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Selection of UBC Campus Gators Based on Life Cycle Analysis Haligva, Cef; Nagra, Sonny; Yoslim, Jeffry 2006

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         CHBE 484: Term Report  Selection of UBC Campus Gators based on Life Cycle Analysis           Cef Haligva  Sonny Nagra Jeffry Yoslim April 18th, 2006  TABLE OF CONTENTS  1.0 INTRODUCTION .................................................................................................... 1  2.0 BACKGROUND ...................................................................................................... 2  2.1 Life Cycle Inventories ........................................................................................... 2 2.2 Environmental and Health Impact Assessment..................................................... 4 2.3 Total Cost Analysis ............................................................................................... 5 2.4 Evaluation and Ranking of Fuels.......................................................................... 5  3.0 BIODIESEL.............................................................................................................. 6  3.1 Life Cycle Analysis of Biodiesel............................................................................ 6 3.2 Environmental and Health Impact Assessment..................................................... 7 3.3 Effect of Biodiesel Blend Level on Emissions....................................................... 9  4.0 GASOLINE............................................................................................................. 11  4.1 Life Cycle Analysis of Gasoline .......................................................................... 11 4.2 Environmental Impact Assessment ..................................................................... 14 4.3 Health Impact Assessment .................................................................................. 15  5.0 ELECTRICITY....................................................................................................... 16  5.1 Life Cycle Analysis of Electricity........................................................................ 16 5.2 Environmental and Health Impact Assessment................................................... 18  6.0 CONCLUSION....................................................................................................... 20  7.0 REFERENCES ....................................................................................................... 24               i   1.0 INTRODUCTION  UBC Plant Operation is considering replacing several of their utility vehicles, which are used for gardening and performing daily campus maintenance.  The UBC SEEDS program has provided this project in-conjunction with UBC Plant Operations in order to choose which fuel alternative is most suitable.  With the mindset of sustainability, UBC is considering utility vehicles that are safe for the environment and also within budget.  Based on all of these considerations, our study will compare three types of fuels: • Biodiesel (Section 3.0) • Gasoline (Section 4.0) • Electric (Section 5.0)  The comparison will be based on total emissions and energy use of the upstream processing and downstream vehicle operations.  Furthermore, there are certain vehicle specifications that have to be followed in choosing a suitable utility vehicle, such as fuel economy and maximum load abilities.  Based on this comparison, advantages and disadvantages from each type of fuel alternatives and total emission will be discussed in this report.   One of the purposes of this study is to assess the environmental impacts of electricity and biofuels such as biodiesel relative to conventional automotive fuels such as gasoline.  The best environmental option is then identified by performing a Life Cycle Analysis, LCA, which takes into account the entire emissions generated during the life cycle of the fuel.  The second purpose of this project is to help UBC Plant Operations make an “environmentally friendly” and “cost effective” decision on which John Deere Gator to choose.     1   2.0 BACKGROUND  To meet the requirements slated by UBC Plant Operations via the UBC SEEDS Program, the three fuels, biodiesel, gasoline and electricity must be compared.  The most effective way of comparing fuels is known as a Life Cycle Analysis (LCA).  The LCA incorporates all types of emission rates associated from producing the fuel to transporting the fuel to disposing the fuel or in other words, “Cradle-to-Grave” analysis.  The types of emission rates associated with a LCA are air, water and soil.  In more specific detail, these emission rates will include compounds such as CO2, CO, NOX, SOX, and CFCs.  When fuels are being compared, another more common phrase is “Well-to-wheel” analysis.  LCA is a relatively recent method of environmental analysis for qualifying the environmental effect of any product, process or service over its entire life cycle.  2.1 Life Cycle Inventories  The first criterion for a LCA involves gathering or calculating all of the emission rates.  A clearer picture of which emissions are associated with the life cycle of a fuel can be determined by developing the system boundary.  Figure 2.1.1 shows the typical system boundary and life cycle of a fuel.  Figure 2.1.1: Process Flow of Fuel Life Cycle and Study Boundary.      2   In Figure 2.1.1, the production box indicates how the fuel produced.  The emissions associated with the production of the fuel represent only a fraction of the overall emissions from its life cycle.  These emission rates can be found in literature or from the US Environmental Protection Agency website.  For our case, we were introduced to software known as GREET, which is developed by Argonne National Laboratory in Illinois, USA.  The acronym GREET represents Greenhouse Gases, Regulated Emission and Energy Use in Transportation.  It is a user-friendly interface that provides simulation studies on energy efficiencies and emissions for different transportation fuels and vehicle technologies.  The user will enter information regarding the production of the fuel by via fuel pathways and regarding the end-use of the fuel such as what type of vehicle will utilize the fuel.   Figure 2.1.2 shows the criteria considered by GREET in its evaluation of the fuel’s life cycle and Figure 2.1.3 shows several fuel pathways incorporated into GREET’s interface.   Figure 2.1.2: Stages covered in GREET Fuel-Cycle Analysis       3    Figure 2.1.3: Fuel Pathways included in GREET  2.2 Environmental and Health Impact Assessment  The environmental impact of chemicals can be local, regional and global environmental issues.  Global warming is a problem with potential global implications whereas smog formation and acid rain are problems with potential regional implications.  In this report, three particular environmental impact indices will be evaluated, global warming, smog formation and acid rain.  These three categories have been chosen for this study because all of them have been identified as the major environmental concern in North America.  There are two toxicity indices used in this report to discuss health issue in workplace.  The first one is TLV (Threshold Limit Value) method, which is set by The American Conference of Governmental Industrial Hygienists (ACGIH) to address airborne exposure concentration limit at workplace.  The second one is PEL (Permissible Exposure Limit) method, which is set by Occupational Safety and Health Administration (OSHA) for workplace exposure.  After the emission rates have been determined, the second criterion is to determine the environmental and health impact values.  The following equations are used to determine the overall impact indices for each GWP, ARP and MIR:                                             4       ∑= )()( EixGWPiGWPEI                                                   (2.2.1) ∑= )()( EixARPiARPEI                                                   (2.2.2) ∑= )()( EixMIRiMIREI                                                   (2.2.3) where i is the chemical compound The following equation is used to determine the total health impact: ∑= )/( PELiorTLViEiimpacthealthTotal                                (2.2.4)  2.3 Total Cost Analysis  The final criterion is to determine the costs associated with the fuels.  This will include raw material acquisitions costs, production costs, transporting costs, end-use costs and disposal costs.  However it can be difficult to obtain information about these costs.  Therefore in our assessment, we looked at the end-use costs of the fuels, more specifically the purchasing costs and operating costs of the John Deere Gators.  2.4 Evaluation and Ranking of Fuels  The final step in the comparison of the fuels is to determine which one meets the required criteria, based on the findings from the LCA, environmental and health impact indices and the total cost analysis.  It is difficult to rank each criterion since they are determined in different units.  Therefore each criterion is non-dimensionalized and then specific weighting factors are given to each criterion in order to determine the overall score.  In our case, we chose to analyze several weighting factors such that we could compare how sensitive the criterions are to changes in weight.  .  The completion of this step will allow the most thorough comparison between a product, process or service.  However there are uncertainties associated with the LCA such as being able to determine a complete life cycle inventory.  The uncertainties associated with our analysis will be discussed in the conclusion.      5   3.0 BIODIESEL   The first type of fuel analyzed is biodiesel, a clean burning alternative fuel, produced from domestic, renewable resources.  Biodiesel contains no petroleum, but it can be blended at any level with petroleum diesel to create a biodiesel blend.  It can be used in compression-ignition (diesel) engines with little or no modifications.  Biodiesel is simple to use, biodegradable, non-toxic, and essentially free of sulphur and aromatics.  Currently the UBC Biodiesel Project, led by Professor Naoko Ellis, proposes to supply UBC Plant Operations with approximately 1000 litres of biodiesel per week.  The UBC Plant Operations are also looking at off-campus biodiesel suppliers.  Therefore biodiesel is ranked high for UBC Plant Operations when it comes to their preference of fuel type.  However it is not enough just to base the decision just on simple knowledge or facts about biodiesel.  The more effective way is to perform the LCA. 3.1 Life Cycle Analysis of Biodiesel  The first step in order to determine the LCA of biodiesel is to determine the system boundaries associated with life cycle of biodiesel.  Figure 3.1.1 shows the typical life cycle of biodiesel based on a soybean production. 6            Figure 3.1.1: Biomass Carbon Balance for Biodiesel Life Cycle      The emission rates associated with the LCA of biodiesel were determined using GREET and scholarly journals.  However, the specific blend of biodiesel that was analysed was 25% biodiesel and 75% conventional diesel.  It is difficult to model such a specific type of fuel so we determined the emission rates for 100% conventional diesel using GREET.  The biodiesel emission rates were determined from literature results, more specifically, GHGenius.  Then 25% of the biodiesel emission rates were accounted for along with 75% of the conventional diesel emission rates.  Table 3.1.1 summarizes the results obtained for a 25% biodiesel and 75% conventional diesel lend of fuel.  Table 3.1.1: Total Emission of Biodiesel Production and Transportation 0.142 0.0700.0460.025 SOx: 0.193 0.1780.0120.004 PM10: 1.049 0.8380.0890.122 NOx: 0.968 0.9190.0200.029 CO: Total 0.104 0.0730.0190.012 VOC: 324.980 269.56035.85719.562 GHGs   4,20930452 Petroleum   4,209614186 Fossil   4,209614186 Total Total emissionVehicle Operation Fuel Feedstock Btu/mile or grams/mileItem        Note: Total energy, fossil fuels and petroleum values assumed from 100% Diesel  3.2 Environmental and Health Impact Assessment  Most of the emissions associated with the biodiesel life cycle occur during the operation of the vehicle.   The largest environmental factor for biodiesel is the greenhouse gases, as indicated by the emission rate.  However since the utility vehicles will only be used on      7   campus under low mileage conditions, the net emission of greenhouse gases per year is considerably less then an automobile.  Table 3.2.1 summarizes the environmental impacts and health impacts associated with the biodiesel.  For the environmental impact of biodiesel, the total GWP is 368.232 equivalent kg CO2, the MIR is 0.207 kg equivalent C2H4 and the ARP is 1.070 kg equivalent SO2.  For the health impact, there are two values determined, one using the TLV method and the other using the PEL method.  Both methods are correct but there are discrepancies as can be seen from the biodiesel results.  To improve the accuracy, we considered taking the average of both values during the evaluation and ranking of each fuel option.  Table 3.2.1: Summary of Environmental and Health Impacts   Global Warming Smog FormationAcid RainTotal Impact  based on TLV ([kg/hr]/[mg/m3]) Total Impact     based on PEL ([kg/hr]/[mg/m3])8    G MIR ARP TLV PEL   GHGs 1 324.98 0 0 0 0 9000 0.036 18000 0.018  VOC: Total 0 0 2 0.207 0 0 188 0.001 375 0    CO: Total 1.34 1.297 0 0 0 0 29 0.033 40 0.024   NOx: Total 40 41.955 0 0 0.885 0.928 5.60 0.187 1.80 0.583    PM10: Total 0 0 0 0 0 0 2.137 0.090 2.055 0.094   SOx: Total 0 0 0 0 1 0.142 5.200 0.027 5 0.028    Total Impact  368.232   0.207   1.070   0.375   0.748    WPHEALTH IMPACT ENVIRONMENTAL IMPACT          3.3 Effect of Biodiesel Blend Level on Emissions   The above results obtained for biodiesel were evaluated for the 25:75 biodiesel to conventional diesel blend.  To understand the effect of different blends of biodiesel on emission rates, experiments or models must be conducted at different blend ratios.  The following plots developed by the US Department of Agriculture and the US Department of Energy illustrate the effect of biodiesel blend level on emissions.  Figure 3.3.1 shows the effect on CO2 emissions, Figure 3.3.2 shows the effect on CH4, SOX, HF, PM and CO emissions.  Figure 3.3.3 shows the effect on NOX, HCl and HC emissions.  As the blend ratio increases, the amount of CO2 release increases.  This is evident from the fact as biodiesel is produced from oils containing chains of carbon molecules.  The benefit of biodiesel is that as the blend ratio increases, less on CH4, SOX, HF, PM and CO emissions are released.  The downside of biodiesel is that a higher ratio of biodiesel results in the increase of NOX, HCl and HC emissions.  Therefore an optimum level or range must be used to satisfy all emissions.  In places such as southern United States, blend ratios of 100% biodiesel are being used.  It would be recommended that UBC Plant Operation at least consider increasing the blend ratio to 40-50% biodiesel in order to reduce a certain degree of emissions.  9                Figure 3.3.1: Effect of Biodiesel Blend Level on CO2 Emissions       10                  Figure 3.3.2: Effect of Biodiesel Blend Level on CH4, SOX, HF, PM and CO Emissions                    Figure 3.3.3: Effect of Biodiesel Blend Level on NOX, HCl and HC Emissions      4.0 GASOLINE   The second type of fuel analyzed is gasoline, a petroleum-derived liquid mixture consisting primarily of hydrocarbons that is used as a fuel in internal combustion engines.  Material that is separated from crude oil via distillation, called natural gasoline, does not meet the required specifications for modern engines.  The bulk of typical gasoline consists of hydrocarbons with between 5 and 12 carbon atoms per molecule.  There are various refinery streams blended together to make gasoline and each of those streams have different characteristics.  Gasoline contains about 45 mega joules per kilogram.  4.1 Life Cycle Analysis of Gasoline  Assumptions have been made to the production and transportation of gasoline in order to complete the simulation.  Figure 4.1.1 shows the simplified diagram of the fuel cycle.          Figure 4.1.1: Life Cycle Diagram of Gasoline   In this simulation, oxygenate blending ads oxygen to the fuel in oxygen bearing compounds such as MTBE, and so reduces the amount of carbon monoxide and unburned fuel in the exhaust gas, thus reducing the smog. Assumptions associated with life cycle analysis of gasoline are shown in Tables 4.1.1, 4.1.2, 4.1.3 and 4.1.4 below.      11   Table 4.1.1: Pathway selections of gasoline production Conventional Gasoline Vehicle Technology Spark Ignition Engine Pathway Options Conventional Gasoline O2 Content (%): 0.4 Conventional Gasoline Sulphur Level (ppm): 340 Conventional Gasoline Oxygenate: Methyl Tertiary Butyl Ether  Table 4.1.2: Fuel Production Assumption Petroleum Items  Assumptions  Crude Recovery Efficiency (%)  97.7% CG Refining Efficiency (%)  85.5% CD Refining Efficiency (%)  89.0%  Table 4.1.3: Gasoline Transportation Assumption Feedstock and Fuel Transport Transport Transport Transport Transport Distribution Transportation Mode   Ocean Tanker Barge Pipeline Rail Truck Truck Petroleum Mode Share  57.0% 1.0% 100.0% 0.0% 0.0%  Crude for U.S. Average  Distance  5,080 500 750 800 30  Mode Share  20.0% 4.0% 73.0% 7.0%  100.0% CG  Distance  1,700 520 400 800  30      12   Table 4.1.4: Gasoline Tanker Size Assumption Ocean Tanker Items Ocean Tanker Size (tons) Crude Oil 1,143,000 Gasoline 150,000  The GREET software was used to determine emission rates for the life cycle of gasoline based on the assumptions mentioned above.  After all the assumptions have been made and the life cycle analysis is collected, the next step is to perform environmental impact, health impact and overall impact assessment based on the total emission summarized in Table 4.1.5 below.  Table 4.1.5: Total Emission of Gasoline Production and Transportation                13   0.197 0.085 0.079 0.033 SOx: Total 0.049 0.033 0.013 0.003 PM10: Total 0.479 0.275 0.097 0.108 NOx: Total 5.596 5.517 0.037 0.042 CO: Total 0.290 0.207 0.067 0.016 VOC: Total 507.623 401 76 31 GHGs   0.028 0.001 0.000 N2O   0.084 0.101 0.470 CH4   390 74 21 CO2   5,067 495 64 Petroleum   5,156 1,046 228 Fossil Fuels   5,156 1,046 228 Total Energy  Total Emission Vehicle Operation Fuel Feedstock Btu/mile or grams/mile Item      Most of the emission that being released to the environment is coming during vehicle operation compare to feedstock and fuel as can be seen in Figure 4.1.2.          Figure 4.1.2: Contribution of Each Stage: Gasoline Vehicle  4.2 Environmental Impact Assessment  The environmental impact results are summarized on Table 4.2.1 below.  Table 4.2.1: Summary of Environmental Impact ENVIRONMENTAL IMPACT   GWP Global Warming MIR Smog Formation ARP Acid Rain GHGs 1 507.623 0 0 0 0 VOC: Total 0 0 2 0.580 0 0 CO: Total 1.340 7.499 0 0 0 0 NOx: Total 40 19.165 0 0 0.885 0.424 PM10: Total 0 0 0 0 0 0 SOx: Total 0 0 0 0 1.000 0.197 Total Impact   534.287  0.580  0.621      14   Based on the results, the overall environmental impacts on global warming, smog formation and acid rain are 507.623 equivalent kg CO2, 0.580 kg equivalent C2H4 and 0.621 equivalent kg SO2 respectively.   4.3 Health Impact Assessment  The health impact results are summarized in Table 4.3.1.  Table 4.3.1: Summary of Health Impact HEALTH IMPACT   TLV Total Impact based on TLV ([kg/hr]/[mg/m3]) PEL Total Impact based on PEL ([kg/hr]/[mg/m3]) GHGs 9000 0.056 18000 0.028 VOC: Total 188 0.002 375 0.001 CO: Total 29 0.193 40 0.140 NOx: Total 6 0.086 2 0.266 PM10: Total 2.137 0.023 2.055 0.024 SOx: Total 5.200 0.038 5.000 0.039 Total Impact   0.397  0.498  Based on the results, the overall health impacts based on TLV and PEL are 0397 and 0.498 ([kg/hr]/[mg/m3]) respectively.         15   5.0 ELECTRICITY  The third type of fuel that was studied is electricity.  For this category, the same procedure was followed and a well-to-wheel analysis has been conducted. The environmental and health impact results are also obtained from the GREET software.    5.1 Life Cycle Analysis of Electricity  As it is widely known, there are numerous sources to produce electricity from such as fossil fuels, biomass, nuclear power, and renewable sources (solar, wind, hydro, geothermal).  Fossil fuels are the most common sources used in electricity production in North America (70% of whole electricity production).  Coal is the major fossil fuel used since there are many coal reserves available in North America.  However, as these reserves are continued to deplete, in the following 50-60 years came the prominence of renewable sources.  Since this project is related to UBC Plant Operation’s Gator utility vehicle selection, a more realistic combination of electricity production sources is used in our calculations.  Since the water resources are abundant in British Columbia and a large amount of electricity is being produced from the motion of water, it is assumed that 90% electricity that will be used in the Gators are coming from that source. The remaining 10% is assumed to be coming from a natural gas plant and both environmental and health impacts are calculated based on these assumptions.   After entering the assumed data in the GREET software, the results in Table 5.1.1 are obtained.     16   Table 5.1.1: Total Emission of Electricity Production and Transportation Btu/mile or grams/mile Item Feedstock Fuel Vehicle Operation Total emission Total Energy 301.872 4810.006 0.0 - Fossil Fuels 30.187 481.001 0.0 - Petroleum 1.721 0.000 0.0 - CO2 2.251 29.814 0.0 -CH4 0.083 0.001 0.0 - N2O 0.0 0.001 0.0 -GHGs 29.615 30.049 0.0 59.664 VOC: Total 0.031 0.001 0.0 0.032 CO: Total 0.022 0.011 0.0 0.033 NOx: Total 0.099 0.013 0.0 0.112 PM10: Total 0.018 0.002 0.002 0.022 SOx: Total 0.046 0.0 0.0 0.046  As it can be observed from the results in Table 5.1.1, most of the CO2 is generated during the fuel production.  A very small amount is produced in the extraction of the feedstock. There is no CO2 generated during the vehicle operation, which is the most significant reason for electric vehicles to be considered as an alternative.  The other greenhouse gas contributors, CH4, N2O, and CFCs’ amounts are relatively very small.  Again, generated volatile compounds, CO, NOx, large particulate matters (PM10), and SOx are nearly insignificant. None of these products are created during the vehicle operation. The generated small amounts are coming either from feedstock extraction or fuel production. The major contribution to the environmental and health impact comes from CO2 generation.      17   5.2 Environmental and Health Impact Assessment  In the following table, the total emissions are multiplied with the corresponding potential factor and impacts of the emissions on global warming, smog formation, acid rain and health impact based on TLV and PEL values are calculated.   Table 5.2.1: Summary of Environmental and Health Impacts ENVIRONMENTAL IMPACT HEALTH IMPACT  GWP Global Warming MIR Smog Formation ARPAcidRain TLVTotal Impact based on TLV ([kg/hr]/[mg/m3]) PEL Total Impact based on PEL ([kg/hr]/[mg/m3])GHGs 1 59.664 0 0.000 0 0 9000 0.007 18000 0.003 VOC: Total 0 0 2 0.063 0 0 188 0 375 0 CO: Total 1.340 0.044 0 0 0 0 29 0.001 40 0.001 NOx: Total 40 4.484 0 0 0.885 0.099 5.60 0.020 1.80 0.062 PM10: Total 0 0 0 0 0 0.000 2.137 0.010 2.055 0.011 SOx: Total 0 0 0 0 1 0.046 5.20 0.009 5 0.009 Total Impact  64.192  0.063  0.145  0.047  0.086  The biggest impact of electrical vehicles is on global warming as it can be seen in Table 5.2.1. These types of vehicles do not contribute to smog formation and acid rain significantly.  Furthermore, two types of health impact analysis are conducted; one based on TLV and the other one based on PEL factors.  Consistent results are obtained from both analyses, which show that the biggest health impact was due to the generated NOx. However, in that case it is a very small impact indeed.          18   The following graph is a distribution of emission rates based on their sources.  This graph is also produced by using Greet software and demonstrates the contribution of each stage on the generated emission rates.     Figure 5.2.1: Contribution of Each Stage: Electric Vehicle  As it can be observed from Figure 5.2.1, only particulate matters are produced during the vehicle operation and none of the other gases are being generated.  Only the majority of CH4 and SOx are being generated during the fuel extraction from the feedstock and the rest of the gases are predominantly formed in the fuel production.       19   6.0 CONCLUSION  In this well-to-wheel life cycle analysis, three types of fuels are compared by using GREET, which is a rigorous software specialized on lifecycle analysis of transportation vehicles.  The three types of fuels studied are bio-diesel (25% bio-diesel and 75% diesel mix), conventional gasoline, and electricity.  The well-to-wheel analysis included the emission rates generated during the extraction, production, and use of the fuel in the utility vehicle.  Furthermore, a cost analysis is also conducted for the specifications required by UBC Plant Operations.  The costs are obtained for utility vehicles from John Deere, which is a very well known company.  Table 6.1: Emission Rate Comparison between Gasoline, Biodiesel and Electric Vehicles Item Gasoline (gram/mile)Bio-Diesel/Diesel Mix (gram/mile) Electric (gram/mile)GHGs 507.623 324.980 59.664 VOC: Total 0.290 0.104 0.032 CO: Total 5.596 0.968 0.033 NOx: Total 0.479 1.049 0.112 PM10: Total 0.049 0.193 0.022 Sox: Total 0.197 0.142 0.046 Global Warming 534.287 368.232 64.192 Smog Formation 0.580 0.207 0.063 Acid Rain 0.621 1.070 0.145 Total Impact based on TLV 0.397 0.375 0.047 Total Impact based on PEL 0.498 0.748 0.086 Cost (based on John Deere) $9400 $10900 $12300        20   Based on Table 6.1, electricity has the least emission rates and impact on the environment for each category studied in this analysis.  Bio-diesel has lower greenhouse gases (GHGs), Volatile Organic Compounds (VOC), CO, and SOX emission rates than conventional gasoline.  However, bio-diesel generates more particulate matter (PM10) and NOX than the gasoline vehicles.  The contribution of these gases to the global warming favours the electric vehicle again, followed by bio-diesel and gasoline respectively.  Smog formation has also the same trend. However, in the acid rain category, gasoline vehicles have less contribution than the bio-diesel vehicles.   Health impact is analyzed based on two different potential factors, TLV and PEL.  In the analysis based on TLV factors, electric vehicles are found to be the least influential vehicles followed by bio-diesel and gasoline respectively; however, the difference between gasoline and bio-diesel is very little.  Alternatively, the analysis based on PEL factors led to different results.  Electric vehicles are again found to be the most favourable vehicle type followed by gasoline.   Different vehicles from different companies were considered but the vehicles from John Deere met the standards that the UBC Plant Operations required.  Since John Deere is the only company providing all three types of engines for their utility vehicles, its prices are compared and unlike the environmental and health impact results, electric vehicles are found to be the most expensive choice among the three options.   Bio-diesels are found to be $1500 more expensive than the currently cheapest vehicle type, which is gasoline.  The high cost of electric vehicles is mainly due to frequent battery changes (1-2 per year) since they die very often.  Another concern is about the charging system.  The battery of an electric car is being charged in around 12 hours, which is a very problematic and inconvenient comparatively.  The higher cost of the bio-diesel vehicles are due to the infrastructure of this relatively new technology.        21   Next, a sensitivity analysis is conducted for different scenarios, in which different weighting factors are assigned for each category.  Basically, a score of 10 is given to the one that has the highest contribution to the related category and the ratio of the others to the highest one is multiplied by 10 to get the dimensionless scores.  Then these weighting factors are multiplied with the impacts calculated and the sum of them gave the overall score for different weighting factor options.  The lower the overall score is, the more preferable the fuel option is.  Table 6.2: Sensitivity Analysis for the Weighting Factors  Weighting Factor 1 Weighting Factor 2 Weighting Factor 3 Weighting Factor 4 Weighting Factor 5 Global Warming 0.200 0.250 0.300 0.400 0.150 Smog Formation 0.150 0.150 0.100 0.250 0.100 Acid Rain 0.100 0.100 0.050 0.050 0.050 Total Impact based on TLV 0.050 0.100 0.050 0.100 0.050 Total Impact based on PEL 0.050 0.100 0.050 0.100 0.050 Cost (based on John Deere) 0.450 0.300 0.450 0.100 0.600 Overall Score Gasoline 8.352 8.539 8.562 9.221 8.209 Overall Score Bio-diesel 7.874 7.861 7.884 6.980 8.180 Overall Score Electric 5.157 3.834 5.154 2.055 6.474  Based on the sensitivity analysis conducted, electric vehicles have the lowest overall score in all cases and should be most preferable vehicle.  Bio-diesel utility vehicles have the second lowest overall score.  Therefore, they should be preferred rather than gasoline vehicles.    Based on the life cycle and cost analysis conducted, and the sensitivity analysis performed for different scenarios, the most preferable choice is the electric utility      22   vehicles.  However, after taking the cost of the maintenance (batteries and charging system) into considerations more, it is wiser to have a combination of two bio-diesel and two electric vehicles or even three bio-diesels and one electric vehicle since UBC Plant Operations is considering replacing four of their utility vehicles.   Another suggestion is to increase the blend ratio of bio-diesel and diesel mixture from 25% to 40-60%.  By doing so, the environmental impacts would be lessened without affecting the performance of the vehicle. The blend ratio could be increased gradually to see the real impacts associated with the change and could be acted accordingly.  As mentioned before, the most uncertainties in a LCA arise under product or process comparison.  Uncertainties are mainly related to the lack of emission data from other sources within the lifecycle such as incineration and landfills and the uncertainty associated with the recycling rate of used product.  The uncertainties associated with the comparison of biodiesel, gasoline and electricity come from the difficulty in assessing the overall environmental impacts of the wastes and pollutants, the renewable versus non-renewable source, the biodegradable versus non-biodegradable product and as well as the overall emissions associated with the construction of the infrastructure that produces these fuels.  The most uncontroversial use of a LCA is product or process improvement.  From our individual analysis of each fuel, it can be concluded that majority of the emissions come during the operation of the vehicle.  Therefore it would valuable to look at ways of improving the vehicle’s daily operation.         23   7.0 REFERENCES  Air Info Now, Particulate Matter, March 2006.  <http://www.airinfonow.org/html/ed_particulate.html>  Argonne National Laboratory, GREET 1.6, University of Chicago, March 2006 <http://www.anl.gov>  Australian Greenhouse Office, Comparison of Transport Fuels, Department of the  Environment and Heritage, January 2006. <http://www.greenhouse.gov.au/  transport/comparison/index.html>  Bi, X., A Case Study On: Life-Cycle Assessment of Alternative Fuel Sources For  Automobiles, Department of Chemical and Biological Engineering, University of  British Columbia, March 2006.  ISO 14040 (1997). Environmental Management – Life Cycle Assessment – Principles  and Framework. International Organisation for Standardisation, Geneva.  ISO 14041 (1998). Environmental Management – Life Cycle Assessment – Goal and  Scope Definition and Inventory Analysis. International Organisation for Standardisation, Geneva.  ISO 14042 (2000a). Environmental Management – Life Cycle Assessment – Life Cycle  Impact Assessment International Organisation for Standardisation, Geneva.  ISO 14043 (2000b). Environmental Management – Life Cycle Assessment – Life Cycle  Interpretation. International Organisation for Standardisation, Geneva.  Lin, Roger, Lifecycle Assessment of Alternative Fuel Vehicles, UBC Chemical  Engineering Undergraduate Thesis. April 9, 2003.  U.S. Department of Energy, Alternative Fuel Vehicles, The Alternative Fuels Data  Center, March 2006. <http://www.eere.energy.gov/afdc/afv/bio_vehicles.html>  Natural Resources Canada, Biodiesel GHG Emissions using GHGenius, S&T Consultants  Inc, Delta, British Columbia, March 2006.  US Department of Agriculture and US Department of Energy, Life Cycle Inventory of Biodiesel and Petroleum Diesel, March 2006.  US Environmental Protection Agency, March 2006, <http://www.epa.gov>       24   

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