Andreas Froemelt

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Froemelt

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Andreas

ORCID

0000-0001-9388-7816

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Publications 1 - 10 of 26

Environmental impacts of natural resource use
Hellweg, Stefanie; Pfister, Stephan; Cabernard, Livia; et al. (2019)
International Resource Panel ~ Global Resources Outlook 2019
Decoupling economic growth and environmental degradation requires sustainable sourcing and management of resources over the whole life cycle. While the mass-flow indicators of chapter 2 are very useful for understanding the environmental pressures from material consumption, information about the environmental impacts of resource use and resource management practices is also needed to support policymaking for the sustainable use of natural resources (Voet et al., 2005). This chapter focuses on the environmental consequences of resource extraction and processing. It illustrates the legitimate need for appropriate policy to manage natural resources, which is required if we are to remain within the safe operating space (Steffen et al., 2015) and achieve the SDGs.
Zernez Energia 2020 - Leitfaden
Wagner, Michael; Weyell, Christian; Christiaanse, Kees; et al. (2015)
Energy and greenhouse gas emission reduction potentials resulting from different commuter electric bicycle adoption scenarios in Switzerland
Bucher, Dominik; Buffat, René; Froemelt, Andreas; et al. (2019)
Renewable and Sustainable Energy Reviews
Carbon footprint hotspots in a Swiss municipality
Froemelt, Andreas; Mauchle, Manuela; Steubing, Bernhard; et al. (2015)
Zernez, a municipality with 1003 inhabitants in the Swiss Alps, has recently initiated a collaboration with ETH Zurich to identify ways to reduce its greenhouse gas (GHG) emissions. The present study aimed thus at determining the current carbon footprint of Zernez so as to identify the most relevant sectors and reduction potentials regarding GHG emissions. For this purpose, material and energy flows were assessed. The main data source was a database established during the project which contains comprehensive information about energy consumption at household level and specific data for all buildings in the municipality. Additionally, this dataset was amended by means of interviews, statistics of federal or cantonal offices, federal surveys, traffic censuses, literature values and life cycle inventory databases. The CO2-balance was then set up by combining energy and material flow analyses with methods of life cycle assessment. Special attention was paid to the consistent definition of system boundaries, adopting two perspectives: the consumption and the production perspective. The former concentrates on the impacts caused by the domestic final demand and includes therefore imported upstream emissions, whereas the latter quantifies the direct emissions within the geographical boundaries of the municipality. The production perspective allows identifying the most relevant direct emitters, while the consumption perspective uncovers the most important consumption areas by taking into account all consequences of consumer demand. Even though the result of the consumption perspective with total GHG emissions of 10.7 t CO2-eq/(cap yr) is very close to the production perspective with 10.9 t CO2-eq/(cap yr), these two viewpoints are fundamentally different. The production perspective revealed that 70% of the direct emissions in Zernez are caused by agricultural activities, in particular live-stock farming. From a consumption-oriented point of view, however, mobility, housing and nutrition are the most important areas causing more than 50% of the consumption induced emissions. Compared with the national average of 12.8 t CO2-eq/(cap yr) for the consumption perspective, the inhabitants of Zernez entail slightly lower GHG emissions. For example, lower emissions incur in the area of housing due to a large share of buildings heated by wood and by a low-carbon electricity mix. Based on this study, the municipality of Zernez is currently developing an action plan to reduce GHG emissions and increase the shares of renewable energy sources in the future.
Robust high-dimensional screening
Kim, Aleksandra; Mutel, Christopher Lucien; Froemelt, Andreas (2022)
Environmental Modelling & Software
Global sensitivity analysis (GSA) is a valuable tool for filtering out non-influential model inputs. In combination with robustness, convergence and validation analyses, GSA can be particularly beneficial in interpreting and simplifying models with tens of thousands of independent inputs. However, there is lack of research on robust screening of such large models, where the curse of dimensionality can make existing analyses obsolete. We aim to close this gap by evaluating the computational performance of Spearman rank correlation coefficients, Sobol and delta indices, and gradient boosted trees regression. Numerical experiments are conducted for the Morris test function and a life cycle assessment model with 10'000 inputs each. Our results enable us to recommend a standardized procedure for higher-dimensional models which efficiently tests for model linearity, GSA screening, and convergence and robustness analyses of sensitivity indices, screening and rankings.
Source-specific dynamics of organic micropollutants in combined sewer overflows
Furrer, Viviane; Froemelt, Andreas; Singer, Heinz; et al. (2025)
Water Research
Combined sewer overflows (CSOs) discharge organic micropollutants (MPs) into open water bodies, posing potential environmental threats. Knowledge of the numbers, sources, and dynamics of MPs during CSOs is scarce but crucial for assessing their impact and developing mitigation strategies. To shed light on the dynamics of dissolved organic MPs in CSOs, we conducted high-temporal-resolution sampling (10 min composite samples) followed by liquid chromatography high-resolution mass spectrometry analysis, both target (60 substances) and nontarget, at two CSO sites in a small [17 hectares reduced (hared)] and a large (368 hared) catchment for over 10 events each. We observe similar patterns among indoor substances in the large catchment and among tire-associated compounds in both catchments, indicating source-specific behavior. Due to high and diverse concentration variability, no temporal correlations were found among indoor substances in the small catchment or among pesticides in either catchment. A random forest classifier was applied to assign nontarget time series to indoor and road sources in the large catchment. The results indicate that CSOs discharge several thousand substances from indoor sources, followed by a few hundred from outdoor sources with continuous leaching. These high numbers substantially surpass the scope of traditional target lists and underscore the importance of broad-spectrum screening methods when assessing MP contamination.
A Model Faces Reality: Energy Demand of Swiss Residential Buildings
Froemelt, Andreas; Hellweg, Stefanie (2015)
A virtual platform to evaluate policy scenarios targeting environmental impacts from household consumption
Froemelt, Andreas; Heeren, Niko; Buffat, René; et al. (2017)
Household demand for products and services triggers a multitude of economic activities along the supply chain of each product and service, involving the use of resources and the release of emissions. Assessing environmental footprints of households is thus an important basis to identify environmental strategies. This study aimed to develop a comprehensive regionalized bottom-up model for Switzerland which is able to assess the environmental impacts induced by individual households. The purpose of this overarching model is to provide a virtual platform for detailed scenario analysis which shall support effective political decision making on different scales. Three existing bottom-up models were merged: a building stock energy model, an agent-based transport simulation and a household consumption model. All of them were tested and evaluated beforehand. The physically-based building energy model estimates space heating, hot water and electricity demand for each residential building based on simplified energy balances as a function of time, site, climate data, building characteristics, surrounding topography and 3D-geometries. The mobility sub-model builds upon the simulation results of MATSim, an agent-based traffic simulation framework. The application of MATSim to Switzerland reproduced the mobility behavior of the Swiss population and provides spatio-temporal information on chosen traffic modes and driven routes for each agent. The third sub-model derives a detailed financial budget for each Swiss household and enables the quantification of consumption of food, consumables, and other goods and services. Linking these sub-models with environmental background data enabled to compute an environmental profile for each individual household in Switzerland. The application of this model to the current situation of Switzerland revealed interesting differences between individual households, different regions and different consumption areas. These differences emphasize the importance of bottom-up modelling. However, the potential of this model goes even beyond: The high resolution of all three sub-models permits detailed scenario analysis. The component-based approach of the building sub-model facilitates the investigation of detailed refurbishment scenarios with regard to improved insulation or new heating technologies. The link to MATSim allows for analyzing future mobility scenarios, ranging from electric car penetration and increased home office activities to autonomous vehicle systems. The household consumption model considers these scenarios not only in the context of total household consumption and potential burden shifts between consumption areas (rebounds), but enables additionally the simulation of further scenarios such as changes in diets. In follow-up research, the interlinking of the three sub-models is currently reinforced in order to form a complete agent-based model for Switzerland in which agents can manage their expenditures and interact with the mobility system as well as with buildings. This improved model will allow for analyzing also dynamic scenarios such as the diffuse penetration of new technologies and associated rebound effects. By covering the variability of household behavior and quantifying the demands and environmental footprints of households in the current state and in scenarios, the model identifies reduction potentials of environmental impacts and delivers important insights for the derivation of constructive and targeted environmental strategies for different regions and different household types.
Comparison of an energy demand and CO2-footprint model for the life cycle assessment of individual housing in two municipalities
Froemelt, Andreas; Saner, Dominik; Hellweg, Stefanie (2014)
Global Sensitivity Analysis of Background Life Cycle Inventories
Kim, Aleksandra; Mutel, Christopher Lucien; Froemelt, Andreas; et al. (2022)
Environmental Science & Technology
In recent years many Life Cycle Assessment (LCA)studies have been conducted to quantify the environmentalperformance of products and services. Some of these studiespropagated numerical uncertainties in underlying data to LCAresults, and several applied Global Sensitivity Analysis (GSA) tosome parts of the LCA model to determine its main uncertaintydrivers. However, only a few studies have tackled the GSA ofcomplete LCA models due to the high computational cost of suchanalysis and the lack of appropriate methods for very high-dimensional models. This study proposes a new GSA protocolsuitable for large LCA problems that, unlike existing approaches,does not make assumptions on model linearity and complexity andincludes extensive validation of GSA results. We illustrate thebenefits of our protocol by comparing it with an existing method in terms offiltering of noninfluential and ranking of influentialuncertainty drivers and include an application example of Swiss household food consumption. We note that our protocol obtainsmore accurate GSA results, which leads to better understanding of LCA models, and less data collection efforts to achieve morerobust estimation of environmental impacts. Implementations supporting this work are available as free and open source Pythonpackages.

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Andreas Froemelt

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