Germany’s environment minister said Tuesday that the country might have to slow its shift to renewable energy to quell concerns about rising consumer costs. A year after the government decided to phase out nuclear power following Japan’s Fukushima disaster, Germany has indeed been able to increase renewable energy generation, with solar and wind incentives helping the country produce more than 25 percent of its power from cleaner sources. But that rapid growth is causing higher costs for consumers and placing an increased strain on the energy grid, Environment Minister Peter Altmaier told the Financial Times Deutschland. “These are costs that can be avoided with good planning,” Altmaier said. While a senior Social Democrat called a slower shift to renewable energy “unacceptable,” members of Chancellor Angela Merkel’s administration are seeking legislation that would reduce the burden on consumers. On Monday, the energy group Vattenfall reported that Germany’s current green energy targets would likely require an investment of 150 billion euros by 2020, causing a 30-percent increase in electricity costs.