Turbulent times for network operators When the weather is volatile, it wreaks havoc on the German electricity grid, pushing it to its limits. New electricity lines are supposed to provide more stability, but gas power stations also play a crucial role.
Jörg Riemann suspected as much: Heini would cause considerable problems. Heini, as it happens, was the name of a low pressure area that was heading for Germany in November of last year. And the closer it drew, the clearer it became that behind this amusing name the first big storm of the autumn season was brewing.
Whenever strong winds are roaring outside, Riemann’s telephone starts roaring, too. Riemann is a meteorologist at the Berlin weather service Meteogroup. And when things become unpredictable, customers want his advice. The automatically calculated forecasts merely give from-and-to indications: fluctuations of 1 or 2 hectopascals of air pressure, 1 percent humidity or 0.2 degrees Celsius are always possible. Experienced meteorologists, on the other hand, can spot details in the overall weather picture that allow them to make more precise statements. “Customers want me to tell them where the meter will point to, the upper or the lower end.” Many aren’t interested in knowing about hectopascals or degrees Celsius. All they want to know is, “Is it more likely to be 23,000 or 25,000 megawatts?
“These customers are companies from the energy sector – often utilities, but also network operators. It is a sector that only began using weather services like this a few years ago. “They used to be very keen to know how long the heating period would last,” Riemann says. That was in the days before the Energiewende, Germany’s green energy transition. However, the energy transition has made the weather a crucial factor in energy supply, and since it began the German electricity market has been performing a balancing act between two opposing requirements: keeping the network stable, while at the same time giving priority to energies whose production is the least stable – solar and wind power. A balancing act that only works because fossil fuels continue to be available in reserve as balancing power. Heini illustrated this difficultly particularly well. When the storm reached the peak of its momentum, at up to 170 kilometers an hour on November 18, Germany’s wind turbines achieved a collective output of 32,600 megawatts – as much as 25 nuclear power stations. A new record. The previous record was 29,000 megawatts and had been set just under a year earlier.
Although this was a record that operators of wind farms were happy about, it caused problems for others in the energy industry. This is because most wind turbines in Germany are located in the north near the coast, where it is naturally windy. But most of the electricity is actually needed in the south, which is densely populated and has many industrial areas. The electricity networks would not take such record loads, which would lead to overheating and voltage fluctuations. If that happens, power plants in the north are switched off. At the same time, the four German network operators, Tennet, 50hertz, Amprion, and Transnet, have to fire up power plants in south Germany at short notice. When Heini came to visit last year, for the first time the “winter reserve” was activated. This includes deliveries from power stations in Austria and Italy. It doesn’t just require a great deal of coordination, it also costs a lot of money.
Redispatching guzzles millions
The electricity prices traded every day on the Leipzig exchange, the EEX, do not reflect this reality. Here, if production rises, the price falls. It is an opportunity for buyers to order large volumes of electricity, regardless of where the electricity is produced or consumed. “People assume that Germany is like a copper plate: you can feed in any amount of electricity anywhere and withdraw it again somewhere else,” says Patrick Graichen, Director of Berlin-based think tank Agora Energiewende. “But it’s not that simple.”
The reality is called dispatching – the planning of power plant deployment. Dispatching is a kind of road map by which the network operators decide which power plants will have to run the next day at what capacity in order to keep the electricity market stable and balanced. Heat waves or storms can quickly throw this road map into disarray. That is when redispatching comes into play – when power plants are fired up at short notice. And as the share of renewable energies increases, these extremes are becoming the norm. “About ten years ago we used to intervene in network operations about three times a year,” says Dr. Christoph Thiel, who works for network operator Tennet. At Tennet they estimate that collectively the stabilization measures undertaken in 2015 swallowed up €500 million. That is a new record, and one which places a considerable burden on consumers, who have to bear a portion of these costs via their electricity bill. But that is now set to change. “There is a whole portfolio of measures to deal with this,” Thiel says. “But one thing is clear: without new power links, nothing else will help.” The German Federal Network Agency estimates that 2,700 kilometers of new electricity lines are necessary to ensure the electricity’s smooth transmission. Thiel is the overall project manager for a link that plays a key role here – the “Südlink”. A plan for an 800-kilometer power link from Schleswig-Holstein to Baden-Württemberg and Bavaria – a plan that Tennet intended to realize, but which was recently consigned to the wastepaper bin. Both citizens and politicians protested against the installation of such a long above-ground electricity line, so the two chambers of the German parliament, the Bundestag and the Bundesrat, decided in December 2015 that the Südlink would be built underground. “In electrotechnical terms, it is no problem to install underground electricity cables,” Thiel says. “But the construction logistics for a project of this size take things to a new dimension.”
Tennet has already laid a total of more than 1,000 kilometers of underground cables, and has experience with wind farms in the North Sea. However, no individual section was ever longer than 90 kilometers. Furthermore, the underground version of Südlink is only 500 kilometers long because it doesn’t have to bypass certain obstacles as would have been necessary above the surface. And yet, “It will still be a world record,” Thiel says. It is estimated the project will cost several billion euros. Nature itself is the biggest unknown factor. Thiel expects to meet a cross-section of the various types of subsurface in Germany when implementing Südlink – from marshland to rocky underground. So far projects of this magnitude have only ever been realized with gas pipelines. “So we are studying gas infrastructure very closely to see how it was planned and realized,” Thiel says.
No lights without power stations
For logistical reasons such as these, plans for new electricity lines will only secure the stability of the networks in the long term, says Frank Sensfuß, Coordinator of the Electricity Markets Business Unit at the Fraunhofer Institute for Systems and Innovation Research ISI. “Grid expansion is good and necessary. But it is a question that will occupy us for decades.” Especially when you consider that electricity consumption is likely to increase. Even if household consumption looks set to fall in future, there are other areas being electrified, for example, e-mobility,” says Sensfuß. “Redispatching is a solution that should not be applied on a very large scale, but it is one that we will have to live with for the time being.”
Provided the power stations suitable for this purpose are even available. It is undisputed that gas power stations are best suited for the job because they can be fired up quickly to cover short-term peaks. No one is more aware of this than Oliver Schwadtke; he runs a gas-fired power station in Irsching, Bavaria, operated by Uniper Kraftwerke GmbH. Two of the most powerful gas power plants in the world, Blocks 4 and 5, were commissioned here in 2010 and 2011. The plants have an efficiency of nearly 60 percent: in other words, the ratio of electricity generated to energy used. Older power plants often have efficiency levels of less than 40 percent. But the only records being set at Schwadtke’s workplace are minus records, for the blocks are barely used, sometimes for just a few days a year. The plant cannot compete with current prices on the electricity exchange, partly because of increasing production of the very energy that Irsching has to compensate for because of its volatility – renewable energy. And partly because Germany’s coal-fired power stations are running at full blast again.
In contrast to new power plants such as the one in Irsching, these coal power stations have long since recouped their investment costs. But even more importantly, burning coal is cheaper than it has been for a long time. “One of the principal reasons for this has been the crumbling of certificate prices,” says Agora Director Graichen. For every ton of emissions released by a power station, the operator of the power station must have a CO2 certificate. These certificates were about €14 each in 2010, but at the moment the price is around €8, and in 2013 the price even dropped to €5 for a time. The results of this development were investigated and published by Agora in a study titled “The Energy Transition Paradox,” which found that emissions in the German electricity sector fell from 2007 to 2010, increased again in the last few years, and recently settled at a level of 313 tons. For these reasons, Eon already submitted a request to take Irsching 4 and 5 offline for the time being. But that could have caused difficulties for Tennet during the next redispatch measures. Irsching had to stay on the grid because of its “systemic importance”, the network operator argued. In the meantime, an agreement has been reached which will remain in place until 2018. According to this, Tennet will pay the operating costs for the periods when Irsching is in effect running on standby. Schwadtke occupies his staff during this time with maintenance work, among other things. Because the plant cannot cover its costs, even with compensation payments, he even arranged to have some of his employees train in tasks that outside firms were supposed to perform – for example, maintenance of fire doors and inspecting compressors. “We have adapted to the situation,” Schwadtke says, “but of course it is unsatisfactory for us as a power station operator. We want to earn money with our product.”
Certificate prices must change
And what of the objectives of the energy transition? “Germany and the EU have set themselves ambitious climate targets: one in two coal-fired power stations is to be decommissioned by 2030,” the Agora director says. “If we want to achieve this, we must take action.” Other countries are taking the lead. The UK, for example, has declared that it will phase out coal. Minimum prices for CO2 certificates there already punish power stations that run on coal. “And that made power stations switch back to gas,” says Graichen. “Either way, fossil fuel power stations are indispensable as back-up solutions. If you want to source at least 80 percent of your electricity from renewable energies long-term, you have to ask yourself where you’re going to get the electricity when the weather doesn’t permit it.” After all, the next storm is just round the corner.
Text: Claus Hornung | Photos: Norman Konrad
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