Overcoming generators: ‘How can I work in construction without acting to decarbonize it?’

“While working at Kier Group —one of the UK’s largest construction companies, ed.— I asked myself: ‘Can I work in the construction industry without doing something to decarbonize it?’ given my connection with this industry, I felt the need to act to change it,” recalls Teun van ‘t Veer. This question led him to found Renset, a company developing portable, modular power stations as a cleaner, more sustainable alternative to generators in construction sites.

The battery modules – each with a 1.25 kW capacity fitting in a unit that can house four –  can be quickly ejected without interrupting the load. The unit can provide energy to power any handheld device, such as breakers, large saws, and even a small forklift. A battery management system allows the control of batteries using a smartphone to optimize module switches and track energy usage. 

Renset comes from Van 't Veer’s background. His family has been involved in the industry, and he also worked in it himself after getting a bachelor’s in industrial design engineering at Delft’s University of Technology and a Master of Business Administration at the Queen Mary University of London. Another thing the founder got from his family is the entrepreneurial spirit. His father, mother, and sister all started their own ventures—so did he. A few months ago, his brother  Stijn van ‘t Veer also joined Renset as co-founder and CTO, bringing his technical background acquired from previous experiences working for Philips and telecom company KPN. 

So, he started working on Renset next to his main job while living in the UK. After two years, he decided it was time to devote all his energies to the project, moving back to the Netherlands and founding Renset. Three years later, the team expanded, and the venture found a space to thrive at the startup incubator YES!Delft and is kicking off production.

Challenges in replacing generators

Although the founder had knowledge and a network in the construction industry, creating a product from scratch was “way more difficult” than the engineer could have ever imagined. Visiting many building sites, he knew of their reality—the widespread usage of generators for power on-site. At the same time, given the looming climate targets, Renset’s CEO was aware that those polluting power units had to be replaced by cleaner ones. 

These generators are the preferred way to bring energy to construction sites where there is no power connection. For every megawatt produced, the average generator produces 0.79 metric tons of CO₂ – a metric ton is size-wise equivalent to a medium-sized van. The building industry is responsible for 37% of global emissions, and its dynamics make it often resistant to change. 

“The key is having a good product and a commercial proposition. Contractors—people overseeing construction projects, ed.—make low margins, making them resistant to invest. Besides, our battery is a replacement for an established product. Initially, we had a heavy box, which would cost three times the amount of a generator. Many contractors were happy with it but couldn’t afford it.”

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Perfecting portable power– a continuous iteration

“The first prototype was just a wooden box with a few batteries and an inverter,” says Van ‘t Veer. After that first concept, three more came, resulting from more trials in the field. In addition to conducting pilots on construction sites, the portable battery was tested in different settings, such as the music festival Mysteryland.

The Delft team used every bit of feedback it could to improve the product. “In the Netherlands and the UK– where all pilots were conducted–  it rains a lot, meaning that modules need to be changed even when it rains to make the battery as usable as possible. We didn’t initially think of this feature. Still, as we learned about it during a pilot, we went back to our lab and redesigned our product to make it possible,” the CEO says, underlining the continuous learning in creating the best product. 

Although the heavy wooden box he started with was nothing but perfect, Van ‘t Veer believes it has helped the company a lot. “One of the keys to our successes has been to go to construction sites and show it, to get feedback from workers.” With production in full swing, the startup reached an agreement with a UK distributor to sell the first units.

Van 't Veer and part of Renset team posing with the battery - © Renset

Flexible energy systems 

Meanwhile, the Delft-based startup is considering new ways to improve its offerings. The company’s in-house asset management platform coming with the Renset certainly offers module owners more flexibility, but more can be done. With the battery modules being at the core, refilling stations can be created to swap on the go and open up their usage to more applications, too. 

Implementing such a vision would pave the way for a battery-as-a-service system, reducing ownership costs and boosting adoption. The batteries could also help relieve stress on the electricity grid. 

Excitement as fuel for progress

Visiting construction sites to talk with workers remains Van ‘t Veer’s favorite part of the job. “If you have a good tool to show, they love it. And it is always nice to see them enjoying it, but perhaps it is just me being an engineer.” 

This excitement is an excellent fuel to progress in the venture. The bulk of the decarbonization of society - and the construction industry – remains to be done, and everyone should contribute, as per Van ‘t Veer. “With Renset, I found the right balance between sticking to an industry close to me in many ways and doing something different. It is great to see our product finally being implemented. Every generator we replace with a battery might be a small leap for the industry, but it is still a good step forward.”