France Cuts Nuclear Output as Heat Triggers Water Restrictions

Electricite de France SA will curtail production at one nuclear reactor this weekend as a heat wave restricts the amount of water that can be discharged into the Rhone River.

(Bloomberg) — Electricite de France SA will curtail production at one nuclear reactor this weekend as a heat wave restricts the amount of water that can be discharged into the Rhone River.

The utility had warned of possible curbs on output earlier this week as warm weather swept southern France, pushing up temperatures on the Rhone. EDF uses water to cool its reactors before releasing it into the river, and overheating the waterway can threaten fish and other wildlife.

One of four 900-megawatt reactors at the Bugey power station will reduce generation to zero from Saturday morning to Sunday evening due to “environmental issues”, EDF said in a notice Thursday. It added that that the duration may change if the weather forecast changes. 

The move isn’t a cause for concern in terms of near-term security of supply, especially as power demand will probably be lower this weekend as a result of the Bastille Day holiday. But it’s a reminder that EDF will have to keep adapting its atomic plants to warmer summers and potential natural disasters caused by climate change.

The company and competitors such as Engie SA may use more natural gas to generate power in the coming days, potentially slowing the seasonal filling of gas storage. They may also tap hydro reservoirs, which are ample for the time of year, and France may export less electricity or turn to imports at times.

Last year, when France also had a hot summer, EDF was able to secure several waivers from the grid operator. That meant the company could continue to release water into rivers when a string of reactor outages tightened supply.

But river temperatures are strictly monitored and controlled. Rules on discharges have cut EDF’s annual nuclear output by an average of 0.3% since 2000. That could deepen to 1.5% in 2050, company projections show. As a result, the utility is seeking ways to curb water use as part of its plans to adapt to global warming.

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