IEEE Power & Energy Society
IEEE

Guest Editorial

European Electric System

Driving its Modernization

The European power system is facing tremendous changes and challenges to improve its sustainability and the security of supply and to implement the integration of the internal EU-28 energy market and its liberalization. Aging assets with the need for decommissioning and upgrading the entire electrical power infrastructure (generation, transmission, and distribution) is also a considerable concern in the European energy landscape. Indeed, secure, sustainable, available, and affordable energy is fundamental to modern societies and to the well-being of citizens as well as for industry competitiveness.

An important driver for changes was the 2009 adoption of the “climate and energy package” with ambitious and binding energy targets for 2020. These targets include a binding reduction of CO2 emissions by 20% compared to 1990 levels, a binding increase of the share of renewable energy in the energy mix to 20%, and an aim to increase energy efficiency by 20%. The 20% renewable target for the whole energy sector will likely require up to 35% renewable energies for the electricity sector. The adoption of these targets by all European Union (EU) member states gives a clear signal for the evolution of the generation, transmission, and distribution of energy, defining a way forward for a transition to a more carbon-efficient (and even free) society. These have been complemented by aims to further drastic evolution to a low-carbon economy expressed in the EU Energy Roadmap 2050, published in 2011. For the electricity sector, all involved stakeholders are impacted and have undergone significant changes in their specific area to accommodate the agreed targets. Strong regulation incentives were issued by EU member states to encourage heavy investments in low carbon technologies, which in turn implied significant technical innovations as seen by key enablers to meet the sustainability targets.

These policies have a particularly important impact on the European electrical system, which is one of the largest and most complex man-made systems. The speed of the required changes is very challenging as power systems are used to evolve in well-defined and “mastered” transitions as any failure can have a catastrophic impact on the whole society.

The European power system serves more than 500 million people distributed over a large territory, with an annual consumption of over 3,000 TWh. The corresponding generation portfolio is still composed primarily of traditional plants using hydroelectric (mainly in Alpine and Scandinavian countries), nuclear, and fossil energies. The renewable energies are undergoing a steep development with a significant share/penetration of wind energy historically in Denmark, Germany, and Spain and more recently in the United Kingdom, France, Italy, Portugal, and Ireland. Total installed wind power in Europe was 106 GW at the end 2012 (of which about 5 GW offshore). For solar photovoltaic (PV) energy, the installed capacity in the EU at the end of 2012 was close to 70 GW (representing about 68% of the world’s installed PV capacity).

On the other hand, the renewal of overall EU generation assets is expected to require the replacement and expansion of 900 GW by 2030 (the retirement of about 300 GW and an additional capacity of about 600 GW) while the energy consumption is expected to increase with an average of 1.5–2% per year and reach about 4,000 TWh by 2030, but this strongly depends on, for example, the future electrification of heating and transport application, the evolution of fuel prices, and energy efficiency policies. The transmission and distribution infrastructure investments, for renewal and expansion including the accommodation of renewable energy sources and distributed generation, are foreseen to represent several hundreds of billions of euros by 2030.

The current high-voltage transmission grid is made of approximately 300,000 km of overhead lines and cables. It has historically been developed on a national basis with a limited number of interconnections at the boundaries of neighboring countries initially built for security support with small energy exchanges, and not to support the open market. The recent opening and expansion of cross-border markets has drastically modified this situation, leading to a fast and continuous increase in cross-border exchanges and emphasizing the need for a new infrastructure enabling a better European market integration. A plan for expanding critical European connections is developed in the ten-year network development plan of ENTSO-E (the association of European Transmission Operators and the European Commission); in October 2013, a list of agreed “Projects of Common Interest” was published to reinforce transmission grids. About 100 bottlenecks can be identified on the European network by the end of the decade (among them, 40% are interconnectors). Of the bottlenecks, 80% are related to renewable energy sources (RESs) integration, either because the direct connection of RESs is at stake or because the network section or corridor is a keyhole between RESs and load centers. The north–south internal corridors in Germany are typical examples of the latter.

Distribution grids at medium and low voltages cover about 5 million km of lines and cables and are managed by about 5,000 distribution operators in all EU countries. In Europe, a large fraction of the PV and wind generation is connected at the distribution level, and this requires a major shift in the operation of distribution networks.

An Unprecedented Revolution for the European System

To fulfil the European climate and energy policies, the electrical system is in a period of very fast and radical evolution with a very high development of renewable energies. Variable renewable sources already reach more than 20% of the total electric energy mix in Denmark and will soon reach this level in Germany, Spain, and other countries. In these countries, the share of instantaneous power from variable, inverter-connected generation has exceeded 50% of the total generation mix a number of times. This situation is challenging grid stability and also impacts the economic value of the traditional thermal power portfolio. The time use of gas turbines has, in some cases, fallen below the profitability ratio while the flexibility potential is important to balance the variability of renewable generation.

The EU power grid can be a facilitator of the development of the new renewable portfolio through the mutualization of different energy sources and consumption patterns as well as through economies of scale, but it is facing major challenges in planning, developing, and deploying the appropriate technology solutions to respond to the political objectives and support the convergence to a decarbonized and sustainable economy.

The need for coordinating an R&D and deployment agenda was already apparent to stakeholders in Europe since the beginning of 2000. On the basis of experience in collaborative projects in successive European framework programs, EU stakeholders involved in the electricity industry assembled in the SmartGrids European Technology Platform for Electricity Networks of the future. It formulated a strategic research agenda in 2007, which was updated in 2012 to embrace 2035 targets.

A concerted effort to promote the development and deployment of low-carbon technologies in Europe was initiated in 2007 with the Strategic Energy Technologies (SET) plan, complemented in 2010 by a number of industrial initiatives, in particular the European Electricity Grids Initiative (EEGI) for a coordinated planning of research, development, demonstration, and deployment of modernized electricity grids in Europe. The EEGI produces roadmaps and implementation plans that represent a blueprint of needs of the sector, agreed between transmission and distribution network operators, equipment manufacturers, regulators, and public authorities. The roadmap shows the need and the path to modernizing the European grid, including distributed intelligence in the operation of networks to deliver electricity from all new and old generation and to cover new uses of electricity in a secure and economical way.

Early advances by individual players have shown the way forward, for example, in the area of smart metering and distribution automation. ENEL (currently Enel Distribuzione) started the deployment of electricity two-way digital meters to about 30 million Italian households since the beginning of the 2000 decade. Since then, an overall deployment of smart meters to 80% of households by 2020 has been agreed at the European level, and several other EU utilities, particularly in Sweden, Finland, France, and Cyprus, have already launched their deployment.

Currently, many efforts are directed toward large-scale demonstration facilities and projects that include smart metering, intelligent customer interaction with demand response, and distributed intelligence embedded into the existing grid. Some large projects have been launched at the EU level such as the FP7 GRID4EU project; others take place at the member-state level such as the e-Energy program in Germany, the low-carbon network projects in the United Kingdom, or the demonstration project within ERDF, the largest distribution operator in France, for the Linky smart meters supported by the French ADEME agency.

From the transmission grid perspective, the development of off-shore wind generation at a significant scale and new concepts for the efficient integration of these generation units into the main EU grid are under consideration. They motivate the development of supergrids and especially new high-voltage dc meshed grids interconnecting wind farms with dc cables to the classical ac network. European projects such as TWENTIES and Best Paths support the validation of such technologies, whereas other projects support the coordinated operation of national transmission grids.

The development of smart grids is now bustling all over Europe with a very large number of demonstration projects in all member states covering the whole energy chain (generation, transmission, distribution, and customer interaction) with the aim of introducing, testing, and deploying low-carbon technologies into the existing grids from very local to supergrid concepts. In many cases, these projects are linked with the emergence of smart cities concepts integrating smart electricity grids, smart buildings, multi-utility energy, smart transport, and sometimes water and waste management. As such, the announced massive development of plug-in electrical vehicles in cities must be anticipated, as it can be a source of difficulties or opportunities for the power sector, depending on whether or not the charging processes can be exploited and coordinated with power system management.

The Articles in This Issue

The Articles in This Issue

The first article, by Henry et al., explains the evolutions of the EU transmission system networks in a contribution from transmission system operators (TSOs) and analyzes the impact of renewable energies on the operation of transmission grids.

The European transmission grid and TSOs are at the core of the complex European electrical system. They face four challenges critical for guaranteeing the success of the EU energy transition:

1) Enabling the development of renewable energies.

At the European level, the objective is to push toward an optimal usage of available renewable resources, leading to growing wind power generation on and off shore in the Northern Seas, the Baltic Sea, and surrounding areas; increasing production of solar electricity from Southern Europe; exploiting bio and hydro energy where available; and in a longer time frame, ocean and geothermal energies.

2) Toward a flexible electrical consumption: the contribution of intelligent load control.

The supply and demand balancing process is complex and continuously challenging in the context of current and future EU energy mix. The variability of a number of renewable sources requires increased flexibility from the power system and, in particular, increased flexibility from electricity consumption.

3) Developing and adapting grid infrastructures for strengthening the support between heterogeneous areas.

The pan-European electrical transmission grid, as a vector of integration between national, regional, and European levels, allows local energy policies to be set while ensuring overall adequacy. It helps to compensate regional imbalances by using complementarities and support between areas. Cross-border flows of electricity have rapidly increased with the opening of markets and with the large renewable installations. These will require a substantial increase in transmission capacity in the pan-European grid.

4) Developing the intelligence of the transmission grid, allowing the deployment of new services for more flexibility and for system optimization.

An architectured market “software” will allow the optimal use of these infrastructures. These mechanisms allow flexibility, ensure liquidity to market participants, and provide optimization of electricity imports-exports through interconnections.

The second article, by Feix, illustrates this discussion with a description of the challenge of the German energiewende. Renewable energies (wind and PV) have already reached a very high level of integration (up to 35% of the total energy generation mix in Northern and Eastern Germany), which stresses the balance between RESs and conventional power plants to ensure security of supply. Moreover, transmission capacities between the north and south are stressed and at times insufficient to deliver electricity from high wind generation and low consumption in the north and a heavy consumption and limited generation capacities in the south. The difficulties encountered by the TSOs are amplified by the number of actors and the evolution of market processes.

To cope with these problems four measures must be taken rapidly:

  • Increase as soon as possible the transmission capacity, in part by streamlining the administrative process.
  • Set up a tight cooperation between TSOs and distribution system operators (DSOs).
  • Reinforce investments on conventional generation technologies.
  • Control the total cost of energy including a fair allocation of grid costs.

The third article, written by Bompard et al., addresses the security challenges to cope with the criticalities of the future European transmission grid.

An upgraded and interoperable electricity infrastructure is needed to allow for increased cross-border trading and integration of the wholesale electricity markets, ensuring secure supplies everywhere, and enabling the access to diversified sources of energy (e.g., renewable wind and solar sources).

The forecasts for production from renewable sources and their localization and the potential connection to neighboring power grids (e.g., the Russian Federation, Northern Africa, and the Middle East) will define the structural and operational characteristics of the European grid and therefore have a significant influence on its criticality.

This article discusses the current and foreseeable susceptibility of the European grid to different criticalities. In particular, it discusses four categories: natural hazards, accidental threats, malicious threats, and emerging threats due to variability and the interdependency between the power system and other infrastructures. It will conclude with the necessary international political strategies and anticipated EU policy initiatives to suggest possible long-term solutions for the outlined emerging criticalities.

The fourth article, authored by ­Mallet et al., describes distribution grids and their possible evolution in terms of architecture, ancillary services, and the regulatory framework needed in this context.

Major changes are expected for the distribution part of the future power system, and DSOs will see a new set of roles and duties:

  • Distributed generation, connected to distribution networks, is expanding very rapidly.
  • To cope with increasingly fluctuating volumes of supply, such as solar energy and wind farms, the potential of demand response has to be used.
  • Electric vehicles will constitute mobile customers.
  • The development of decentralized storage, connected to distribution networks, is also anticipated.

Local distribution systems will become much more complex as local grid constraints occur more frequently. DSOs are nevertheless expected to continue to operate their networks in a secure way and to provide high quality to their customers at the best economic conditions.

The article addresses a number of fundamental questions:

  • Is a change in system architecture needed?
  • What types of system services are needed at distribution level and how can they be procured?
  • How can distribution systems provide services to the transmission system?
  • How should the regulatory framework be developed?

The specific features of the European power system (such as an integrated energy market, the fast development of renewable energy sources, and the unbundling of energy segments) are presented as well as their consequences on the future distribution system.

Finally, we conclude with a general article, written by Lorubio and Schlosser, on the possible policy of the EU in the energy sector and the required innovation.

The authors explain that the 2020 policy feels like tomorrow for a sector that invests in long-lived generation and grid assets. This is arguably why the European Commission has developed the Energy Roadmap 2050 and more recently published a green paper to kick start a discussion with member states and stakeholders on the optimal policy for 2030, with a view of adopting a new and comprehensive regulatory framework before the end of the next commission mandate.

As a contribution to this new discussion, this article first reviews and assesses the coherence of the existing EU energy policy (including its innovation instruments) and its impact on the energy industry, before developing six competing scenarios for possible 2030 EU energy policy pathways.

The article then ranks the developed options based on a set of indicators derived from the official EU energy policy, as outlined in its reference document “An Energy Policy For Europe,” with two new policy imperatives: innovation and affordability.

In This Issue

Feature Articles

Departments & Columns

Upcoming Issue Themes

  • January/February 2018
    Societal Views of the Value of Electricity
  • March/April 2018
    Controlling the Unpredictable Grid