Germany Runs Up Against the Limits of Renewables [View all]

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https://www.technologyreview.com/s/601514/germany-runs-up-against-the-limits-of-renewables/

[font face=Serif][font size=5]Germany Runs Up Against the Limits of Renewables[/font]
[font size=4]Even as Germany adds lots of wind and solar power to the electric grid, the country’s carbon emissions are rising. Will the rest of the world learn from its lesson?[/font]

by Richard Martin | May 24, 2016

[font size=3]At one point this month renewable energy sources briefly supplied close to 90 percent of the power on Germany’s electric grid. But that doesn’t mean the world’s fourth-largest economy is close to being run on zero-carbon electricity. In fact, Germany is giving the rest of the world a lesson in just how much can go wrong when you try to reduce carbon emissions solely by installing lots of wind and solar.

After years of declines, Germany’s carbon emissions rose slightly in 2015, largely because the country produces more electricity than it needs. That’s happening because even if there are times when renewables can supply nearly all of the electricity on the grid, the variability of those sources forces Germany to keep other power plants running. And in Germany, which is phasing out its nuclear plants, those other plants primarily burn dirty coal.

Now the government is about to reboot its energy strategy, known as the Energiewende. It was launched in 2010 in hopes of dramatically increasing the share of the country’s electricity that comes from renewable energy and slashing the country’s overall carbon emissions to 40 percent below 1990 levels by 2020 (see “The Great German Energy Experiment”). What happens next will be critical not only for Germany, but also for other countries trying to learn how to best bring more wind and solar online—especially if they want to do it without relying on nuclear power.

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However, an expert commission appointed by the country’s minister of economy and energy has said the 40 percent target probably won’t be reached by 2020. And the energy revolution has caused problems of its own. Because fossil-fuel power plants cannot easily ramp down generation in response to excess supply on the grid, on sunny, windy days there is sometimes so much power in the system that the price goes negative—in other words, operators of large plants, most of which run on coal or natural gas, must pay commercial customers to consume electricity. That situation has also arisen recently in Texas and California (see “Texas and California Have Too Much Renewable Energy”) when the generation of solar power has maxed out.

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