In Werkendam, SDK Engineering prepares construction machinery for the energy transition.

From within Werkendam, Steven de Kam runs an engineering company that gives construction machinery a second life. With hybrid and electric conversions, a new production facility, and magnet-free motors, SDK Engineering is taking the next step.

Anyone who speaks with Steven de Kam quickly notices that he is not one to sit still. The director of SDK Engineering combines the down-to-earth mindset of a diesel specialist with the enthusiasm of an engineer constantly pushing boundaries. From its base in Werkendam, the company delivers complete drivetrain solutions for heavy machinery, ranging from fully electric to hybrid and everything in between. The recent expansion with a 1,800-square-meter production hall marks a new chapter.

“We already had a 940-square-meter workshop, but we’ve now added a high-bay facility with large doors,” says De Kam. “This allows us to handle the full conversion and construction of machines. From challenge to solution, to execution, to certification—literally from A to Z.”

Practice over theory

SDK Engineering clearly positions itself as a system integrator. The company designs, engineers, and builds complete drivetrain systems, both electric and hybrid. What sets it apart is the breadth of its expertise. Electrical engineering, mechanical engineering, drafting, and software development are all handled in-house. De Kam sees this as the key to delivering practical solutions.

“Our roots are in diesel engines—we truly have boots on the ground,” he explains. “Over the past seven years, we’ve built our own expertise in electrification and machine construction. That enables us to deliver highly practical, out-of-the-box solutions.”

Broad portfolio, always tailored

SDK Engineering’s order portfolio reads like a catalogue of the energy transition in construction. The company builds complete hybrid generator sets from scratch, electrifies machines with battery packs or grid connections, develops mobile battery containers on crawler tracks, and provides hybrid retrofit solutions for existing equipment. The power range spans from 5 kW to 1,500 kW and from 20 kWh to 2 MWh in storage capacity.

“Every client has specific requirements,” De Kam explains. “One operates their machine in one way, another in a completely different way. You can go for a one-size-fits-all solution, but that’s like a Swiss Army knife, it does everything, but nothing perfectly. We truly focus on customization.”

Silent Piler and anchor drilling machine

A strong example is the conversion of a Giken Silent Piler for contractor Sterk. SDK Engineering replaced the original power unit with an electric-hybrid drivetrain and designed an entirely new undercarriage to accommodate the battery packs.

“The batteries didn’t fit anywhere,” says De Kam. “So we engineered a complete base unit that sits underneath the machine. Everything is fully integrated into one functional system.”

Previously, the company converted an anchor drilling machine for Hakkers into a hybrid system. Currently, SDK Engineering is working on converting a 35-ton Doosan for sheet pile extraction, fully electric with 833 kWh. A 120-ton Sennebogen crane has also been equipped with a hybrid system featuring a custom-built battery pack.

“Just name it,” says De Kam. “We’re now working on the third machine for Hakkers and the third for Sterk. Clients keep coming back.”

The operator determines success

Behind all the technology lies a philosophy centered on the user. De Kam emphasizes that a converted machine must feel familiar to the operator.

“It may be a kind of space shuttle on the inside, but it shouldn’t feel like one on the outside. Keep it simple. An operator should be able to use it instinctively.”

That’s why SDK Engineering closely involves operators throughout every project, even after delivery.

“We keep communication lines very short. What are they running into? What do they feel? What do they experience? That feedback feeds directly into the development of future machines.”

The best compliment came recently from an operator who described a delivered Woltman 5525DD in one word: “Monster.”

“That’s what gets me out of bed,” De Kam says.

Magnet-free motors as the next step

In addition to expanding production capacity, SDK Engineering has partnered with a manufacturer of so-called reluctance motors. These electric motors operate without permanent magnets and without copper, while delivering the same efficiency as conventional permanent magnet motors. The coils are made of pressed aluminium and the rotor consists of laminated steel.

“It works exactly the same, just without copper and magnets,” De Kam explains. “This significantly reduces environmental impact, especially regarding the mining of rare earth materials. It also reduces dependency on countries like China.”

De Kam expects this to become increasingly relevant in tenders.

“When you start looking at the full well-to-wheel picture, this is a significant advantage.”

Knowledge as capital

Keeping up with rapid developments in the sector happens largely organically at SDK Engineering.

“I’d almost call it a habit,” De Kam laughs. “We don’t do it deliberately, but when you’re passionate about what you do, you find yourself reading about it even at home on the couch.”

The company also continuously invests in the further development of electronics, data analytics, and machine learning software for predictive maintenance.

The message is clear:

“If you think something isn’t possible, or you have questions about batteries, drivetrains, electric, hybrid, combustion engines, whatever, just get in touch. Let’s have a coffee. Because nine times out of ten, there is a solution.”