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Hydro plant upgrades show benefits for the power grid. And for the environment.

The first results of a European research and development initiative to extend the flexibility of hydropower plants have been unveiled in Switzerland this week. They promise benefits for power plant owners, for the power grid, and for the environment.

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SION, 16 FEB. 2023- Nineteen organisations taking part in a European research and development project met in Switzerland this week to review a series of upgrades on hydropower plants.

Participants in the XFLEX HYDRO 7th Technical Meeting received confirmation that the technological solutions implemented delivered a range of environmental and technical benefits for hydropower plant owners and transmission system operators.

Hardware and software upgrades carried out in hydropower plants across Europe have saved indirect CO2 emissions, increased renewable energy generation, and extended the lifespan of equipment.

More importantly, the upgrades improved the capacity of the plants to respond to frequency variations on the power grid. Frequency variations are the result of deviations between electricity production and consumption. The decentralisation of power generation assets and the influx of intermittent renewable energy into the grid, including solar and wind, will increase imbalances between production and consumption in the future.

“The changes we are witnessing in energy systems are putting pressure on the power grid and calling for a greater control capacity, which hydropower can provide” explains Matteo Bianciotto, Energy Expert at the International Hydropower Association.

“Our objective with the XFLEX HYDRO upgrades is to improve the capacity of hydropower plants to respond in real time to variations on the grid, in other words: to be more flexible” Cécile Münch-Alligné, professor at the University of Applied Sciences and Arts of Western Switzerland, describes.

“Flexibility has a cost though: it pushes the equipment in the power plant beyond its original design” Prof. Münch-Alligné explains. “Which is why optimisation is at the heart of XFLEX HYDRO upgrades: we want to get the most out of the equipment while minimising wear and tear.”

Participants in the 7th Technical Meeting of XFLEX HYDRO

At Grand’Maison pumped storage plant (France), the creation of hydraulic short circuit, a new operating mode, led to a gain of 240MW in balancing power during pumping, which represents 20% of France’s requirement for frequency restoration reserve (FRR). By replacing gas-fired power plants for this service, the project saved the equivalent of about 90,000 tons annual tons of CO2 emissions.

At Frades 2 pumped storage plant (Portugal), the implementation of variable speed technology combined with hydraulic short circuit added 70% regulation capacity during pumping, and 17% during generation.

At Vogelgrun run-of-river plant (France), the hybridisation of a Kaplan generating unit with a battery delivered faster frequency containment provision: from 300s to only 30s, and a 40% save in wear and tear on mechanical components of the hydropower unit.

At Alqueva pumped storage power plant (Portugal), a digital control enabling optimized damage management allowed the improvement in the availability of the power plant by 1% and increased up to 10% maintenance intervals.

At Alto Lindoso storage power plant (Portugal), a set of advanced numerical simulations showed the extended operating range feasibility which approximately doubles the FRR capacity.

More results are expected to be announced later this year. At Z’mutt pumped storage plant in Switzerland, studies have showed that replacing the existing fixed speed pump with a new variable speed pump may lead to a ten-fold decrease in equipment damage resulting from turbine startup. The power plant operator will seek to confirm these findings during full-scale tests in the spring.

XFLEX HYDRO upgrades also enabled direct increase of power generation: Frades 2 reduces the power consumption of auxiliary equipment by 10%; the improvement of runner technology at Grand’Maison increased power by 64 MW; the reduction of outage time due to battery hybridisation at Vogelgrun increased power generation by 0.5%.

Experts presented the initial results of the upgrades at the 7th Technical Meeting & General Assembly of XFLEX HYDRO at Energypolis, HES SO Valais, in Switzerland from 14-16 February 2023. XFLEX HYDRO is part of Horizon2020, the EU's Framework Programme for Research and Innovation.