I think now that we may be on the verge of major breakthroughs in battery technology, we could soon see the beginning of the end of using gasoline and diesel fuel for motor vehicles anyway.
Around 2010, Volkswagen Chairman Martin Winterkorn predicted that by 2020, a vehicle about the size of today's VW Golf model--with similar carrying capacity in terms of passengers and cargo--could travel 800 km (497 miles) on a single full charge of the car's electric battery pack. Thanks to new forms of lithium-ion batteries that use dry electrodes and graphene sheets and carbon nanotube supercapacitors, such a goal may not be such a far-fetched idea; if Winterkorn's prediction proves true, that will truly start the transition from away from using internal combustion engines fueled by gasoline or diesel fuel for personal vehicles.
However, gasoline and diesel fuel will be around longer until the change I mention above is complete, thanks to new industrial catalysts ("cat crackers") that can convert natural gas into very clean-burning forms of gasoline and diesel fuel--and it will be cheap to make, too. This will provide a "bridge" of fuel technology until long-range electric cars I described earlier become common.