Startup Story: Solar Monkey

The sun is perhaps one of the most consistent and environmentally-friendly sources of energy we have – and with non-renewable energy resources set to decline eventually, it is now the time to embrace technology and make the most out of solar power. Jan Pieter Versluijs and Mels van Hoolwerff had a similar idea, too, when they co-founded Solar Monkey about three years ago. Today, their startup offers software to solar panel installers, which allows them to design solar systems within minutes, and exactly calculate and guarantee the energy output.


The idea for Solar Monkey was born around the time when Mels was graduating from his Master’s in Sustainable Energy Technology – a degree Jan Pieter got as well – where he was working on an algorithm for calculating the exact output of solar panel systems. “It was then that we came to the idea of turning this into a business,” Jan Pieter remembers.

When they looked into the then-existing products on the market, however, Jan Pieter and Mels discovered that many of them had significant flaws. While some of the tools available for calculating energy output involved a lot of modeling, thus being very time-consuming, others did not even have the necessary precision to calculate, let alone guarantee, that output.

“What we wanted to achieve was more security in the solar panel market, so that we shift the paradigm from buying and selling a solar panel system to actually guaranteeing sustainable solar energy output,” Jan Pieter explains.

Today, Solar Monkey’s offering is mainly two-fold: On the one hand, they provide installers with software that makes use of 3D data and already existing aerial images, and allows for the design of solar panel systems remotely and within minutes. On the other hand, the team also offers an output guarantee, which installers can use to (as the name suggests) guarantee the output of their solar panel systems.


With a current team of eleven full-time employees and several interns, Solar Monkey has worked hard to get to where they are now. In the summer of 2015, they were accepted into YES!Delft’s Incubation Program, which seems to have given them a boost of confidence, among many other things.

“YES!Delft has helped us a lot,” says Jan Pieter, emphasizing the ‘a lot’ at the end of the sentence. “What you get there is a tremendous network with other entrepreneurs but also with a lot of businesses. We got a lot of help with legal [and other] advice, and we also got in touch with our investors through YES!Delft.”

Currently, the startup has more than 300 clients of its own and makes between 45.000-55.000 euros in revenues each month. Last year, they also secured a large subsidy for a TKI (Topconsortia voor Kennis en Innovatie) project with a number of partners and are currently raising an investment round of 1.9M to facilitate further growth.


The number-one priority now is to roll out their product even further, until they are able to offer installers a completely automated process for designing solar panel systems. “As soon as we have that,” Jan Pieter explains, “it will have a tremendous value, as installers will be able to design PV systems for whole areas [100.000 buildings or more] within days.” The longer-term goal is to target municipalities and scale up the use of solar energy in the Netherlands.

In terms of growth, Solar Monkey is looking towards increasing revenues and consolidating market share in the Netherlands, whilst continuing growth internationally.

“Currently we are the Dutch market leader in solar software. We are now raising 1.9M to continue our international growth.” It’s like they say: Go big or go home. From the looks of it, team Solar Monkey is focused on the big.


January 2015 – Company founded

January 2016 – Investment from Innovation Quarter and one private investor

March 2016 – STW subsidy secured

August 2015 – Admission into YES!Delft’s Incubation Program

November 2016 – Subsidy for TKI project secured

December 2017- Became market leader in the Netherlands, serving more than 300 installer clients

September 2018 – International pilot version online


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