A Hybrid E-Bike Case Study
Total Page:16
File Type:pdf, Size:1020Kb
sustainability Article Are Personal Electric Vehicles Sustainable? A Hybrid E-Bike Case Study Mihai Machedon-Pisu * and Paul Nicolae Borza Department of Electronics and Computers, Transilvania University of Bras, ov, 500036 Bras, ov, Romania; [email protected] * Correspondence: [email protected]; Tel.: +40-726-392-909 Received: 22 November 2019; Accepted: 14 December 2019; Published: 18 December 2019 Abstract: As the title suggests, the sustainability of personal electric vehicles is in question. In terms of life span, range, comfort, and safety, electric vehicles, such as e-cars and e-buses, are much better than personal electric vehicles, such as e-bikes. However, electric vehicles present greater costs and increased energy consumption. Also, the impact on environment, health, and fitness is more negative than that of personal electric vehicles. Since transportation vehicles can benefit from hybrid electric storage solutions, we address the following question: Is it possible to reach a compromise between sustainability and technology constraints by implementing a low-cost hybrid personal electric vehicle with improved life span and range that is also green? Our methodology consists of life cycle assessment and performance analyses tackling the facets of the sustainability challenges (economy, society, and environment) and limitations of the electric storage solutions (dependent on technology and application) presented herein. The hybrid electric storage system of the proposed hybrid e-bike is made of batteries, supercapacitors, and corresponding power electronics, allowing the optimal control of power flows between the system’s components and application’s actuators. Our hybrid e-bike costs less than a normal e-bike (half or less), does not depend on battery operation for short periods of time (a few seconds), has better autonomy than most personal electric vehicles (more than 60 km), has a greater life span (a few years more than a normal e-bike), has better energy efficiency (more than 90%), and is much cleaner due to the reduced number of batteries replaced per life time (one instead of two or three). Keywords: life cycle assessment; personal electric vehicles; hybrid energy storage system; e-bike 1. Introduction In the context of the recent expansion of urban transportation systems, followed by rapid development of road infrastructure and motorization, the increase in the number of vehicles is completely justified [1,2]. Hopefully, in the near future, these will be seen as both smart and green transportation systems [3], and the corresponding infrastructure will be provided [4]. This could lead to the implementation of smart cities. Until that day, one has to wonder whether these transportation systems are sustainable [5–8]. In order to sustainably develop transportation systems, the following factors must be taken into account—economic growth, society demands, and environmental impact. Figure1 illustrates these sustainability challenges and their relation to transport systems, which need to be considered in order to develop sustainable, green and resilient cities [9]. Figure1 also hints out at the need to use the appropriate methodology for implementing the vehicles of tomorrow (EVs), according to the sustainability challenges mentioned above. Going back in time, the first electric vehicles have appeared in the first half of the 19th century thanks to Aynos Jedlik in 1828 [10]. In 1834, Thomas Davenport built a small electric car [11]. Between 1832 and 1839, Robert Anderson invented the first crude electric vehicle powered by non-rechargeable chemical cells. In 1859, Gaston Planté Sustainability 2020, 12, 32; doi:10.3390/su12010032 www.mdpi.com/journal/sustainability Sustainability 2020, 12, 32 2 of 24 Sustainability 2019, 12, x FOR PEER REVIEW 2 of 25 invented the first rechargeable battery (lead-acid), thus paving the way for electric cars. In 1901, Planté invented the first rechargeable battery (lead-acid), thus paving the way for electric cars. In Ferdinand Porsche invented the first hybrid electric car, the Lohner-Porsche Mixte. Since 1969, General 1901, Ferdinand Porsche invented the first hybrid electric car, the Lohner-Porsche Mixte. Since 1969, Motors has been preoccupied on developing hybrid driving cars (see GM XP-883 in 1969), and in 1973, General Motors has been preoccupied on developing hybrid driving cars (see GM XP-883 in 1969), they proposed a hybrid car prototype due to pollution issues, based on the previous model of the Buick and in 1973, they proposed a hybrid car prototype due to pollution issues, based on the previous Skylark. This prototype was designed by Victor Wouk. In 1997, Toyota developed the Prius, the first model of the Buick Skylark. This prototype was designed by Victor Wouk. In 1997, Toyota developed mass production hybrid car. the Prius, the first mass production hybrid car. FigureFigure 1. 1. SustainabilitySustainability challenges challenges for for transport transport systems. systems. TheThe technologies forfor transporttransport systemssystems have have always always looked looked for for compromises compromises that that can can smooth smooth the thetransition transition from from motor motor vehicles vehicles with ICEwith to ICE electric to el cars.ectric Thus, cars. “mild Thus, hybrid” “mild carshybrid” have beencars have developed, been developed,which are capablewhich are of reducingcapable of fuel reducing consumption fuel cons byumption 5–7%. by This 5–7%. is done This by is done recovering by recovering the braking the brakingenergy andenergy by optimizing and by optimizing the operating the curvesoperating of thecurves ICE asof athe result ICE of as adding a result a certain of adding power a certain supply powerfrom a supply small electric from a carsmall [12 ].electric The demand car [12]. for The energy demand storage for energy on board storage has led on toboard the increasehas led to in the the increasestandard in voltage the standard of the electrical voltage of energy the electrical sources energyenergyper sources vehicle energy from per 12 or vehicle 24 V to from 48 V, 12 respectively, or 24 V to 48above V, respectively, hundreds of above volts for hundreds pure electric of volts vehicles. for pure Also, electric plug-in vehicles. electric Also, vehicles plug-in with electric increased vehicles range withwhen increased operating range in an electricwhen operating regime have in beenan electr proposed,ic regime being have known been as proposed, “extended being ranger” known systems. as “extendedThey can increase ranger” thesystems. range They of the can vehicle, increase but the with rang a sacrificee of the vehicle, in nominal but performancewith a sacrifice [13 in]. nominal performanceThe main [13]. types of EVs can be classified in two categories—(i) heavy-duty and medium EVs, like electricThe trams, main types trains, of trucks, EVs can buses be classified and e-cars, in two and categories—(i) (ii) light EVs (LEVs) heavy-duty or personal and medium electric EVs, vehicles like electric(PEVs), trams, like electric trains, motorcycles, trucks, buse scooters,s and e-cars, and bikes.and (ii) PEVs light can EVs be (LEV alsos) split or personal into medium electric battery vehicles EVs (PEVs),(BEVs), like such electric as e-motorcycles, motorcycles, big scooters, e-scooters, and and bike smalls. PEVs BEVs, can likebe also e-bikes split andinto small medium e-scooters. battery EVs (BEVs),Heavier such as EVs e-motorcycles, are made up big of electrice-scooters, motors and andsmall batteries BEVs, like together e-bike withs and or small without e-scooters. ICE or fuel cells,Heavier while smaller EVs are EVs, made such up as of PEVs, electric use motors only motors and batteries and batteries together and with possibly or without also other ICE storageor fuel cells,elements. while For smaller example, EVs, e-bikessuch as canPEVs, be use electric only assisted,motors and battery-based, batteries and or possibly hybrid (e.g.,also other batteries storage and elements.supercapacitors For example, (SCs), batteries e-bikes andcan fuelbe electric cells (FCs)). assisted, A clear battery-based, distinction shouldor hybrid be made (e.g., betweenbatteries these and supercapacitorsterms, as it is not (SCs), always batteries clear, as and in reference fuel cells [14 (FCs)).]. Electric A clear assisted distinction bikes, or should electrically be made power between assisted thesebikes terms, (EPAC), as orit is pedelecs, not always get clear, propulsion as in referenc by meanse [14]. of anElectric electric assisted motor bi connectedkes, or electrically to batteries power and assistedstill can bebikes pedaled (EPAC), by theor pedelecs, rider. E-motorcycles get propulsion cannot by bemeans pedaled, of an as electric they are motor only battery-based.connected to batteriesThey are alsoand knownstill can as be BEVs. pedaled Hybrid by e-bikes,the rider. or E- HESSmotorcycles bikes [15 ],cannot which be belong pedaled, to the as class they of are assisted only battery-based.hybrid vehicles They (AHVs), are also use additionalknown as BEVs. storage Hybrid elements, e-bikes, like supercapacitors,or HESS bikes [1 to5], drive which the belong motor to when the classbattery of operationassisted hybrid is not required.vehicles (AHVs), use additional storage elements, like supercapacitors, to driveUnfortunately, the motor when the battery current operation development is not required. of vehicles can have a damaging effect on the environmentUnfortunately, [16]. Air the pollution current caused