The project will demonstrate a set of innovative hydroelectric technologies at selected sites across Europe, covering different types and sizes of hydropower stations. When integrated with the Smart Power Plant Supervisor (SPPS), the following technologies aim to improve flexibility services for operators as well as average annual efficiency and availability.
‘Variable speed’ provides an added degree of flexibility, as operators can vary rotational speed of reversible units and use this for enhanced grid services in both pumping and generating modes. In particular, variable speed pump-turbines enable power regulation and load following even in pumping mode. Variable speed pumped storage projects can operate at a wider range, higher efficiency and quicker response time – in both modes of operation.
In XFLEX HYDRO, extended flexibility will be demonstrated at Frades II using a Double Fed Induction Machine (DFIM), and at Z’Mutt using a Full Size Frequency Converter (FSFC).
HYDRAULIC SHORT CIRCUIT
‘Hydraulic short circuit’ is when pumped storage plants undertake pumping and generating modes at the same time for increased flexibility. Fixed-speed pumping units can be operated to ensure net power consumption from the grid, while in parallel a unit is run in generating mode to regulate the load. This technology will be tested at Grand'Maison using a new Pelton turbine for regulation and improved efficiency, and at Alqueva with two reversible pump-turbine units. Use of hydraulic short circuit with variable speed machines is also a potential method for increasing flexibility, and will be tested at Frades II.
‘Batteries’ are well suited to fast frequency control, quick response times and very high ramping rates, and can be operated in combination with hydropower turbines for optimum flexibility. In XFLEX HYDRO, a battery system will be integrated at Vogelgrun, a run-of-river plant, adding short-period energy storage and frequency control capability, while also reducing control requirements on an existing Kaplan turbine, thereby reducing wear and tear.
EXTENDED OPERATING MODES
‘Extended flexibility’ modes will also be demonstrated at generation-only plants, Alto Lindoso and Caniçada, representing high and medium head reservoir storage sites.