Fraunhofer-Institut für System- und Innovationsforschung ISI

Filters

5
Reset filters

Settings
Now showing 1 - 5 of 5
  • Publication
    Impact of electric trucks powered by overhead lines on the European electricity system and CO2 emissions
    ( 2019)
    Plötz, Patrick orcid-logo
    ;
    Gnann, Till orcid-logo
    ;
    Jochem, Patrick
    ;
    Yilmaz, Hasan Ü.
    ;
    Kaschub, Thomas
    Despite the comparatively limited stock of vehicles, heavy-duty road transport is responsible for a major share of CO2 emissions from the European transport sector. Electric trucks powered by overhead lines, so-called trolley trucks or catenary hybrid trucks, have been proposed as a potential GHG mitigation option. However, from the perspective of the energy system, trolley trucks constitute an additional and inflexible electricity demand. Here, we analyse scenarios with an ambitious European market diffusion of trolley trucks and their impact on the electricity system and CO2 emissions. Our results show that trolley trucks can noteworthily reduce the CO2 emissions from heavy road transport even when the additional CO2 emissions from electricity generation are taken into account. Furthermore, the actual impact of the additional load from trolley trucks on the total energy system is limited. Compared to the anticipated electricity demand from passenger cars in 2030, trolley trucks require less energy and the load is more equally distributed over daytime. Our findings thus show that electric trucks are an interesting option for CO2 mitigation in heavy road transport.
  • Publication
    Simulating the service lifetimes and storage phases of consumer electronics in Europe with a cascade stock and flow model
    ( 2019)
    Glöser-Chahoud, Simon
    ;
    Pfaff, Matthias
    ;
    Walz, Rainer orcid-logo
    ;
    Schultmann, Frank
    Durability of products and lifetime extension through improvements in product design, repair, reuse and refurbishment are integral components of the circular economy concept. Extended service lifetimes reduce the demand for new resource intensive products and hence contribute to an increase in resource efficiency and resource conservation. However, the use of a consumer product does not only depend on its functioning. Particularly consumer electronics such as smartphones are often only used for comparatively short periods of time before they are replaced by new devices. Even though these used electronics may still have significant value and could be resold as secondhand products, they often remain in households (compartments, shelves, cellars) for long periods of time. When analyzing the effects of technical improvements for lifetime extensions of consumer products, these storage times, which are also referred to as hibernation, need to be taken into account. Hibernation counteracts efforts towards increasing the service lifetimes of consumer electronics and should therefore more strongly be addressed in the discussion about lifetime extension and higher durability. In this paper, we present a dynamic cascade stock and flow model to simulate different use and storage phases of consumer electronics in Europe. This model enables a detailed analysis of modifications in service lifetimes and storage phases. The simulation results emphasize the significant proportion of unused but functioning electronic devices when regarding overall product stocks in society. Based on the simulation results, we show that particularly for small consumer electronics such as smartphones, the systematic implementation of a cascade use system avoiding storage phases could significantly reduce total product demand and the associated resource use. Subsequently, we discuss potential measures that could lead to a reduction of storage time of unused consumer electronics in typical housholds.
  • Publication
    Resource efficiency in the German copper cycle: Analysis of stock and flow dynamics resulting from different efficiency measures
    ( 2018)
    Pfaff, Matthias
    ;
    Glöser-Chahoud, Simon
    ;
    Chrubasik, Lothar
    ;
    Walz, Rainer orcid-logo
    In the context of the increasing depletion of finite natural resources and associated environmental and social problems, it is vital for societies to understand the drivers of resource demand and develop strategies to reduce its negative impacts. One such strategy is the move towards a circular economy, in which linear industrial systems are turned into circular systems where former waste streams from one part of the system can act as inputs in other parts. This includes the substitution of primary with secondary materials, thus reducing some of the negative impacts of primary production. The extent to which this is possible depends on the amount of retired material stocks that are made available for re-use. This article develops a methodology for analyzing material flows in relation to the wider economic system for the special case of copper. For this, a macroeconomic simulation model and a substance flow model are coupled to determine sectoral copper demand on the one hand, and the availability of secondary copper on the other hand. A number of scenarios aimed at reducing primary copper demand or increasing the supply of secondary copper are modeled. The results vary considerably between scenarios, depending on which material efficiency measure is analyzed. Due to delays in the retirement of copper stocks, trade-offs can be observed between reductions of original material demand and the availability of secondary material.
  • Publication
    The impact of daily and annual driving on fuel economy and CO2 emissions of plug-in hybrid electric vehicles
    ( 2018)
    Plötz, Patrick orcid-logo
    ;
    Funke, Simon Á.
    ;
    Jochem, Patrick
    The potential of plug-in hybrid electric vehicles (PHEV) to reduce greenhouse gas emissions highly depends on vehicle usage and electricity source. The electric driving share, i.e. the share of kilometres driven electrically, is specific to PHEV and a key factor for its fuel economy. Altogether, a detailed understanding of all factors influencing PHEV fuel economy is missing, especially with regard to driving distances. We analyse the influence of driving behaviour on fuel economy and more precisely the influences on the electric driving share based on mobility data. We applied a regression with mobility data of 780 vehicles to identify the main factors explaining this variation. Our results indicate that real-world fuel economy of PHEV differs widely among users. The resulting factors that explain up to 80% of the fuel economy are the all-electric range, the annual mileage, the regularity of daily driving, and the likelihood of long-distance trips. In our empirical analysis, the average electric driving share of N=1,831 Chevrolet Volt in real world driving is 78%. When the electricity for charging comes from renewable energy sources the resulting real-world well-to-wheel CO2 emissions of these PHEV are 37 gCO2/km. However, even with the current US electricity mix, the annual CO2 savings of all registered Chevrolet Volts in the U.S. amount to about 57 kt CO2 in comparison to conventional cars. Furthermore, a full charge per day is necessary for high fuel economy and any necessary recharging during the day increases the share of electric driving and lowers the consumption of conventional fuel. Current test-cycle fuel economy ratings neglect these factors. Although fuel economy ratings are good estimates for average usage patterns, they fail to account for the high variation in individual driving behaviour. This should be taken into account by future test-cycles and policies should incentivise high electric driving shares.
  • Publication
    Nutzerakzeptanz von Elektrofahrzeugen: Berufspendlerfahrgemeinschaften als Anwendungsfall
    ( 2018)
    Ensslen, Axel
    ;
    Wohlfarth, Katharina
    ;
    Jochem, Patrick
    ;
    Schücking, Maximilian
    ;
    Fichtner, Wolf
    Die dreijährige sozialwissenschaftliche Begleitforschung eines Feldtests untersucht an sechs Pendlergruppen Treiber und Barrieren der Nutzung von E-Pkw zum Berufspendeln. Es wird analysiert, inwieweit die Nutzung von E-Pkw im Rahmen eines Feldtests (Intervention: organisierte Fahrgemeinschaft, Kostenreduktion, Verfügbarkeitsgarantie) die Akzeptanz von E-Pkw steigern kann und inwiefern diese mit der Nutzungshäufigkeit zusammenhängt sowie ob das Umweltbewusstsein der TeilnehmerInnen einen positiven Effekt auf die Akzeptanz hat. Zur Identifikation der Treiber und Barrieren sowie zur Bewertung der Intervention wurden qualitative Fokusgruppen-Interviews zu Beginn und gegen Ende des Feldtests durchgeführt. Zur Analyse der Korrelation zwischen Akzeptanz und Nutzungshäufigkeit sowie zwischen Akzeptanz und Umweltbewusstsein wurde auf Basis quantitativer Onlinebefragungen ein Querschnittsvergleich mit E-Pkw-NutzerInnen anderer Feldtests durchgeführt. Die Ergebnisse zeigen, dass bei einer hohen Nutzungsfrequenz die Akzeptanz von E-Pkw nachhaltig steigen kann. Die begleitenden Maßnahmen des Feldtests ermöglichten, dass elektrofahrzeugspezifische Barrieren überwunden werden konnten. Trotz regelmäßiger technischer Probleme wurden die E-Pkw im Pendelbetrieb akzeptiert. Es konnte ein deutlicher Zusammenhang zwischen Umwelteinstellungen und der Akzeptanz der E-Pkw festgestellt werden.