Low-voltage grids, which are connected to decentralized PV systems, heat pumps, charging stations or even entire microgrids, hold great potential for the future. However, a lack of digitalization means operators have been flying blind when it comes to this grid level. We spoke to Ulrich Hempen, Vice President Business Unit Solutions at WAGO Kontakttechnik, about how to better monitor and regulate the grid and protect it from cyberattacks.
Germany still heavily relies on fossil energy sources. Where do you see the greatest potential to become less dependent?
While nearly half of our electricity is already generated from renewable sources, the share of fossil fuels is still at 84% for overall energy consumption. This goes towards kinetic energy for vehicles, generating process heat for energy-intensive industries as well as other sectors in need of fossil energy sources. E-mobility is the solution for the transport sector, and more and more process heat for industry is generated electrically. However, hydrogen is also set to play a more important role. This transformation will put a heavy strain on power grids.
On one hand, demand for electricity keeps going up. On the other hand, we are aiming to replace fossil energy sources by volatile solar power and wind energy. What measures are being put into place to guarantee supply security and grid stability?
WAGO has calculated how we can meet the growing demand. Let’s take a scenario in which all vehicles registered in Germany, including HGVs, would switch to e-mobility today. This would see the demand for electricity go up by 25%, and this extra power would need to be generated. Currently, Germany’s electricity consumption amounts to 540 terawatt hours (TWh). Add to that these additional electric cars, and this figure would go up to around 730 or 740 TWh.
According to our calculations, such an output could for example be achieved with a solar farm of 60 x 60 kilometers. Generating so much electricity would be an enormous challenge, but it is feasible. We must leverage any free spaces – provided it makes sense and does not harm the environment – to generate electricity. Even buildings must be used as sources of energy. However, no solar power is generated unless the sun is shining, which means that more power from photovoltaics makes the grid highly volatile. This must be stabilized, which is our second challenge next to power generation.
Is it true that we need both storage and measures to promote flexibility in power grids to overcome this challenge?
Yes. We definitely need storage, but mainly we need to make the power grid transparent to stabilize power supply – low-voltage grids in particular. In this context, transformer stations play an important role. I believe that they will become the real hubs of the energy transition, equipped with the “synapses” of the power grid. Most transformer stations are not yet digitalized. Consequently, we don’t really know what is happening in low-voltage grids. So if all homeowners in a village would go ahead and install a PV system tomorrow, then the transformer station would not be able to handle the bidirectional flows of energy. This is why we need digitalized transformers.
Why is the low-voltage grid in particular so important?
We consider it important that the energy system is transformed in a way that decentralizes it – as opposed to the last 120 years, where the focus has been on centralization. What this means is that towns, regions and sectors must generate as much energy as they need. Districts and sectors will enable this energy to be exchanged, making residential areas essentially energy-neutral or self-sufficient. This would allow us to do away with high-voltage transmission lines to transport for example wind energy across long distances. Mathematically, such a cross-district and cross-sector exchange would be feasible, but not everywhere. There is a specific voltage range for decentralized power supply, which houses are connected to: the 400 volt level, i.e. the low-voltage grid.
But how can low-voltage grids be digitalized? Has WAGO come up with any solutions yet?
We have gained a lot of experience with digitalization over the last 15 years, both at large-scale providers in Europe and smaller municipal utilities. Several factors need to be taken into consideration when it comes to digitalization, including monitoring voltage, output and frequency as well as analyzing harmonic waves. Another factor is the way these stations communicate via superimposed control units, as is the stability of the system used. Utility companies have an interest in long-term, stable solutions, including in terms of protecting against hacker attacks.
What role are storage systems going to play in stabilizing the power grid?
Storage is definitely a factor next to power generation and digitalization of the grid. It has yet to be determined what kind of storage systems – chemical or mechanical. At the moment, we need quick solutions, and I think grid-serving storage systems are a first step in the right direction.
People are used to switching on electrical devices or charging their e-cars whenever they please. But as we mentioned earlier, power generation is volatile. Does flexibility offer a solution?
You are talking about the needs of customers, which will remain relevant in the future. We cannot force people to turn on their washing machine or oven only at a specific time. There would be huge protests. We need to enable people to have access to energy when they need it, for example by using storage systems that contribute to the stability of the grid. From a technological point of view, this would not be an issue.
We are hearing again and again that there might be blackouts if, for example, everyone charges their e-car at the same time. What technological solutions are there to prevent something like that, or do you see supply security at risk in the medium term?
I don’t think we risk power outages because there are technological solutions to prevent them. By making the grid transparent, we can balance loads so that the grid doesn’t get overwhelmed. However, this is a real danger as long as the grid is not made transparent.
But we do occasionally experience blackouts. What goes wrong for that to happen?
This mainly happens at medium or high-voltage level, when transmission lines fail unexpectedly. So this is a problem on the supply end. Blackouts due to low-voltage grids being overwhelmed are rare.
Another risk to power supply are hacker attacks, something we have been increasingly warned against since the Ukraine war started. Does more digitalization mean more risk? How well are our systems equipped to fend off such attacks?
The transparency we aim for would also open the door to hackers worldwide. However, there are various IT security mechanisms that can be incorporated into controllers to encrypt communication. It is possible to protect the operating system of controllers. The worst-case scenario would be that a station needs to be taken offline and run by electrotechnical means. Another option would be to use two controllers at the same time. IT security for digital stations is something we are going to have to live with. So we need to outsmart the people who mean us harm and be one step ahead. This is going to be an ongoing challenge in future.
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