I am assistant professor of energy systems modelling at TU Delft, in the Department of Engineering Systems and Services. My current research is on understanding the spatiotemporal variability of renewable generation and on quantifying the technical, economic and political trade-offs between different possible ways to build a 100% clean and renewable energy system. You can reach me by email. Are you a student interested in working with me? See the group page.

Spotlight: Trade-offs between geographic scale, cost, and infrastructure requirements for fully renewable electricity in Europe

Source: Adapted from Tröndle, Marelli, Lilliestam and Pfenninger (2020).

Renewable electricity supply in Europe would be cheapest with a continent-wide optimised system where wind and solar power are deployed at the best locations. However, it is also possible to build nationally or subnationally balanced supply systems with cost penalties of 20% or less. Such a low-cost but regionally balanced electricity supply requires continental-scale balancing of renewable fluctuations and an expansion of cross-border transmission capacities, but not necessarily an overall large transmission grid. → Tröndle, Marelli, Lilliestam and Pfenninger (2020), Joule.


My group’s research is on the global transition to a 100% clean and renewable energy system, and on identifying and resolving the technical, economic and policy barriers on the way to that goal. I have a background in environmental science and policy and work on energy as one critical component of the pathway towards an ecological human civilisation.

Open code and data

In the course of my work I created and lead development of the open-source energy system modelling tool Calliope. I am also the creator and lead developer of the Renewables.ninja platform to simulate wind and solar power plants worldwide. I am a member of the Open Energy Modelling Initiative, which promotes openness and transparency in energy system modelling, and of the Open Power System Data project, which provides a free and open data platform for power system modelling.

Recent publications

  • High-Resolution Large-Scale Onshore Wind Energy Assessments: A Review of Potential Definitions, Methodologies and Future Research Needs. Russell McKenna, Stefan Pfenninger, Heidi Heinrichs, Johannes Schmidt, Iain Staffell, Christian Bauer, Katharina Gruber, Andrea N. Hahmann, Malte Jansen, Michael Klingler, Natascha Landwehr, Xiaoli Guo Larsén, Johan Lilliestam, Bryn Pickering, Martin Robinius, Tim Tröndle, Olga Turkovska, Sebastian Wehrle, Jann Michael Weinand, Jan Wohland. (2022). Renewable Energy. doi: 10.1016/j.renene.2021.10.027
  • Mitigating a Century of European Renewable Variability with Transmission and Informed Siting. Jan Wohland, David J. Brayshaw, Stefan Pfenninger. (2021). Environmental Research Letters. doi: 10.1088/1748-9326/abff89
  • Trends in Tools and Approaches for Modelling the Energy Transition. Miguel Chang, Jakob Zink Thellufsen, Behnam Zakeri, Bryn Pickering, Stefan Pfenninger, Henrik Lund, Poul Alberg Østergaard. (2021). Applied Energy. doi: 10.1016/j.apenergy.2021.116731

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