Securing High-Voltage Infrastructure location TenneT: A Collaborative contribution by Heijmans and Heras

Network operator TenneT required a coupling point for underground high-voltage transmission lines in Oirschot. Long-time partners Heijmans and Heras collaborated to complete the job. Construction company Heijmans realised the coupling point, and Heras provided optimal site security for this vital infrastructure. Heras secured the site with 143 meters of steel mesh fencing, a sliding gate, two emergency gates, and a height restriction portal. This setup ensures TenneT can keep out unauthorized persons, vehicles, and small animals, maintaining the connection point’s continuity.



The Challenge

An enormous crownstone. That is the simplest explanation of how TenneT’s new connection point in Oirschot functions. TenneT manages 25,000 kilometers of high-voltage cables in the Netherlands and much of Germany. The grid operator is replacing the above-ground high-voltage connection between Tilburg and Best with an underground connection. “To maintain the connection with Boxtel, a coupling point in Oirschot was needed,” explains Koen Hartjes, Project Manager of Infra Civil Specialisms at Heijmans. “You can see it as a crownstone because, in this case, three high-voltage routes converge.”

Heijmans was contracted to build the interconnection point. It is a location with vital infrastructure where continuous operation is crucial. Ensuring parts of the country are not without power is paramount. This is why TenneT often designs the site of such a connection point, including stringent requirements around site security, such as materials, heights, design, and durability. Hence, we quickly knew we needed Heras.”


The Approach

Heijmans and Heras are companies with a rich history; Heijmans has been around for over 100 years and Heras for 70 years. They have collaborated for a long time, forming a powerful Brabant alliance. “For TenneT substations like this one, Heras is the perfect partner,” Hartjes continues. “Heras is reliable and provides high-quality security solutions, fitting well with the strict requirements and expectations of grid operators like TenneT. For example, consider the thickness of coatings and the resistance of fencing materials.”

The cooperation between the parties extends beyond execution. “Before Heijmans made the offer for this project, we analyzed the design together,” says Daan van Gastel, Key Account Manager at Heras. “This collaboration allows us to complement each other’s expertise. For example, the original TenneT design proposed swing gates, but we quickly saw that a sliding gate would be better for traffic flow. By discussing the design with Heijmans, we arrived at an optimal, feasible, realistic, and high-quality proposal. And the fact that we are both from Brabant is a nice bonus: we understand each other, know what we can achieve together, and like to get things done.”

“Heras is reliable and provides high-quality security solutions. That fits well with the strict requirements and expectations of grid operators such as TenneT.”

– Koen Hartjes, Project Manager Infra Civil Specialisms at Heijmans

The Solution

After TenneT accepted the tender, Heijmans and Heras commenced work. “We installed 143 meters of steel mesh fencing,” Van Gastel reveals. “Each steel mesh element consists of a single unit three meters long, a requirement from TenneT. Moreover, the fencing is buried about fifty centimeters to prevent people and small animals from digging underneath. The bottom of the fencing is therefore finer meshed. Heijmans arranged for a trench to be dug, so we only had to install the fencing. On top of the fencing are Y-heads, making it difficult to climb over. We also provided two emergency gates, a sliding gate, and a height restriction portal.”

Apart from some planting, the interconnection point in Oirschot is complete. “The pressure on grid operators like TenneT is incredibly high,” says Hartjes. “They have to manage the Netherlands’ energy transition at breakneck speed. Hence, completing such a connection point on time is crucial. Heras was excellent at keeping up with our schedule, which was really appreciated.” Moreover, Heras’ experience with similar projects proved beneficial. Van Gastel adds, “In this kind of vital infrastructure project, you really need each other. We know this from our previous projects in locations requiring high site security. The stakes are high, so it’s essential to rely on each other, both literally and figuratively.”