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Electrification of transport is an important option to reduce greenhouse gas emissions. Although many studies have analyzed emission implications of electric vehicle charging, time‐specific emission effects of charging are inadequately understood. Here, we combine climate protection scenarios for Europe for the year 2050, detailed power system simulation at hourly time steps, and life cycle assessment of electricity in order to explore the influence of time on the greenhouse gas emissions associated with electric vehicle charging for representative days. We consider both average and short‐term marginal emissions. We find that the mix of electricity generation technologies, and thus, also the emissions of charging, vary appreciably across the 24‐h day. In our estimates for Europe for 2050, an assumed day‐charging regime yields one‐third‐to‐one‐half lower average emissions than an assumed night‐charging regime. This is owing to high fractions of solar PV in the electricity mix during daytime and more reliance on natural gas electricity in the late evening and night. The effect is stronger during summer months than during winter months, with day charging causing one‐half‐to‐two‐thirds lower emissions than night charging during summer. Also, when short‐term marginal electricity is assumed, emissions tend to be lower with day charging because of contributions from nuclear electricity during the day. However, the results for short‐term marginal electricity have high uncertainty. Overall, our results suggest a need for electric vehicle charging policies and emission assessments to take into consideration variations in electricity mixes and time profiles of vehicle charging over the 24‐h day. [ABSTRACT FROM AUTHOR]

The ongoing needs to develop power systems towards more environmentally friendly technologies with respect to climate change in conjunction with the continuous evolution of the respective market conditions is leading to a transition away from the traditional system operation. The upcoming challenges have motivated the development of an increasing number of models for transmission grids. Nevertheless, the high complexity of such models renders it exceedingly difficult to compare their results as well as any corresponding conclusions. In this paper, we develop an open framework to compare a variety of pan-European transmission grid models with a strong focus on the German power system. The comparison is performed in both a qualitative and quantitative manner, depending on the investigated modeling aspect including input data, methods, system boundaries and results. The quantitative model comparison is done by performing harmonized model experiments, one for 2016 as back testing and one for 2030 for analyzing the future system. Core elements of our comparison framework are: We proved that our comparison framework is suitable to make similarities and differences between the different model results visible, e.g. using quadratic heat maps. To ensure transparency and to support the open modeling community, the fact sheets with the model specifications and the database with selected model results are uploaded on the open energy platform. • Development of a novel framework to compare transmission grid models. • Proof of concept for the comparison framework using indicators and visualizations. • Definition and publication of reference data sets for the years 2016 and 2030. • Transparency by publishing the developed factsheets with detailed model specifications. • Support of the open modeling community by using the open energy platform. [ABSTRACT FROM AUTHOR]