XFLEX - Modernising hydropower plants

Modernising hydropower plants: hydraulic short circuit at Grand`Maison pumped storage plant (France)



Sitting in the French Alps, Grand`Maison is Europe`s largest pumped storage plant at 1,800 MW capacity. Pumped storage plants are giant batteries that are powered by renewable energy. They currently operate in two mutually exclusive modes, either generating power or pumping water to be released in the form or energy at a later date.

The innovative ‘hydraulic short-circuit` system implemented at Grand`Maison pumped storage plant will enable the power plant to enter a third mode: simultaneously generating power and pumping water for energy storage.

Modernising hydropower plants: variable speed (FSFC) at Z`Mutt pumped storage plant (Switzerland)



Z`Mutt is a pumping station located in Canton Valais, Switzerland, and feeds water into the main reservoir of the Grande Dixence hydroelectric scheme. Originally commissioned in 1964, Z`Mutt has a total pumping capacity of 88 MW across five existing pumps.

As part of the XFLEX HYDRO project, one unit will be replaced with a new 5 MW variable speed reversible pump-turbine which, when installed with modern power electronics and smart controls, will demonstrate a high range of flexibility.

Modernising hydropower plants: enhanced fixed speed at Caniçada and Alto Lindoso (Portugal)



Modernisation is a decision of utmost importance for hydropower plant owners. The International Energy Agency estimates that between 2020 and 2030, USD 127 billion – or almost one-quarter of global hydropower investment – is set to be spent on modernising ageing plants.

Alto Lindoso is a 630 MW hydropower plant situated on the Lima river in Portugal, installed with a 110m tall dam impounding its reservoir. Commissioned in 1992, the site represents a conventional hydro plant including two Francis turbines designed for high head (pressure) and power generation (without pumping). Through the XFLEX HYDRO project, low cost opportunities to extend operating range and optimise power flexibility are being tested at the plant, and compared to the variable speed case.

Caniçada is a 70 MW hydropower plant with reservoir storage located in northern Portugal, originally commissioned in 1954 and more recently refurbished in 2017/2018. With two generating units rated at medium head and power generation, studies conducted via the XFLEX HYDRO are designed to evaluate flexibility opportunities for medium scale hydro and, in particular, simulate potential conversion to variable speed.

Modernising hydropower plants: hydraulic short circuit at Alqueva pumped storage plant (Portugal)



Modernisation is a decision of utmost importance for hydropower plant owners. The International Energy Agency estimates that between 2020 and 2030, USD 127 billion – or almost one-quarter of global hydropower investment – is set to be spent on modernising ageing plants.

Alqueva is a pumped storage scheme in southern Portugal that was built in two phases, Alqueva I and II, now totalling 520 MW. The first station was operational in 2004 and the second commissioned more recently in 2017, each installed with two reversible Francis pump-turbines.

Modernising hydropower plants: variable speed (DFIM) at Frades 2 pumped storage plant (Portugal)



Frades 2 is a new 780 MW pumped storage hydropower plant in northern Portugal. Commissioned in 2017, the two generator sets are the largest and most powerful of their kind in Europe.

With XFLEX HYDRO, the site will demonstrate an innovative operating regime: hydraulic short circuit operation using variable speed units and smart controls to optimise power services onto the grid network, focusing on fast frequency services.

Modernising hydropower plants: battery/turbine hybrid at Vogelgrun run-of-river plant (France)



Vogelgrun is a 142 MW run-of-river hydropower plant in France, situated near the border with Germany along the river Rhine. The plant has four low head Kaplan turbines, in service since 1959.

As part of the European XFLEX HYDRO project, one of the units has been hybridised with a battery. Complementing the turbine`s operations, the battery system will add energy storage to share response capability with the hydraulic unit, and use a master control to optimise both flexibility and wear and tear effects.