There is currently a debate about various new energy sources, such as gas, as in the following message from PhillipsConoco: http://www.powerincooperation.com/EN/Pages/index.htm
Gas, or any other fuel, will not solve our future transport needs on its own. A number of systems decisions and very large investments need to be made in order to use it for transportation. We can decide to use it to produce electricity and heat, like in the combined heat-and-power-plant (CHP) Öresundsverket in the city of Malmö in Southern Sweden: http://www.eon.se/om-eon/Om-energi/Produktion-av-el-gas-varme-och-kyla/Kraftvarme/Vara-kraftvarmeverk/Oresundsverket-eng/The-Oresundsverket/
In order to do this we need large numbers of electric or plug-in hybrid vehicles. It is also advantageous to have a district heating system, like the one in Malmö, which provides heat to a large share of the houses in the city. A district heating system is not necessary, but without it the heat generated by the plant is lost to entropy. In order to use large numbers of electric and hybrid cars there is also a need for a large-scale charging infrastructure.
We can also decide to use the gas as vehicle gas. Gas fuelled vehicles are much less fuel efficient than electric ones, so we can drive only half the distance using vehicle gas, compared to using electricity. In order to use vehicle gas as a fuel we need a distribution infrastructure for gas at filling stations, large numbers of gas vehicles, and gas-pipes, or a large scale distribution system for gas using trucks.
None of these alternatives comes cheap and there is a huge difference between the alternatives in terms of cost-, capital- and energy efficiency. The new systems also need to become attractive for users, meaning that it needs to be relatively easy to locate and travel to filling stations etcetera.
We can also use vehicle gas for purposes where electricity is not so well suited, such as for heavy vehicles. There are numerous alternatives with widely different cost aspects, capital needs and other factors. We cannot look at the fuels and vehicle technologies in isolation. We need to evaluate them from a systems perspective.