Many changes ahead
By Nouredine Hadjsaid, Jean-Claude Sabonnadiere, and Sebastien Henry
The European electric power system [comprising generation, transmission, and distribution (GTD)] is undergoing remarkable changes to support the energy transition put forward by the policy makers. For this system, it definitely represents a tremendous challenge to reach the assigned ambitious objectives, in terms of security of supply and sustainability as well as in the affordable and efficient use of energy. In this issue of IEEE Power & Energy Magazine, these challenges as well as the current evolution of the European Union (EU) GTD have been detailed. When relevant, a special focus on systems such as the German system and its ìenergiewendeî transition was provided.
Several initiatives have been launched by the European Commission to define the way forward to support this energy transition as well as by EU industry and utilities associations and groups such as ENTSO-E, EDSO, and EEGI.These initiatives cover short-, medium-,and long-term perspectives up to the year 2050. Some EU industrial instruments have already been launched such as the supervision of transnational EU power grids, the enforcement of information exchange, and the emergence of the supergrid concept to integrate offshore wind generation to the main EU grid.
However, it should be noted that the EU GTD is facing additional challenges where the existing initiatives only partially address some of these critical issues. Indeed, the fast development of renewable energies of an intermittent nature [such as wind and photovoltaics (PVs)] often requires additional high-voltage transmission lines that are increasingly becoming more difficult to build, mainly for environmental and social acceptability reasons. As a consequence, a growing gap appears between the dynamics of the development of these intermittent energies and the achievement of the needed transmission lines. In fact, while the time required to complete a transmission line ranges between five to seven years in normal conditions (no opposition) to infinite (never to be built), the time needed to build these renewable energies is only a few years (often fewer than three years). The situation is similar at the distribution level where additional capacity is required to accommodate distributed generation (DG) while the initial opinion was that DG may require less additional capacity since it is supposed to be sited closer to the customer.
On the other hand, the EU power grids are more and more interdependent, increasing their vulnerability to outages that may occur outside a specific member-state power grid (similar to the Italian 2003 blackout or the 2006 outage triggered in Germany that impacted the whole EU power grid). In addition, the variability of wind and PV power outputs can not only affect one region but its impact may be spread throughout several countries, putting the whole system at high stress if not at risk. Another risk that is already touching some EU countries is that the operation time of some classical generation units such as gas turbines is below their profitability threshold as a consequence of the high-level generation of renewable sources that forces the owners to envisage closing these classical units. This situation may appear to be a positive impact with respect to sustainability targets; in reality, it has adverse effects. Indeed, these classical units are valuable for the grid security, especially for dynamic operation and control purposes. As a consequence, a different business model, such as capacity value, is needed for these units to reinforce grid security.
Distribution grids are facing a similar situation with respect to the rapid changes in the energy paradigm. These changes are technical and industrial as well as economical and institutional. Distribution grids have never been confronted with such rapid changes and a significant number of simultaneous challenges. The traditional role of distribution operators is clearly challenged and rapidly evolving. In addition, the presence of information technology (IT) factors in the framework of smart grids is adding some stress in the perspective of merging energy and IT.
Overall, the EU GTD is entering into some turbulence. It appears that just keeping the security of the whole EU power grid while dealing with all these challenges in the context of responsibility partitioning is more and more complex and requires joint actions, including research and development activities, from the entire electricity sector.