Willem Kesteloo
Co-founder PHYSEE


Ever since I was a little kid I've wondered how stuff works - watching my dad wind surfing, looking at lightning when sitting in the car, or playing with remote controlled race cars (those were seriously awesome if you ask me). This curiosity lead me to physics. Both its philosophical nature and its analytical framework offer me perspective on things I don't yet understand. Even the more complex issues or challenges we face. Like for instance our energy problem or 'global warming', 'climate change', however you want to call it. This discussion turned into politics with way too many opinions (and emotions) if you ask me. In its most basic form it is just an unbalanced energy balance, where we simple use (a lot) more fossil fuels than we are replenishing and we will therefore run out (purposefully avoiding the polluting factor). Thankfully there are other resources available for this equation, for instance the sun. However I believe innovations that run on solar power will only become and remain successful it they do not require compromise in functionality, design or costs throughout the entire value chain. We are only going to drive electric if the Tesla looks awesome, has some range, and is not too expensive. That is sustainable innovation without compromise, and that is what we are realizing at the company I co-founded with Ferdinand Grapperhaus, PHYSEE, also.

When we look at buildings and especially their glass façades, we see a lot of untapped potential. We aim to use all those glass surfaces, transparent or tinted, to produce power. We created and patented a technology that allows us to do so in an economical, ecological and aesthetical way with our PowerWindows. PowerWindows are patented and transparent double-paned windows that convert light into electricity. Conventional glass reflects about 30% of the incoming light, we instead collect that with our coating on the outside windowpane, transport it through the glass and convert it at our solar cell strips inside the window frame. PowerWindows can save up to 50% of the total electricity demand when renovating conventional commercial buildings, and up to 100% of newly constructed commercial buildings.



Let's say it is my first real company.. I did have some 'business ideas' when I was younger ;) as a kid a did some DJ-ing at birthday parties for some extra money or later on with 3 friends started an unofficial painting business (good money for that age I'll tell you). 

What do you wish you knew before you started your business?

Ah man, that's an impossible question.. I mean, I've never learned as much as I did in the two years we are now building this company, but I do believe I really needed to go through all those phases to - aside from building the company - develop as a person. So what I wish I knew before I started? Pfff, I wish I knew that it is alright not to know everything before you start (I know that sounds lame). 

What was the strangest marketing (or just in general) experiment you ever did?

We are not too big in marketing just yet, so a general experiment it is. After high school a friend and I decided to travel the world in a Volkswagen Transporter (yes one of those hippy vans). We failed miserably, 'our home' broke down after three months after we already had it repaired once with all the money we saved (from the painting business) and we just got kicked from a vineyard job in France. So no money, no transportation, and absolutely no desire to give up and go home already we did the most awesome human experiment possible: hitchhiking. I won't go into too much detail/anecdotes but if you ever loose faith in mankind, hitchhiking is the most heartwarming experience there is to help you restore faith. I mean, the people we met and the experiences we shared were simply incredible.

What is the biggest thing you struggle with as entrepreneurs and how do you go about it?

I think the biggest struggle there is for entrepreneurs building something from scratch, is the uncertainty if the path you are taking is the right (and quickest) one. One solution might be to simply not worry about it (many ways to Rome, that sort of thing). But if you do struggle with this, the best advice I could give you is to find (an) amazing co-founder(s). Don't take this too lightly, it should be a perfect marriage between individuals, but if you succeed it is the best there is to be able to constantly iterate your train of thoughts with somebody who is in it just as much as you are. I'm most certain that I wouldn't be who I am without my co-founder Ferdinand, and the company sure as hell wouldn't be where it is today without him.  

If you had one piece of advice for someone just starting out, what would it be?

Sometimes friends stuck on their corporate ladder with their golden handcuffs enviously say 'yeah but for you it was easy, you happened to stumble upon this great idea during your studies'. And that is absolutely true. 'The jump' to entrepreneurship for me in that sense was easy. We had the idea, we had a patent backed by the university, some papers published, no mortgage or kids to provide, and we could definitely continue to live on a student budget for a little longer. The advice however I want to give anyone thinking about starting out, the same advice I give those friends, is that after you've made the jump you'll find out it is not about the jump itself but about the swimming after. So if you are worried about taking the jump because you are afraid that your idea is not good enough to make it, allow yourself to jump! After the jump you will find out that it is not about your idea if you will make it, but about your execution ;) good luck!