When coal-fired power plants burn coal, what’s left over is a toxic ash mixed with water that gets stored in ash ponds. They look pretty much like you’d imagine – huge, contained pools of slurry and particulates – and environmentalists worry about their potential effects on the ecosystem and drinking water. Georgia Power is on track to quit adding to its ash ponds by sometime next year. That’s a mandate in the Integrated Resources Plan the Georgia Public Service Commission approved this summer.