,The project is located on the 1,020km long Daugauva river in Latvia.
Under the €100m contract, Alstom will modernize the turbines, the generators, a new control system and auxiliary equipment.
The company will refurbish one unit a year for the next eight years and the renovation project is scheduled to be completed in 2022.
Alstom Nordic & Baltic countries director Eric Staurset said: "Our dedicated team will be fully committed to refurbish the Riga hydropower plant in a manner that improves reliability, lowers long term operating costs, and benefits the environment."
The refurbishment will extend the operational life of the plant for at least 40 years, and increase the annual production by at least 20GWh.
The Riga hydropower plant refurbishment project is a part of Latvenergo’s €200m investment in the Daugava river hydropower plants.
Latvenergo production director Maris Kunickis said: "The Riga hydropower plant is strategically important for energy supply in Latvia, and we will be able to raise the efficiency of the hydropower plant and enhance its operation safety for the coming decades.
"We have chosen Alstom because they will implement specific solutions reducing the outage duration of each unit to the benefit of Latvenergo."
Hydropower accounts for more than 50% of the total power generation in Latvia.
Image: The Riga hydropower plant in Latvia. Photo: courtesy of Alstom 2015.
