The shift towards probabilistic risk assessment in the operation of the Belgian power system GRASP & Garpur

New approaches are required to evaluate grid reliability taking into account the variability and inherent uncertainty of the RES production.

Elia is working on the development of new methods for the different stages to plan and operate the Belgian power system with the Phd project GRASP and EU project GARPUR.

What is
the project about?

The power system and the practices required to operate it are approaching a tipping point. The Europeanisation of the electricity landscape – with energy being traded across national borders – and the emergence of variable renewables both necessitate changes in transmission system operation.

However, Elia's top priority remains guaranteeing the reliability of the power supply. New approaches are required to evaluate grid reliability while taking account of the intrinsic variability and inherent uncertainty of RES generation.

What can Elia use and what will be the outcome for society?

The increased share of RES and involvement of international power exchanges in the Belgian electricity mix are creating new challenges that current operational practice can only partially solve.

New approaches need to be developed that take account of the probability of wind or PV generation. Power systems have to be designed and operated to take on board their uncertainty.

This way, Elia will be able to continue ensuring the reliability of the power supply at an affordable cost for society.

Elia is currently working on the development of new methods for different planning and operational aspects of the Belgian power system:

GRASP, a PhD project, aims to develop a methodology for evaluating grid reliability at the operational planning stages that factors in forecasting errors regarding wind and PV generation.

The EU project GARPUR aims to develop new probabilistic criteria and relevant indicators for assessing reliability at different stages (system development, asset management and system operation) and evaluating their practical use (with respect to the current N-1 criterion).

While both projects focus on the same challenges, they approach them from different angles and have different objectives:

  • GRASP is starting out from current practices and propose new procedures, aiming to produce recommendations based on a prototype that can be directly tested based on real situations in Belgium[r1].
  • Garpur is fully reviewing the approach from the grid development stage (decided years in advance) to real-time operation and aims to produce EU recommendations on how to shift gradually towards a probabilistic approach.

Key dates timeline

As the power system operational situations are much more diverse and frequently evolving compared to the past, risk-based decision criteria need to evolve from fixed and deterministic criteria such as the well-known "N-1 criterion" towards criteria which explicitly quantify the risks and which evolve with the encountered operational situation based on a probabilistic assessment of the grid reliability in order to maximize the power systems interests.

Jonathan Sprooten,
Head of power system planning


GRASP: Free University of Brussels (ULB); Brussels Institute for Research and Innovation (INNOVIRIS)

Garpur: Aalto University, CEPS, DTU-Wind, Elia,, ESO EAD, KU Leuven, Landsnet, NTNU, Reykjavik University, RTE, Sintef, Statnett, Technion, Technofi, TU Delft, University of Strathclyde, University of West Bohemia, University of Duisburg-Essen, ULG.

Elia is not just Belgium's transmission system operator - it is also a key player at European level.