When Bill Gates arrived at the Élysée Palace to meet the French president François Hollande and other officials in June, he brought a message. Mr. Gates told Mr. Hollande that energy innovation needed to be a top agenda item at the climate change conference now taking place in this airport suburb outside Paris. For years, Mr. Gates had prodded governments to increase spending on research and development of clean technologies. He had sunk $1 billion of his own fortune into start-ups working on new kinds of batteries and nuclear reactors. “Honestly, I’ve been a bit surprised that the climate […]