By Alexander Jung
In Brauweiler, on the outskirts of Cologne, two engineers are making sure that 27 million German citizens are able to make coffee or start up their computers at any time -- without any power cuts whatsoever. From where they are sitting in the control room of Amprion, a subsidiary of energy utility RWE, the two engineers manage a power grid that is 11,000 kilometers (6,875 miles) long.
It is shortly after 1 p.m., time for a shift change in the control room. The new team sits down in front of the "world view," their name for the giant screen that opens up in front of them. At a width of 16 meters (52 feet) and a height of 4 meters, the screen depicts an oversized grid of red and blue dotted lines, which represent power lines between the Ruhr region in western Germany and the Alps in the south. Based on the data on the screen, the engineers can determine that the power plants, which they can activate with a click of the mouse, generate precisely the amount of electricity customers need at any given moment.
This is something of a sacred formula for electric utilities. Only when consumption and generation are perfectly balanced does the grid remain stable.
More recently, the engineers have had to add a new variable to their equations. And this new variable throws their entire calculation into disarray. "Everything can be planned, except the wind," says Amprion Managing Director Klaus Kleinekorte.
The wind fluctuates between gentle breezes and powerful storms, but at some point Kleinekorte and his team will have to come to terms with its incalculable power. Every week, new wind turbines are built in Germany and more solar panels appear on roofs.
Fragile Balance Thrown Out of Kilter
The grid operators are required by law to give priority to these "clean" forms of energy when feeding electricity into the grid. The only problem is that the sun and the wind are very unpredictable. The fluctuations complicate their work. "The job has become much more stressful," says Kleinekort. "The grids are reaching maximum load more and more often."
And this is only the beginning. In the coming years, the German government plans a massive expansion in renewable energy and expects it to make up 30 percent of total power production by 2020. Giant wind power projects are in the works for the North Sea and the Baltic Sea. At the same time, the Mediterranean countries intend to utilize the massive potential of solar energy with the Desertec project in the deserts of North Africa.
Wind power from the north and solar energy from the south: If this fantastic vision becomes reality, the fragile balance could be thrown completely out of kilter. "The grid is prepared for anything, just not the requirements posed by renewable energy sources," says Klaus Töpfer, the former head of the United Nations Environment Program and today a representative of Desertec.
But what is missing is the modern power grid that will transport green electricity to consumers in the center of Europe, a grid that, moreover, is capable of integrating fluctuating loads into the existing system. Without such a capable system, fears the German Energy Agency, the situation could turn disastrous. According to a study, "an elevated number of critical grid situations could arise" in the coming years, "which will also lead to bottlenecks within the German transmission network."
Millions of households experienced exactly what can happen during such a bottleneck shortly after 10 p.m. on Nov. 4, 2006. Technicians with network operator E.on had shut down an important transmission line during the transport of a cruise ship, and had incorrectly assessed the consequences. The rest of the grid became overloaded, causing one line after the next to shut down automatically. Some electricity customers were in the dark for up to one-and-a-half hours.
Urgent Need to Modernize
Such blackouts will become more and more difficult to prevent, as a result of fluctuations in the levels of electricity being fed into the grid from wind turbines. If the transformation of the system proceeds as planned in the next 10 years, wind turbines generating a total of 42 gigawatts will be installed in Germany. By then, photovoltaic systems will be generating about half as much electricity as the wind turbines. This is far more than is needed on some weekends, when demand can drop to less than 30 gigawatts. In other words, if the sun is shining and the wind is blowing at the same time, the grid can be quickly thrown off balance.
Today, electric utilities are even paying others to take excess electricity off their hands during nighttime storms. The operators of an Austrian pumped storage hydroelectric power plant use the free energy to pump water into lakes at higher altitudes. Once prices have recovered, they release the water from the lakes, which drives generators that produce electricity that is then sold. "They have two reasons to celebrate," says a piqued German utility executive.
Such grotesque situations make it clear how urgent it is that the providers modernize the infrastructure and grid management. The companies are about to embark on the most radical change in their history. Power highways that will cost billions to build are needed to connect renewable energy sources in the north and south to the markets in-between. Massive power lines will be installed across Europe, some through desert sand and some on the ocean floor.
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