Explained: Electric or hydrogen cars? Why Asian economies are backing the latter

Hydrogen's proponents point to how clean it is as an energy source as water and heat are the only byproducts and how it can be made from a number of sources, including methane, coal, water, even garbage.

China, Japan and South Korea have set ambitious targets to put millions of hydrogen-powered vehicles on their roads by the end of the next decade at a cost of billions of dollars. But to date, hydrogen fuel cell vehicles (FCVs) have been upstaged by electric vehicles, which are increasingly becoming a mainstream option due to the success of Tesla Inc’s luxury cars as well as sales and production quotas set by China.