Several climate activists were arrested after their group entered the grounds of a coal power plant in Jänschwalde, about 100 kilometres south-east of Berlin, on Monday. Two units – half of those in operation – were taken off the grid as a result of the protest, a spokesman for the operator LEAG said, describing it as an “attack on the security of energy supply.” The activists blocked three areas around the site including around rail tracks and conveyor belts, a police spokesperson said. The demonstrators did not enter the open-cast mine itself, which is Germany’s third-largest source of brown…