More solar than nuclear energy produced in Belgium … or maybe not

Last Thursday, a Belgian nuclear reactor (Tihange 3) went offline just after midnight. There seemed to be a technical defect that triggered an automatic stop. Luckily this didn’t happen in winter. The defect was fixed, but the owner took the opportunity to do the maintenance a couple months earlier than foreseen, so the reactor will only be put back online at the end of the month. That makes five of the seven reactors are now offline.

This gave rise to the expected hooray messages in the media: “More solar than nuclear energy produced in Belgium today for the first time”. A message apparently attributed to the VTM television news. This is how it goes (translated from Dutch, my emphasis):

Because of the failure of Tihange, now five of the seven nuclear reactors in our country are not working. As a result, today more solar energy than nuclear energy was produced in our country.

That never happened before. From a quarter past eleven this morning, solar panels delivered around 1,550 megawatts of electricity, more than the 1,450 megawatts of nuclear power plants.

And then the solar panels delivered less than expected because of mist and light clouds. When the sun is shining, they can generate almost twice as much energy.

Sure, since Tihange 3 went offline, solar energy production was higher than nuclear … for as long as it took:

Sources: Nuclear + wind: http://www.elia.be/en/grid-data/power-generation/energy-cipu-units | Solar: http://www.elia.be/en/grid-data/power-generation/Solar-power-generation-data/Graph

Indeed, at least 1,550 MW was put on the grid by solar panels after 11 am and, also true, the production of the two remaining nuclear reactors was less than that in the same time frame. What the journalist forgot to mention was that this only lasted 5 to 6 hours, while nuclear production was continuous throughout the whole day.

The next day (August 14) solar production even stayed below that threshold the whole day. Today the highest peak was around 500 MW and the forecast is it will stay below nuclear production for the following next three days. So far for the “More solar than nuclear power” message.

The statement is not only misleading, it is downright wrong. The headline would only be true if solar energy kept this peak production for 24 hours … which it obviously didn’t.

It was only the top of the peak of solar energy production that was compared with the (continuous) production of nuclear. I seen this kind of error before, it is rather common. I think it is rooted in the misconception that alternative sources produce electricity in the same way as conventional sources do. I would agree that the same electrons are produced, but solar (and wind) produces them in an intermittent way.

This misconception was also visible in the optimistic message: “When the sun is shining, they can generate almost twice as much energy”. I can imagine that when one looks only at the peak production during a small part of the day, that this is reason for optimism. But in fact, it is one of the issues with solar energy. It can lead to an overload of the grid and possible blackouts. Intermittent sources that on average just deliver a couple percent of our consumption, but at times will deliver 30%, can be a disturbance in a continuous working grid. We have been there several times in the last couple years.

The fact that this is brought seemingly as something positive, let me think that the journalist has no clue what he is talking about.

Coming back to the central message: when we look at the production throughout the whole day on August 13, nuclear plants provided in total 35,184 MW, while solar had only 14,088 MW over the same period. In other words, solar delivered only 40% of the energy produced by nuclear last Thursday. That is the exact opposite of what the article claims.

So the headline should rather have been: “Even with only two reactors online, solar power was not able to produce more energy than nuclear today”. I haven’t seen that headline in the media though.

Exactly the same error was made by the first commenter of that article (translated from Dutch):

This is a powerful signal from Mother Nature that those nuclear plants are redundant, the technology is developing..

That is true only if you look at the five/six hour time frame of the top of the peak during that particular day or the days before that. But if you also look at the rest of the day and at the next five days, Mother Nature is giving a different, even more powerful signal 😉

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