Stabilising the Electricity Grid with Water from the Valle Mesolcina

The main job of power plants in the Valle Mesolcina is to regulate the grid. As important as this task is, the hydropower plants do their job hidden away in the seclusion of the Grisons valley.

If holidaymakers find themselves spending public holidays stuck in traffic jams in front of the Gotthard Road Tunnel, they should consider taking an alternative route: the A13 through Chur and the San Bernardino Tunnel is a good option. The 6.6 kilometre-long road tunnel has connected the canton of Grisons with the Valle Mesolcina, its south-westernmost valley, for over fifty years. It is here that the canton of Grisons switches to its third national language: Italian. Lago d’Isola is a welcome sight to travellers shortly after they exit the tunnel at the southern end. The sparkle of the sunlight reflecting on the lake adds a touch of glamour to the ski resort on sunny winter days. 

The main job: grid stabilisation

The reservoir holds 6.5 million cubic metres of water, so it isn’t one of the major players in Switzerland – not by far. In comparison, the Muttsee dam at the Limmern pumped storage plant (which is Axpo’s latest addition and was put into operation in 2015) has three times the storage volume. “Lago d’Isola doesn’t actually make any sense at all as a winter reservoir,” admitted Mr Faccanoni frankly.

In line with this, parent company Axpo has assigned the hydropower plants in the Valle Mesolcina a different, but no less important, task: “We stabilise the electricity grid.” With their flexibility, the two 40 MW machine groups at the head office in Soazza are ideal for regulating the grid. “Another advantage is that we feed the electricity straight into the 220 kV grid.”

The electricity grid relies on maintaining a frequency of 50 hertz (Hz), so it is important to strike a constant balance between supply and demand at all times. If the specified frequency is incorrect, this impairs the function of individual electrical appliances. Some people may have noticed that the clock on their oven is often wrong. This is a direct result of kitchen clocks being connected to the electricity grid. There is a risk of blackout when the frequency drops below 47.5 Hz. In a case such as this, all of the power plants would be disconnected from the grid, and the electricity supply would then have to be re-established afterwards. We must do everything in our power to prevent an outage like this.

The schedule comes from Baden

The Soazza head office is located 20 kilometres down the valley on the A13, past the defiant ruins of Castello di Mesocco. The outdoor switchgear is the only indication to suggest this is an electricity production site. It is deceptively calm and quiet in the command room, which is as large as a classroom and filled with monitors. The operators work in 24 hour shifts. “One staff member is on site at all times. Others are on call,” explained Mr Faccanoni. Dispatching at the Axpo grid control centre in Baden sets the rhythm every quarter of an hour. “We usually know the plans a day in advance. But we occasionally receive last-minute changes.”

Various monitors display live images from different webcams dotted around the power plant infrastructure, as well as current values and water levels. The water from Lago d’Isola is used over and over again: It is used for the first time in the Spina cavern head office in Pian San Giacomo, where there is also a compensating reservoir. From there, the water flows through the mountain via tunnels to the surge tank above Soazza. From there, it drives the two machine groups waiting in the cavern by means of a pressurised water line over a 700 metre gradient as needed.

The machine groups can each be fully operational within six minutes. “Because the machine cavern is located deep inside the mountain, here in the office building we don’t even notice when our turbines start up remotely if we don’t have the planning specifications in front of us,” remarked Mr Faccanoni. So the work done in the Valle Mesolcina for the Swiss electricity grid remains hidden from the human eye.

33 important jobs for the Grisons valley

The office desks and workbenches only see 1.5 hours of sunshine during the winter. Before and after, the unassuming building in the narrow valley leads a shadowy existence. There are 33 jobs spread across three power plants. “Axpo is an important and good employer in the Valle Mesolcina,” emphasised Mr Faccanoni. The electrical engineer, who lives in Bellinzona, joined the energy company six years ago after completing his work for Alp Transit on the Gotthard Base Tunnel.

The two other power plants are also controlled from the control room in Soazza. The Sassello power plant run by Calancasca SA and the plants run by Elettricità Industriale SA (ELIN) are located a few kilometres to the south in Lostallo and Grono. ELIN was once part of Monteforno, which at one point was the largest industrial company in Ticino. Following a change of ownership, the industrial group Von Roll closed the steelworks in 1995. The hydropower plants were put up for sale. Axpo immediately seized the opportunity and is now the majority shareholder of all three companies, runs the plants and ensures that the necessary operational maintenance work is performed. 

Working hand in hand with nature

In addition to maintaining and modernising the plants, at the moment Armando Faccanoni is mainly involved in renaturation projects and compensatory measures relating to fluctuations in water levels. “During grid regulation, the River Moesa can swell or sink significantly below the respective water returns, which has an adverse impact on the environment.” This undesirable effect is likely to be an even more frequent occurrence in the future, because the more irregularly generated solar and wind energy is fed into the electricity grid, the more intervention to regulate the grid will be required. “We’re aware of the issue and are working hard to find solutions,” the Operations Manager commented.

Mr Faccanoni does not shy away from unconventional solutions. Ideas currently include building a compensating lake or a special canal together with SWISS LACHS, a salmon farm based in Lostallo. The cool water temperatures of Lago d’Isola would be almost perfect for fish farming. “Collaborative relationships like this are extremely valuable – especially here in the Valle Mesolcina, where companies rarely set up shop,” highlighted Mr Faccanoni. Stability and perseverance are key arguments that the power plants in the Valle Mesolcina can bring to the table. Hydropower plants are always long-term investments and promise to bring jobs and solid structures to the valley.

To get an idea of just how important Axpo is as an employer, all you have to do is look around the workshop at the Soazza head office – it is filled with young people. The young tradespeople benefit from knowledge transfer, will be able to establish themselves as experts over the years and often maintain the plants for half their working lives.

While holidaymakers on the A13 are probably only interested in the unimpeded flow of traffic, the crew in the Valle Mesolcina is making sure that the flow of electricity in Switzerland stays smooth too.