Tienen – Kersbeek - Diest

Elia is preparing the electricity network in the area around Tienen, Kersbeek and Diest for the future via various restructuring projects. This is necessary because the energy transition is expected to lead to a rising demand for energy from businesses and homes, for example due to the increased use of electric vehicles and the battery charging that goes along with it. To meet that demand, Elia is upgrading the grid in the Hageland region from 70 kV to 150 kV. Doing so will enable more energy to be transmitted. 

Specifically, Elia will install new electrical facilities at various high-voltage substations in the region and will install a new underground high-voltage connection (150 kV) between the Tienen, Kersbeek and Diest high-voltage substations. In addition, the underground cable connection that currently runs from Avernas to the Tienen transition substation will be extended to the high-voltage substation in Tienen. Once these works are completed, Elia will ultimately dismantle the 70 kV high-voltage overhead line between Diest and Tienen.

Interactive map of the works:

Elia is carrying out the following works at the high-voltage substation on Aarschotsesteenweg in Tienen:

• Replacement of outdated 70 kV installations with 150 kV installations
  This is needed in order to prepare the high-voltage substation for connection to the 150 kV grid.
• New transformer
  Transformers are used to increase or decrease voltage. Of the transformers currently in place, one 150 kV transformer will be moved and a second 150 kV transformer will be added. The new transformer is a low-noise device that will produce less humming.
• Compact extension of high-voltage bays
  The switchgear in a high-voltage substation — comparable to the circuit breaker panel in a home – is under high voltage and must be isolated in order to prevent short circuits. It can be isolated in two ways: with air (Air Insulated Switchgear, or AIS) or with SF6 gas (Gas Insulated Switchgear, or GIS). The current AIS installation at the Tienen high-voltage substation will be converted into a GIS installation, which is smaller and more compact. The current relay room, the 'control room' as it were, where the operation of the high-voltage substation is monitored and from which data is continuously sent to Elia, will also be replaced by a new one in connection with the new GIS installation.
• Dismantling of the Elzenbosveld transition substation
  A transition substation is currently located on Elzenbosveld, a few hundred metres from the Tienen high-voltage substation. This high-voltage substation will be dismantled and the cables running from Avernas to the transition substation on Elzenbosveld will be extended to the high-voltage substation in Tienen.
  
  

  This work will take place within the current plot boundaries of the high-voltage substation.

  Schedule

• February 2025: submit environmental permit application
• September 2025: start work on the Tienen substation
• June 2029: end work on the Tienen substation

Elia is laying new double underground electricity cables (150 kV) between the Tienen high-voltage substation and Elzenbosveld. This is not part of the environmental permit application that Elia is submitting for the upgrade of the Tienen substation.

• Construction of a new double underground cable connection 
  Elia is dismantling the transition substation located on Elzenbosveld. The current double underground electricity cables (150 kV) that run between Avernas and Elzenbosveld will be extended to the Tienen high-voltage substation.
  
  

  Schedule

• Q4 2026: start construction of the underground cable connection
• Q1  2027: end construction of the underground cable connection

Elia is carrying out the following work at the high-voltage substation in Kersbeek-Dorp :

• Replacement of outdated 70 kV installations with 150 kV installations
  This is needed in order to prepare the high-voltage substation for connection to the 150 kV grid.
• Compact extension of high-voltage bays
  The switchgear in a high-voltage substation — comparable to the circuit breaker panel in a home – is under high voltage and must be isolated in order to prevent short circuits. It can be isolated in two ways: with air (Air Insulated Switchgear, or AIS) or with SF6 gas (Gas Insulated Switchgear, or GIS). The current AIS installation at the Kersbeek high-voltage substation will be converted into a GIS installation, which is smaller and more compact. The current relay room, the 'control room' as it were, where the operation of the high-voltage substation is monitored and from which data is continuously sent to Elia, will also be replaced by a new one in connection with the new GIS installation.
• Replacement of existing transformers
  Transformers are used to increase or decrease voltage. Two new transformers will be installed at the Kersbeek high-voltage substation, replacing the two old ones. These will be low-noise transformers, in accordance with noise legislation. Elia will also install noise barriers around the new transformers.
• Installation of a phase-shifting transformer
  This special transformer looks like a normal transformer, but is used to regulate the flow of electricity over the high-voltage grid, a bit like a tap. Elia will also install the appropriate noise barriers around this transformer.
  
  This will entail the extension of the high-voltage substation on the site.
  
  

  Schedule

• April 2025: submit environmental permit application
  
• January 2026: start work on the Kersbeek high-voltage substation
• June 2031: end work on the Kersbeek high-voltage substation

Elia will carry out the following work at the high-voltage substation on Turnhoutsebaan:

• Replacement of outdated 70 kV installations with 150 kV installations
  This is needed in order to prepare the high-voltage substation for connection to the 150 kV grid.
• Compact extension of high-voltage bays
  The switchgear in a high-voltage substation — comparable to the circuit breaker panel in a home – is under high voltage and must be isolated in order to prevent short circuits. It can be isolated in two ways: with air (Air Insulated Switchgear, or AIS) or with SF6 gas (Gas Insulated Switchgear, or GIS). The current AIS installation at the Diest high-voltage substation will, for the most part, be converted into a smaller and more compact GIS installation. The current relay room, the 'control room' as it were, where the operation of the high-voltage substation is monitored and from which data is continuously sent to Elia, will also be replaced by a new one in connection with the new GIS installation.
• Replacement of existing transformers
  Transformers are used to increase or decrease voltage. The 70 kV transformers at the Diest high-voltage substation will be replaced with 150 kV transformers, plus an additional transformer will be added. These will be low-noise transformers, in accordance with noise legislation. Elia will also install noise barriers around the new transformers.
  
  This work will not necessitate an extension of the high-voltage substation.
  
  

  Schedule

• September 2025: submit environmental permit application
• April 2026: start work on the Diest high-voltage substation
• December 2032 (probably): end work on the Diest high-voltage substation

Elia will install a new underground connection (1 x 150 kV) between the Tienen and Diest high-voltage substations via the Kersbeek high-voltage substation.

Schedule

• September 2025: submit environmental permit application
• August 2026: start construction of the Diest-Tienen underground cable via Kersbeek
• December 2029: end construction of the Diest-Tienen underground cable via Kersbeek

Elia plans to dismantle the outdated high-voltage line (70 kV) between Tienen, Diest and Kersbeek (two twee three-phase transmission lines) as it has nearly reached the end of its life and the installation of the new underground cables (150 kV) will ensure energy supply in the region. The high-voltage line will only be dismantled once the new underground cable is in service.

Elia always takes local residents and the surrounding area into account in its work. The high-voltage system operator takes a range of measures intended to minimise disruption and impact on the surrounding area and local residents.

• Work only takes place during the day, between 7 a.m. and 7 p.m.
• Elia guarantees that homes and businesses will remain accessible at all times while the work is under way. 
• If local residents are set to experience a temporary increase in disruption for a specific reason, Elia or its subcontractor(s) will individually notify those affected.
• If normal traffic has to be diverted, the diversions will be agreed with the road authority and clearly communicated to local residents.
• Once work is complete, the land is always restored to its original state.

Information sheet - What is a high-voltage substation? (in French)
Information sheet - What is a high-voltage substation? (in Dutch)

Information sheet - Noise near high-voltage substations (in French)
Information sheet - Noise near high-voltage substations (in Dutch)

Information sheet - Construction of underground electricity connections (in French)
Information sheet - Construction of underground electricity connections (in Dutch)