One of the big items — but still nowhere near a solution — is creating new storage options for electricity. This is imperative because of the fluctuations inherent in renewable energy sources. In short, the wind doesn’t always blow and the sun doesn’t always shine. The trick is in absorbing any immediate surplus power and then making it available when required.
This sounds easier than it is. There is currently no way to store electrical energy when the wind blows steadily or the sun shines in force. This is why Germany is currently sinking 200 million euros a year into R&D on storage options alone. “Exploring storage technologies and bringing them to full maturity for industrial applications is a strategic task which is indispensable if we want our energy transition policy to work,” said Germany's environment minister in March. So far, Germany hasn’t put all of its chips on one option; indeed there are a bewildering array of storage possibilities that are receiving funding, which shows just how wide open the field still is — and how distant a remedy might be.
The most efficient, cheapest, and today the only technologically mature means is the pumped storage of hydroelectricity. (Pumped storage uses surplus electricity to pump water into elevated reservoirs. When electricity is needed, the water flows back down through channels and drives turbines to produce more electricity.) But, sadly, there is little hope of expanding it beyond its present capacity in light of Germany’s limited space, topography, and population density. The one pumped storage plant currently under construction in the Black Forest has the local population in the streets blocking it.
Matthias Kurth, the former director of the Federal Network Agency, warned against underestimating the task: “Things that might be accomplished in decades are today regularly spoken about as if they could already function by next Friday,” wrote Kurth in an op-ed in the Frankfurter Allgemeine Zeitung. “If we were to compare the amount of storage capacity that we have today with a glass of water, we’d need an amount comparable to Lake Constance in order to have renewables alone account for Germany’s energy supply.”
But Philipp Vohrer, the director of the Agency for Renewable Energies in Berlin, warns about postponing the expansion of renewables until a storage solution is in sight. “They aren’t mutually exclusive,” he says. “If the electricity grid is updated to handle more renewable sources, then part of the storage problem is already solved. We have to pursue both the expansion of renewable energies and the storage question at the same time.”
See Paul Hockenos's own blog "Going Renewable" on the site of the German Council on Foreign Relations.
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