The Acceptable Alternative Vehicle Fuel Price

Article The Acceptable Alternative Vehicle Fuel Price

Antonina Kalinichenko 1,* , Valerii Havrysh 2 and Igor Atamanyuk 3 1 Institute of Technical Science, University of Opole, 45-040 Opole, Poland 2 Department of Tractors and Agricultural Machines, Operating and Maintenance, Mykolayiv National Agrarian University, 54020 Mykolayiv, Ukraine; [email protected] 3 Department of higher and applied mathematics, Mykolayiv National Agrarian University, 54020 Mykolayiv, Ukraine; [email protected] * Correspondence: [email protected]; Tel.: +48-787-321-587

Received: 7 September 2019; Accepted: 10 October 2019; Published: 15 October 2019

Abstract: Historically, petroleum fuels have been the dominant fuel used for land transport. However, the growing need for sustainable national economics has urged us to incorporate more economical and ecological alternative vehicle fuels. The advantages and disadvantages of them complicate the decision-making process and compel us to develop adequate mathematical methods. Alternative fuel (compressed natural gas, liqueﬁed petroleum gas, and ethanol fuel mixtures), the standard prices and their ratios were investigated. A mathematical model to determine a critical ratio between alternative and conventional fuel prices had already been developed. The results of this were investigated. The results showed that the critical ratio is not a linear function on annual conventional fuel consumption costs. According to our simulation gaseous fuels were economically more attractive. Whereas, the use of bioethanol blends had more risk.

Keywords: alternative fuel; conventional fuel; investment; lifetime; eﬃciency; mathematical model

1. Introduction Energy is a key element in sustaining the social and economic development of society. Energy use is the basis of the quality of life and the driver for its enhancement [1]. The combustion of fossil fuels results in the release of harmful emissions into the atmosphere. It will lead to an inevitable increase in the concentration of carbon dioxide, greenhouse gases, and other toxic compounds (nitrogen oxides, carbon monoxide, sulfur oxide, non-methane organic gas, soot, etc.) which are hazardous to human health [2,3]. Therefore, the usage of hydrocarbon energy resources negatively effects climate change [4]. Improvements in living standard have resulted in an increase of fossil fuel consumption, especially in transportation [5,6]. That is why they are currently playing a dominant role despite the ecological effects [4]. Petroleum fuels are still dominant for all kinds of transport (air, marine, and land) because of their relatively high economic efficiency. Reserves of crude oil (feedstock for the conventional fuel production) are limited and exhaustible, and there has been a rise in the world crude oil price. A total of 22% of global air pollution comes from transportation [7]. It has been proven that there is a relationship between energy consumption, harmful emission, and economic growth [8]. Ecological issues may slow down economic growth [9]. To improve the current situation in the energy sector and ecology, 195 countries in 2015 agreed to targets directed at reducing greenhouse gas emissions [10–12]. The increase in the price of crude oil, an increase in the demand for energy resources, and harmful emission has forced us to develop alternative fuels that can both reduce harmful emission and strengthen national energy security [5,13]. Therefore, the utilization of alternative fuels, including renewable ones, is relevant. Their usage has a lot of benefits: a reduction in greenhouse emissions; the diversification of energy resources; an increase in energy security; the creation of new jobs; and the development of business [14,15].

Energies 2019, 12, 3889; doi:10.3390/en12203889 www.mdpi.com/journal/energies Energies 2019, 12, 3889 2 of 20

Therefore, sustainable economic development of our civilization requires energy saving technologies, logistics optimization, alternative energy resources and fuels. Some alternative technologies are capable of delivering a sustainable land transport system: the battery electric vehicle (BEV); the hydrogen fuel cell electric vehicle (FCEV); biofuels; and gaseous fuels. Electricity and hydrogen can be produced from renewable energy or nuclear energy. In this case BEV and FCEV are transport systems with zero-carbon emissions. However, since the focus of this study is internal combustion engine vehicles, electric vehicles are not considered. Alternative fuels may be both renewable and nonrenewable. Liquid and gaseous biofuels (ethanol, biodiesel, biogas, etc.) positively influence sustainable economic growth [16]. Nonrenewable alternative fuels (compressed natural gas, liquefied petroleum gas, etc.) improve economical, environmental, and social areas of a sustainable economy [17]. There are various drawbacks to the use of alternative fuels: technical, infrastructural, and economic. In choosing an alternative fuel, the price is the most important criteria in addition to user acceptance, reducing hazardous substances, improvement of life quality, vehicle life, etc. [18]. Consumers should have a simple method to evaluate the attractiveness of a certain vehicle fuel. The decision should be made easily based on the absolute value of the prices of different types of fuels. To predict the optimal vehicle fuel simulation models have been developed. The simulation took into account the fuel price differentials (difference between the prices of conventional and of alternative fuels) [19]. The fuel price differentials and the ratio of fuel prices were used in a number of studies [20–22]. However, the fuel price differential is an absolute value. This indicator cannot identify the optimal fuel because it depends on absolute prices. The alternative/conventional fuel price ratio is a relative indicator and gives more reliable information about preferable fuel. Abundant research discussions on alternative vehicle fuels have applied an alternative to conventional fuel price ratio: the LPG to gasoline price ratio was used to analyze the LPG market in Poland [23]; the same indicator was used for techno-economic Analysis of Liquid Petroleum Gas Fueled Vehicles for Public Transportation in Indonesia [24]; the compressed natural gas (CNG)/petroleum and LPG/diesel price ratios were used to study the development of natural gas vehicles in China [25] and to study sustainability between CNG vehicle innovative ecosystem and other vehicle innovative ecosystem [26]; the ratio of ethanol and gasoline prices was used as an indicator of ethanol blending economics [27–30]; the LNG/HFO price ratio was used to study low emission engine technologies for future legislation [31]; and the biodiesel to petroleum diesel fuel price ratio was used to study the efficiency of biodiesel utilization [32]. However, to make an optimal decision, it is necessary to take into account a number of factors: lifetime of the vehicle, fuel prices, fuel properties, investment costs, salvage income, etc. Therefore, consumers need a model that takes the above factors into account. The aim of this study was to give information to decision-makers in order to utilize alternative fuels. The alternative fuel economics are complicated and require a sophisticated mathematical model for an analysis. To obtain this, a new mathematical model was developed to determine a maximum relative alternative fuel price when its application is feasible. The model is based on the following: a conventional fuel price, the investment costs, the discount rate, fuel properties, annual conventional fuel consumption, share of conventional fuel in dual fuel mode, and total lifetime of investment project.

2. Materials and Methods The methodological basis of the study was relevant literature, information resources, and statistical data. Economic and mathematical modeling was employed to determine the effectiveness of fuels used. Most land transport vehicles are designed to be operated on petroleum derived fuels (gasoline and diesel fuel). Conventional fuels are fuels derived from petroleum. Alternative fuels are not petroleum fuels and can be produced from fossil energy resources (compressed natural gas, liquefied natural gas, liquefied petroleum gas, etc.) or biomass [33]. In practice, both pure and blended biofuels are used. Compressed natural gas competes with petroleum fuels in the vehicle fuel market and it is expected to be a growing vehicle fuel in the world in the next decade [34]. The classification of Energies 2019, 12, x FOR PEER REVIEW 3 of 20 Energies 2019, 12, 3889 3 of 20 are used. Compressed natural gas competes with petroleum fuels in the vehicle fuel market and it is expectedfuels was to considered be a growing in previous vehicle investigationsfuel in the world [35 in,36 the]. Alternative next decade vehicle [34]. The fuels classification can be divided of fuels into wasrenewable considered and nonrenewable in previous investigations ones (Figure1). [35,36]. Alternative vehicle fuels can be divided into renewableThe main and nonrenewable physical and chemical ones (Figure properties 1). of biofuels and conventional petroleum fuels are different.The main Hydrotreated physical and vegetable chemical oil properties is an exception of biofuels [37]. and This conventional fact complicates petroleum their utilization fuels are different.and compels Hydrotreated us to use blended vegetable fuels oil whichis an exceptio containn both [37]. petroleum This fact complicates and non-petroleum their utilization components. and compelsIt makes us alternative to use blended fuel properties fuels which closer contain to conventional both petroleum fuels. Diesel and non-petroleum fuel and pure plantcomponents. oils; diesel It makesfuel and alternative vegetable fuel oil methylproperties esters; closer gasoline to convention and bioethanolal fuels. are Diesel popular fuel blends.and pure plant oils; diesel fuel and vegetable oil methyl esters; gasoline and bioethanol are popular blends.

Alternative fuels

Nonrenewable ones Renewable ones Spirits Spirits Biogas Syngas Synfuels Liquefied Liquefied Natural gas gas Natural vegetable oils oils vegetable vegetable oils oils vegetable Hydrotreated petroleum gas Pure plant oils Dimethyl ether Gas condensate condensate Gas Methyl esters of Methyl esters of

Figure 1. ClassificationClassiﬁcation of of alternative alternative vehicle vehicle fuels.

The determination of of alternative alternative vehicle vehicle fuel fuel ec economiconomic viability, viability, Net Net Present Present Value Value (NPV), and ProfitabilityProﬁtability IndexIndex (PI) (PI) analysis analysis were were applied. applied. The mathematicalThe mathematical model includesmodel includes the following the following variables: variables:Alternative Alternative and conventional and conventional fuel prices; Investment fuel prices; costs; Investment Remaining costs; salvage Remaining value; Operating salvage lifetime; value; OperatingDiscount rate; lifetime; Ecological Discount charges, rate; Ecological etc. charges, etc. InIn the the study study retail retail prices prices for for each each fuel fuel were were used used.. Major Major alternative alternative fuels fuels currently currently in in widespread widespread use (liqueﬁed(liquefied petroleumpetroleum gas gas or or propane, propane, natural natural gas, gas, biomethane, biomethane, biodiesel biodiesel blends, blends, bioethanol bioethanol blends, blends,and a special and a kindspecial of kind energy—electricity) of energy—electricity) were analyzed. were analyzed. Hydrogen fuel cell vehicles have been demonstr demonstratedated in Australia, Canada Canada,, China, the the European European Union, Japan, Japan, the the USA, USA, etc. etc. However, However, the the drawback drawback of the of theabove above projects projects waswas high high capital capital costs costs and theand lack the lackof hydrogen of hydrogen delivery delivery infrastructure. infrastructure. It resulted It resulted in intermination termination of of some some programs programs [38]. [38]. Therefore, thisthis technologytechnology is is currently currently developing developing but but still still not not widespread. widespread. That That is why is why hydrogen hydrogen was wasnot considerednot considered in this in paper.this paper. InIn the the study study research research such such indicators indicators as as energy energy cost cost,, ratio ratio of offuel fuel prices, prices, etc., etc., have have been been used. used. In orderIn order to make to make a decision a decision on onthe the use use of a of certain a certain fuel fuel,, it is it necessary is necessary to know to know the the energy energy cost cost (EC). (EC). It canIt can be bedetermined determined as asfollows follows [14]: [14 ]: =FprFpr ECEC= , EUR, EUR/GJ,/GJ, (1) QQρ⋅ ρ · 3 where FprFpr isis the the fuel fuel price, price, EUR EUR/m/m3; Q; isQ theis the lower lower heating heating value value of the of fuel, the MJfuel,/kg; MJ/kg;ρ is the ρ fuel is the density, fuel 3 density,t/m3. t/m . Energy cost of blended fuels is calculated as follows [[14]:14]: n ()⋅ Pn  Fprі сi =( ) EC = i 1Fpri ci , EUR/GJ, i=1n · (2) EC = ()⋅ ρ ⋅ , EUR/GJ, (2) Pn  Qi i сi i=(1Qi ρi ci) i=1 · ·

Energies 2019, 12, 3889 4 of 20 Energies 2019, 12, x FOR PEER REVIEW 4 of 20 where Fprі is the price of the ithth component of fuel, EUR/m3; 3Qі is the lower heating value of the ith where Fpri is the price of the i component of fuel, EUR/m ; Qi is the lower heating value of the componentth of fuel, MJ/kg; ρі is the density of the ithth component of fuel, t/m3;3 n is the number of i component of fuel, MJ/kg; ρi is the density of the i component of fuel, t/m ; n is the number of components; ci is the volume fraction of the itthh component of fuel. components; ci is the volume fraction of the i component of fuel. The efficiency efficiency of an internal combustion engine depends on a number of factors, including the type of fuel used. Therefore, Therefore, the energy cost for useful work (ECU) is equal to [[14]14] n ()⋅ Pn Fprі сi EC =(Fpr c ) ECU = = i 1 i i , EUR/GJ, EC η i=1n · (3) ECU = = η ⋅ ()⋅ ρ ⋅ , EUR/GJ, (3) η Pn Qi i сi η i=(1Qi ρi ci) · i=1 · · where η is the efficiency of an engine. whereWeη isexamined the efficiency the ofratio an engine.of alternative fuel and conventional fuel prices as an indicator of alternativeWe examined fuel economics. the ratio ofWe alternative also assumed fuel and that conventional alternative fuel prices asdo an not indicator need to of be alternative adjusted tofuel their economics. lower heating We also value assumed (petroleum that alternative gasoline and fuel diesel prices fuel do nothave need different to be adjustedlower heating to their values). lower heatingPenetration value (petroleum of alternative gasoline fuels and dieseland alternativ fuel havee difuelfferent vehicles lower heatingdepends values). on the fuel retail infrastructurePenetration and of alternativethe price of fuels vehicles and alternative that can us fuele these vehicles fuels depends [39]. Therefore, on the fuel investment retail infrastructure costs of fuelingand the stations price of and vehicles conversion that can kit use costs these were fuels taken [39 into]. Therefore, account. In investment the study coststhe following of fueling countries stations wereand conversion selected: kit costs were taken into account. In the study the following countries were selected: • The USA isThe the worldUSA biggestis the world consumer biggest of alternative consumer vehicle of alternative fuels, including vehicle renewable fuels, including ones; • Germany andrenewable Sweden ones; hold leading positions in renewable fuels consumption (biofuels and • • biomethane);Germany and Sweden hold leading positions in renewable fuels consumption (biofuels and biomethane); Ukraine has a large CNG and LPG fleet. • • Ukraine has a large CNG and LPG fleet. 3. Results 3. Results 3.1. Modeling Procedure 3.1. Modeling Procedure Fuel price differentials depend on the absolute value of conventional fuel prices. The linear correlationFuel price coeffi differentialscient r measures depend the strengthon the absolute of the linear value relationship of conventional between fuel two prices. variables: The linear price correlationdifferentials coefficient and conventional r measures fuel the prices strength (Figures of th2e andlinear3). relationship The linear correlation between two coe variables:fficients price were differentialscalculated by and authors: conventional fuel prices (Figures 2 and 3). The linear correlation coefficients were calculated by authors: the differential• between gasoline and E85 prices in the USA is equal to 0.81; • the differential between gasoline and E85 prices in the USA is equal to 0.81; the differential• between gasoline and LPG prices in Ukraine is equal to 0.84. • the differential between gasoline and LPG prices in Ukraine is equal to 0.84. 1.2 1.1 1.0 0.9 0.8 0.7 0.6 0.5 0.4 y = 0.0005x - 20.313

Differentials/price, USD/l Differentials/price, 0.3 25/01/2017 16/03/2017 05/05/2017 24/06/2017 13/08/2017 02/10/2017 21/11/2017 10/01/2018 01/03/2018 20/04/2018 Period differential gasoline trend

FigureFigure 2. 2. FuelFuel price price differentials differentials (the difference difference between gasoline and LPG prices) in Ukraine. The above means that there is strong correlation between price differentials and conventional fuel The above means that there is strong correlation between price differentials and conventional prices. Therefore, it is reasonable to use a ratio between alternative and conventional fuel prices. fuel prices. Therefore, it is reasonable to use a ratio between alternative and conventional fuel prices.

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0.8 0.7 0.6 0.5 y = 0,0011x - 44,838 0.4 0.3 0.2 0.1 Differentials/price, USD/l Differentials/price, 2017/3/6 2017/8/3 2017/4/25 2017/6/14 2017/9/22 2018/2/19 2018/4/10 2018/5/30 2017/11/11 2017/12/31 Period differential gasoline trend FigureFigure 3. 3. FuelFuel price price differentials diﬀerentials (the difference diﬀerence be betweentween gasoline and E85 prices) in the USA.

If ACFC is the the annual annual costs costs of of conventional conventional fuel fuel and and AAFCAAFC isis the the annual annual costs costs of of alternative alternative fuel, fuel, the return of alternative fuel utilizationutilization can bebe foundfound asas theirtheir didifferencefference " # M M  MM Q ⋅QAFprAFpr⋅η η  R = ACFC − AAFC = ⋅ DFpr + EC − ϕ ⋅ DFpr ⋅ + ()1− ϕ ⋅ M ⋅ C +CEC , R = ACFC AAFC = ρDFpr + ECC C ϕ DFpr ρ+ (1 ϕ) M ⋅·ρ ⋅η · +AEC A ,(4) − ρ · − · · ρ − · Q· AQA AρAA ηA  · · where M is the annual consumption of conventional fuel, t; DFpr isis the the price price of of conventional conventional fuel, fuel, ρ ρ EUR/L;EUR/L; ρ isis the the density density of of conventional conventional fuel, fuel, kg/L; kg/L; Aρ isA isthe the density density of alternative of alternative fuel, fuel, kg/L; kg /ECL; CEC is Ctheis annualthe annual ecological ecological charges charges for the for theconventional conventional fuel, fuel, EUR; EUR; ECAEC is Atheis annual the annual ecological ecological charges charges for the for alternativethe alternative fuel, fuel, EUR; EUR; AFprAFpr is theis price the priceof the of alternative the alternative fuel, EUR/L; fuel, EUR ϕ is/ L;theϕ conventionalis the conventional fuel energy fuel shareenergy in share fuel blends in fuel blendsor for a or dual for afuel dual mode; fuel mode;Q is theQ islower the lowerheating heating value valueof the of conventional the conventional fuel, η MJ/kg;fuel, MJ Q/kg;A is QtheA islower the lowerheating heating value valueof the ofalternative the alternative fuel, MJ/kg; fuel, MJ C/ kg;is theηC efficiencyis the effi ciencyof vehicle of vehicle which η whichruns on runs the onconventional the conventional fuel; A fuel; is theηA efficiencyis the effi ciencyof vehicle of vehicle which whichruns on runs the onalternative the alternative fuel. fuel. Alternative fuel vehicles can use single and multiple fuel sources. Dual fuel vehicles use two types of fuelfuel atat thethe samesame timetime withwith a a di differentfferent fuel fuel tank, tank, for for example, example, CNG CNG and and diesel diesel fuel. fuel. The The share share of ofconventional conventional fuel fuel in fuelin fuel blends blends (ϕ )(ϕ ranges) ranges from from 0 to 0 1.to 1. After transformation, the above equation will have the form " ⋅ ρ ⋅ ⋅η #  = ()−ϕ ⋅ MM ⋅ ⋅ − QQ ρ AFprAFprηC C + − RR= (1 ϕ) DFpr 11 · · · + ECECC C ECECA.A . (5) − · ρρ · · − QQ ⋅ρρ ⋅DFprDFprη⋅η −  AA · AA· · A A  Denoted by γ thethe ratio ratio of of alternative alternative fuel pr priceice to conventional fuelfuel priceprice γγ = AFpr/DFprAFpr/DFpr,, then then the the Equation (5) will have the following form " #  Q ⋅ ρ ⋅η  = ()−ϕ ⋅ M ⋅ ⋅ − γ ⋅ Q ρ ηCC + − RR= (11 ϕ) DFprDFpr 11 γ · · + ECECC C ECECA.A . (6) − · ρ · · − · QQA ⋅ρρA η⋅ηA −  A· A· A  For electric vehicles, a mathematical expression for return is didifferent.fferent. Annual consumption of electricity by vehicle is equal to M Q ηC W = · ⋅ · ⋅η, kWh, (7) M3.6 Qη C W = E , kWh, (7) 3.6· ⋅η where ηE is the efficiency of vehicle which runs on electricity.E Then, return for electric vehicles is determined as following where ηE is the efficiency of vehicle which runs on electricity. Then, return for electric vehiclesM is determined as following RE = DFpr + ECC [W EEpr + ECE], (8) Mρ · − · R = ⋅ DFpr + EC − []W ⋅ EEpr + EC , E ρ C E (8) where EEpr is the price of electricity, EUR/kWh; ECE is the annual ecological charges for electricity. where EEpr is the price of electricity, EUR/kWh; ECE is the annual ecological charges for electricity. After transformation, the return for electric vehicles utilization is

Energies 2019, 12, 3889 6 of 20

After transformation, the return for electric vehicles utilization is

M M Q ηC RE = DFpr · · EEpr + ECC ECE, EUR. (9) ρ · − 3.6 ηE · − · Net Present Value (NPV) and Proﬁtability Index (PI) were considered as criteria for investment projects. If NPV is a criterion of an investment project, then for a regular cash ﬂow its value is

n 1 (1 + g)− NPV = R − I, (10) · g − where g is the discount rate; I is the investment costs, EUR; n is the lifetime of a certain investment project, year. For consumers, it is important to know a break-even point of a certain alternative fuel project. In this point total costs and revenue are equal. It means that the Net Present Value is equal to zero. A critical value on the return can be found from an equation

n 1 (1 + g)− NPV∗ = R∗ − I = 0, (11) · g − where R* is the critical value of the return, EUR. From the above equation the critical value of the return is equal to g R∗ = I n . (12) · 1 (1 + g)− − It should be equated with the right parts of Equations (6) and (12) " # M Q ρ g R∗ = (1 ϕ) DFpr 1 γ∗ · + ECC ECA = I n , (13) − · ρ · · − · QA ρA − · 1 (1 + g)− · − where γ* is the critical value of the relative price for the alternative fuel. Further " # M Q ρ g (1 ϕ) DFpr 1 γ∗ · = I n (ECC ECA). (14) − · ρ · · − · QA ρA · 1 (1 + g)− − − · − The critical value of γ* can be found from Equation (14). Therefore

 ( )  QA ρA  g 1  γ = · 1 I (EC EC ) . (15) ∗  n C A M DFpr  Q ρ ·  − · 1 (1 + g)− − − · (1 ϕ) ·  · − − · ρ Denoted by ACFC the annual conventional fuel consumption cost

M DFpr ACFC = · . (16) ρ

Then Equation (15) takes the form " ( ) # QA ρA g 1 γ∗ = · 1 I n (ECC ECA) . (17) Q ρ · − · 1 (1 + g)− − − · (1 ϕ) ACFC · − − · From the above equation the critical ratio of fuel prices can be found. If actual ratio of fuel prices γ is less than the critical one γ*, then an investment project is expedient. The above ratio can be used Energies 2019, 12, 3889 7 of 20 for the sensitive analysis procedure of investment projects [40–42]. Let us explore the above function Energies 2019, 12, x FOR PEER REVIEW 7 of 20 in Equation (15). * If DFpf = 0, thenγ γ* =∞ . It means that the alternative fuel price must be less than 0. This If DFpf = 0, then = - −∞. It means that the alternative fuel price must be less than 0. This statement statementdoes not doesmake not sense make (Figure sense 4). (Figure 4).

1 0.75 0.5

* 0.25 γ ACFC* 0 -0.25 0 200 400 600 800 1000 1200 -0.5 ACFC, EUR -0.75 ratio upper limit of the ratio of fuel prices -1 ACFC* FigureFigure 4. 4.The The dependence dependence on on the the ratio ratio of of alternative alternative fuel fuel price price to to conventional conventional fuel fuel price price on on the the annual annual conventionalconventional fuel fuel consumption consumption cost cost (criterion— (criterion—NPVNPV).).

* 1 1 If DFpf = ∞, then γγ * → QA ρρA Q− 1 ρρ− 1 . If DFpf =∞ , then → QA·· A·Q· ·· . ACFC* LetLet us us find find a a critical critical value value of of the the annual annual conventional conventional fuel fuel consumption consumption cost cost ACFC*from from Equation (14) Equation (14) ( ) g 1 1 I (EC EC ) = 0. (18)  n C A ( ) − −· 1 ⋅ (1 + g)− − − ()− − · 1⋅ ϕ ACFC1 ∗ = 1 I− − ECC ECA  − · 0 . (18) 1− ()1+ g n ()1−ϕ ⋅ ACFC* Therefore ( ) g 1 = ( ) Therefore 1 I n ECC ECA . (19) · 1 (1 + g)− − − · (1 ϕ) ACFC∗ − − · Therefore, the cost of the=  conventional⋅ g fuel− () cost consumed− ⋅ is equal1 to (Figure4) 1 I −n ECC ECA  * . (19) 1(− ()1+ g ()1)−ϕ ⋅ ACFC  g  1 ACFC∗ = I n (ECC ECA) . (20) Therefore, the cost of the conventional· 1 (1 + fug)el− cost− consumed− is equal· (1 ϕto) (Figure 4) − − To ensure the sustainable development of anyg organization, the profitability 1 index of the investment ACFC* = I ⋅ − ()EC − EC ⋅ . project must be at least 1.2. If the profitability index is−n used asC a criterionA  on()− anϕ investment project, the(20)  1− ()1+ g  1 critical value of the return will be To ensure the sustainable development of anyg organization, the profitability index of the R∗ = 1.2 I n . (21) investment project must be at least 1.2. If the profitability· · 1 (1 + gindex)− is used as a criterion on an investment project, the critical value of the return will be − In this case critical value of γ* can be found from an equation * = ⋅ ⋅ g " R 1.2 #I − . (21) Q ρ 1− ()1+ g n g R∗ = (1 ϕ) ACFC 1 γ∗ · + ECC ECA = 1.2 I n . (22) − · · − · QA ρA − · · 1 (1 + g)− In this case critical value of γ * can be found· from an equation − Then " #  Q ρ Q ⋅ ρ  g g * = ()−ϕ ⋅ ⋅ − γ * ⋅ + − = ⋅ ⋅ . (1R ϕ)1ACFCACFC1 γ∗ 1 · = 1.2 I ECC ECA n 1.(2ECIC ECA).−n (23)(22) − · · − · QA ρAQ ⋅ ρ · · 1 (1 + g)− − 1−− ()1+ g  · A A  − * FromThen the Equation (23) the critical value of γ is equal to " ( ) # QA ρA  1.2 g ⋅Iρ  1 γ()=−ϕ ⋅ · 1⋅ − γ * ⋅ ·Q· =(EC ⋅ ⋅EC ) g − ()− . (24) ∗1 ACFC 1 n 1.2C I A − EC EC . (23) Q ρ · − 1 (1 + g⋅ )ρ− − − − ()+· (1 n ϕ) ACFCC A ·  − QA A  1 1 g − · InFrom this case the theEquation function (23) obtained the critical gives value the resultof γ * is which equal is to somewhat less than a function according to Equation (14) (Figure5). Q ⋅ ρ   1.2 ⋅ g ⋅ I  1  γ * = A A ⋅ 1− − ()EC − EC ⋅ . ⋅ ρ   − ()+ −n C A  ()−ϕ ⋅  (24) Q  1 1 g  1 ACFC 

Energies 2019, 12, x FOR PEER REVIEW 8 of 20

EnergiesIn2019 this, 12 case, 3889 the function obtained gives the result which is somewhat less than a function8 of 20 according to Equation (14) (Figure 5).

1 0.75 0.5 0.25 ACFC

g* 0 ACFC (criterion - PI) -0.25 0 200 400 600 800 1000 1200 -0.5 ACFC, EUR -0.75 ratio (criterion - NPV) upper limit of the ratio -1 ACFC ratio (criterion - PI) -1.25 -1.5 ACFC (criterion - PI)

Figure 5. The dependence of the ratio of alternative fuel price to conventional fuel price on the annual Figure 5. The dependence of the ratio of alternative fuel price to conventional fuel price on the annual conventional fuel consumption cost (criterion—PI). conventional fuel consumption cost (criterion—PI). 3.2. Initial Data for Modeling 3.2. Initial Data for Modeling To evaluate the efficiency of an alternative fuel vehicle compared to a conventional one, initial dataTo should evaluate be found. the efficiency The most of important an alternative initial fuel information vehicle compared is lifetime, to fuela conventional prices, fuel one, properties, initial datadiscount should rate, be investment found. The costs, most salvageimportant income, initial etc. information is lifetime, fuel prices, fuel properties, discount rate, investment costs, salvage income, etc. 3.2.1. Lifetime of a Project 3.2.1. Lifetime of a Project Firstly, tractors were considered. The lifetime of any project cannot exceed the economic life for aFirstly, certain tractors agricultural were tractor.considered. The The economic lifetime life of (anyEL) project is a function cannot of exceed a service the economic life and average life for aannual certain utilization. agricultural tractor. The economic life (EL) is a function of a service life and average annual SL utilization. EL = , years, (25) AAU SL where SL is the service life, h; AAU is the averageEL = annual, years, utilization, h/year. (25) AAU For agricultural tractors a service life is around 10,000–12,000 h [43,44]. According to the whererecommendation SL is the service of experts, life, h;the AAU economic is the average life must annual not exceedutilization, 15 years h/year. [45 ,46]. ForAs foragricultural automobiles, tractors there a hasservice been life an is increase around in 10,000–12,000 the average vehicleh [43,44]. lifetime. According According to the recommendationto statistical data, of theexperts, expected the economic median lifetimelife must is, not in exceed years: 15 car—16.9; years [45,46]. light truck—15.5; heavy truck—28.0As for automobiles, [47]. In 2016 thethere average has been age ofan theincrease USA automobilesin the average was vehicle 11.6 years. lifetime. Estimated According annual to statisticalvehicle mileage data, the of travelexpected depends median on lifetime the type is, of in vehicle. years: Itcar—16.9; is 9721 miles lightfor truck—15.5; cars and 10,353 heavy miles truck— for 28.0light [47]. trucks In [201648]. the average age of the USA automobiles was 11.6 years. Estimated annual vehicle mileage of travel depends on the type of vehicle. It is 9721 miles for cars and 10,353 miles for light trucks3.2.2.Fuel [48].Prices and Their Ratio The most widespread fuels were considered: gasoline, conventional diesel fuel, compressed 3.2.2.natural Fuel gas Prices (CNG) and (compressed Their Ratio biomethane), liquefied petroleum gas, biodiesel, and bioethanol blends.The Our most calculations widespread (for fuels conditions were considered: of Ukraine, thegasoline, USA, andconventional Germany) diesel showed fuel, that compressed the ratio of naturalalternative gas/ conventional(CNG) (compressed fuel prices biomethane), is not stable liquefied (Figures 6petroleum–11). As itgas, can biodiesel, be seen, in and Ukraine bioethanol there blends.was a drop Our incalculations the ratio. Therefore, (for conditions alternative of Ukraine, fuels (LPGthe USA, and and CNG) Germany) may compete showed with that conventional the ratio of alternative/conventional(petroleum) fuels. fuel prices is not stable (Figures 6–11). As it can be seen, in Ukraine there was aThe drop same in the method ratio. wasTherefore, applied alternative to the fuel fu marketsels (LPG of and diff erentCNG) countries: may compete the USAwith andconventional Germany. (petroleum)The above ratio fuels. was determined for bioethanol blends in the USA (Figures 12 and 13), and LPG in GermanyThe same (Figure method 14 and was Figure applied 17). to Figures the fuel 12 market–17 presents of different the following: countries: the USA and Germany. The above ratio was determined for bioethanol blends in the USA (Figures 12 and 13), and LPG in The actual alternative to conventional fuel price ratios; Germany• (Figures 14 and 17). Figures 12–17 present the following: The optimal• ratio of alternative/conventional fuel prices (RCAP)[14] • The actual alternative to conventional fuel price ratios; • The optimal ratio of alternative/conventional fuel prices (RCAP) [14] ρA QA RCAP ρ= ⋅Q· .(26) (26) RCAP = A ρ AQ. ρ ⋅Q· If the actual ratio is less than the optimal ratio then the use of the alternative fuel may be profitable.

Energies 2019, 12, x FOR PEER REVIEW 9 of 20

If the actual ratio is less than the optimal ratio then the use of the alternative fuel may be profitable. Energies 2019, 12, 3889 9 of 20 0.750 Energies 2019, 12, x FOR PEER REVIEW 9 of 20 0.700

If the actual0.650 ratio is less than the optimal ratio then the use of the alternative fuel may be profitable. 0.600 0.750

Ratio 0.550 0.700

0.500 0.650 0.450 0.600 y = -0.0002x + 9.2096

0.400Ratio 0.550 0.500

0.450 y = -0.0002x + 9.2096 2017/3/6 2017/8/3

0.4002017/1/15 2017/4/25 2017/6/14 2017/9/22 2018/2/19 2018/4/10 2018/5/30 2017/11/11 2017/12/31 Time, date diesel gasoline trend diesel trend gasoline 2017/3/6 2017/8/3 2017/1/15 2017/4/25 2017/6/14 2017/9/22 2018/2/19 2018/4/10 2018/5/30

2017/11/11 2017/12/31 Time, date Figure 6. LPG/conventional fuel prices ratio in Ukraine. diesel gasoline trend diesel trend gasoline Figure 6. LPG/conventional fuel prices ratio in Ukraine.

0.750 Figure 6. LPG/conventional fuel prices ratio in Ukraine.

0.700 0.750

0.650 0.700 0.600 0.650 0.600

Ratio 0.550 y = -0.0002x + 9.2096

Ratio 0.550 0.500 y = -0.0002x + 9.2096 0.500 0.450 0.450

0.400 0.400 2017/3/6 2017/8/3 2017/3/6 2017/8/3 2017/1/15 2017/4/25 2017/6/14 2017/9/22 2018/2/19 2018/4/10 2018/5/30 2017/1/15 2017/4/25 2017/6/14 2017/9/22 2018/2/19 2018/4/10 2018/5/30 2017/11/11 2017/12/31 2017/11/11 2017/12/31 Time, date Time, date diesel upper limit of the ratio of fuel prices trend diesel diesel upper limit of the ratio of fuel prices trend diesel

Figure 7. LPG/diesel prices ratio in Ukraine. FigureFigure 7. 7. LPG/dieselLPG/diesel prices prices ratio ratio in Ukraine.in Ukraine.

0.750 0.750 0.700 0.650 0.700 1 0.600 0.650 0.550 Ratio 0.600 0.500 0.550 0.450

Ratio y = -0.0001x + 6.7826 0.500 0.400

0.450 y = -0.0001x + 6.7826 2017/3/6 2017/8/3

0.400 2017/1/15 2017/4/25 2017/6/14 2017/9/22 2018/2/19 2018/4/10 2018/5/30 2017/11/11 2017/12/31 Time, date

gasoline upper limit of the ratio of fuel prices trend gasoline

2017/3/6 2017/8/3 2017/1/15 2017/4/25 2017/6/14 2017/9/22 2018/2/19 2018/4/10 2018/5/30 Figure 8. LPG/gasoline prices ratio in2017/11/11 Ukraine.2017/12/31 Figure 8. LPG/gasolineTime, prices date ratio in Ukraine.

gasoline upper limit of the ratio of fuel prices trend gasoline Figure 8. LPG/gasoline prices ratio in Ukraine.

Energies 2019, 12, x FOR PEER REVIEW 10 of 20 Energies 2019, 12, x FOR PEER REVIEW 10 of 20 Energies 2019, 12, 3889 10 of 20 Energies 2019, 12, x FOR PEER REVIEW 10 of 20 0.800 0.800 0.750 0.800 0.750 0.700 0.750 0.700 0.6500.700

Ratio 0.650

0.600Ratio 0.650 0.600 Ratio y = -0.0004x + 17.062 0.5500.600 y = -0.0004x + 17.062 0.550 y = -0.0004x + 17.062 0.5000.550 0.500 0.500 2017/8/3 2017/8/3 2017/4/25 2017/6/14 2017/9/22 2018/2/19 2018/4/10 2018/5/30 2017/4/25 2017/6/14 2017/9/22 2018/2/19 2018/4/10 2018/5/30 2017/11/11 2017/12/31 2017/11/11 2017/12/31 2017/8/3 2017/4/25 2017/6/14 2017/9/22 2018/2/19 2018/4/10 2018/5/30 Time,Time, date date2017/11/11 2017/12/31 Time, date dieseldiesel gasolinegasoline trendtrend diesel diesel trendtrend gasoline

diesel gasoline trend diesel trend gasoline FigureFigure 9. Compressed 9. Compressed natural natural gas gas (CNG)/convention (CNG)/conventionalal fuel fuel pricesprices ratio inin Ukraine.Ukraine. FigureFigure 9. Compressed 9. Compressed natural natural gas (CNG)gas (CNG)/convention/conventional fuelal fuel prices prices ratio ratio in Ukraine. in Ukraine.

1.001.00 0.950.951.00 0.900.95 0.90 yy = = 7E-16x 7E-16x ++ 0,930,93 0.85 0.85 0.90 y = 7E-16x + 0,93 0.80 0.80 0.85 0.750.80

0.75Ratio

Ratio 0.70 0.70 0.75 Ratio 0.650.70 0.65 0.600.65 0.60 0.550.60 0.55 0.500.55 0.50 0.50 2017/8/3 2017/4/25 2017/6/14 2017/9/22 2018/2/19 2018/4/10 2018/5/30 2017/11/11 2017/12/31 2017/8/3 2017/8/3 2017/4/25 2017/6/14 2017/9/22 2018/2/19 2018/4/10 2018/5/30 2017/4/25 2017/6/14 2017/9/22 2018/2/19 2018/4/10 2018/5/30 2017/11/11 2017/12/31 Time, date2017/11/11 2017/12/31 Time,Time, date date diesel upper limit of the ratio of fuel prices trend gasoline

dieseldiesel upperupper limit limit of theof the ratio ratio of offuel fuel prices prices trendtrend gasoline gasoline Figure 10. CNG/diesel prices ratio in Ukraine. FigureFigureFigure 10. 10.CNG 10.CNG/diesel CNG/diesel/diesel prices prices prices ratio ratio ratio in in Ukraine. in Ukraine. Ukraine.

1.000

1.0000.9001.000 0.9000.8000.900

Ratio 0.800 0.8000.700

Ratio 0.700 Ratio 0.7000.600 y = -0.0003x + 11.665 0.5000.600 0.600 y = -0.0003x + 11.665 0.500 y = -0.0003x + 11.665 0.500 2017/8/3 2017/4/25 2017/6/14 2017/9/22 2018/2/19 2018/4/10 2018/5/30 2017/11/11 2017/12/31 2017/8/3 2017/4/25 2017/6/14 2017/9/22 2018/2/19 2018/4/10 2018/5/30 2017/11/11 2017/12/31 2017/8/3

2017/4/25 2017/6/14 2017/9/22 Time, date 2018/2/19 2018/4/10 2018/5/30 2017/11/11 2017/12/31 gasoline upper limit of theTime, ratio ofdate fuel prices trend gasoline Time, date gasoline upper limit of the ratio of fuel prices trend gasoline gasoline FigureFigureupper 11. 11.CNG limit CNG/gasoline/ ofgasoline the ratio prices of pricesfuel ratioprices ratio in Ukraine.in Ukraine.trend gasoline Figure 11. CNG/gasoline prices ratio in Ukraine. Figure 11. CNG/gasoline prices ratio in Ukraine.

Energies 2019, 12, 3889 11 of 20

Figure 12. E10/gasoline prices ratio in the USA [49].

Figure 13. E85/gasoline prices ratio in the USA [49].

Figure 14. LPG/diesel prices ratio in Germany.

2 Energies 2019, 12, x FOR PEER REVIEW 12 of 20

Energies 2019, 12, 3889 12 of 20 Energies 2019, 12, x FOR PEER REVIEW 12 of 20 0.75 0.7 0.75 0.65 0.7 0.6 0.65 0.55 0.6 Ratio 0.5 0.55 y = 0.0001x - 5.7566

0.45Ratio 0.5 0.4 y = 0.0001x - 5.7566 0.45 0.35 0.4 0.35 2017/3/6 2017/6/14 2017/9/22 2018/4/10 2018/7/19 2016/11/26 2017/12/31 2017/3/6

2017/6/14 Time, date2017/9/22 2018/4/10 2018/7/19 2016/11/26 2017/12/31 actual ratio upper limitTime, of the date ratio trend actual ratio upper limit of the ratio trend Figure 15. LPG/gasoline prices ratio in Germany. FigureFigure 15. 15.LPG LPG/gasoline/gasoline prices prices ratio ratio in Germany.in Germany.

1.50 1.50 1.40 1.40 1.30 1.30 1.20 1.20 1.10 Ratio 1.10 Ratio 1.00 1.00 y = -2E-05x + 1.5801 0.90 y = -2E-05x + 1.5801 0.90 0.80 0.80 2017/3/6 2017/3/6 2017/6/14 2017/9/22 2018/4/10 2018/7/19 2017/6/14 2017/9/22 2018/4/10 2018/7/19 2016/11/26 2017/12/31 2016/11/26 2017/12/31 Time,Time, date date diesel upper limit of the ratio trend diesel upper limit of the ratio trend

FigureFigureFigure 16. 16.CNG/dieselCNG CNG/diesel/diesel pricesprices prices ratio ratio ratio in in Germany.in Germany. Germany.

1.5001.500 1.4001.400 1.3001.300 1.2001.200 1.1001.100 Ratio Ratio 1.0001.000 0.900 0.900 y = 4E-05x - 0.8622 0.800 y = 4E-05x - 0.8622 0.800 0.700 0.700 2017/3/6 2017/6/14 2017/9/22 2018/4/10 2018/7/19 2017/3/6 2016/11/26 2017/12/31 2017/6/14 2017/9/22 2018/4/10 2018/7/19 2016/11/26 Time, date 2017/12/31 Time, date Figuregasoline 17. CNG/dieselupper prices limitratio of the in ratio Germany. trend gasoline upper limit of the ratio trend Figure 17. CNG/diesel prices ratio in Germany. Figure 17. CNG/diesel prices ratio in Germany.

2 Energies 2019, 12, x FOR PEER REVIEW 13 of 20 Energies 2019, 12, 3889 13 of 20 Energies 2019, 12, x FOR PEER REVIEW 13 of 20 The analysis carried out shows the following. The actual ratios for E10 fuel range from 0.84 to 1.0. TheseTheThe analysis analysisvalues carriedare carried from out out84.8% shows shows to the101% the following. following.of the opti The Themal actual acratio.tual ratios Theratios for actual for E10 E10 fuelratios fuel range for range E85 from fuelfrom 0.84 varied 0.84 to 1.0. to fromThese1.0. These0.61 values to values are0.755. from are These 84.8%from values 84.8% to 101% toare 101% of 79.2%–98.7% the of optimal the opti ratio.ofmal the Theratio. optimal actual The actualratio ratios for forratios this E85 for fuelalternative E85 varied fuel varied fromfuel. Therefore,0.61from to 0.61 0.755. the toThese prices0.755. values ofThese E85 arewerevalues 79.2%–98.7% more are competitive 79.2%–98.7% of the optimalthan of thethe ratioprices optimal for of thisE10. ratio alternative for this fuel.alternative Therefore, fuel. theTherefore, pricesThe ratios of the E85 ofprices were CNG/diesel of more E85 competitive were and more CNG/gasoline competitive than the prices prices than of in the E10. Germany prices of are E10. stable (Figures 16 and 17) [50,51].TheThe Additionally, ratios ratios of of CNG CNG/diesel the/diesel use andof LPGand CNG CNG/gasolineand/gasoline CNG can prices guaranteeprices in Germany in Germany profitability are stable are of (Figuresstable transport. (Figures 16 and 1716)[ and50,51 17)]. Additionally,[50,51].For Additionally,Sweden, the use ratios of the LPG of use Alternative/Conventional and of LPG CNG and can CNG guarantee can guarantee proﬁtability fuel prices profitability ofare transport. presented of transport. in Figure 18. The calculationsForFor Sweden,Sweden, were made ratios using of of Alternative/Conventionaldata Alternative from the/Conventional website [52]. fuel As fuel canprices prices be seen,are are presented thos presentede alternative in Figure in Figurefuels 18. have The18. attractiveThecalculations calculations prices. were For were made estimation made using using data of the from data cost the from parameters website the website [52]. in the As [ 52 futurecan]. be As periodsseen, can bethos of seen, etime, alternative those forecast alternative fuels models have canfuelsattractive be have used attractiveprices. [53,54]. For prices. estimation For estimation of the cost of parameters the cost parameters in the future in the periods future periodsof time, of forecast time, forecast models modelscan be canused be [53,54]. used [ 53,54]. 1.462 1.358 1.5 1.224 1.2 1.462 1.25 1.358 1.5 1.224 1.2 1 0.709 0.769 1.25

Ratio 0.75 1 0.709 0.769 0.5

Ratio 0.75 0.25 0.5 0 0.25 CNG/Diesel CNG/Gasoline E85/Gasoline 0 CNG/Diesel CNG/Gasoline E85/Gasoline actual ratio upper limit of ratios actual ratio upper limit of ratios Figure 18. Ratios of Alternative/Conventional fuel prices in Sweden. Figure 18. Ratios of Alternative/Conventional fuel prices in Sweden. Figure 18. Ratios of Alternative/Conventional fuel prices in Sweden. 3.2.3. Investment Costs 3.2.3. Investment Costs 3.2.3. Investment Costs Investment costs include two components:components: conver conversionsion kit price and infrastructureinfrastructure costs.costs. E85 conversion kit ranges from USD139 to USD800. CNG conversion kit costs much more especially for conversionInvestment kit ranges costs frominclude USD139 two components: to USD800. CNGconver conversionsion kit price kit and costs infrastructure much moreespecially costs. E85 tractor diesel engines. Its value depends on vehicle type and origin of equipment. Therefore, its cost forconversion tractor diesel kit ranges engines. from Its USD139 value dependsto USD800. on CN vehicleG conversion type and kit origin costs of much equipment. more especially Therefore, for for an agricultural tractor MTZ-1221.2 is USD1600 [55]. Omnitek Engineering, Corp develops diesel- itstractor cost for diesel an agricultural engines. Its tractorvalue depends MTZ-1221.2 on vehicle is USD1600 type [and55]. origin Omnitek of equipment. Engineering, Therefore, Corp develops its cost to-natural gas engine conversion kits. For engines without turbocharger, the conversion kit may cost diesel-to-naturalfor an agricultural gas tractor engine MTZ-1221.2 conversionkits. is USD1600 For engines [55].without Omnitek turbocharger, Engineering, the Corp conversion develops kit diesel- may from USD7000 (gas tanks and installation are extra) [56]. costto-natural from USD7000 gas engine (gas conversion tanks and kits. installation For engines are extra) without [56 ].turbocharger, the conversion kit may cost To reduce CNG cost, a certain company can build their own CNG fueling station. Their fromTo USD7000 reduce CNG (gas cost,tanks a certainand installation company are can extra) build their[56]. own CNG fueling station. Their investment investment costs vary from capacity (daily gaseous fuel demands) and station type (fast-fill or time- costs varyTo reduce from capacity CNG (dailycost, gaseousa certain fuel company demands) can and build station their type (fast-fillown CNG or time-fill) fueling (Figure station. 19 )Their [57]. fill)investment (Figure 19) costs [57]. vary from capacity (daily gaseous fuel demands) and station type (fast-fill or time- fill) (Figure 19) [57]. 2000 18002000 16001800 actual station trend 14001600 actual station trend 12001400 10001200 8001000 y = -9E-06x2 + 0,2918x + 88,728 600 800 R2 = 0,9482 y = -9E-06x2 + 0,2918x + 88,728 400600 R2 = 0,9482 Total cost, thousand USD thousand Total cost, 200400

Total cost, thousand USD thousand Total cost, 2000 0 1000 2000 3000 4000 5000 6000 7000 8000 0 0 1000 2000 3000 4000 50003 6000 7000 8000 Station capacity, m /day Station capacity, m3/day Figure 19. CNGCNG fueling fueling station cost [56]. [56]. Figure 19. CNG fueling station cost [56]. 3.2.4. Fuel Fuel Economy Economy 3.2.4.High Fuel octaneoctane Economy bioethanolbioethanol blends blends enable enable to improveto improv energye energy eﬃciency efficiency and, asand, a result, as a result, vehicle vehicle energy economy [58,59]. Fuel economy impacts on decision-making. The use of bioethanol blends changes the energyHigh economy octane [58,59]. bioethanol Fuel economyblends enable impacts to improvon decision-making.e energy efficiency The use and, of asbioethanol a result, blendsvehicle energy economy [58,59]. Fuel economy impacts on decision-making. The use of bioethanol blends

Energies 2019, 12, 3889 14 of 20 fuel economy of vehicles (Table1)[ 60]. The average ratio of E85 consumption per 100 km to gasoline consumption per 100 km is 1.367. According to our calculation, the coefficient of variation is 0.0458. If the above ratio is lower than ratio between gasoline price and E85 price, then the alternative fuel is appropriate. From September 2017, in the USA E85 is economically justified. From April 2017 to April 2018 in the USA the average ratio gasoline price/E85 price is 1.45 (Figure 13). In March 2018 in Sweden the above ratio ranges from 1.42 to 1.466 [52]. The dual-fuel mode engine (diesel fuel and CNG) population is rising in the world. They have better ecological features and energetic performance. Their efficiency depends on load and speed. They are more economical on the conventional diesel mode with lower loads. The increase of load results in an improvement in dual-fuel mode engine efficiency [61]. The effective efficiency increases when a diesel engine is fueled with LPG too. For compressed ignition engines, the substitute ratio of diesel fuel with LPG is up to 30% [62].

Table 1. Fuel economy (adapted from [59]).

Fuel Economy, gal/100 miles E85/Gasoline Make Gasoline E85 Ratio Ford Focus FWD FFV, Automatic (AM6) 3.2 4.3 1.344 Ford Focus FWD FFV, Manual 5-spd 3.6 4.8 1.333 Mercedes-Benz CLA250 4matic 3.7 5.15 1.392 Chrysler 200 3.7 5 1.351 Audi A5 quattro 4 5.6 1.400 Jeep Renegade 2WD 4 5.3 1.325 Chevrolet Equinox FWD 4 5.9 1.475 GMC Terrain FWD 4 5.9 1.475 Jeep Cherokee FWD 4 5.6 1.400 Audi A5 Cabriolet quattro 4.2 5.9 1.405 Ford Escape FWD FFV 4.2 5.6 1.333 Jeep Cherokee 4WD 4.3 5.9 1.372 Chevrolet Equinox AWD 4.3 5.9 1.372 Ford Transit Connect Van FFV 4.3 5.9 1.372 Chysler 200 4.3 5.9 1.372 Dodge Charger 4.3 5.9 1.372 Audi Q5 4.5 5.2 1.156 Ford F150 Pickup 2WD FFV 4.5 6.2 1.378 Ford F150 2WD FFV BASE PAYLOAD LT TIRE 4.8 6.2 1.292 Chevrolet Silverado C15 2WD 5 7.1 1.420 GMC Sierra C15 2WD 5 7.1 1.420 Ford Explorer 2WD FFV 5 6.7 1.340 Mercedes-Benz GLE350 4matic 5.3 7.1 1.340

The energy share of diesel fuel depends on a fuel supply system and operational load. Common rail diesels have better of the above. It ranges from 5% to 17% [20,63]. If a diesel engine is fueled with an in-line high pressure pump, the energy share can be calculated as

P0 ϕ = 1 (1 ϕ0) , (27) − − · Pr where P0 is the operational power, kW; Pr is the rated power, kW; ϕ0 is the energy share of diesel fuel on the rated power, ϕ0 = 0.25–0.3.

4. Results of Modeling In this section results of modeling for gaseous fuel and liquid biofuel are presented. CNG and E85 were selected as widespread fuels. CNG was examined for a dual fuel diesel engine. The results Energies 2019, 12, 3889 15 of 20 Energies 2019, 12, x FOR PEER REVIEW 15 of 20 Energies 2019, 12, x FOR PEER REVIEW 15 of 20 are acceptable both for tractors and diesel-powered trucks. Biethanol blend was examined for spark are acceptable both for tractors and diesel-powered trucks. Biethanol blend was examined for spark areignition acceptable engine both vehicles. for tractors and diesel-powered trucks. Biethanol blend was examined for spark ignition engine vehicles. ignitionThe engine Agricultural vehicles. CNG-powered tractor MTZ-122.1 [54] in Ukraine was examined. A municipal The Agricultural CNG-powered tractor MTZ-122.1 [54] in Ukraine was examined. A municipal ﬂeetThe runs Agricultural the tractors (no CNG-powered investment in tractor their own MTZ-122.1 CNG fueling [54] in station). Ukraine Figure was examined. 20 shows the A municipal maximum fleet runs the tractors (no investment in their own CNG fueling station). Figure 20 shows the fleetacceptable runs the values tractors of the (no ratio investment of CNG/diesel in their fuel own prices CNG versus fueling the annual station). diesel Figure fuel 20 consumption shows the maximum acceptable values of the ratio of CNG/diesel fuel prices versus the annual diesel fuel maximumcosts for two acceptable types of fuelvalues systems: of the anratio in-line of CNG/diesel high-pressure fuel fuel prices pump versus and the a common annual raildiesel system. fuel consumption costs for two types of fuel systems: an in-line high-pressure fuel pump and a common consumptionThe actual ratios costs of for the two studied types fuels of fuel are alsosystems: shown an here:in-line the high-pressure upper value andfuel thepump lower and value a common (actual rail system. The actual ratios of the studied fuels are also shown here: the upper value and the lower railmarket system. price The ratios). actual ratios of the studied fuels are also shown here: the upper value and the lower value (actual market price ratios). valueAccording (actual market to our price calculations, ratios). CNG-powered tractor utilization is feasible if annual conventional According to our calculations, CNG-powered tractor utilization is feasible if annual fuelAccording (diesel fuel) to consumption our calculations, is at least CNG-powered EUR9500. It correspondstractor utilization to 600 his offeasible annual utilization.if annual conventional fuel (diesel fuel) consumption is at least EUR9500. It corresponds to 600 h of annual conventionalIf common rail fuel is used(diesel instead fuel) consumption of an in-line highis at pressureleast EUR9500. pump, It the corresponds eﬃciency increases.to 600 h of To annual cover utilization. If common rail is used instead of an in-line high pressure pump, the efficiency increases. utilization.expenses in If tractor common conversion, rail is used it is instead enough of to an have in-line EUR6200 high annualpressure conventional pump, the efficiency fuel consumption increases. or To cover expenses in tractor conversion, it is enough to have EUR6200 annual conventional fuel To400 cover operating expenses hours in (Figure tractor 20 conversion,). it is enough to have EUR6200 annual conventional fuel consumption or 400 operating hours (Figure 20). 0.90 0.90 0.85 0.85 0.80 0.80 0.75 0.75 0.70

Ratio 0.70 Ratio 0.65 0.65 0.60 0.60 0.55 0.55 0.50 0.50 4 6 8 10 12 14 16 18 20 22 4 6 8 10 12 14 16 18 20 22

Annual diesel fuel cost, thousand EUR ratio (in-line high pressure fuel pump) actual ratio up ratio (in-line high pressure fuel pump) actual ratio up actual ratio down ratio (common rail) actual ratio down ratio (common rail)

Figure 20. The dependence of the ratio of CNG/diesel fuel prices on the cost of the annual conventional Figure 20. The dependence of the ratio of CNG/diesel fuel prices on the cost of the annual fuel (no CNG fueling station). conventional fuel (no CNG fueling station). Figure 21 shows the acceptable E85/gasoline price ratio versus annual gasoline consumption cost. Figure 21 shows the acceptable E85/gasoline price ratio versus annual gasoline consumption cost.The actualThe actual ratios ratios of E85 of and E85 gasoline and gasoline prices prices are also are shown also shown here: upper here: value,upper lowervalue, value, lower and value, average and cost.value The (actual actual market ratios price of E85 ratios). and gasoline As can be prices seen, are at thealso maximum shown here: market upper prices value, for lower E85, thisvalue, type and of average value (actual market price ratios). As can be seen, at the maximum market prices for E85, this typefuel isof not fuel competitive. is not competitive. Although, Although, the average the average value of value its price of ensuresits price theensures proﬁtability the profitability if a vehicle if isa typeused of intensively. fuel is not competitive. Although, the average value of its price ensures the profitability if a vehicle is used intensively. 0.8 0.8

0.75 0.75

0.7 0.7 Ratio Ratio 0.65 0.65

0.6 0.6 0.25 0.5 0.75 1 1.25 1.5 1.75 2 2.25 2.5 2.75 0.25 0.5 0.75 1 1.25 1.5 1.75 2 2.25 2.5 2.75 Annual gasoline cost, thousand EUR ratio (calculated) upper limit ratio actual ratio up ratio (calculated) upper limit ratio actual ratio up actual ratio down average actual ratio actual ratio down average actual ratio FigureFigure 21. TheThe dependence dependence of of the the ratio ratio of of E85/gasoline E85/gasoline pr pricesices on on the annual conventional fuel cost (the(the USA). USA).

Energies 2019, 12, 3889 16 of 20

The economic eﬃciency of an E85 vehicle is lower than CNG utilization (Figure 21). Therefore, if there are not any incentives that bioethanol blend utilization undertakes risks.

5. Conclusions Efforts to reduce climate change and find the answer to the world crude oil crisis have resulted in the production and use of alternative vehicle fuels. In conditions of a market economy, fuel producers and consumers make decisions which depend on economic efficiency. Therefore, the price of fuel is the most important criterion. To evaluate the feasibility of alternative fuels, a mathematical model was developed. The ratio between of alternative fuel price and conventional fuel price proved to be an optimal criterion for the model. It took into account fuel properties, vehicle performance whilst running on different fuels, and financial indicators. If the calculated ratio is higher than actual one, then the use of alternative fuel is rational. According to calculations made, a more preferable alternative fuel is natural gas. The efficiency of its utilization depends primarily on the annual conventional fuel consumption, lifetime of a project, and the current ratio of alternative to conventional fuel prices. Moreover, the above model may be used for the sensitivity analysis of investment projects. Separate issues remain outside of this study. The use of electric vehicles is a multifaceted problem. In the above mathematical model cost of the infrastructure for electric vehicles (BEV and FCEV) should be incorporated. For a sustainable transport system, power generation and hydrogen production must be coupled with renewable energy sources. This should be factored in. Moreover, electric trucks and buses are starting to be produced and they must be the subject of further research.

Author Contributions: Data curation, A.K. and V.H.; Formal analysis, I.A.; Methodology, A.K. and V.H.; Project administration, A.K.; Resources, V.H. and I.A.; Writing—original draft, A.K. and V.H.; Writing—review & editing, I.A. Funding: This research received no external funding. Conﬂicts of Interest: The authors declare no conﬂict of interest.

Nomenclature

AAU the average annual utilization, h/year ACFC the annual conventional fuel consumption cost, EUR AFpr the price of the alternative fuel, EUR/L BEV the battery electric vehicle th ci the volume fraction of the i component of fuel DFpr the price of conventional fuel, EUR/L ECA the annual ecological charges for the alternative fuel, EUR ECC the annual ecological charges for the conventional fuel, EUR ECE the annual ecological charges for electricity, EUR EEpr the price of electricity, EUR/kWh EL the economic life, year FCEV the hydrogen fuel cell electric vehicle Fpr the fuel price, EUR/m3 th 3 Fpri the price of the i component of fuel, EUR/m g the discount rate I the investment costs, EUR M the annual consumption of conventional fuel, t n the lifetime of a certain investment project, year NPV Net Present Value P0 the operational power, kW Pr the rated power, kW PI Proﬁtability Index Energies 2019, 12, 3889 17 of 20

Q the lower heating value of the fuel, MJ/kg QA the lower heating value of the alternative fuel, MJ/kg th Qi the lower heating value of the i component of fuel, MJ/kg R* the critical value of the return, EUR SL the service life, hours ρ the fuel density, t/m3 th 3 ρi the density of the i component of fuel, t/m ρA the density of alternative fuel, kg/L η the efficiency of an engine ηA the efficiency of vehicle which runs on the alternative fuel ηC the efficiency of vehicle which runs on the conventional fuel ηE the efficiency of vehicle which runs on electricity ϕ the conventional fuel energy share in fuel blends or for a dual fuel mode ϕ0 the energy share of diesel fuel on the rated power γ the ratio of alternative fuel price to conventional fuel price γ* the critical value of the relative price for the alternative fuel

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