Reuters: Old coal-fired power plants should be closed and replaced by cleaner gas plants to slash carbon emissions, the Chief Executive of the biggest gas producer in Europe said on Wednesday. Helge Lund, the head of Norway’s StatoilHydro, told the World Petroleum Congress in Madrid that substituting coal for gas was a sound strategy for fighting climate change. “Climate change is perhaps the challenge of our time,” he said. “I see gas as an energy bridge to a less carbon …