Frozen Fish Help Reel in Germany's Wind Power

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Cuxhaven, a small city on Germany’s blustery North Sea coast, has ample supplies of fish and wind. A new project is exploring how these two abundant resources can work together to solve some of the problems that have bedeviled Germany’s renewable energy drive.

In short, Germany’s electric grid operators need a place to store all that wind power. And in Cuxhaven, they think they’ve found an answer -- in frozen fish.

One of renewable energy’s most vexing issues is the sheer variability of wind and solar power. It’s a headache for managers of the power system, whose customers need a steady, predictable stream of electricity. Germany is feeling the pain as a leader in alternative power, with 7 percent of its electricity from wind energy -- one of the highest rates in the world.

“Sometimes there’s a high feed-in of wind power, and at other moments, renewables can only take a small part,” says Wolfram Krause, a researcher at Germany’s EWE power company and manager of Cuxhaven’s 20 million euro ($27 million) eTelligence pilot project, half of which is funded by the German government. “We need to damp out fluctuations of wind power,” he says, “and this is what cold storage can do.”

Deep Power Freeze

In a 5.5-million cubic foot (155,742 cubic meter) warehouse at the mouth of the Elbe River, Cuxhaven’s Erwin GOOSS warehouse unloads and stores the catch from fishing boats sailing in the North Sea. Ordinarily, the warehouse needs to be kept at a chilly -4 F (-20 C). But the temperature inside can be pushed as low as -22 F (-30 C) when local windmills are spinning. The deep freeze gives the warehouse breathing room at times when the wind -- and the power -- dies down. Then, if allowed to warm slowly, the facility still will stay cold enough for the frozen fish. “It’s not that we’re using less power, it’s just that we’re using it when it’s cheaper,” GOOSS technical director Gunter Krins says.

In the summer, the well-insulated warehouse warms about 2 degrees F (1.1 degrees C) every 24 hours when the cooling is turned off. In the winter, the building warms at about half that rate. Depending on the season, that means the shelves stacked with frozen fish can “store” energy equivalent to a week’s worth of refrigeration.

Krins’ warehouse isn’t alone. The pilot project, launched in November 2008, aims to connect all types of power users and electricity providers over the Internet. Hundreds of smart meters that monitor energy usage multiple times per second and transmit the information to an iPod touch have been distributed to local homes.

Major power consumers like the local wastewater treatment facility and the local pool are getting in on the act--adjusting how much electricity they use depending on how hard the wind is blowing. A sophisticated communications network lets people know when power is cheap and when to conserve. “We’ve built a measurement and information control infrastructure that can suck up all this data and give it to all the actors,” Krause says.

Curbing Wind Waste

The hope is that projects like eTelligence will help Germany curb a costly kind of energy waste. By law, German renewable energy producers are guaranteed a certain price for wind and solar power. That has helped Germany create a thriving renewable energy industry, but meshing it into a system accustomed to steady power -- like that from coal power plants -- has been a challenge. “Right now, we’re switching off wind farms if we have too much power in our grid,” says Oliver Weinmann, innovation manager for power company Vattenfall. That essentially means that consumers, through their utility bills, are paying wind farms not to produce energy. “It’s not a very good situation,” Weinmann says. “We have to find a solution to integrate all this wind power in our grid.”

Local efforts like eTelligence are catching on. Initially, Krause says, Cuxhaven’s fish warehouse owners were skeptical. But when it became clear that there was money involved -- cooling primarily during hours of peak wind production will be cheaper than just drawing electricity at all hours -- the proposal became a lot more appealing.

Over the next year, Krause and Krins will be closely watching the warehouse’s savings. “We need to see what the savings are,” Krins says. “But it’s a good idea – we’ve got plenty of wind right outside the door.”