On sunny holidays like Pentecost, the power grid blows up in our faces? Solar expansion is critical? Andreas Piepenbrink is fed up with this narrative. “It’s not true,” says the head of the energy company E3/DC in an interview. According to him, the solar power does not overload the grid on the hottest summer days or on sunny holidays, but rather seeps away locally - to the neighbors without a solar system. "This is the perfect energy sharing." According to Piepenbrink, the problem is completely different: many network operators simply do not know how busy their electricity network is. Others have no interest in renewables being successful. You want to get rid of the cheaper competition. “Margins are falling in electricity sales,” says Piepenbrink. “We want to compensate for this through network expansion and increasing network fees.”
ntv.de: How much time do you spend mentally on solar power generation?
Andreas Piepenbrink: Because of Ms. Reiche's energy policy in the last few months, a few hours. For our study, even a few days to analyze this data in a watertight manner.
You examined solar power generation at Pentecost. Why?
I would like to take a counter-position to the common assumption that solar expansion is critical and that the power grids will collapse as a result. We also wanted to find out whether it really makes sense to abolish the fixed feed-in tariff: It doesn't. We have proven that.
Where did the skepticism come from?
Solar energy is the cheapest way to generate energy. We need them for heat pumps and electric cars. There are currently 5.5 million systems in the distribution network. We have to build more. Apparently the networks also need to be massively expanded. That's why network fees are rising. I wanted to know if that was justified.
How did your calculation go?
We operate 190,000 solar systems across Germany and started equipping each one with energy management in 2010. That's why we can measure all customers' systems in real time and evaluate the voltage of our self-developed inverters. We did this for the 110,000 largest systems in order to obtain a broad data base. We are currently the only ones who can do this.
From the providers or does this also apply to the network operators?
There are different network levels: the extra-high voltage network. These are the major power highways from the coast to the south. Then follows the high-voltage network with 110 kilovolts, the small medium-voltage network and the local network. The local network transformer is responsible for 20, 30 or 40 classic single- or multi-family houses in a street. This connects the medium-voltage network with the local network. The distribution network operators could possibly measure this transformer. But they are missing the cable run of the generation systems and the voltage curve.
That means?
The line is the power line in the street. When electricity is generated, the voltage changes: it increases when there is a lot of production and little consumption. The energy industry claims that the voltage is too high due to all the solar power and that the transformers in the local network are overloaded. Therefore, solar expansion should be limited. We can measure exactly whether this is true.
And?
It is not true. The classic model in a neighborhood is a solar system that generates electricity exactly where there is consumption: the building, a heat pump, the electric car or the neighbors. Nothing is regulated. The electricity does not overload the transformer, even on the most massive summer days or when consumption is lowest on sunny holidays, but rather seeps into the distribution network.
This year, German solar systems generated 46 gigawatts of electricity around midday on Pentecost. Of this, only 41 gigawatts were consumed. This is exactly the threatening scenario that underlies Economics Minister Katherina Reiche's plans: the net is flying around our ears.
Yes. But the scenario is simply wrong. It's even more insane. This electricity is consumed locally but is rebalanced into the market. This is physically nonsense, but it has to be represented this way to calculate the flexibility in the system. However, the market acts as if we still have to find buyers for this electricity. This is a bit like collecting rainwater at home and taking the bin to the city council so that it can be dumped into the dam. If they need water a little later, the bin will be returned to them. The fact is: 98 percent of the electricity from small solar systems up to 25 kilowatts finds its buyers.
Does it end up with the neighbors without a solar system?
Exactly. This is the perfect energy sharing. The electricity finds its customers via existing local and distribution networks. On this point, Germany did everything right. Solar needs to be expanded further because more consumers such as electric cars and heat pumps are being added and we still have many more non-system owners and tenants than electricity producers.
But if 46 gigawatts of electricity are generated but only 41 gigawatts are consumed, there is definitely too much electricity in the grid.
At Pentecost, 0.15 percent of the network connections in the local network were above 253 volts. That's not a lot. Nothing happens with these values. This can also be easily prevented by cleverly distributing the electricity and sensibly delaying it using storage or load management. That's where the surplus ends up. What you definitely don't have to do is massively expand the low-voltage networks.
Which would cost a lot of money?
Absolutely. One must not forget: The networks are always designed for the absolute maximum. They should be able to absorb the maximum possible power plus overload. This doesn't happen in 98 percent of cases. At Pentecost, 80 percent of all network connections had no problems. 18 percent were in the upper warning band and 0.15 percent were, as mentioned, in the critical area, as the network operator would say. Then it would be his job to install an adjustable local network transformer instead of expanding the network.
What is he doing?
You can imagine it like a volume control. This regulates the voltage so that the transformer can transfer the excess current to the next voltage level in a compatible manner and is no longer overloaded.
The solution is that simple? Why don't the network operators know this?
They know this, but the adjustable local network transformer costs money. It's easier not to install it and tell the press that we have a huge problem. We see that politicians do not want to make a consistent energy transition, but rather stop the expansion of renewables. Keyword: 50 percent reduction: Small solar systems should only be allowed to feed in a maximum of half of their electricity. Apparently nothing more is possible. The opposite is the case. But the decentralized energy supply with heat pumps and electric cars is in competition with the energy industry. Margins in electricity sales are falling. They want to compensate for this by increasing network fees.
Energy industry? Are these the classic energy suppliers?
Exactly. They want to get rid of the cheaper competition. The remuneration is already inadmissible: the electricity from the solar system owners is de facto seeped into the neighbors and is not transported through the network.
That means? The electricity suppliers shouldn't charge any network fees at all?
There would have to be at least something in between. Every solar system and every storage device helps in the distribution network. The feed-in tariff of seven cents per kilowatt hour is absolutely justified. The network operators should be grateful for this. Also with regard to the acts of sabotage. Renewable energies, storage and decentralized systems create redundancy. Every kilowatt hour that does not have to be generated externally brings security. But the network operators are not grateful. They view solar systems as an annoying, unstable, decentralized accessory that disrupts the grid.
Grid fees should only be due if the wind power has to be brought from the coast to southern Germany via the major electricity highways?
Absolutely.
Is network expansion also needed there?
In any case. For large battery storage systems, the larger distribution networks must also be expanded so that the renewable electricity can be stored on a larger scale from midday and transferred to the evening and night hours.
And the feed-in tariff? It sounds like seven cents per kilowatt hour isn't enough for you.
Electricity is demonstrably worth more. If a solar household physically supplies electricity to a household two streets away, it receives seven cents per kilowatt hour. However, the non-solar household still has to pay the energy supplier 33 cents per kilowatt hour: 12 cents energy price plus network fee plus taxes and duties.
Will solar households make a loss due to the loss of the feed-in tariff?
The elimination will actually be worth it for our customers because with E3/DC we will pay at least seven cents per kilowatt hour, and probably more. The only thing that scares me is the lack of smart meters. For this we need the support of the distribution network operators. They have to accept the smart meter at least for direct marketing and enable market communication. But they are not as digitalized as we all would like. That will be a challenge. In the long term, the forecast for decentralized producers is still extremely positive. The costs are falling. Electricity consumption is increasing. The economic opportunities are enormous.
Then the elimination of the feed-in tariff is a good thing.
No. I have the impression that the energy suppliers and Katherina Reiche are not clear about what exactly they have decided. If the feed-in tariff is eliminated, more than 400,000 system owners will leave their energy suppliers. Every year.
To look for a service provider for mandatory direct marketing?
Exactly. The municipal utilities will lose customers and income. Ms. Reiche is doing them a disservice.
