geplante Inbetriebnahme 2018

The modernization of the transmission grid is a key factor for the energy revolution. Swissgrid is creating a secure, efficient and sustainable energy future in dialogue with Switzerland.

«Strategic Grid 2025»
A modern grid
for Switzerland
Technischer Bericht (German) Grid Expo (German)

01Point of departure

The Strategic Grid 2025 is the grid for Switzerland's energy future.

Swiss electricity system
in upheaval

  • The “Strategic Grid 2025” is your grid

    Switzerland places the highest demands on its transmission grid. However, opinions on how it is to develop differ widely. Consequently, a broadly based dialogue on the measures needed and their configuration is absolutely vital to Swissgrid. The grid of the future will be your grid.

    By 2025 Switzerland can have the grid it needs. Modernisation of the transmission grid is and will remain a key factor for a sustainable energy future. The “Report on the Strategic Grid 2025” drawn up by Swissgrid is a transparent presentation of the measures needed for grid expansion. Moreover, it illuminates the conscientious considerations on which these plans are based.

    It is now clear what has to be done. The projects described below must be implemented without delay, to ensure that supply security remains guaranteed in the future, and that Switzerland can make its contribution to Europe’s energy transformation.

    Get an initial impression from the following pages and take part in the dialogue on the “Strategic Grid 2025”. We look forward to it.

  • A modern grid for Switzerland

    The electricity system is facing the greatest upheaval of its successful history. Because of this, it is not just that general technical conditions are changing - the entire electricity economy is being transformed.

    However, the further development of the transmission grid has slowed dramatically in the last 40 years. Only a third of the total of 6 700 kilometres of grid length of Swissgrid dates from after 1980. And it is precisely in recent decades that the demands on the grid have been transformed. On the one hand, there are new energy sources and power plants, and on the other hand the consumption of electricity has grown over recent years.

    In addition, as a result of its central location and topography, Switzerland is also an important electricity hub for Europe. The country’s storage lakes are not only extremely valuable for its own supply security, but are also used by its neighbours to ensure the stability of their grids.

    The rising overall demands are already leading to structural congestion in the transmission grid. In future this development is likely to continue. It is urgently necessary to compensate for these weaknesses, because they endanger the supply security and economic efficiency of the Swiss electricity system.

  • How Swissgrid is planning for 2025 today

    Swissgrid is responsible for economic operation of the electricity transmission grid and is consequently pursuing modernisation of the grid that is technically secure, as environmentally friendly and economically efficient as possible, and as a result, sustainable. The “Strategic Grid 2025” must meet the still unknown supply task in 2025 without significant structural congestion. At the same time the conversion and expansion required should not occur in instalments, but according to understandable, transparent considerations.

    Based on the most realistic scenarios possible, Swissgrid is simulating where recurrent congestion will occur in the grid. Subsequently potential development measures will be evaluated carefully according to technical, economic and social criteria. If the evaluation is positive, a project will be pursued as part of the “Strategic Grid 2025.”

    If a grid expansion is technically necessary or makes economic sense, it will be implemented in a manner that conserves the landscape as far as possible. Expansion will only be planned if optimisation of the existing infrastructure is out of the question and enhancement of the existing grid would not create the relief needed either.

Bericht S.15
Bericht S.31

02Analysis of driving factors

Swissgrid has identified the basic driving factors in Swiss grid development

Factors influencing grid development

Bericht S.96

Direct driving factors

Indirect driving factors

  • Major new power plants in Switzerland

    This can for example include the new construction of a large pumped storage facility, which greatly changes the transport task in a region. New pumped storage power plants in thinly populated regions with fewer strong lines in particular cause overloading of the grid.

    Switzerland’s nuclear energy phase-out

    The effect of this driving factor in the “Strategic Grid 2025” is that the missing capacity has to be replaced by other domestic and foreign sources.

    CO2 and fuel price development

    The level and volatility of these prices as well as international differences have an effect on the costs of grid congestion and the flow of electricity between Switzerland and its neighbours.

  • International association

    Exchanging electricity abroad increases Switzerland’s supply security. It permits the export of domestically produced electricity and the import needed at times of low domestic production (primarily in winter). In the event of increasing volumes overloading of the grid can occur. Expected imports and exports make domestic grid expansion necessary.

    Power plant fleet and electricity
    demand in neighbouring countries

    Changes in the power plant fleet and the demand abroad influence the international flow of electricity. The type of power plants and their availability have to be taken into account in this respect. Moreover, the expansion of the transmission grids between European countries outside Switzerland has an additional influence on the international flow of electricity.

  • Supply
    of downstream grids

    The distribution grids are constantly adjusting to changes in electricity demand and generation. New connection requests can lead to structural congestion and as a result change the supply task for Swissgrid, which also has an effect on the “Strategic Grid 2025.”

    Electricity demand in Switzerland

    The development of population and economic power, increases in energy efficiency, and new growth trends like electric cars also influence electricity demand. They influence the import and export volumes too.

    Expansion of renewable energy in

    The expansion of photovoltaics, wind and hydroelectric generation has not proven to be the main driving factor for the expansion of the transmission grid. The energy transformation operates far more via primary driving factors like the modified deployment profiles of major power plants and inter- national electricity flows.

03The “Strategic Grid 2025”

The “Strategic Grid 2025” is technically secure, makes economic sense and is sustainable

Measures for the conversion
and expansion of the grid

Bericht S.183

planned commissioning 2018

  • Important grid
    expansion projects and legally justified grid projects

  • Project of Common
    Interest (PCI)

    not part of the
    “Strategic Grid 2025”

  • Projects from the
    Strategic Grid 2015 that are no longer relevant

Mathod – Mühleberg

Froloo – Flumenthal

Obfelden – Samstagern

Balzers route laying

Génissiat – Foretaille

Bassecourt – Mühleberg

Chamoson – Chippis

Chippis – Bickigen

Chippis – Lavorgo

Beznau – Mettlen

Mettlen – Ulrichen


Pradella - La Punt

San Giacomo

Lake Constance interconnector

Mettlen – Verderio

Mathod – Galmiz

Riddes – Chamoson

Wattenwil – Mühleberg

Mettlen – Airolo

Obfelden – Thalwil – Grynau

Lavorgo – Morbegno

Auwiesen – Fällanden

Ova Spin connection

04Grid planning brings us together

Swissgrid worked together with representatives from the stakeholder groups to lay out the key features of the plan.

Dialogue for a future of
sustainable energy

Bericht S.21

Swissgrid Logo







Event calendar
30.4.2015 Annual Media Conference (german)
Park Hyatt, Zurich
12.5.2015 Grid forum
Museum of Transport, Lucerne

Recordings (german)


Quotes about the Grid Expo

21.5.2015 «Le réseau électrique de demain»
EPFL, Lausanne

Recordings (french)


Expert opinions

1.–5.6.2015 Exhibition
BEKB, Bern
9.6.2015 Parliament event
Lorenzini, Bern
16.–19.6.2015 «The grid of the future»
ETH, Zurich

Recordings (german)



Swissgrid relies on the latest recognised methods in grid planning.

Latest grid planning techniques

Bericht S.45
Bericht S.55

Scenario funnels

Scenarios instead of forecasts

The grid planning for the “Strategic Grid 2025” is based on two different core scenarios for the years 2025 and 2035. These are flanked by two marginal scenarios for 2035. These should not be understood as a prediction of the future, but rather constitute a possible scope of developments, the so-called scenario funnels. The scenarios used are based on the energy perspectives 2050 of the Swiss federal government and the data of the European Network of Transmission System Operators for Electricity. As far as possible they have been discussed and agreed with representatives of the industry and politics and environment associations.

Core scenarios (2025 & 2035)

On Track – rise of renewables

and up NPP phase-out by 2035


Slow Progress – modest expansion of renewables and no complete

NPP phase-out by 2035

On Track


Slow Progress


Marginal scenarios (2035)

Sun – strong expansion of photovoltaics


Stagnancy – energy prices remain on the current level




Market simulation for the greatest transparency

The different scenarios constitute the foundation for the simulation of the future electricity market. The goal is to estimate how many power plants will be producing at home and abroad to cover the respective demand. The resulting domestic and cross-border electricity flows can be deduced from this and the electricity prices simulated.

Bericht S.58
Bericht S.215

Scenarios and hypotheses 2025

    GRID 2015


  • SLOW

  • «Starting grid 2015»

    Swissgrid’s transmission grid is continually adapted to the changing requirements within the scope of the planning time frames given by the approval procedures. Therefore, after the grid take-over, improvement measures were identified that either are already being carried out or will be realized in 2015. Together with today’s transmission grid, these measures constitute the starting grid 2015. With this grid, the load flow calculations are performed, bottlenecks are identified and measures for removing the bottlenecks are derived.

    All values pertain to the year 2013.

    Swiss consumption(TWh/a)

    Wind (GW)

    Solar (GW)














    CO2 prices (EUR/t)

    Net transfer capacity (GW)

    Pumped-storage power plants







    (AT, D, F)




    Nant de Drance

    Power plant development ENTSO-E(GW)

    Fuel prices



    Black coal


    Brown coal


    Light oil


    Heavy oil


    Fossil-fueled thermal

    Nuclear power



    Hydroelectric power


  • «On Track 2025»

    The On Track scenario assumes that the transition to sustainable energy sources contained in the federal energy strategy will be completed on time. In terms of Swiss consumption and relevant developments, On Track is based on the New Energy Politics scenario from the federal Energy Perspectives 2050. Switzerland will have completely withdrawn from nuclear energy production. The expansion to photovoltaic and wind power sources is making progress and totals 4.2 GW by 2025 and 8.2 GW by 2035. Energy efficiency measures result in a slight reduction in Swiss power consumption.

    Swiss consumption(TWh/a)

    Wind (GW)

    Solar (GW)














    CO2 prices (EUR/t)

    Net transfer capacity (GW)

    Pumped-storage power plants






    (AT, D, F)





    Nant de Drance

    Power plant development ENTSO-E (GW)

    Fuel prices



    Black coal


    Brown coal


    Light oil


    Heavy oil


    Fossil-fueled thermal


    Nuclear power





    Hydroelectric power

  • «Slow Progress 2025»

    The Slow Progress scenario, in terms of Swiss consumption and relevant developments, is based on the Stay Present Course scenario from the federal Energy Perspectives 2050. It presumes that a transition to sustainable energy in Switzerland is delayed. Switzerland has not yet completely withdrawn from nuclear power production by 2035 and the expansion of photovoltaic and wind power sources is slow than hoped. At the same time, Swiss energy consumption increases continuously until 2035.

    Swiss consumption(TWh/a)

    Wind (GW)

    Solar (GW)














    CO2 prices (EUR/t)

    Net transfer capacity (GW)

    Pumped-storage power plants






    (AT, D, F)





    Nant de Drance

    Power plant development ENTSO-E (GW)

    Fuel prices



    Black coal


    Brown coal


    Light oil


    Heavy oil


    Fossil-fueled thermal






    Nuclear power

    Hydroelectric power

Bericht S.135
Bericht S.145


  • TOOT

  • Grid

  • CBA

  • TOOT-Process





    reference grid






    Impact on


    and/or NTC*

    Adapting the

    market simulation



    Grid losses /


    in grid losses




    Robustness /





    of supply






    of renewable




    multi-criteria cost-benefit analysis

    Result of the multi-criteria cost-benefit analysis

    * NTC – Net Transfer Capacity

    TOOT – Take Out One at a Time

    The effect of a project is evaluated on the basis of a comparative case (here: comparative grid) in the context of the cost/benefit analysis. The benefit arises from the advantage that occurs if the project is removed from the comparative grid. TOOT stands for “Take Out One at a Time” and corresponds to the removal of a project from a completely expanded comparative grid.


    Grid today

    8736 models

    Load flow analysis

    (n-1), U/Q










    Expansion of

    the grid system

    Market Data

    > Grid




    of worst




    Results of market


    Gen/pump load


    of measure



    PINT 2025







    Grid mapping

    The results of the market simulation are mirrored in a further step on the current grid. It now becomes clear whether the existing grid is capable of transporting the future energy flows. Where structural congestion emerges there is a need for planners to act.

    Grid simulation

    The focus will now be placed on Switzerland to determine the grid expansion projects needed in the Swiss transmission grid. The current grid will be supplemented by gradual measures until the structural congestion from the grid simulation has been eliminated. This will occur according to the so-called PINT procedure (Put In One at a Time). The following applies to minimise environmental and landscape influences: grid optimisation, before grid enhancement, before grid expansion (the NOVA principle). The result is a grid that permits secure operation in the scenarios used.

  • planned grid measures:

    Project 1

    Project 2


    decision basis

    Quantifiable factors

    Qualitative factors

    in categories

    (e.g. positive-neutral-negative)

    in CHF

    for future projects


    Factors in detail

    Energy economy


    Costs through grid losses


    Direct costs

    Supply security for

    electricity recipients

    Grid security


    Robustness and flexibility

    Environmental effects

    Project will be realised


    Project will be rejected


    Multi-criteria cost-benefit analysis

    The expansion measures determined will now be evaluated in a multi-criteria cost/benefit analysis for Switzerland. Apart from easily measurable monetary costs and benefits, this analysis takes qualitative criteria into account with equal weight, such as the contribution to supply security or environmental effects. If an expansion measure is evaluated according to the multi-criteria evaluation as positive, it is included in the “Strategic Grid 2025”.


Questions about the Strategic Grid 2025?

Grid expansion

  • Why is expansion of the grid system needed at all?

    The Swiss transmission grid will have to be converted and expanded in the coming years to maintain a secure and efficient supply of electricity in the future.

    In its report «Strategic grid 2025» Swissgrid identified and presented the fundamental driving factors behind the grid development. The analysis of driving factors shows what movements in the electricity system affect the transmission grid. The direct driving factors demand technical expansion of the existing grid. These are:

    • Major new power plants in Switzerland. The major new hydroelectric plants are bringing about clear changes in the transport task of a region.
    • International interconnected operation. Exchanging electricity abroad increases Switzerland's supply security. Expected imports and exports make domestic grid expansion necessary.
    • Supply of downstream disruption grids. Distribution grids adapt to the demand for and generation of electricity. Connection requests can lead to structural congestion in the transmission grid.

    Apart from this there are indirect driving factors which determine the need for grid expansion. These are:

    • Expansion of renewable energy in Switzerland. Acts via direct driving factors, such as use profiles of major power plants and international electricity flows.
    • Switzerland's nuclear energy phase-out. Lack of capacity is to be replaced to an increased extent by decentralised electricity generation, e.g. solar and wind power plants or imports.
    • Power plant fleet and electricity demand in neighbouring countries. Changes determine flows of electricity.
    • Electricity demand in Switzerland influences the volume of imports and exports.
    • CO2 and fuel price development affects the costs of grid congestion and energy flows.
  • Who benefits from expansion of the grid system?

    Expansion of the grid system primarily serves maintenance of the security of supply from which all households and enterprises benefit. The benefits of the individual projects emerge from the detailed evaluation that Swissgrid carried out for every project. Swissgrid at the same time evaluated the technical, economic and ecological benefits.

  • Why is it claimed that expansion of the grid system is necessary for maintenance of the security of supply although there are no interruptions in the electricity supply?

    The task of operating the grid securely despite greater loads is becoming increasingly demanding. It is already the case today, and will be in future without expansion of the grid system to an increased degree, that supply security is only guaranteed because Swissgrid intervenes actively in power plant feed-in. Measures are required daily in real time operation to maintain the balance between feed-in and consumption. These interventions have to be kept operationally as small as possible and are economically inefficient.

  • Is the primary purpose of the expansion of the grid system in Switzerland not for transit?

    In general it must be borne in mind that the European interconnected operation makes an important contribution to supply security in Switzerland. Imports and exports of electricity are economically inefficient. Swissgrid draws a clear distinction in its grid planning between projects that are technically necessary and make economic sense and those that could be worthwhile from the point of view of the European grid association.

    Lines that are not primarily needed for national supply are pursued in the European context if it is certain that this makes sense for the overall electricity system and the financing is properly regulated from the Swiss point of view.

  • Who pays for expansion of the grid system?

    The costs for expansion of the grid system are paid for by charges for use of the grid.

Grid planning

  • Why is Swissgrid engaged in grid planning (right now)?

    Meticulous, forward-looking grid planning is indispensable for timely further development and modernisation of the grid according to needs and a crucial prerequisite for avoiding bad investments. Moreover, as the national grid company Swissgrid is legally obliged to draw up strategic plans for the grid at regular intervals. Based on this, multi-year planning is established, which on request is presented to the regulator.

  • What happens to Swissgrid's grid planning? How binding is it?

    The «strategic grid 2025» constitutes the basis for Swissgrid's multi-year planning. Swissgrid does not implement any projects that are not included in the «strategic grid 2025.» As before, the projects themselves are confirmed as part of the sectorial planning procedure by the Federal Council.

  • The decisions on the new energy policy of Switzerland and Europe have not yet been taken. Has the time for grid planning not been chosen incorrectly?

    Swissgrid planning is deliberately based on known or expected developments in the market, technology and politics. Care is taken that any changes in national and European energy policy are addressed as far as possible by means of various scenarios.

    Should there be change of direction that affects grid planning, this will be taken into account in the following planning cycle. Consequently, the process of grid planning runs in parallel, but not independently of political decisions.

  • Why did the grid planning take so long?

    For the first time, Swissgrid has performed grid planning for Switzerland as a whole. The work proved to be very complex and required more effort than originally assumed. At the same time, what counted for Swissgrid was to carry out comprehensive planning, i.e. taking current changes in the environment into account and using modern planning methods.

  • Do other TSO perform such grid planning? In the same way as Swissgrid?

    As one of the first grid operators in Europe, Swissgrid concentrated on a consideration of the overall economic benefit of the grid measures, apart from consideration of the technical criteria.

    Comparison of the techniques and tools used by Swissgrid in the market and grid simulation with those of other European transmission system operators shows that the transparent, but also elaborate Swissgrid grid planning has to be viewed as progressive by European standards.


  • On what assumptions is the planning based?

    To counter the fear of partisanship or lack of impartiality, Swissgrid decided to make use of external sources wherever possible. The scenarios used are based on the energy perspectives 2050 of the Swiss federal government and the data of the European Network of Transmission System Operators for Electricity. As far as possible they have been discussed and agreed with representatives of the industry and politics and environment associations.

  • How did Swissgrid proceed?

    Swissgrid proceeded in four steps in its grid planning:

    • Provision of scenarios for a scenario funnel: provision of scenarios for a scenario funnel.
    • Conduct of a market simulation: the number of power plants needed at home and abroad to cover the particular consumption is produced for every hour.
    • Conduct of a grid simulation: what grid expansions the Swiss transmission grid needs is determined in order to be able to transport the electricity flows resulting from the market simulation.
    • Conduct of a multi-criteria cost-benefit analysis: expansion measures determined are finally evaluated using quantitative (such as monetary) and qualitative criteria.
  • How widely is the planning coordinated with authorities, industry and other partners?

    The scenarios used are based on the energy perspectives 2050 of the Swiss federal government and the data of the European Network of Transmission System Operators for Electricity. As far as possible they have been discussed and agreed with representatives of the industry and politics and environment associations.

    • To compare the major assumptions for the core scenarios the neighbouring transmission system operators were asked about their scenarios.
    • Swissgrid brought in the Environmental Alliance to develop the «Sun» marginal scenario.
    • The plans of the distribution grid and power grid operators were included as part of the regular working group meetings in the grid planning.
  • You speak of the «strategic grid 2025» but at the same time refer to 2035? How do you reconcile that?

    The calculations for the «base year» 2035 document the robustness of the grid configuration and underline the necessity of the projects in the «strategic grid 2025.»


  • Summarised briefly, what are the most important results of the planning?

    • No building instalments. The «strategic grid 2025» pursues the principle of the NOVA grid expansion according to needs. According to this, a grid optimisation must be preferred to an enhancement, which in turn has priority over expansion.
    • The following kilometres have to be modernised or built new:
      • Optimisation and enhancement of 280 km (previously 1000 km)
      • New construction of 370 km (previously 300 km)
    • The projects from the «strategic grid 2015» have been confirmed with a few exceptions. The following will no longer be pursued by Swissgrid:
      • Mathod – Galmiz
      • Wattenwil – Mühleberg
      • Mettlen – Airolo
      • Anschluss Ova Spin
      • Lavorgo – Morbegno
      • Obfelden – Thalwil – Grynau
      • Riddes – Chamoson
      • Auwiesen – Fällanden
  • How much needs to be expanded?

    The following grid modernisations are shown in the «strategic grid 2025»:

    • Optimisation; increase in voltage from 220 to 380 kV on lines dimensioned for this: 193 km
    • Enhancement; replacement of existing lines to increase the voltage from 220 to 380 kV: 87 km
    • Expansion; new construction of transmission lines on a new route: 370 km
  • What will the expansion of the grid system cost? What is the cost breakdown?

    The total investment costs in the grid expansion and preservation until 2025 amount to almost CHF 2.5 billion. The costs are made up as follows:

    • Something over CHF 1.4 billion to realise all expansion projects.
      • General planning cost estimates for overhead lines are used for projects in an early planning stage or which have not yet been implemented (e.g. typical specific CHF/km costs).
      • Costs from the project-specific calculation are used for projects whose planning is already far advanced and more precise information is consequently available on the technical solution approaches.
    • Over CHF 1 billion for grid preservation (replacement, maintenance and easement renewal)
  • Why are projects suddenly no longer needed although it was claimed for 30 years that they were needed?

    The projects are no longer needed on account of changes in the generation and grid structures in Europe and Switzerland.

  • What will happen to the projects not confirmed in the «strategic grid 2025»?

    Swissgrid will withdraw projects that were not confirmed in the «strategic grid 2025» compared to the «strategic grid 2015» in consultation with the Swiss Federal Office of Energy and project partners involved from the in part running procedures. The consequences from the non-continuation will be evaluated and drawn up together with the relevant partners and parties affected.

  • What makes Swissgrid sure that this is really the grid which will be needed in 2025?

    All long term planning is subject to uncertainty. Swissgrid has dealt with this by developing two core scenarios for 2025 and 2035 as well as two additional marginal scenarios for 2035. This expanded long term opening scenario funnel ensures that the reality is probably somewhere in between.

    The assumptions made on the direct driving factors of the grid developments for the time horizon 2025 can be regarded as assured (e.g. the PSPP NdD, LLPP and Veytaux+).

  • What is the difference between the results between the grid 2025 and grid 2035?

    Swissgrid is focused on the «strategic grid 2025.» Scenarios were calculated for 2035 in order to carry out the cost-benefit analysis over two base years and substantiate the projects in the «strategic grid 2035.» The results for 2035 indicate more projects which could be required in all or a large part of the scenarios.

  • What will happen if the grid projects are not realised by 2025?

    The hydroelectric plants would not be able to produce as planned, which would involve an economic loss. No Swiss supply interruptions are to be expected directly. In the worst case there could be consumption restrictions or also regional interruptions.

Contact form

Questions about the Strategic Grid 2025?