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Germany as a testbed for renewable energy

15 Nov 2012 by Jim Fickett.

Germany has been a leader for some time in trying to replace fossil fuels with renewable solar and wind power, and this direction was reinforced by the recent strong German reaction against nuclear, following Fukushima. Despite the fact that I favor nuclear, I hope very much they succeed, as the world will definitely need, in the next few decades, working examples of power grids based largely on renewable sources.

For now, though, it is a rocky road. There is a very revealing interview in Spiegel today with Stephan Kohler, the head of the German Energy Agency. It is well worth reading the whole thing to get a sense of how the transformation is going.

When a new wind farm is opened and we're told how many thousands of households it can supply with electricity, that number applies to only a quarter of our demand. In Germany, 75 percent of electricity goes to industry, for which a secure supply – that is, at every second, and with constant voltage – is indispensable. Neither solar nor wind power are suitable for that purpose today. Both fluctuate and provide either no secure supply or only a small fraction of a secure supply. Solar energy has a load factor of about 1,000 hours a year. But there are 8,670 hours in a year. …

Photovoltaic systems are distributed across hundreds of thousands of small power plants, which sounds nice. But when the sky is blue over Germany, these hundreds of thousands of decentralized plants act like a single, large power plant. All of the sudden we have 30,000 megawatts coming into the grid, which, in many cases, we can't use.

… a surplus and fluctuations lead to very unpleasant systemic effects. We have voltage fluctuations within the grid that create problems for industry. Or we overload the grids in neighboring countries. Poland is in the process of installing technical equipment to protect its grids by keeping out surplus German electricity. …

Nowadays, solar systems are often in operation around noon, when there is high demand for power and the price was high in the past. As a result, conventional power plants can no longer make enough money, which is why existing plants are being shut down and no new ones are being built. Anyone who guarantees the security of supply in the future has to be paid for it, even if his power plant is only needed at certain times. …

Nowadays wind energy is mostly generated where it isn't needed, that is, in the north. But the power lines that are supposed to carry this electricity to the south only exist on paper at the moment. I would propose that we permit the construction of more wind farms only once the power lines have actually been built.

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