Hydropower plants have a long history in Switzerland. At the beginning of the twentieth century more than 7,000 small-scale hydro plants were in operation throughout the country, and as recently as the beginning of the 1970s, hydropower still accounted for nearly 90 percent of domestic electricity production.
However, hydropower's share of production fell to about 60 percent by 1985, after the commissioning of Switzerland's nuclear power plants. Today, it is around 56 percent, and remains the country's most important domestic source of renewable power.
A federal decision in 2011 to build no more nuclear facilities in Switzerland, and to decommission the existing ones as they reach the end of their service life has led to a new energy strategy focused on energy efficiency, renewable energy and the renovation, expansion and modification of the country's electricity networks.
Upgrade doubles capacity
Around 90 percent of Switzerland's total current hydropower production is from large-scale plants with capacity greater than 10 megawatts (MW), but there are still around 1,000 small-scale hydropower plants in operation, with production capacity up to 10 MW.
The 11.6 MW Russein hydropower plant in the canton of Grisons had been in service for 67 years, when work began in 2013 to expand its capacity to 24.2 MW. The plant operator is the Swiss utility Axpo Group, which generates, trades and sells electrical power to more than three million consumers and thousands of companies in Switzerland, and in more than 30 European countries.
Axpo upgraded the infrastructure, including the Russein dam, pressure pipe and operations center, so the plant produces 52 gigawatt hours of energy per year and can meet the electrical demand of 17,000 households. The 72.5 kilovolt (kV) high-voltage switchyard was also upgraded, but needed a reliable switchgear solution that ensures out of service disorders are minimized.
A fast, reliable solution
ABB's answer was the innovative hybrid switchgear module PASS M0H, a solution that offers a complete high-voltage switchyard with an 'H' configuration as a single, compact product, ready for rapid energization.
With PASS M0H technology, Axpo was able to refurbish the high-voltage switchyard in four days, instead of the estimated eight weeks needed to install equivalent air-insulated switchgear bays, while at the same time saving 70 percent of the switchyard footprint as a result of the PASS M0H's capacity for functional integration.
Rapid installation is possible because PASS M0H undergoes high-voltage testing at the factory, and is then transported without dismantling, or the need for onsite reassembly. For the Russein power plant, a PASS M0H hybrid module meant the high-voltage switchyard could be refurbished quickly and easily, ensuring reliable power is delivered to consumers as soon as possible.
