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Electricity security in the EU: features and prospects

This article is based upon doctoral research conducted by the JRC (G. Fulli) and Politecnico di Torino (F. Profumo, E. Bompard) - for more info click on the PhD thesis download link or go at the bottom of this page.

1. What is electricity security?

Electricity security can be defined as the power system's capability to withstand disturbances - i.e. events or incidents producing abnormal system conditions -, or contingencies - i.e. failures or outages of system components - with minimum acceptable service disruption.

In the following, having in mind the above reported definition, we identify some electricity properties security in relation to threats, possibly materialising into adverse events, occurring in different dimensions (not necessarily internal to the power system) and at different time and spatial scales.

Power system can be vulnerable to threats that, when materialised, may cause foreseeable and unforeseeable disruption. Within the energy system, the power system faces several security threats - natural, accidental, malicious, as well as linked with emerging low-carbon systemic changes. The threats potentially affecting electricity security can be characterised in terms of impact areas, time duration, internal or external provenance, intrinsic nature (natural, accidental, malicious and systemic).

Four overarching dimensions of electricity security can be identified, and they can be visualised as the physical or virtual corridors across which the electricity commodity/service has to travel to reach the users: an infrastructure dimension, a source dimension, a regulation and market dimension, a geopolitical dimension.

Electricity security can be considered as a combination of several electricity security properties:

  • Operational security is the ability of the power system to maintain or to regain an acceptable state of operational condition after disturbances. It covers dynamic issues and real-time network management issues.
  • Flexibility is the capability of the power system to cope with the short/mid-term variability of generation (like renewable energy) and demand so that the system is kept in balance.
  • Adequacy is the ability of the power system to supply the aggregate electrical demand at all times under normal operating conditions. It generally includes:a generation/storage adequacy component, a transmission network/import adequacy component, distribution network and end user adequacy components,a market adequacy component.
  • Resilience is the mid-term capability of the power system to absorb the effects of a disruption and recover a certain performance level.
  • Robustness is the long-term capability of the power system to cope with constraints/stresses originating outside the infrastructure dimension.

Electricity security can be mainly characterised via operational security, flexibility and adequacy, with special reference to the internal electricity value chain challenges and constraints.

Electricity security can be mainly described in terms of robustness and resilience in the event of pressures originating outside the electricity system.

To sum it up (see the electricity security properties mind map below), electricity security is a multiple-aspect issue, namely: a multi-threat, multi-scale & dimension, multi-property, multi-stakeholder & discipline, multi-problem, multi-model & approach, multi-action issue.

2. What models are used for electricity security analysis?

As suggested above, a great variety of methods and models are employed to assess electricity security. This depends on several factors including: the policy maker’s requests, the researcher's background, the characteristics of the system/phenomenon under observation.
Electricity security models (see also Table below) can be clustered against the time horizon, the time granularity and the domains of the electricity value chain they primarily consider:

  • Dynamic power system/grid models;
  • Static power system/grid models;
  • Power market/system models;
  • Energy system/power market models.

Their main features are represented and described in the following:

Afterward, electricity security assessment approaches - tackling operational security, flexibility, adequacy, resilience and robustness - were assessed and mapped to the model clusters.

Mirroring the definitions and grouping of the electricity security properties, two main electricity security assessment approaches were identified:

  • Reliability approaches (addressing operational security, flexibility and adequacy), focusing on the ability of the system to perform its intended function.
  • Vulnerability approaches (addressing the lack of resilience and robustness), focusing on the inability of the system to withstand strains and on the effects of the consequent failures.

Solutions for integrated analyses, like those based upon cost-benefit analyses, multi-criteria analyses and indicators, were also analysed.

3.Who are the main electricity security actors?

An increasingly diversified number of actors is involved and affected by the energy system transition and has a stake in the energy and electricity security issues: policy decision makers and operators, regulators, market operators, generation companies, asset owners, aggregators, manufacturers, consumers, emerging actors (offering new services and/or proposing new business models), all play a role in the security of supply problem definition and solution.
Each EU Member State is still largely in charge of their own energy security assessment and safeguard; however, as pointed out by the European Commission, a key to improve energy security relies on a greater cooperation and a more collective approach, since national choices and decisions over energy markets, sources and infrastructure have immediate cross-EU security implications.

The current status and some the main issues relating to electricity transmission system security in the different spatial scales are summarised in the following:

  • At national level, the main electricity security actors are the TSOs, partly flanked by governmental/regulatory bodies. The TSOs have very detailed and complete dynamic and static models of the national transmission system under their responsibility and they are considered as the official owners of the related datasets. The further electricity modelling moves from grids towards market/energy systems, the larger the number of actors, including market operators, having a stake (in terms of data ownership) and playing a role (in terms of assessment perspectives). Electricity security models are used for supporting decision making across all the electricity security actions - operation, operational planning and scheduling, system planning, strategic energy planning. R&D actors frequently contribute to electricity security analyses and propose methodological improvements but they lack reliable data for their models. The whole range of electricity security analyses is conducted, both on reliability (operational security, flexibility, adequacy) aspects and vulnerability (resilience and robustness) aspects. Electricity models, from the time frame viewpoint, tend to be more and more combined or at least soft linked; probabilistic approaches (vs deterministic ones) are increasingly used - but their results are not necessarily embedded in the decision making process - for reliability analyses, whereas vulnerability analyses rely upon the most diversified (not always sophisticated) approaches.
    • Areas for improvement at national scale include: following the best practices (e.g. UK) for model interlinking, including domains/subsystems/systems like: the electricity distribution grid, the gas system, the heat system etc; encouraging utilities to fully incorporate innovative approaches - as e.g. those based on advanced probabilistic/complex system techniques, generally proposed by the R&D community -, in the decision making process.


  • At regional (cross-national) level, there are emerging actors - even though not fully formalised yet - performing electricity security analyses: particularly CORESO, the Pentalateral Energy Forum and other nascent regional operational initiatives. R&D actors are less active than at national and EU level as the regional scale represents a rather recent EU development. Electricity models are quite detailed and (compared to the national scale) better capture the cross-border aspects of the region under study. The electricity security models are used for supporting some of the electricity security actions: the focus is more on operational planning and scheduling actions and system planning actions (since operational actions and strategic energy planning actions are beyond the current remit of these regional bodies). As for the electricity security analyses, operational security, flexibility and adequacy analyses seem to have priority on resilience and robustness analyses. Time-wise, selected electricity security models are better linked and probabilistic approaches (vs deterministic ones) begin to be used for reliability analyses.
    • Areas for improvement at regional scale include: better defining roles and responsibilities of the actors (so that the even accurate and innovative analyses can be used to support the decision making process), expanding security analyses in the vulnerability area and in modelling the interfaces with other energy systems.


  • At EU level, the main actors are the ENTSO-E, ACER and the European Commission. ENTSO-E is tasked to perform EU-wide analysis and coordinated national/regional studies. ENTSO-E is progressing well in combining primarily static power system/grid models with power market/system models. Like explained above for the regional scale, the electricity security models are used for supporting decision making (especially) on operational planning and scheduling actions and system planning actions, (rather than) operational actions and strategic energy planning actions). In the scientific area, several R&D (FP7/H2020) projects are producing advanced models however with partially reliable datasets (if no formal agreement with the TSOs/ENTSO-E is in place). Probabilistic approaches (vs deterministic ones) begin to be proposed in the reliability assessment area, particularly for power system adequacy and flexibility. At this level, the visibility/observability of dynamics/issues occurring at regional/local level is however limited.
    • Areas for improvement at EU level include a deeper assessment of issues occurring at the transmission-distribution interface, whereas first trials for interlinking gas and electricity models are ongoing, streamlining the modelling interactions and the assessment processes between the EU-wide and the regional scale, advancing the dynamic representation of the whole transmission system (e.g. via real-time simulation) targeting the emerging smart/super electricity systems challenges and tensions.


Elements of the current decision framework for electricity security analysis are depicted in the figure below,  where the different spatial scales (EU, regional and national) and the main actors involved in reliability analyses for the planning phase are represented. This representation of course does not capture the whole spectrum of methodologies, actions and actors involved (as an example, aspects more linked to the real time system management are not fully covered by this case study as well as the analyses of the interfaces with the distributed/decentralised domains of the electricity value chain).
In the current situation, one can distinguish two main parallel though interacting decision making processes: the one at the EU-wide scale and the one at the national level, where adequacy and operational security analyses are conducted. The interaction necessarily happens on the regional scale, through actors and via platforms which are only partly formalised and enforced. Thus, this interaction between the EU and the national scales cannot but be limited. It has also to be noted that the security aspects represent just one of the perspectives considered in this electricity system analyses: equally important, the affordability and sustainability aspects are assessed - and possibly monetised - when performing cost-benefit analyses defining investment priorities. The models mostly deployed (from top to bottom) are energy system/power market models, power market/system models and static power system/grid models, since dynamic power system/grid models are currently rarely used in combination with the others for the reliability studies (e.g. the TYNDP does not include specific inputs from stability studies).

Additionally, a crucial, overarching issue regards the interaction between science and policy in the electricity security sphere. As seen, specific electricity security models and analysis are pervasively embedded in the decision making process of power system industry, particularly in the operational and planning phases. The same, despite society heavily depends on electricity service provision, does not generally hold for the connections between scientific/technical electricity security analysis and the policy decision making process. There are several reasons for this disconnection: the political and scientific/engineering communities speak different languages; policy making is a mixture of politics, facts and values, whereas science primarily contributes to one of these, namely facts; technical results are often too complex to interpret and grasp, etc. However, as a paradox, even if politicians’ risk aversion can be generally considered high, not being aware or informed of the security implications of some policy decision may lead to security of supply deterioration rather than safeguard.

4. How electricity security decision making currently works?

Most of the techno-economic challenges to electricity security have to do with the fact that electricity is not easily (or better, economically) storable; consequently, frequency and voltage, due to continuous changes both in demand and supply side, are constantly subject to variations in the electric power system. Keeping the transmission system secure and stable is a complex task. In order to avoid disruptions and wide-area disturbances, power flows should be kept within the thermal and stability limits of the transmission infrastructure while taking care of regulating frequency and voltages. Coping with variability when balancing supply and demand is not a new task (especially on the demand side), even though renewable power uptake significantly increases the imbalance correction challenges on the supply side.

  • Short-term challenges. Power system security in this time frame critically depends from the interaction of a few stakeholders, in particular TSOs and DSOs and conventional and renewable generation companies; also residential, industrial and commercial consumers play a role, depending on the system/region under observation. The main technical challenges in this time frame can be summarised in the following ones: keeping the system stable following a perturbation, balancing generation and demand across the whole system taking into account generation and demand statistical variability and planned/unplanned system component outages.
  • Mid-term challenges. Power system security in this time frame depends from the interaction of an expanding number of stakeholders including: wholesale and retail market actors; ENTSO-E; TSOs and DSOs; conventional and renewable generation companies; asset owners; aggregators (bringing together demand); residential, industrial and commercial consumers. In this time scale, while the system stability is not the first concern, the need for balancing generation and demand is still a primary challenge for the power system. Additionally, several risks of market failures emerge.
  • Long-term challenges. Power system security in this time frame depends from the interaction of an even larger number (compared to the short- and mid-term) of stakeholders including: EU institutions and agencies, including the European Commission and the Agency for cooperation of Energy Regulators (ACER); national governments and institutions; National Regulatory Authorities (NRAs); wholesale and retail market actors; ENTSO-E; TSOs and DSOs; conventional and renewable generation companies; asset owners; aggregators; residential, industrial and commercial consumers. In this time scale, network planning and market design actions are expected to counteract the main security challenges. However, current electricity security performance and regulatory arrangements are largely a legacy of investments dating back to several decades ago. Ageing capacity needs to be replaced within a competitive market framework while also decarbonising the electricity sector.
  • Very long-term challenges. Power system security in this time frame depends from the interaction of a multitude of stakeholders including: EU institutions and agencies, particularly ACER; national governments and institutions; National Regulatory Authorities (NRAs); wholesale and retail market operators; ENTSO-E; TSOs and DSOs; conventional and renewable generation companies; asset owners; aggregators; manufacturers; residential, industrial and commercial consumers; possible new actors not yet existing and/or conceived (offering new services and/or proposing new business models). Beyond the investment cycle, there are several challenges and strains affecting power system security, particularly in correlation with renewable energy deployment (primarily in terms of technologies, performances, and geographical siting); extension of the European electricity network towards neighbouring power grids; and the diffusion of distributed energy sources and self-consumption steering the development of a smarter power system.

The following figure frames the electricity security actions which can be put in place to maintain/increase the previously introduced electricity security properties and with respect to the different domains of the electricity supply chain.

More in detail:

  • Short-term system operation actions, including: transient/dynamic stability management, pre-fault and post-fault remedial actions (based on contingency analyses) and system balancing actions.
  • Mid-term operational planning and scheduling actions, including forecasting, power scheduling, ancillary service procurement, outage coordination and asset management actions.
  • Long-term system planning actions, including: system (network) optimisation, enhancement and expansion actions.
  • Very long-term system planning actions, including: strategic energy planning/provision actions and a wide range of policy and regulatory initiatives which may impact not only the electricity system but the wider energy system (starting from the primary energy sources made available for electricity production).

5. How to improve electricity security decision making?

A structured platform for cooperative governance and decision making is crucial to ensure that electricity security objectives and actions are discussed, agreed and implemented in a transparent, effective and fair way.

To his end, a novel decision-analytic framework is proposed, based upon elements and recommendations grouped in four macro-categories: governancestrategicmethodological and enabling categories.


Multi-stakeholder platforms; Regional scale of decision making; Collaborative and integrated security analyses; Cooperative decision making mechanisms.


Integrated coverage of all electricity security dimensions (infrastructure, sources, market and regulation, geopolitics), Smart/super grid and multi-energy carrier systems assessments, move from assessing flow security to assessing service security, emerging vulnerability assessment approaches based on complex network science, deeper interplay of complex network and engineering approaches.


Common definitions for flexibility, resilience and robustness; Cost-benefit analyses vs. multi-criteria analyses; Indicators used with care; Sensitivity analyses supporting security analyses; Soft/hard linking of electricity security models (Energy system/power market models, Power market/system models, Static power system/grid models and Dynamic power system/grid models); Flexibility as driver for modelling integration; Probabilistic approaches for reliability analyses.


Geographic Information System and visual analytics; Supercomputers, real time simulators and parallel processing; Reliable and representative datasets.

The novel conceptual framework for electricity security analyses - encompassing multiple actors, dimensions and models - is then contextualised in the European Union's power system planning process (see figure below), in order to show how it could better support the policy decision making on electricity security; reliability analyses and vulnerability analyses might be conducted, fundamentally by the same actors, on two different layers and combined through an integrated assessment approach.

Looking deeper into the reliability analyses, one can see additional assessment blocks and models introduced. As for the models deployed (from top to bottom), along with the energy system/power market models, power market/system models and static power system/grid models already featuring in the previous framework, also dynamic power system/grid models are utilised for integrated reliability studies. The key point here is the need to study flexibility issues, which requires to go closer to real time to assess the system performances.

Full research material available for download

This doctoral research was carried out in the context of the cooperation between Politecnico di Torino and the European Commission’s Joint Research Centre. The information and views set out in this publication are those of the author and do not necessarily reflect the official opinion of the European Union. Neither the European Union institutions and bodies nor any person acting on their behalf may be held responsible for the use which may be made of the information contained therein.