I think the more promising automotive developments await in discovering the economical means to produce ethanol from “all cellulose” materials (not just those containing high levels of sugar, such as sugar cane, corn and beets). The reason for that is that all of the automobiles on the road today can be easily and cheaply converted (I’ve seen estimates of “about $100 per vehicle”) to run on any combination of gasoline, ethanol and methanol. Since filling stations already exist for the cars on the road today, it’s relatively simple to add tanks for methanol and ethanol and sell whatever mix the customer wants, pumped through a single hose.
The current problem with ethanol production is cost (related to supply, of course). As long as we use high-demand feed stocks (corn, sugar cane and beets), we drive up the cost of those materials for all users—including people who use them to feed themselves and livestock. So all food costs rise, too.
When we learn to make ethanol from grasses, including waste grasses (lawn clippings?), wood, waste wood and fallen leaves (“all plant materials” in other words) and do it at a cost that makes the fuel competitive with gasoline, then we’ll have a workable alternative that doesn’t have to drive up food costs around the world, too.