Switzerland’s electricity system is in the midst of the greatest upheaval in its successful history. Energy reform is bringing a paradigm shift from a centralised to a decentralised energy system. The increasing volatility in power generation, caused by the growing share of renewable energies as well as the growth in consumption due to e-mobility and heat pumping technology, brings additional challenges for secure grid operation. This has far-reaching implications for the electricity industry in Switzerland and throughout Europe.
The modernisation of the transmission grid has slowed down in the past few decades. Only a third of Swissgrid's entire 6,700-kilometre-long transmission grid dates from the period after 1980, but the demands on the grid have changed significantly in recent years. This development will intensify in the coming decades. New decentralised energy sources and power plants (photovoltaics, wind power) are being connected to the grid, and electricity consumption will grow noticeably in the future due to decarbonisation.
The constantly rising demands are already leading to structural bottlenecks in the transmission grid today. These are expected to increase even further in the future. To ensure the safe, powerful and efficient operation of the Swiss electricity system, these bottlenecks must be eliminated. That is why Swissgrid periodically draws up a multi-year plan – the Strategic Grid – for the further development of the transmission network.
The modernisation of the transmission grid is the key to a sustainable energy future and is aligned with the scenario framework for Switzerland set out by the Federal Government. As the backbone of a secure energy supply, the transmission grid makes a key contribution to achieving the goals of Energy Strategy 2050.
Grid development process
The provisions of the Federal Act on the Renovation and Expansion of the Grids («Electricity Grid Strategy»), which are entering into force gradually, have been regulating the grid development process in Switzerland since 2021.
In the planning phase of the grid development process, the Swiss Federal Office of Energy (SFOE) drafts an energy policy scenario framework for Switzerland. It is approved by the Federal Council and used as the future basis for planning the Swiss electricity grid – with the aim of ensuring that the electricity grids are optimally aligned with the future energy policy developments in Switzerland. The scenario framework contains three scenarios that reflect the range of possible energy policy developments. Swissgrid then uses this scenario framework to determine the need for adjustments to the transmission system. The planning phase is repeated every four years. This ensures that the grid development can be continuously adapted to changing framework conditions.
In the project planning phase, Swissgrid develops specific projects covering the demand identified in the Strategic Grid report. Every project normally passes through a national sectoral plan process for transmission lines at the SFOE as well as a planning approval procedure with the Federal Inspectorate for Heavy Current Installations (ESTI).
Once all the necessary approvals are in place, Swissgrid starts the implementation phase with the construction of the relevant projects.
After commissioning the installations, Swissgrid also checks whether the project costs assumed in the Strategic Grid and their expected benefits reflect reality and possible reasons for deviations. The findings from these analyses are then included in the next planning phase.
Principles for long-term grid planning
Sustainable, resource-saving, environmentally friendly and economically efficient grid planning is important to Swissgrid. The transmission grid of the future should be stable and secure to operate. Grid expansion is not carried out to accumulate reserve capacity, but on the basis of comprehensible and transparent considerations. Accordingly, Swissgrid is guided by the following key principles when creating the Strategic Grid:
- Minimise environmental impact: Swissgrid is not expanding the grid to accumulate reserve capacity. The existing grid is operated as efficiently as possible. Wherever possible, Swissgrid first optimises the existing grid and enhances it as necessary. Obsolete lines and substations are dismantled wherever possible. If a new line is required, Swissgrid takes into account the spatial and environmental impact, as well as technical aspects and cost-effectiveness, when searching for the best line corridor and selecting the transmission technology (overhead line or cabling).
The bundling of transmission lines with trunk roads and railway lines reduces the number of parallel routes. The need for expansion between grid nodes is determined as part of the Strategic Grid. The line corridor and transmission technology are definitively determined within the framework of the subsequent «Spatial Coordination (National Sectoral Plan Procedure)».
- Avoid future grid congestion: Swissgrid identifies grid elements where congestion will repeatedly occur in the future. For this purpose, Swissgrid refers to findings from current grid operations as well as a grid simulation for the target year 2040. Existing and future congestion will be eliminated via grid optimisation, grid enhancement and grid expansion.
- Ensure dynamic grid stability: The dismantling of large power plants throughout Europe reduces the rotating mass on the transmission grid. The inertia stored in large generators continues to stabilise the frequency of the grid. Swissgrid and foreign transmission system operators conduct stress tests to determine whether grid stability can still be guaranteed in the future or whether measures need to be taken as part of grid planning.
- Take into account the flexibility of storage systems, generators and consumers: In grid planning, Swissgrid can only take into account the potential for flexibility offered by artificial intelligence, decentralised consumption control and smart peak shaving in photovoltaic and wind production if it can be activated and used by Swissgrid at any time. To achieve this, the regulatory framework conditions must be created, products developed and contracts concluded. This has not yet happened to a sufficient extent.
- Ensure a positive cost-benefit ratio: For every grid project costing more than CHF 1.0 million, Swissgrid carries out and documents a uniform cost-benefit comparison. The benefit of each grid project is shown in monetary, quantitative or qualitative terms according to various criteria.
- Communicate transparently and coordinate with relevant stakeholders: Swissgrid coordinates long-term grid planning with all the relevant stakeholder groups. These include, for example, the transmission system operators of neighbouring countries, the distribution system and power plant operators connected to the Swiss transmission grid, the Swiss Federal Office of Energy (SFOE) and the Swiss Federal Electricity Commission (ElCom). Swissgrid communicates the procedure and results of the Strategic Grid in a transparent and comprehensible manner.
Strategic Grid 2040
In view of the new statutory provisions, the SFOE is developing the first scenario framework for Switzerland for the target years 2030 and 2040. These are based on the Federal Government’s energy policy objectives and the overall economic framework data and take the international environment into account. The distribution system operators (DSO) in grid level 3 have worked together with Swissgrid to define a process that breaks down the production and consumption provisions from the scenario framework to the individual grid nodes (regionalisation process).
The expectation is that Swissgrid will start updating its multi-year plan for long-term grid planning, the «Strategic Grid», in autumn 2022, following the approval of the scenario framework for Switzerland by the Federal Council. The «Strategic Grid 2040» describes and provides the reasons behind the intended grid projects for the target year 2040. After nine months, Swissgrid is required to submit the «Strategic Grid 2040» to the Swiss Federal Electricity Commission (ElCom) for review, which also takes nine months. Afterwards, Swissgrid will publish the «Strategic Grid 2040» via its communication channels; this is expected to occur in the summer of 2024.
The legislation stipulates that this process must be repeated every four years.
Strategic Grid 2025
Swissgrid had already developed a multi-year plan for the needs-based modernisation of the transmission system back in 2015, before the entry into force of the statutory provisions on the grid development process: the «Strategic Grid 2025». The «Strategic Grid 2025» includes ten projects. The defined projects are all in various stages of implementation. The following diagram provides an overview.
Swissgrid has already been able to complete some of the projects from the «Strategic Grid 2025», while others are in the construction phase. Through these projects, Swissgrid makes an important contribution to the security of supply in Switzerland.
But many projects remain in various project planning phases. The reasons for this are the protracted approval procedures as well as delays due to objections or legal proceedings.
As part of the grid planning for the «Strategic Grid 2040», Swissgrid reviews the need for the as yet unrealised projects from the «Strategic Grid 2025». Only projects that continue to be required are implemented. The needs-based expansion of the grid is crucial for Switzerland’s long-term security of supply. It is therefore important that political bodies, the authorities and the public support this critical infrastructure and that the modernisation of the transmission system is accelerated by means of efficient approval procedures.