BERN. On the wall of Swissgrid's control centre in Aarau, Switzerland appears as a lattice of red and blue lines, and lately the red ones, marking congested corridors, have been multiplying. The company's answer is the largest construction programme in the history of the Swiss electricity system, and its deadline has a name: 2030.
The bottleneck is a convergence. Rooftop solar surges at midday, the future of the nuclear fleet is unresolved, and electrified heating and transport are adding winter load, all of it flowing over a transmission backbone largely designed between the 1960s and the 1980s. Swissgrid's strategic grid plan lists dozens of projects that must be built or reinforced within the decade. Internal simulations show that without reinforcement, several corridors would hit their thermal limits in a cold, calm winter well before the decade ends.
The engineering menu is familiar but the dose is new. Existing 220 kilovolt corridors are being rebuilt for 380 kilovolts, high-temperature conductors raise the capacity of lines without touching the pylons, and phase-shifting transformers steer flows around the pinch points. On a few sensitive stretches, partial undergrounding is being piloted at a multiple of the overhead cost.
The institutional machinery is elaborate. Lines above a certain importance proceed through the federal sectoral plan process, with Swissgrid, owned by the cantons and the utilities, as builder, and the regulator ElCom policing the tariffs through which every franc is ultimately recovered from consumers.
The politics are as high-voltage as the physics. Valais has resisted new pylons across tourist valleys and demands buried cables; the industrial north demands reliability above all; and every route announcement produces a coalition of communes, landscape groups and, occasionally, competing cantons. In Graubünden, where the lines cross Romansh-speaking valleys, route consultations are held in three languages and run late into the evening.
The bill is large and arrives regardless. The upgrade programme is costed at four to five billion francs over the decade, adding a fraction of a centime per kilowatt hour to grid tariffs. Yet the cost of standing still is already visible: redispatch measures to relieve congestion have run into the hundreds of millions of francs a year.
Geography concentrates the pain. The critical transfer is north to south, from the consumption centres of the plateau to the alpine powerhouses and the Italian border, and the corridor from Valais to Zurich is the most watched line on the planners' map. Without an electricity agreement with the European Union, cross-border capacity in a crisis is less certain than it was, which raises the premium on domestic strength.
“Every year of delay costs more than the concrete we are arguing about,” said a spokesperson for Swissgrid. The arithmetic of congestion, the company argues, has become the strongest case for building.
For consumers the stakes are double. Security of supply in winter depends on the backbone holding, and so does the bill: an efficient grid keeps both the lights and the tariffs steadier. Data centres and the electrified railway are queueing to connect, and both are impatient.
The calendar is public. Federal hearings on the priority lines run through this year, construction windows cluster between 2027 and 2032, and appeals to the Federal Supreme Court are expected on the contested routes. Swissgrid schedules its contractors around the probability of delay. The first of the new transformers, ordered years in advance because global waiting lists now stretch past four years, arrive on site next spring.
Switzerland is not alone in the dig. Every European grid operator is rebuilding at once, contractors and transformers are scarce from Lisbon to Helsinki, and the alpine storage role Switzerland wants to sell to its neighbours presupposes wires that can carry it. Grid planners from the Alpine countries now hold an annual working meeting on cross-border congestion, an institution that did not exist five years ago.
The 2030 deadline, in other words, is a test of state capacity as much as of engineering. The lattice on the wall in Aarau will record the verdict in red, or otherwise.