What is the impact on our electricity production?

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This Monday, July 18, the temperature was up to 39.3 ° C in Brest. More than 4 degrees Celsius above the previous temperature record It dates back to July 1949. Many, many other records have been broken across the western side of the country. But, for several days already, especially high temperatures have been recorded throughout France. A difficult situation to live with. Our electrical system, too.

To understand, let us first note that, unlike what can happen in winterWhen it is very hot in summer, consumption peaks at midday. When the air conditioners are operating at full capacity. International Agency forenergy reminds him air conditioner It is one of the jobs that has caused the greatest demand for electricity in the building in recent years. cause for concern, even more so when this electricity is produced from fuel fossils.

Let’s see how our electrical system worked on Monday, July 18th. Bad news first emissions From greenhouse gases. At least 11% of the electricity consumed at peak time was produced from fossil gas. But the good news is that with a peak in the middle of the day, solar PV can provide good production. At least 21% on Monday. Hydraulics and nuclear components, too low sources carbon12% and 51% of production, respectively.

Heat wave What are the problems of nuclear power plants?

The problem is that these two energy sources, through their interaction with the environment, are affected by periods of high temperatures. Let us first examine the case of nuclear power. In recent days, several power plants have announced that they will reduce their production. Selection nuclear plant Golfech (Tarn-et-Garonne), located on the banks of the River Garonne, for example. That’s from July 13 and possibly even 24, EDF estimates. Safety reason? No way.

What happens is that nuclear power plants take water from rivers to cool their reactors and turbines. So far, no fear of this aspect. Cooling of nuclear power plants is still possible, even in periods heat wave. Safety is fully guaranteed.

So why reduce production? for environmental reasons. Because the water used to cool nuclear power plants is then discharged into rivers or rivers. In the process, it will have warmed up somewhat. In France, regulatory limits for the temperature of discharges have been established. Under normal summer conditions, at 28°C downstream for the Golfech power plant, for example, and at 30°C in exceptional weather conditions. Heating between upstream and downstream is also controlled in the plant. In any case, the temperature should not exceed 1.25 ° C on the Tarn-et-Garonne side. Environmental Protection Restrictions: wild animals and plants that live in the respective waterways.

First major use of restrictions

But exceptions are possible. ” If necessary for the proper functioning electrical networkAccording to EDF. The device has been implemented so far only once. In 2018, for Golfech factory, specifically and for Duration Only 36 hours. This time, four nuclear power plants submitted the application to the Nuclear Safety Authority (ASN). The Golfech factory – again -, the Blayais (Gironde) factory, the Bugey (Ain) factory and the Saint-Alban (Isère) factory. Request accepted, but limited” Situations where the operator of the electricity transmission system requires operation of the installation to ensure network security or consumption/production balance And that’s until July 24 for now.

To return to our example of the Golfech power plant, let’s confirm that EDF has chosen to run it at only one-fifth of its power. In order to comply with regulatory limits as much as possible. Also note that only the discharge limit temperatures are held up. The temperature rise boundary between upstream and downstream of the plant – perhaps this is where the real impact of activity on the environment is measured – is not.

Effects of global warming on nuclear production

Do we have to conclude that a file Global Warming Human activity also threatens nuclear production? Perhaps in part, if we consider our current nuclear fleet, which is made up of large reactors with relatively large cooling requirements. But the climate threat does not seem critical enough today. The opt-out request submitted today is also the result of the current state of our fleet. With part of the reactors on our territory currently closed for other reasons, maintenance and Eat, In particular. In his report on Energy Futures 2050electricity transmission network)ten) asserts that the one-year production loss due to climatic hazards alone is estimated today at less than 1%, but recognizes that for some power plants, particularly on river banks, the risk of future unavailability of units can increase with production losses that can be multiplied by ten For example, for the Golfech plant.

For those who are concerned about the impact of these exceptions on aquatic life, here’s what the ASN answers: “The EDF proposals are acceptable in light of feedback from environmental monitoring specifically conducted during past heat waves as well as long-term monitoring of Ecosystems concerned. » But we may have our say in the discussion. By asking ourselves, again, how comfortable we are – which, in summer, sometimes involves overuse air conditioner It should take precedence over the preservation of the environment.

Hydroelectric power stations under tension

Another production that needs to be watched closely in the climatic situation we are witnessing today: hydropower production. Did you know that it was the second source of electricity supply in France? Just behind nuclear power. And what is worrying in this regard is not so much the heatbut the drought Very exceptional too, which our country has been experiencing for a few months now.

In Portugal and California, hydroelectric power plants have already been closed. Water shortage in dams. We are not there. Even if a lack of precipitation was recorded at the beginning of this year 2022 over the entire capital region. As a result, the filling rate the sound Dams in our country increased by 72%. This is it ” Just “8 points below average. Thanks to the dynamic management of the hydraulic stock by EDF. Dynamic management based on accurate monitoring of weather report and the Debt waterways. However, a production drop of 25-30% has been recorded in recent weeks. If the situation persists, even greater difficulties may arise inFall.

Because it is interesting to remember that if the EDF manages more than 7 billion cubic meters of surface water in mainland France in its dams and reservoirs, this water is not only used in Electricity production. It is also used to supply drinking water, irrigation and even preservation Biodiversity. and this is, finally a governor who prioritizes use, knowing that drinking water and civil security take precedence over everything else.

In the context of climate change, the RTE report on Energy Futures 2050 determines that “Hydraulic inventory management has to evolve. While park capacity has been stable for several years, significant differences in future production can be seen at scale. annual. But production capacity by 2050 remains equivalent to that we know today. »However, this conclusion should be taken with caution given the uncertainty still swirling around the evolution of river flows in the coming decades. Also depending on the potential development of uses – more watering, for example.

Other means of production are also affected

In conclusion, let us determine that if nuclear energy andHydroelectricity It seems that it wants to be the first means of production that depends on heat and drought, as other means can be affected. production wind turbines You may suffer from having a tornadofor example.

Perhaps even more unexpected, the effect of drought on electricity production from… coal ! It is the German Federal Institute ofhydrologyWhich alerts about this, noting that the rivers of Central Europe at levels “Abnormally low”. and continue to decline. However, goods are sometimes traded on these rivers. On the Rhine, in particular, coal is transported: 17 million tons in 2020. A lot of products are derived from oil Moreover.

With a historically low level, the Rhine was no longer able to accommodate fully loaded cargo ships. Since July 13, coal supplies have been disrupted at two German power plants. Although, under the pressureBecause of the war in Ukraine, the government decided to relaunch this type of production in the country.

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