Rapidly transitioning to clean and sustainable energy

I am assistant professor of energy systems modelling in the Department of Engineering Systems and Services at TU Delft. 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.

Research 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.

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.


You can contact me by email. I am always interested to speak to enthusiastic students looking for thesis projects or research experience. Get in touch by email with a CV and some detail on your research interests.

Recent publications

  • 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
  • Policy Decision Support for Renewables Deployment through Spatially Explicit Practically Optimal Alternatives. Francesco Lombardi, Bryn Pickering, Emanuela Colombo, Stefan Pfenninger. (2020). Joule. doi: 10.1016/j.joule.2020.08.002
  • Trade-Offs between Geographic Scale, Cost, and Infrastructure Requirements for Fully Renewable Electricity in Europe. Tim Tröndle, Johan Lilliestam, Stefano Marelli, Stefan Pfenninger. (2020). Joule. doi: 10.1016/j.joule.2020.07.018

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