Tesla's all-electric car starts at $70,000 and goes up from there. This week, GM unveiled an electric with a price tag closer to $30,000. The Chevy Bolt – not to be confused with the hybrid Volt -- goes 200 miles on a single charge, just like the Tesla. But cost is hardly the only difference. Is the international combustion engine about to become obsolete, or will a "super battery" still be required to change the market forever? Steve LeVine is Washington correspondent for Quartz. His new book, The Powerhouse: Inside the Invention of a Battery to Save the World, will be out next month.