Feb 19 (Reuters) - Veolia has agreed to buy a 430-megawatt, gas-fired power plant in Hungary from German energy firm Uniper, the French utility said on Monday.

The gas-fired, combined-cycle power plant is in Göny, north-west Hungary.

It helps to provide flexible electricity generation capacity, which is crucial as more intermittent renewable capacity comes online and European countries need flexible baseload capacity that can come on or offline quickly to balance their grids, Veolia said.

"This agreement is right in line with our ambitions to develop flexibility capacities, an essential complement to the stability of the European power grid," said Estelle Brachlianoff, Veolia's chief executive officer.

Financial details were not disclosed. The purchase agreement was done via Veolia's Hungarian subsidiary and the transaction is subject to obtaining the necessary authorisations and complying with regulations, the firm added. (Reporting by Nina Chestney Editing by Mark Potter)