Oil prices would need to stay high for years — not weeks or months — to drive a lasting shift away from the fossil fuel.The big picture: Every time oil spikes, the same question surfaces: Will this push more people into electric cars or install solar panels onto rooftops?State of play: That's happening again following oil prices zoomed past the $100-a-barrel mark in the wake of the Iran war. Driving the news: Prices dropped at least temporarily in the wake of President Trump signaling Monday eve...