Virtual energy plant: cheap and (going towards) 100% renewable

Hooraaaaay, our energy problems were just solved! I just viewed a short video about a “smart” energy system (Dutch ahead) that will power a new residential area called “De Nieuwe Dokken” in Ghent (Belgium). According to the video, the components of this system are:

  • solar panels on the roof
  • a big battery
  • charging points for electric vehicles
  • heat pumps
  • a very smart computer system to control all those energy flows.

Of course, it will be cheap, dirt cheap even. At several occasions in the video, the economic benefits of the system were praised. For example, electricity prices went negative on May 30 and one even got paid to take electricity from the electricity grid.

Wow, where do I have to sign up for that!?

When there is no(t a lot of) sun combined with high consumption, don’t worry, then the system could provide the electricity stored in the car batteries (after those gorged themselves with plentiful of energy during day) to the households.

Easy peasy. See, it doesn’t have to be that complicated.

Our Minister of Energy also made an appearance, proudly stating that this is how our (national) energy system will look like in the future, just on a larger scale. How cool is that! Our tiny country is showing the world how it is possible to realize 100% renewable energy on the cheap.

You are welcome, just thank us later 😉

There are however some, ahem, small details that for some reason were not explained in the video…

Quite some time was spent on the you-get-paid-to-consume-on-May-30 argument. In the video and its description, it was mentioned in 4 out of 20 sentences. That is one fifth. Not only the interviewee was lyrical about it, also the journalist loved to take about it, emphasizing the word “money” when he clarified that one would receive money to consume electricity at that moment… He also used the second person singular in the present tense (translated from Dutch, my emphasis):

To be clear, you receive money for the electricity you are using at that moment. You don’t pay for it and the battery can already store something.

That seems odd. As far as I understood from the rest of the video, it was the system that got paid to take electricity from the grid, apparently drawing electricity from the grid at spot prices. That doesn’t necessarily mean that the individual electricity consumer will get paid at that specific moment. Private electricity consumers in Belgium pay fixed prices for their electricity. By using the second person singular in the present tense, the journalist is suggesting that it is the consumer (or more generally the viewer if he/she would subscribe to such a system) who is the beneficiary. That is a pretty misleading construction.

By the way, May 30 is just one day of the year. Why such heavy focus on that one specific event, ignoring the 364 other days of the year? The journalist basically took one (favorable) day to explain the performance of the system.
Some of those other days will for sure be favorable for solar, but that is by no means guaranteed. In Belgium, we have something called “winter”, when days are short, solar power in short supply and electricity consumption roughly doubles. In that case, electricity supposedly would need to come from those car batteries (at a time when those cars need more electricity themselves) or from the grid (which will be at a premium). It will be a completely different story on say November 30.

That was not the only statement that raised my eyebrows. The journalist also said (translated from Dutch, my emphasis):

And the smart energy system also powers the batteries of the electric cars. It charges it automatically when there is surplus of solar energy. With four cars you already have a second large neighborhood battery, which can also supply the apartments with power in the future.

That also sounds pretty odd. I understand that one big battery can accommodate four cars. That is an extra cost, adding to the investment in the system, not something that the individual consumer “has”. That is the same technique as in the one-get-paid-to-consume example. He seems to attribute an advantage to the individual consumer that this consumer doesn’t have in reality, probably to make such system more attractive to the public.

I was a bit surprised though. This journalist showed in the past that he has a profound knowledge about energy and his writings learned me a lot about Belgian energy. It is therefor cringeworthy to see him reporting in this way on this topic.

Now to the statement of the Minister of Energy. These are the two lines she said in the video (translated from Dutch):

We are moving towards 100% renewable energy, which means that we will have to be able to store and use solar and wind at a later date. This is happening here on a small scale, but this is what our energy grid will look like on a large scale in the future.

The first sentence is pretty clear, she indeed mentioned before that her goal is to move Belgium towards 100% renewable energy and it is nice to hear that she acknowledges that storage will be crucial for this to happen.

The second sentence is confusing. The “this is happening here on a small scale” part of the sentence could be interpreted in two ways: it could relate to the moving towards 100% renewable (as we are doing now) or to the being 100% renewable (in the future). The “that is what our energy grid will look like in the future” part however seems to suggest that this system is already 100% renewable since it is what the future grid would look like, just on a larger scale. So, what is it? Is this system 100% renewable or just moving towards it?

There is no way to tell that from the information given in the video. We only get to know that the “big battery” has a “capacity of 240 kWh or “the equivalent of the consumption of about 25 families per day”. I think I know where that number comes from. In Belgium we assume an average consumption of 3,500 kWh per family per year. That is 9.59 kWh per day and a capacity of 240 kWh is indeed mathematically enough for 25 families for one day. That doesn’t necessarily mean that 25 families consume exactly 9.59 kWh every day, the real consumption will vary over the year. There will be much less consumption in summer and much more in winter.

So, if that battery would be dimensioned for 25 families having a consumption of on average 9.59 kWh per day, then this system will experience a chronic surplus in summer (high production and low demand) and a chronic shortage in winter (low production and high demand).
If it would be dimensioned for less families, then the system will be better off in winter, but the battery will regularly overflow in summer.
It all depends on the number of families relying on that system, the total capacity of those solar panels, how many loading points, how many cars and how many big batteries there are.

Time to search some more data on that system. Luckily it was pretty easy to find and I soon landed on the website of the cooperation that manages the system. They called the system a “virtual energy plant” and stated their goal as helping to stabilize the grid. They didn’t claim that it is 100% renewable, but that this stabilization is crucial for the transition towards a 100% renewable grid.

I also found the numbers that I was looking for. The new residential area counts 400 houses and apartments, a school and some commercial spaces (shops and offices).

There are also 20 loading points for electric cars. Okay, does this then means that there are also 5 extra batteries, as suggested in the video?


There is only one battery in the system.

So, that one “big” battery is used for 400 families, a school, commercial spaces and an unidentified number of electric cars…

But then, those solar panels could support a large part of those families, right?


The total capacity of those solar panels is 80 kWp. That may seem a lot, but if we really want to see this through the lens of that battery powering families, then the average production of that capacity is enough for the average consumption of roughly 20 families. Without an electric car, that is. That is on average 380 families, all electric cars, the school and the commercial areas that will have to take their electricity directly from the grid. That is very far from 100% renewable energy.

Finally, do the individual consumers get paid to consume electricity when there is a surplus of electricity, as suggested in the video?


This is just a possibility for the future, “when legislation on electricity tariffs changes”. Currently, the participants need to choose their own electricity supplier or can join a group purchasing project. The use of the second person singular in the present tense by the journalist is therefor unwarranted.

That is quite a different story from what we seen in the video. This style of reporting strongly reminds me of the reporting on the Hornsdale Power Reserve. That battery is reported as the solution for the intermittency of solar and wind. It was even credited with helping to save South Australia from a blackout. Yet when looking at the numbers, its impact is very limited and its actions to “help preventing the blackout” were pretty pathetic.
The same here with this energy system. It is glorified in the video, but when contrasted with the actual numbers, it is all rather underwhelming.


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