We constantly hear that electric cars are the future—cleaner, cheaper and better. But if they’re so good, why does California need to ban gasoline-powered cars? Why does the world spend $30 billion a year subsidizing electric ones?

In reality, electric cars are only sometimes and somewhat better than the alternatives, they’re often much costlier, and they aren’t necessarily all that much cleaner. Over its lifetime, an electric car does emit less CO2 than a gasoline car, but the difference can range considerably depending on how the electricity is generated. Making batteries for electric cars also requires a massive amount of energy, mostly from burning coal in China. Add it all up and the International Energy Agency estimates that an electric car emits a little less than half as much CO2 as a gasoline-powered one.