Possible transport energy sources for the future

In themediumtolongterm,lowfossilfuelavailabilitywillmakeitnecessarytofindalternatives.Mass productionofbiofuelswillnotbeapracticalsolutionbecauseitrequiresstrongcompetitionforland that isusedforgrowingfood.Therefore,itwillbenecessarytorevisetheframeoftransportation energy sources.Thenumberofpurelight-andheavy-dutyelectricvehiclescouldincreaseinurban areas.Instead,itwillbehardtofindaviablealternativetotheinternalcombustionengineforextra- urban transportvehicles,thereforealternativesyntheticfuelscouldbeusedtocompensateforfossil fuel depletion.Asidefromasmallshareobtainablefrombiomass,mostsyntheticfuelsareexpectedto be obtainedfromcoal.Amongthese,syntheticnaturalgasrepresentsaverygoodsolution.Infact, syntheticnaturalgaswillbeadvantageouswithrespecttohydrogen,whoseon-boardstoragewillbean unsolvedprobleminthemediumterm,andwithrespecttosyntheticliquidfuels,whichrequiremore energy intheproductionphase.Moreover,thecarboncontentofliquidfuels,whichishigherthanthat of gaseousfuels,willberesponsibleforhigherCO2 emissionsfromvehicles.Currently,naturalgashas poor diffusioninthetransportsector,andthispaperhighlightsthemotivationsforfavouringapolicy aimedatincreasingtheshareofgaseousfuel-poweredvehicles.Inadditiontothelowenvironmental impact,syntheticnaturalgasalsooffersthepossibilityofoptimisingtheutilisationoffutureresources