System Development Reports

​Developing a secure, reliable, sustainable and economically viable European electricity grid that supports Europe’s growth is the core mission of the ENTSO-E’s System Development Committee (SDC), supported by the Secretariat SDC Team.

The mission of SDC is strategic, as the committee is producing some of the major legally mandated ENTSO-E publications such as the TYNDP and the Outlook Reports. These are cornerstone publications for all stakeholders, policy makers, investors, industry representatives, consumer organisations, and NGOs interested in or impacted by the development of Europe’s electricity grid.

TYNDP – one of the main legally mandated deliverables of ENTSO-E on which pan-European investment decisions are taken.

Outlook Reports – legally mandated publications giving the TSOs’ assessment of security of supply and of ways to resolve potential balancing problems between neighbouring countries.

Scenario Outlook & Adequacy Forecast – the SO&AF forms part of the TYNDP and provides an annual on the mid- to long-term overview and analysis of generation adequacy for all ENTSO-E members, by region and by country.

Adequacy Retrospect – An annual overview in retrospect of generation adequacy in Europe with a focus on power balance, margins, and generation mix.

Regional Plans – A summary of the work achieved by the six regions that form part of the SDC.

Offshore Transmission Technology Report – An overview of offshore electricity transmission technologies


Outlook Reports

​​​​​​​​​​​​​​​​​​​​​​​​​The ENTSO-E Outlook Reports present the views of Europe’s electricity TSOs regarding national, regional and pan-European security of supply for the summer and winter periods. These reports focus on situations where, even well-functioning markets, are no longer able to deliver due to physical unavailability of generation or transmission. ENTSO-E is working to improve the methodology of its outlook reports notably in order to provide more details on the contributions of cross-border flows to system adequacy. This improved methodology should be used as of 2016.


The ENTSO-E winter outlook is put together on the basis of information received from member TSOs by mid-November. The data collected is then used to carry out calculations and simulations which lead to a series of results published in the Outlook. As it is not possible to re-do all the calculations with new information, ENTSO-E has decided to publish as updates any new information (post 15 November) it receives from its member TSOs regarding the situation on their grid this winter. Please note that for the most up to date information on the specific situation of a country we highly recommend you also check the website of the TSO concerned. ​

Situation in Switzerland this winter

Dec 9 2015
Beginning of December, Swissgrid announced that its predictions for winter 2015/16 showed that grid capacity for the Swiss transmission grid, in particular for 380/220 kV transformers, will increasingly reach its limits. A number of special external circumstances affecting the 220-kV grid make the situation for grid operation this winter 2015/16 particularly difficult in Switzerland compared with previous years. Swissgrid estimates the current grid situation and the supply of energy for winter 2015/16 as tense. Energy reserves are tight, due to a number of interconnected special circumstances. As a result of the drop out of the nuclear power plants Beznau 1 and 2, a large share of the base load is missing from t​he 220-kV grid. The missing feed-in into the 220-kV grid can only be offset by imports from the 380-kV grid to a limited extent.

For more information and regulat updates check the Swissgrid website

Winter Outlook 2015/16 and Summer Review

​The ENTSO-E Winter Outlook 2015/16 shows that in general Europe has sufficient generation for both normal and severe demand conditions. While various countries may require imports to cover the expected demand, cross border capacity is expected to be mostly sufficient to accommodate them.

Using the interconnection flexibility, demand side management (from industrial customers) and strategic reserves measures, adequacy for the coming winter should be met in most European countries. However, adequacy in Poland was identified as potentially at risk.

Read the full Winter Outlook 2015/16 and Summer Review​ Winter Outlook 2015/16 input datashee​t​​ Slides of the ENTSO-E and ENTSOG webinar on Winter Outlooks 2015/16

Summer Outlook Reports

Winter Outlook Reports

Regional Plans

The System Development Committee has defined six regional groups. The regional groups are designed to address the challenges for grid development and the integration of new generation, especially renewable energy sources, at a regional level through a structure which reflects the regions’ particularities and needs.


Offshore Transmission Technology Report

This ENTSO-E report entitled ‘Offshore Transmission Technology Report’ provides an overview of offshore electricity transmission technologies. The focus of the report concerns the use of High Voltage Direct Current (HVDC) systems in particular and focuses also on the development of Voltage Source Converter (VSC) technology. The report outlines the current state of the main technology groups required for offshore HVDC transmission as well as giving examples of offshore projects (both current and future). Finally some indications of likely unit costs for HV assets are given.

This report was prepared for the North Seas Countries’ Offshore Grid Initiative (NSCOGI) by ENTSO-E’s Regional Group North Sea (RG NS). Members of RG NS including Belgium, Denmark, France, Germany, Luxembourg, the Netherlands, Norway, Rep of Ireland and the UK contributed to this report along with contributions from equipment suppliers and manufacturers through the working group of Georg Wilhelm Adamowitsch.

Offshore Transmission Technology Report

ENTSO-E views on the offshore grid development in the North Seas

System Adequacy Retrospect

See Statistics →

Scenario Outlook & Adequacy Forecasts

The 2015 edition of the Scenario Outlook & Adequacy Forecast (SO&AF) looks at how system adequacy -balance between supply and demand- is likely to evolve in Europe up to 2025. Foreseen by the 3rd Package, this long-term system adequacy assessment is one of the tools ENTSO-E provides to stakeholders and decision makers on which to base their investments and policy decisions.

The SO&AF 2015 takes into account most of the feedback received from stakeholders on previous editions. More focus is for instance given to cross-border flows and need for flexibility. Further improvements in probabilistic market-based system adequacy assessments will be implemented in the SO&AF 2016 report.

Regarding demand for electricity, the SO&AF 2015 foresees a 0.8% annual increase from 2016-2025 due electrification of heating and transport, and economic recovery. These results are based on the transmission system operators’ (TSO) highest forecast for electricity demand growth, relevant for risk assessments of generation adequacy.

New generation capacity to come from renewables

In terms of generation capacity, fossil fuel-based capacity decreases to lower values than in previous reports. Gas-fired power stations should replace coal power stations. Nuclear should be reduced by 12% between 2020 and 2025. New generation capacity will actually be provided by renewable energy sources (RES). Hydro power plants generation capacity is expected to remain stable until 2025. However, wind and solar are forecast to increase respectively by 80% and 60%.

By 2025, 22 countries are reported to have a RES capacity penetration level higher than 50% in their systems. In eight countries (DE, DK, GB, GR, IE, NI, NL and PT) demand could at times be totally covered by renewable generation.

Residual load and cross-border impacts to keep systems balanced

To analyse the operational risk to cover sudden changes due to inherent variability in the power system portfolio, several indicators have been defined and quantified using a one-hour resolution. Using data from the Pan-European Climate Database, residual load has been assessed. SO&AF 2015 also includes an enhanced regional assessment showing how electricity imports and exports can improve national system adequacy.

Scenario Outlook & Adequacy Forecast (SO&AF) 2015 Scenario Outlook & Adequacy Forecast (SO&AF) 2015