High Voltage (Energy) Systems
< class=" hyphenate">150 kV upgrade prepares the electricity grid for growth in Flemish Brabant and LimburgBetween Tienen, Kersbeek and Diest, Sweco is working on behalf of Elia on a new underground 150 kV high-voltage connection. The project replaces the outdated 70 kV grid and forms a key link in strengthening the regional electricity network. Thanks to the choice of a fully underground design, the impact on the landscape, agriculture and living environment remains limited.
- Expertise:
- Energy solutions
- Client
- Elia
- Locatiion
- Tienen-Kersbeek-Diest
- Services
- Engineering, permitting management, infrastructure design and planning
For this route, we developed a new alignment, including four kilometres of horizontal directional drilling (HDD) under the N29 between Kersbeek and Diest. This allows the cable to safely cross roads, waterways and existing infrastructure without unnecessary open trenches. Execution is scheduled between 2026 and 2029.
More grid capacity, less disruption
This new 150 kV connection will significantly increase security of supply in Flemish Brabant and eastern Limburg. At the same time, open space, landscape and agricultural activities are maximally preserved thanks to the underground installation. The upgrade from 70 kV to 150 kV represents a substantial increase in grid capacity. The project responds to growing electricity demand and prepares the network for further electrification of industry, mobility and renewable energy.
The electricity grid in this region urgently needed to be modernised. The upgrade to 150 kV is essential to meet future demand. This design enables that transition with minimal impact on people and the environment.
Sarah Martens, spokesperson for Elia
Smart design for a complex cable route
From the outset, we opted for an integrated approach. Sweco’s team was responsible for the full design and permitting process, including the environmental permit (OMV) file, layout plans, longitudinal and terrain profiles, construction drawings and technical reports. The route crosses more than 200 plots and passes through various zoning areas. Through a thorough analysis of regional plans and spatial implementation plans (GRUPs, PRUPs and BPAs), permitting risks were identified and mitigated at an early stage. The design focused on minimising disruption to private and agricultural land, including targeted use of directional drilling at critical crossings such as sewer systems and waterways.
Stakeholder management makes the difference
The realisation of the project required close coordination with numerous stakeholders: private landowners, municipalities, grid operators and environmental authorities. Through intensive consultation, in both Dutch and French, and clear technical substantiation, broad support was achieved. Proactive coordination with parties such as Aquafin and Fluvius proved highly important. A potential conflict with parallel sewer works was resolved in time. At the same time, we developed a flexible execution concept in which open trenching and directional drilling are strategically combined, tailored to the local context.
Directional drilling limits impact
Innovation played a key role in the design. The use of horizontal directional drilling makes it possible to cross infrastructure, roads and waterways without disruptive surface works. In addition, a dewatering study was combined with real-time groundwater monitoring, enabling precise control and adjustment of environmental impact.
Environmental risks under control
A screening (EIA) thoroughly analysed potential environmental effects and translated them into targeted measures. A redesigned crossing with existing sewer infrastructure, in collaboration with Aquafin, illustrates how smart engineering solves complex underground situations without disturbing existing networks.
Ready for the energy transition
With this project, Sweco reinforces its role as a strong engineering partner in complex energy infrastructure. From route study and permitting to detailed design and as-built documentation: the integrated approach ensures efficient delivery and maximum impact. The expertise built up in underground high-voltage connections, stakeholder management and permitting forms a solid foundation for future projects, where technical complexity and societal added value go hand in hand.