A nuclear power plant in Spain had to be shut down due to rising temperature in the river that fuels its refrigeration system. In France, plants were authorised to discharge cooling waters at above normal temperature as an exceptional measure.

The Garoña plant in the Spanish province of Burgos was shut down as a precautionary measure after the temperature in the Ebro River below the plant exceeded the authorised level, the company, Nuclenor, said in a statement on Monday (24 July).

Rivers are used as refrigeration systems for nuclear plants and the hotter water discharged below them is limited to a certain temperature to protect freshwater fish and flora. But the heat wave is causing water to reach those levels more quickly.

The French government on Sunday (23 July) authorised electricity producer EDF to discharge waters at above normal temperature in the rivers that cool down its nuclear plants. France relies on nuclear energy for nearly 80% of its electricity consumption. The heat wave currently hitting Europe is causing a rise in demand for electricity to power air conditioning systems at an unusual period for electricity producers who often perform maintenance work during the empty summer months.

Last week, the heat wave forced EDF to buy electricity on the European wholesale market as a preventive measure in order to meet growing demand. In the UK, National Grid issued an "insufficient margin warning" on 17 July, prompting energy producers to restart idle power plants to make up for potential electricity shortages.