Alstom delivering equipment at worlds first high-capacity, variable-speed pumped storage hydropower station

Alstom is about to deliver a main inlet valve weighing 120 tonnes and measuring 1.7 metres in diameter to the Linthal hydropower station, located 90 km from Zurich.

In the coming months, two other main inlet valves and 4 pump-turbine wheels will be taking the same route from the Alstom facility in Grenoble, devoted to hydropower. The teams at Alstom have developed main inlet valves that can resist the pressure from a 1,050-metre waterfall. Tests were performed in Alstom’s Grenoble workshops to guarantee that the equipment is fully waterproof. In so doing, Alstom is taking part in a world first: the commissioning of the first-ever high-capacity pumped storage dam featuring a variable-speed system.

Developed, designed and manufactured at Alstom’s Grenoble facility, this innovation will help to provide stability on the power grid by regulating the frequency. The Linthal power station will be able to adapt, virtually in real time (within about one minute), to the needs of the grid according to consumption. In periods of low demand, the variable-speed pumping system will fill a reserve tank to store unused water. In periods of high demand, the system will quickly put the turbine back in use in order to produce power to supply the grid. Once the Linthal hydropower station is commissioned in 2015, it will produce 1,000 MW, enough to supply the needs of 150,000 households.

Hydropower has a new role to play in the changing energy mix. It must be in a position to take over from intermittent energy sources (wind, solar) whenever they produce less. Hydropower energy thus represents a reliable, flexible solution in facilitating the inclusion of those renewable energy sources on to the power grid.

Alstom in Grenoble

Founded in 1917, the Alstom Renewable Power facility in Grenoble covers the entire hydropower value chain, including R&D, sales and marketing, engineering and design, purchasing, manufacturing, project management, installation and commissioning, service and retrofit. There are 850 employees working at the facility in the various departments.

The Global Technology Centre at the Grenoble facility heads Research & Development in the fields of hydraulics, hydromechanics and control systems. The Centre’s team also provides support and expertise to Alstom Hydro’s Global Technology Centres in Brazil, Canada, China, India and Switzerland.

The hydropower market has experienced on-going growth these past few years thanks to a growing demand for new, clean sources of energy. The extension and modernisation of the Technology Centre in 2008 was instrumental in helping Alstom meet that demand, going from four trial turbine platforms to six, capable of simulating the real-life conditions found in a hydropower station.

Facilities at the main workshop in Grenoble make it possible to machine, weld and validate extremely large turbine wheels and spherical valves such as the one for the Three Gorges Dam in China, 10 metres in diameter and weighing 400 tonnes. For its part, the models workshop supplies up to 40 “model wheels” every year to supply testing platforms.