Michael Weinold


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Weinold

First Name

Michael

ORCID

0000-0003-4859-2650

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2020 - 202512
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Publications 1 - 10 of 12
  • Estimating Fuel Consumption of Commercial Aircraft
    Item type: Conference Poster
    Weinold, Michael; Marty, Noe; Wild, Peter; et al. (2025)
  • Mapping Future Air Travel Demand from Open Data
    Item type: Conference Poster
    Weinold, Michael; Arendt, Ben; Dedic, Dominik; et al. (2024)
  • Letter to the Editor regarding “Methodological framework for life cycle assessment of sustainable aviation (SA) systems”
    Item type: Other Journal Item
    Weinold, Michael; McKenna, Russell (2025)
    Science of The Total Environment
  • Rapid technological progress in white light-emitting diodes and its source in innovation and technology spillovers
    Item type: Journal Article
    Weinold, Michael; Kolesnikov, Sergey; Díaz Anadón, Laura (2025)
    Nature Energy
    Since their introduction to the market in 1996, white light-emitting diodes (LEDs) have greatly improved in performance, efficiency and manufacturing cost. Understanding the extent and mechanisms of rapid progress in white LED technology can provide valuable insights for accelerating innovation in other demand-side clean energy technologies critical for reducing global carbon emissions. Here we show, through cost and performance modelling based on data from literature review, patent analysis and expert interviews, that the efficiency of top-performing warm white GaN-based LED packages increased from 5.8% in 2003 to 38.8% in 2020. Over the same period, the manufacturing cost of low-to-mid-power LED packages decreased by 95.5% from US$1.1 to US$0.05 (in 2020 US dollars). We find that technology spillovers from other sectors accounted for at least 8.5% of efficiency improvements and nearly all consumer experience enhancements, playing an important role in widespread LED adoption in lighting.
  • Technology Assessment of Future Air Transport Systems
    Item type: Conference Poster
    Weinold, Michael; Rohrer, Philipp; McKenna, Russell (2023)
  • GreenGraph: A Novel Tool for Graph-Based Life-Cycle Assessment
    Item type: Conference Poster
    Weinold, Michael; Ghosh, Tapajyoti; Majeau-Bettez, Guillaume (2025)
  • Novel Diagrammatic Notation for Hybrid Life-Cycle Assessment
    Item type: Conference Poster
    Weinold, Michael (2024)
  • Technology Spillovers in Solid State Lighting
    Item type: Master Thesis
    Weinold, Michael (2020)
    The first commercial white light-emitting diodes (LEDs) were introduced in 1997. Since then, they have seen significant improvements in performance and decreases in cost. Despite the significance of the technology, the sources for improvements in performance and reductions in cost have not been thoroughly investigated. The role of technology spillovers, knowledge originating in other technologies, sectors or other scientific discipline, on these has not been studied at all. By investigating both, we hope to learn lessons for accelerating innovation in clean energy technologies for climate change mitigation. Out of the metrics describing LED performance, we find that device sub-efficiencies allows us to directly quantify the effect of breakthroughs. We further identify metrics relevant to consumer experience in lighting. To identify technology spillovers we employ a multi-method approach including a systematic literature review of scientific publications, industry reports, technical periodicals, patents, as well as semi-structured expert interviews. 11 eminent experts from academia and industry were interviewed. To quantify the effect of spillovers on reductions in manufacturing cost, a bottom-up process step resolution manufacturing cost model was developed. To quantify the effect on performance improvements, a combined approach of systematic literature review and spectral efficiency performance simulations based on Python scripts was used. We find that the overall efficiency of the highest performing warm white light-emitting diode packages has improved from η=5.8% in 2002 to η=38.7% in 2020. No single loss channel dominates the overall the efficiency. Instead, an ensemble of loss channels corresponding to different physical loss mechanisms contributes serially and cumulatively. We further find that light-emitting diodes today excel across consumer experience metrics. Any required range of color temperature and color rendering performance can be obtained by spectral engineering of the device. Results from our cost model show that the manufacturing cost for low-mid power devices manufactured at a US based idealized location has decreased from 1.11USD(2020) in 2002 to 0.05USD(2020) in 2020, a 95% decrease. This was found to be largely due to increases in wafer size. Our research shows that technology spillovers affect all performance dimensions of LEDs. During the period 2002 to 2020, they were responsible for 8.5% of the improvements in the total efficiency of devices. They were responsible for ∼100% of the improvements in consumer experience metrics. Due to the proprietary nature of information on changes in the manufacturing process, their effect on manufacturing cost could not be determined. Out of the 7 identified spillovers, all but one were the result of a systematic search for external knowledge by researchers. 5 originated in basic research in academia. We find that spillovers are more likely to affect loss channels which are physically well understood.
  • Teaching Innovation in the Brightway Software Framework for Life-Cycle Assessment
    Item type: Presentation
    Weinold, Michael (2025)
    We are currently living through a didactic revolution in academia: Away from PowerPoint-slides-converted-to-PDF files hidden on institute servers toward open, maintainable interactive online teaching materials that are built on the most widely used scientific programming language. Only a few years ago, building such interactive sites would have been impossible without significant effort by experienced (and expensive) full-stack developers. Now, thanks to significant community efforts around the combination of Python and Web Assembly, even basic knowledge of Python is sufficient to build them. Every PhD student, PostDoc and Professor can turn their teaching materials into a fully-featured interactive website, application or eBook – and even include in-browser code execution! This is an amazing opportunity that the community of sustainability researchers must seize on – especially since there is already a wealth of open-source tools available that can be integrated into these teaching materials. Here, I present three recent teaching innovations the Brightway development team has released in the past two years: An online eBook, a browser-only development environment for Brightway code and an interactive Dashboard based on complex Brightway calculations… all of which are available as templates for the community to use!
Publications 1 - 10 of 12