Grid expansion: Gigabatteries should relieve the power grid

New power lines are unpopular, so the existing network should transport as much energy as possible. The operators want to test billion-dollar giant batteries - a paradigm shift for security of supply.

Little time? At the end of the text there is a summary.

With record investments in battery storage, the energy industry wants to test a new solution for the urgently needed expansion of power lines. By 2025, three so-called network boosters are to be built in southern Germany according to the plans of the major line operators. The largest plant is to be built in the Baden-Württemberg copper cell. With 500 megawatts, it would be five times as powerful as Tesla's battery park near the Australian city of Adelaide, which was considered the largest in the world when it opened in 2017.

A similarly huge project as in Kupferzell in the Swabian-Franconian border region is currently planned only in the region between Silicon Valley and the California community Moss Landing. The utility PG & E intends to replace a complete gas-fired power plant with lithium batteries by the end of 2020.

Giant battery with 900 megawatts of power for the price of one billion euros

The other two large German stores are to be built in Ottenhofen east of Munich and in Ludwigsburg. The cost of the batteries with a total of 900 megawatts estimate industry insiders to about one billion euros. Mega-investment should justify the possible solution of a conflict that has become increasingly acute in recent years.

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With the energy turnaround, wind power from northern Germany must be transported to the industrial centers in the south and North Rhine-Westphalia. Since 2009, therefore, 7700 kilometers of pipelines have been planned, which are to be reinforced or rebuilt by 2025. Realized was until September last year, but only one-eighth.

In the plans for 2030 that are now being presented, the network operators are proposing a further 4,500 kilometers of newbuilds and conversions in order to reach the green power goal of the German government of 65 percent and to secure the coal exit. However, despite the higher demand, political pressure is increasing to plant as few of the unpopular masts and cables as possible in the landscape.

Power boosters would maximize the existing lines

"For reasons of acceptance and cost, there are limits to further network expansion," Federal Minister Peter Altmaier (CDU) and all of his responsible ministers from the federal states said last September. Unanimous wish of the ministers: Existing lines should be utilized to a greater extent, gladly through greater digitization and the use of modern technologies. With the net booster now the entry into a technology could be prepared, with the power lines are exhausted to the edge of the feasible.

For years now, network companies have had to intervene more and more frequently when more electricity pushes into the north-south lines than they can transport. For the so-called redispatch, the operators then shut down power plants in the north and drive up reserve capacity in the south. The result is a virtual stream of electricity. According to the Federal Network Agency, the costs of these interventions rose in 2017 to the new peak of 1.4 billion euros. The three planned giant batteries are to reduce the future demand for redispatch, according to the network operators by almost ten percent.

The batteries would have to react within seconds to prevent blackout

What is actually new compared to the previous interventions would be that a mains booster should only supply power when an important line or power station has already failed. Technicians talk about the n-1 case. If in this scenario, only another critical component of the network would fail, a large-scale blackout threatens. "Within a few seconds or minutes, individual lines would overheat, so the network booster has to react very quickly," explains Christoph Maurer of the consulting firm Consentec, which co-developed the concept.

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According to Maurer, batteries can jump in within milliseconds. "With the help of the network booster, fewer power plants would have to be preemptively regulated and unused transport reserves in the lines could be better utilized," explains the engineer.

However, the concept has not yet been tested, so a test operation is initially planned. "The network booster should already be used in the pilot phase of the system management and create in appropriate situations, the possibility of actually using the lines higher and to intervene in case of network errors," said a spokeswoman for the responsible company TransnetBW.

The scientist Ulf Häger of the TU Dortmund sees the necessity that the network operators react fast enough in the n-1 case critically. That would only work if "the four transmission system operators work together more closely, so they need to develop common operational and automation concepts to help them to respond to a variety of different incidents."

First, however, the plan for the gigabattery must be confirmed by the Federal Network Agency and the Bundestag. Above all, the regulatory authority has to check whether there are any cheaper alternatives for the expensive technology. Management consultant Maurer has already presented model calculations for six times the amount of battery storage to network agency experts. Estimated costs: up to ten billion euros.

In summary: The four operators of the electricity transmission network want to test three large battery storage units in Southern Germany from 2025 onwards. The net booster should make it possible to transport more power with existing lines and thus to dispense with some new routes. The Federal Network Agency still has to check whether the new technology is economical for consumers of electricity and that the network can be operated safely with it.