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Energies 2016,9, 86
optimizing tourassignmentsofvehicles. This is knownas theVehicleRoutingProblem(VRP) [1].
Numerousvariants of this problemhavebeen addressedover the last years. Thebasic variant is
the so-calledCapacitatedVRP (CVRP),where each customer has a given demand that has to be
satisfiedwithoutexceedingamaximumvehiclecapacity. TheVRPwithTimeWindowsextends the
CVRPbyaddingtimewindowsto thedepotandthecustomers. Toaccount foradditional realworld
aspects, theclassicalVRPhasbeenredefinedinvariousmanners thatareoftencalledRichVRPs[2]
orMulti-attributeVRPs [3]. Despite the extensive literature in theVRParea,most of the existing
contributionshaveassumedthat thefleet tobemanagedcomprisesonly internalcombustionengine
vehicles (ICEVs),which isnotexactly thecurrentpicture.
A large percentage of the oil consumed in regions such as Europe or the USA is used in
transport, while road transport accounts for an important percentage of CO2 emissions of the
overall transport activity. Furthermore, thewhole transport sector causes about 28%of the total
greenhousegas (GHG)emissions in countries suchas theUSA. Inorder tomitigate this situation,
onepossibility is to incorporate emission costs as anobjective tobeminimized in routingmodels,
thus tradingoff environmental andeconomicgoals [4,5]. Adifferent approach is theutilizationof
lesspollutingmeansof transportsuchasplug-inhybridelectricvehiclesandelectricvehicles (EVs),
whose specific characteristicshave tobe included inadequate routingmodels. Ineffect, aspartof
the initiative to improve the local air quality,modern cities encourage fleets of vehicles to adopt
alternative technologies, suchasEVs. Several factors arepromoting theuseof these technologies,
including: (i) companies receive incentives to reduce their carbon footprint; (ii) highvariabilityof
oil-basedproductsandlong-termcost riskassociatedwithdependenceonoil-basedenergysources;
(iii) availabilityofgovernmentsubsidies toreduceacquisitioncost; and(iv)advances inalternative
energy technologies (such as EVs), which have potential for amore environmentally sustainable
solutions at a cost that is starting to be competitive. From both an environmental and energy
standpoints, theuseofEVsshouldbeafirstpriority for thereductionofprimaryenergyconsumption.
Althoughhigherconcernsare theadvantagesofEVs in termsofefficiencyandflexibility in theuse
ofenergy, theEVtechnology is currently facingseveralweakpoints,whichcanbesummarizedas
follows: (i) the lowenergydensityofbatteriescomparedto the fuelof ICEVs; (ii) the longrecharge
timesofEVsbatteriescomparedto therelatively fastprocessof refuelinga tank in ICEVs;and(iii) the
scarcityofpublicand/orprivatechargingstations forEVbatteries. Inearlieryears,EVsfailedbecause
of excessive battery prices andvery short driving ranges. AsEVshave becomeone of themajor
researchareas in theautomotivesector, themagnitudeof theseproblemshasbeennotablydiminished.
Although the replacementof conventional ICEVswithEVs isnotprofitableundermostoperation
scenariosgiven thecurrent cost conditions, theavailabilityof increasingly long-livedbatteries, the
trends forrisingfuelcosts, andlowerEVpurchasecostsare likely tochangethepicture [6]. Figure1
showsthenoticeable increaseexperiencedduringthe lastyears in thenumberofEV-relatedarticles
published inScopus-indexed journals,whichproves thegrowing interest that theuseofEVs isarising
amongresearchersandpractitioners.
Accordingly, thispaper identifiesandreviews, fromanOR/CSperspective, severalopenresearch
challengesrelatedto the introductionofEVs inL&Tactivities, includingthefollowingdimensions:
(a) environmental-related issues; (b) strategic andplanning challenges associatedwith “standard”
EVsandwithhydrogen-basedEVs;and(c)emergingoperational issuesrelatedto theuseofEVs in
VRPs. Table1 summarizes thedifferent researchchallenges thathavebeen identified inour study
andthatwillbeconvenientlydescribedandreviewedindifferentsectionsof thismanuscript. Fora
betterunderstanding, theseresearch issueshavebeenclassifiedin threedimensions: environmental,
strategicandplanning,andoperational. Thepaperalsoanalyzes indetailhowthe introductionofEVs
inL&TsystemsgeneratesnewVRPvariants, i.e., in thecontextof theGreenVRP, thisworkpointsout
someof themostpromisingresearch linesyet tobe fullyexplored. Finally, thepaperalso includes
adiscussiononwhichoptimizationapproaches canbetter contribute todealwith theseopenand
difficult researchchallenges.
86
Emerging Technologies for Electric and Hybrid Vehicles
- Title
- Emerging Technologies for Electric and Hybrid Vehicles
- Editor
- MDPI
- Location
- Basel
- Date
- 2017
- Language
- English
- License
- CC BY-NC-ND 4.0
- ISBN
- 978-3-03897-191-7
- Size
- 17.0 x 24.4 cm
- Pages
- 376
- Keywords
- electric vehicle, plug-in hybrid electric vehicle (PHEV), energy sources, energy management strategy, energy-storage system, charging technologies, control algorithms, battery, operating scenario, wireless power transfer (WPT)
- Category
- Technik