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The old world, based on stable and controllable power generation units, is no more… there is a new world, with new challenges. It’s a world in which power distribution changes at a dizzying pace. Will the smart grid help Germany survive the winter? – asks Piotr Grądzik, energy security expert and contributor to BiznesAlert.pl.
Articles on smart grids often have one thing in common: they are written in the future tense. Someone “intends” or “plans” to transform their own network into a smart grid. A distinctive feature of Germany’s transmission networks in the context of the smart grid is the fact that one can write about them in the present tense.
What is a smart grid? Over the years, the understanding of this concept has changed. Once, a smart grid meant the ability to remotely read meters, or remotely turn on transformers and power lines. Today, the role of a smart grid is to intake the largest possible volume of RES into the network, while maintaining the stability of the electricity system.
Simple but effective
Before renewables, that is, just a few, a dozen years ago, to plan the safe operation of the system, network operators had to only use one scenario for power distribution for the winter and one for the summer.
The power system was designed to be painfully stable and … boring. This was achieved by locating power plants and industrial customers relatively close to each other, so that there was no need to transfer large volumes of energy over long distances. Moreover, they were conventional power plants, and therefore controllable. If necessary, it was possible to order power plants to reduce or increase the power generated at individual nodes of the network. In such a well-thought-out system, power engineers were in danger of dying of boredom.
“Good bye, Lenin!”
It is the title of a 2003 film directed by Wolfgang Becker. The action takes place during the fall of East Geramany. The main character – a communist activist – has a heart attack, falls into a coma, and when she wakes up, East Germany is no more. To protect her from excessive stress, her family hides the fact that a new world is emerging outside.
What if we made a movie where instead of an elderly lady, the hero would be a power engineer controlling the electricity system? He fell into a coma in 2011 and woke up in 2022. What would we have to hide from him, so that his health would not deteriorate drastically?
Well… of the seventeen nuclear reactors, only three are left, and they are about to disappear as well. The modern coal blocks built at that time were melted into razor blades. The installed capacity of wind farms and photovoltaics, once treated like a square peg attempting to fit into a hole, is over 120 GW – this is much more than the maximum demand in Germany (approx. 80 GW). The old world, based on stable and controllable production units, no longer exists…
A crystal ball, or a smart grid in action
The world has changed and is presenting itself with new challenges. The changes in power distribution are taking place at a dizzying pace. A huge transfer of power in the north-south direction, and after only two or three hours a change to the east-west direction – these are today’s realities that our film hero has never seen. Only a four hour (e.g. from 7 to 11 a.m.) increase in PV generation in Germany (in the summer) has enough potential to cover more than Poland’s highest demand in history. This potential disappears at an equally rapid rate in the evening. An engineer awakened from a coma would surely ask the question: “if the system is dominated by unstable and uncontrollable renewables, then surely the power lines are notoriously overloaded. How many blackouts have you had recently?”.
He would not believe there weren’t any so far. He wouldn’t believe it because he slept for 11 years and missed the development of the smart grid.
Today, in a saturated RES system, we also need one scenario of power distribution, but not for the summer and winter, but for every hour of the day! This is necessary to identify upcoming network overloads in advance and implement the necessary countermeasures. But where do you get such scenarios?
Enter smart grid. In the first step, it collects and processes data in an automated manner. Forecasts of renewable energy generation (for each node of the network), operating schedules of conventional power plants, data from the energy exchange, cross – border exchange, availability of transmission infrastructure – these are just some of the necessary data.
However, raw data is not yet knowledge. It’s just useless megabytes on servers. Programs and algorithms are needed to convert the data into specific network models. Based on these models calculations are made, so that, like reading a crystal ball, it can be predicted that, e.g. in 15 hours A, B and C power lines will be overloaded by 30, 26 and 24 percent respectively. The names A, B and C are, of course, used only for the purposes of this article. The list of energy lines that actually required the implementation of remedial measures is published by the Bundesnetzagentur in its annual report. In 2021, the list included as many as 19 items (Monitoringbericht 2022).
These expected/calculated overloads are the knowledge. We know what will happen if we leave the situation to itself and do not implement remedies. However, the job of the smart grid does not end here. On the contrary, the optimization task begins here: calculating the most effective remedies, after which none of the transmission lines will be overloaded in real time. One of the most important remedies is the so-called redispatching, that is, understating the generation of power plants in nodes with excess power and at the same time increasing the generation in the region with a deficit. The second important remedy is to reduce the generation of renewable sources in nodes with excess power. The cost of remedial measures is considerable, as according to the Bundesnetzagentur, it amounted to almost 2.3 billion euros in 2021.
Skeptics might ask: so what is the advantage of a smart grid if you still have to bear such high remedial costs? The benefit is that the engineer or even a team of engineers, without the support of the smart grid has no chance to control the system with more than 120 GW of RES power. This is too much data to process, the changes are too dynamic. For humans, this means a guaranteed information overload at the start. However, the right algorithms can handle this task without any problems.
All in the hands of … executive elements
The smart grid helps network operators maintain situational awareness. Thanks to modern solutions, network traffic is not driving in fog, but is on a conscious and planned journey during the next hours of the day and the next days of the year. However, there is one key issue that can be presented when comparing the performance of a smart home and a smart grid.
Let’s take a look at the scenarios: when it gets dark outside, the smart home rolls down the blinds in the windows. When the owner’s car approaches the property, the smart home opens the gate. When no one is in the room for a while, the smart home turns off the light. The above scenarios have something in common: they cannot happen without actuators. So, at the end of the chain of operations on the data, there must be actuators: roller shutters, a gate, etc.
It is no different with smart grids. You need actuators that you can send commands to.
Energy storage should be the most important actuator. Germany doesn’t yet have storage facilities with a capacity of over 20, or even just several gigawatts, that are connected to the grid, and which can be instructed by the smart grid to charge/discharge. Fingers crossed this is developed, but let’s move on to the next paragraph.
Today, the function of the actuators is performed by traditional power plants, which can reduce or increase the power when the smart grid gives such a command. The problem is, they’re being phased out. The coal zombies from the reserve, which were quickly dusted off and synchronized with the grid at the behest of politicians, will not be of much help.
Renewable sources are also trying to become actuators for the smart grid, but they can only perform half of that role. Reducing the generation of RES at the request of the network operator is already commonplace. But it will not be possible to increase the power generated by wind farms when there is no wind. The same goes for photovoltaics and the sun.
Are there any other actuators with which the smart grid can regulate power flows and system balance? Yes. Energy consumers. In next year’s Bundesnetzagentur report, we will check whether the “demand management” item appeared and how much it cost. Let’s not worry about the winter. The smart grid knows exactly what to do. It’s smart for a reason.
