Peters, Jens F.Iribarren, DiegoJuez Martel, PedroBurguillo, MercedesDeyi Hou2024-12-032024-12-032022-06-29Jens F. Peters, Diego Iribarren, Pedro Juez Martel, Mercedes Burguillo, Hourly marginal electricity mixes and their relevance for assessing the environmental performance of installations with variable load or power, Science of The Total Environment, Volume 843, 2022, 156963, ISSN 0048-9697, https://doi.org/10.1016/j.scitotenv.2022.1569631879-1026https://doi.org/10.1016/j.scitotenv.2022.156963https://hdl.handle.net/20.500.14468/24673The registered version of this article, first published in Science of the Total Environment 843 (2022) 156963, is available online at the publisher's website: ScienceDirect, https://doi.org/10.1016/j.scitotenv.2022.156963 La versión registrada de este artículo, publicado por primera vez en Science of the Total Environment 843 (2022) 156963, está disponible en línea en el sitio web del editor: ScienceDirect, https://doi.org/10.1016/j.scitotenv.2022.156963The ongoing energy transition is causing rapid changes in the electricity systemand, in consequence, the environmental impacts associated with electricity generation. In parallel, the daily variability of generation increases with higher shares of renewable energies. This affects the potential environmental impacts or benefits of deviceswith variable load or power, such as electric vehicles, storage systems or photovoltaic home systems. However, recent environmental assessments of the actual benefit of such systems are scarce, with existing assessments majorly using average grid mixes that are frequently outdated and disregard the dynamic nature of renewable generation. This article provides detailed hourly average and marginal electricitymixes for eachmonth of the year, determined for Spain as an illustrative country with a diversified (renewable) power generation portfolio that experienced a rapid change in the last years. These are combined with specific life-cycle emission factors for each generation technology. Main drivers for the impacts of themarginalmix turn out to be natural gas plants and imports, but also pumped hydropower due to its comparably low storage efficiency. Applied to a hypothetical photovoltaic rooftop installation, the differences between environmental assessments on hourly and on annual basis are found to be surprisingly lowwhen assuming that the generated electricity replaces the average grid mix, but substantial when considering the marginal generation mix (i.e., the generation technologies that respond to a change in demand at a given time). This highlights the importance of considering the dynamics of the electricity system and the corresponding marginal electricity mixes when optimizing flexible load or generation technologies under environmental aspects.eninfo:eu-repo/semantics/openAccess53 Ciencias Económicas::5306 Economía del cambio tecnológico ::5306.03 Transferencia de tecnología53 Ciencias Económicas::5312 Economía sectorial::5312.05 EnergíaartículoEnergy storageDecarbonisationLife cycle assessmentPhotovoltaicsEnvironmental impactInventory dataSpain