How can we adapt the current power grid to the energy system of tomorrow?

The Swiss electricity grid needs to be renewed, strengthened, better integrated into the European grid and made into a “smart grid”. This is necessary in order to meet the growth in consumption and trade with other countries and to be able to absorb the increasing production of electricity from renewable sources (green electricity). This work to modernise our electricity network will determine the success of our nuclear phase-out, whatever strategy we adopt.

Switzerland’s extra-high-voltage electricity network (380 and 220 kilovolts) dates back mainly to the 1970s. In 40 years, our electricity consumption has doubled, our exports have increased sixfold and our imports almost tenfold. Today’s grid is reaching its age and capacity limit for electricity transmission. Grid operators believe that it urgently needs to be strengthened to cope with the continuous increase in demand and our international trade. In particular, our grid has a number of bottlenecks in extra-high-voltage transmission, especially at our borders [→ Q71] and in French-speaking Switzerland. Given the current level of saturation, these weak points in the grid pose an increasing risk to our security of supply, even though not all players in the industry necessarily share the same opinion on the scale of the problem.

Despite the urgency, projects to reinforce the electricity network face a great deal of opposition because of their visual impact, which considerably slows down approval procedures. We can mention the emblematic case of the high-voltage line between Galmiz (Fribourg) and Verbois (Geneva), for which work began in 1976 and which was abandoned in 2015, as well as other projects that have been submitted! Maintaining an efficient electricity transmission and distribution infrastructure is, however, an essential element in guaranteeing our security of supply [→ Q23]. Burying the lines would cost about 10 times more than installing new overhead lines.

The other major challenge facing our electricity grid is the expected increase in electricity production from new renewable energies. The current grid was not designed for highly decentralised electricity injections (with a large number of small producers spread across the entire network). Nor was it designed to handle the variable electricity volumes of solar and wind power plants, whose output is dependent on weather conditions. This complicates grid management, as generation and consumption must constantly balance each other to avoid power outages [→ Q72].

In order to cope with this new situation and to allow the continued growth of renewable electricity, the network will have to undergo a metamorphosis on three levels.

First, the grid must be made “smart” through technologies commonly known as “smart grid” that allow better demand management [→ Q69] and [→ Q78].

Second, it will be necessary to increase storage capacity, whether at the local (batteries), regional (e.g. power to gas) or national (pumped storage) level, to absorb the excesses of fluctuating renewable electricity generation [→ Q74].

Third, the Swiss network will have to be integrated into the trans-European very-high-speed electricity networks (“supergrids” and “electricity highways”), which are designed to ensure the efficient transmission of electricity over long distances. These new infrastructures will play a major role in balancing the grid on a European scale, given the massive advent of solar and wind power. Integration into these grids will provide Switzerland with very interesting commercial opportunities for its pumped storage facilities and allow it to play a “battery” role for Europe [→ Q73].