Electric cars are better for the environment than traditional gasoline models, and that benefit will grow as power generators shift away from coal. That’s the conclusion of research by BloombergNEF, which found carbon dioxide emissions from battery-powered vehicles were about 40% lower than for internal combustion engines last year. The difference was biggest in Britain and the UK, which have large renewables industries. It still held in China, which is more reliant on coal to make electricity.