public fast-charging infrastructure. These factors are hindering the diffusion of electric vehicles (EV). The question of how to address these technical barriers has been widely analyzed in the literature, but so far there has been no cost-efficiency comparison of longer battery ranges and more widespread fast-charging infrastructure that evaluates them both technically and economically. This paper aims to find cost-efficient ways to address limited battery ranges and availability of public fast-charging infrastructure. We focus on German passenger cars that are licensed to commercial owners, since these are an important first market for EV. Our results indicate that fast-charging infrastructure is very cost-efficient as it enables significant proportions of BEV in the fleet at low infrastructure density. The technically feasible maximum BEV shares in the commercial sector can only be achieved with longer battery ranges. However, longer battery ranges are currently associated with comparatively high additional costs

Technologie-Roadmap Lithium-Ionen-Batterien 2030

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Variable Stromtarife aus Kundensicht: Akzeptanzstudie auf Basis einer Conjoint-Analyse

Das Energiewirtschaftsgesetz der Bundesrepublik Deutschland schreibt Energieversorgern vor, bis Ende 2010 lastabhängige und/oder zeitvariable Stromtarife anzubieten. Bisher ist jedoch noch wenig über die Einschätzung dieser Tarifmodelle durch die Konsumenten bekannt. Jedoch nur wenn solche flexiblen Tarife neben den Anforderungen der Energieversorgungsunternehmen (EVU) auch den Bedürfnissen der Kunden Rechnung tragen, können die gewünschten Effekte Lastverlagerung und Energieeinsparung realisiert werden. Die vorliegende Studie ermittelt deshalb Konsumentenpräferenzen in Bezug auf entsprechende Stromtarife auf Basis einer Conjoint-Analyse mit 160 Befragten. Dieses Verfahren erlaubt es, von der Beurteilung ganzer Produktkonzepte auf die Nutzenwerte einzelner Merkmalsausprägungen zu schließen. D. h. im vorliegenden Fall, die Attraktivität der einzelnen Tarifkomponenten zu bestimmen. Die Ergebnisse liefern konkrete Hinweise für die Gestaltung von Tarifmodellen. Die Analyse zeigt, dass Stromkunden einen statischen Tarif bevorzugen, und dass der Nutzen für die Kunden mit steigendem Grad der Dynamik des Tarifs, d.h. der Häufigkeit und Regelmäßigkeit der Schwankung des kWh-Preises, abnimmt. Darüber hinaus wird eine geringe Schwankungsbreite des Preises je kWh gegenüber einer höheren Schwankungsbreite bevorzugt. Für das Lastmanagements bevorzugen die Befragten programmierbare Haushaltsgeräte, die automatisch auf Preissignale reagieren gegenüber einer manuellen Steuerung. Insgesamt weisen die Ergebnisse somit daraufhin, dass eine breite Einführung variabler Tarife vermutlich nur in Kombination mit einer automatischen Steuerung zu positiven Effekten führen kann, da die Konsumenten statische Tarife bevorzugen, mit denen der Umgang im Alltag einfacher ist. --Variable Stromtarife,Lastverschiebung,Kundenakzeptanz,Smart Home

Multicriteria optimization as enabler for Sustainable Ceramic Matrix Composites (SCMC)

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