The German government and energy companies today reached an agreement to shut down the nation’s 19 nuclear power plants by about 2020. The deal, which comes after more than 18 months of contentious negotiations, fulfills a pledge made by the governing coalition of the Social Democratic and Green parties to phase out nuclear energy. Still, many Greens are disappointed that the phaseout won’t happen more quickly. Nuclear power now accounts for about 30 percent of all German energy use. After the phaseout, the nation will likely depend more on natural gas and, ironically, perhaps imported nuclear power from France.