Canadian Prime Minister Mark Carney unveiled a clean electricity strategy Thursday he says will help double Canada’s electricity grid by 2050 and lower energy costs for the majority of Canadian households. Canada is facing major challenges, including tariffs imposed by the United States , higher energy costs resulting from the war with Iran, plus the effects of climate change, Carney said. “When the world fundamentally changes, we must respond with new approaches,” he said. The new strategy includes regulations that will allow natural gas to play a larger role in building the grid. Construction is expected to cost more than $1 trillion Canadian ($730 billon). “The path to affordability is electrification,” Carney told a news conference in Ottawa. “The path to competitiveness is electrification.…