The power of water: hydroelectric power plants in Valchiavenna that produce green energy

But numbers are not everything. They tell only part of the extraordinary relationship between Valchiavenna and water. Water is, in fact, the constant that unites different environments, ranging from the more than 3,000 metres of Pizzo Tambò to the valley floor, where the Mera river leaves its torrential fury to gently bathe the main towns.

And along this network, at various points there are places where water is transformed into energy as is well explained in the Virtual Tour dedicated to our hydroelectric plant in Valchiavenna. That water is so fundamental for Valchiavenna and for our entire country, as it is the most widely used source of renewable energy.

There are mainly two types of hydroelectric power plants in the valley: 

• regulated run-off systems, with the possibility of storing water via storage tanks and thus managing energy production (generating more when demand is higher and less when it is lower, saving it for later);
• run-of-river plants, they produce energy depending on the weather and climate conditions of the river they draw from (during a flood period they generate more, when the flow is lower, they generate less).

Alongside these two main types, there is a third, consisting of smaller power plants, not alternatives to the first but working alongside them. These are Hydroelectric power plants for the energy recovery of the ecological minimum vital flow. This represents the minimum amount of water that must be maintained in the river to protect the river ecosystem. Indeed, these power plants are usually located downstream of a dam and their role is to make the most of this conservation obligation from an energy point of view.

Starting from the assumption that each plant is unique, as it is closely linked to the morphology of the land, it still is possible to identify some basic elements present in every hydroelectric power plant. 

The first are the intake works: these are structures whose task is to capture water from rivers or streams and convey it directly to the power station or dam.
They can assume different shapes and sizes, depending on the characteristics of the watercourse and the specific needs of the installation. They are generally equipped with screens to prevent the passage of large solids, leaves and branches; settling tanks and grit separators to remove the finest particles; and sluice gates, valves and instrumentation to control and intercept flow rates.

In a second step, the water intercepted by the intake works is conveyed to storage reservoirs (such as dams) via derivation canals.

From there, tunnels and penstocks provide a path for the water to be conveyed to the hydroelectric power plant, so that it can begin the process that will transform it into electricity. The latter starts with the water turbines, the beating heart of every hydroelectric plant. This is what converts the hydraulic energy of water into mechanical energy.
Turbines also fall mainly into two categories: 

• action turbines, in which water strikes the turbine blades with a jet at atmospheric pressure, transferring its kinetic energy to the wheel;
• reaction turbines, which are instead submerged under water, and exploit the pressure difference created to generate a rotary motion, and consequently kinetic energy. 

As with all plants dealing with renewable energy sources, but especially hydroelectric power plants, careful maintenance and regular modernisation interventions play a crucial role. These efforts are carried out on a daily basis by the specialised technicians working at the power plants, in addition to the extraordinary interventions, which in Valchiavenna have been considerable. In fact, the entire plant park in the territory has been completely renovated over the past 20 years and equipped with the latest technology.
This is coupled with a constant and extensive monitoring of the entire production chain and of the changes in environmental conditions, carried out by means of a remote control system. It allows operators to remotely supervise and control systems from a centralised control room.

Water is the most strategic resource for meeting the challenges of the ecological transition, because it is the only safe, constant resource. In the first six months of 2024, renewables covered over 43% of the country’s energy needs. Of these, hydropower contributes the greatest amount, thus making a valuable contribution toward achieving the ambitious goal of zero emissions by 2050.
As a Life Company, we are ready to strive more and more for sustainability and to build a future where green energy produced from sun, water and wind is enough to meet our country’s entire demand. And, to some extent, the Valchiavenna experience teaches us that this is possible.