“Here the whole sky is smoke,” the writer Joseph Roth noted as he travelled through the Ruhr, Germany’s old industrial heartland, nearly a century ago. “It hangs in a grey pall over the land that has made it and that continues to make more of it … It is sacrifice, god and priest all at once.”Today the skies have largely cleared, yet as the war in Ukraine throws another spanner into the works of Germany’s stalling shift to clean energy, the coal-fired plant at Datteln, the largest in the region, will belch smoke for years to come.The transformation to clean energy has been slowed to a crawl by botched policies, nimbyism, conflicts with conservationists over birds and bats and cheap Russian gas.The coal-fired plant at Datteln will continue to generate power for yearsALEX KRAUS/BLOOMBERG/GETTY IMAGESLast