IENE 2016

Transmission System Operators (TSO) have to integrate energy from green sources into the grid. Indeed, electricity produced on an offshore wind farm has to be brought to the consumers. To achieve this, TSO have either to create new high-tension lines or to reinforce existing ones on the grid.

Both on existing lines or new high-tension lines, vegetation management is a key issue when dealing with electrical safety of these lines crossing forest areas. In order to avoid any problem, most TSO's proceed to regular vegetation cuttings.

The main idea of the LIFE Elia-RTE project is to test 7 alternative methods to manage vegetation. These methods are both promoting biodiversity and ensuring electrical safety : planting structured forest edges, planting conservatory orchards, restoring natural habitats, digging ponds, fighting against invasive plants, mowing or pasturing, or sowing flowering meadows.

During 6,5 years, this project is implemented in Belgium (along 155 km of lines) and France (7 sites) to combine electrical safety and biodiversity. The project is financed by the European Commission, Elia (Belgian Transmission System Operator), RTE (French Transmission System Operator), and the Walloon Region.

The easement under overhead high-tension lines does never belong to the TSO. Therefore, actions had to be carried out locally, with the involvement of local stakeholders by finding win-win situations. The main idea is to find the most appropriate action that could benefit landowners and land managers.

The methodology developed in the LIFE Elia-RTE encompasses the following steps : initial mapping to identify potentialities, agreements with local stakeholders, works achieved by subcontractors (planting, cutting, soil scrapping…), and writing of a long-term management plan. Besides, biological and economical indicators are also monitored. Results obtained within the ongoing project are encouraging : planting structured forest edges (171 ha), planting conservatory orchards (16,5 ha), restoring natural habitats (37 ha), digging ponds (118 ponds), fighting against invasive plants (29 ha), mowing or pasturing (40 ha), or sowing flowering meadows (24 ha).

By finding win-win solutions to manage vegetation, the project proves that local stakeholders could also benefit from a high-tension line. Furthermore, public acceptance on actions carried out will ensure their sustainability on a larger timescale. Results obtained concerned partnerships in Belgium and France with 48 municipalities in Belgium, 43 local districts of the Public Forest and Nature Department, 25 high-tension lines patroller, around 340 private owners, 5 main public landowners, around 70 local farmers/hunters/subcontractors, and 3 Regional Nature Park in France.

A cost-benefit analysis showed that these alternative methods were cheaper (1.4 to 3.9 times on 30 years) than the ongoing vegetation management, with a return on investment from 3 to 9 years. Other benefits such as a better social acceptance, landscape improvement, or better relation with authorities - much more hard to assess – have also to be taken into account.

These findings can be of great importance for European TSO, and for other linear infrastructures. In order to promote a wide network to implement these techniques, the project has launched a networking campaign towards national Transmission System Operators (TSO). The LIFE Elia-RTE team is in contact with 17 TSO and has organized a two-day event in Belgium that gathered 40 people for all over Europe.

Partnership with this TSO leads to exchanges of vegetation management best practices and to the creation of pilot sites to test LIFE Elia-RTE methods.