From Python Puzzles to 700°C Sand: A Visiting Lecturer’s Journey in Stockholm
I’m still buzzing from an incredible week in Stockholm, where I had the honour of serving as a visiting lecturer at KTH Royal Institute of Technology — a true epicentre of energy research and innovation.
As an R&D Leader at PNDC, my mission was clear: to share insights from real-world energy systems while learning from one of Europe’s most dynamic academic hubs. The week was packed — intense, inspiring, and deeply human.
🎓 Teaching the Foundations: Power Systems in Practice
I delivered a lecture on load flow analysis, contingency analysis, and optimal power flow — core tools for designing resilient, decarbonised grids.
The students were sharp, curious, and eager to connect theory with reality.
“How would this work in a grid with renewables?”
“Can we use this in islanded microgrids?”
“What happens when a line fails during peak demand?”
These weren’t just academic questions — they were the kind of challenges we face daily at PNDC. It was a powerful reminder: the future of energy is being shaped in classrooms, just as much as in labs and boardrooms.
💻 The Great Python Puzzle: When Versions Don’t Play Nice
We moved into a hands-on tutorial using pandapower, a Python library for power system analysis.
Now, here’s the twist: I’ve been using Python for years — but I’m not a coder by trade. I’ve kept my environment stable with older, tested versions.
But the students? Most were installing Python for the first time — and the latest version had broken compatibility with pandapower.
😱 Spoiler: It didn’t work.
We spent the night before the tutorial troubleshooting — trying different versions, virtual environments, and pip installs. The confusion was real. But the lesson was golden: version control is non-negotiable in applied research.
📌 Action Plan for Next Year:
We’ll provide a pre-configured virtual environment with exact versions of Python, pandas, and pandapower — along with a step-by-step setup guide. No more midnight debugging!
🔥 Inside the Labs: Where Sand, Solar, and Heat Meet
The real highlight? A tour of KTH’s High-Temperature and Low-Temperature Labs — two worlds of thermal innovation under one roof.
🔥 High-Temp Lab: Sand as a Supercharged Heat Carrier
- 700°C experiments using sand as a fluid medium to transfer heat from concentrated solar power (CSP) plants to steam generators.
- Fascinating detail: The diameter of pipe ends controls sand velocity — a simple, elegant way to manage flow and efficiency.
- Pyrolysis in molten chloride salts at 400°C — exploring ways to recycle PV panels and plastics at scale. A major step toward circular energy systems.
- High-temperature heat pumps (200–400°C) — pushing the limits of industrial decarbonisation.
❄️ Low-Temp Lab: “High” Temperature at 65°C?
- Here, “high temperature” means 65°C — a gentle reminder: context matters, even within a single department.
- Systems designed for district heating, building efficiency, and integration with renewables.
🌐 Beyond the Lab: Co-Creating the CETP Vision
Amidst lectures and lab tours, Jagruti and I also worked on shaping the broad objectives of the CETP (Centre for Energy Transition Partnership) — a large, multi-country consortium tackling real industry challenges.
It was intense. We worked late — Monday to Thursday, often past midnight — refining, aligning, and finding common threads across diverse partners.
There’s something deeply nostalgic about working late in a university building. It reminded me of my days at IIT Bombay, when I’d stay up until 2 a.m. finishing my thesis.
Coming out of the lab at midnight, lights still on, people laughing over coffee — it wasn’t lonely. It was alive.
(P.S. This isn’t KTH. I still haven’t taken a photo of KTH at midnight — but I promise: next year, I will.)
🚶♀️ Bonus: 15,000 Steps a Day in Stockholm
And yes — I did walk 15,000 steps every single day. Stockholm is a city built for walking: green spaces, canals, bridges, and a rhythm that invites exploration.
I didn’t just walk — I felt the city. The crisp air, the quiet hum of the metro, the way sunlight danced on the water.
It was a perfect blend of professional rigour and personal renewal.
✨ Final Thought
This wasn’t just a visiting lecture — it was a conversation across continents, disciplines, and cultures.
I came to teach. I left with new ideas, new connections, and a deeper belief in what’s possible when academia, industry, and passion collide.
And as I packed my bags, I carried with me not just notes and photos — but a renewed spark.
Next up in the series: Part 2 – The Golden Hall, the City Tower, and the Nail Scissors of Herta Müller
Coming soon: A journey through Stockholm’s cultural soul — where science meets art, and history whispers through every corridor.
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