Background Info: Consider a metro bus system, not unlike Blacksburg Transit, that is planning for changes to its bus fleet. The current fleet uses diesel fuel engines, but compressed natural gas (CNG) and electric buses will be considered as alternatives. For comparison purposes, assume the bus lifetime is 15 years with an annual mileage of 50,000 miles/year. A typical 40-foot passenger bus will have 34 seats and you should assume an average passenger load factor of 40%. The load factor is the average number of passengers divided by total bus seats averaged over the whole year to account for routes and times that vary in number of passengers. National Average Price Between July 1 and 31.2019 Fuel Price Assume the following average transit bus fuel economy for intra-city driving: -2.3 miles/gallon diesel for standard diesel bus? - 1.7 miles/gallon gasoline equivalent (GGE)* for CNG bus - 18.2 MPGe (diesel equivalent) with 155 mile range? ho 5236 Biodiesel 8100) $3.62 Electricity 50 13 Ethanol (E85) 2 Use July 2019 Average US National Fuel/Energy Prices for this analysis Nala CNG) 5221 OCE Liquefied Gas 75DGE * Propane 52.83 Assume the following costs for a new bus: - Standard diesel transit bus - $400,000 - CNG transit bus - $450,000 - Electric transit bus - $750,000 Gasoline S alon Diesel $300 Source: A P R Assume the following major maintenance costs (ignoring tires, fuel, lubrication, etc. which should be similar for all buses) - Diesel and CNG buses need engine/ transmission rebuild at 7.5 years which costs $20,000 - Electric bus needs no engine/transmission rebuild, but new batteries at year 7.5 at cost of $50,000. Assume efficiencies for the internal combustion engines of the diesel and CNG transit bus to be 20%, the efficiency of the electric bus motor to be 60%, the efficiency of the electricity generation to be 35%, and the efficiency of the electricity grid to be 92%, and the efficiency of the batteries to be 96%. The carbon emissions coefficient for diesel fuel is 10.2 kg CO2/gallon and for natural gas is 54.6 kg CO2/thousand cubic feet (MCF). The average US electricity CO2 emission are 0.998 lb/kWh. Notes: *Compressed natural gas (CNG) is gas compressed to 3,600 psi, not compressed high enough for a liquid phase as is the case for liquified natural gas (LNG). This makes volume comparisons confusing, so CNG amounts are typically discussed in equivalent units of energy compared to gasoline or diesel. This is just a unit conversion. 1 Gallon of Gasoline Equivalent (1 GGE) is the typical way CNG is sold at public fueling stations. 1 standard GGE = 114,000 BTU (LHV or lower heating value) which equals 127 SCF (standard cubic feet). Alternatively, 1 Diesel Gallon Equivalent (1 DGE) is another conversion which accounts for the higher energy content of diesel (129,500 BTU) compared to gasoline. 1 DGE = 1.14 GGE. 1. How much diesel (gallons), CNG (standard cubic feet), and electricity (kWh) are used per year for each of these buses? 2. What is the fuel cost/mile ($/mile)? 3. Ignoring other maintenance costs since they are similar for each vehicle, what is the total cost per mile for ownership over the bus lifetime? 4. What is the overall energy efficiency (%) of the diesel vs. CNG vs. electric transit bus? 5. What are the CO2 emissions per year (short tons) for each type of transit bus? 6. What is the primary energy intensity (fuel input per passenger.mile traveled) for each of these types of vehicles (Btu/passenger.mile)? Remember to use primary energy for electricity. 7. For a gasoline car with a fuel economy of 23 miles per gallon, how many passengers, on average, are needed for the annual primary energy intensity (Btu/passenger . mile) to equal each of the 3 bus cases? 8. Do some additional research to qualitatively comment on the other air emissions (criteria air pollutants) for these vehicle technologies relative to each other and provide references to justify these comments. 9. Comment on how the assumptions of passenger load and carbon emissions from electricity in this assignment could change the results if specific data from local or regional transit systems was used. Background Info: Consider a metro bus system, not unlike Blacksburg Transit, that is planning for changes to its bus fleet. The current fleet uses diesel fuel engines, but compressed natural gas (CNG) and electric buses will be considered as alternatives. For comparison purposes, assume the bus lifetime is 15 years with an annual mileage of 50,000 miles/year. A typical 40-foot passenger bus will have 34 seats and you should assume an average passenger load factor of 40%. The load factor is the average number of passengers divided by total bus seats averaged over the whole year to account for routes and times that vary in number of passengers. National Average Price Between July 1 and 31.2019 Fuel Price Assume the following average transit bus fuel economy for intra-city driving: -2.3 miles/gallon diesel for standard diesel bus? - 1.7 miles/gallon gasoline equivalent (GGE)* for CNG bus - 18.2 MPGe (diesel equivalent) with 155 mile range? ho 5236 Biodiesel 8100) $3.62 Electricity 50 13 Ethanol (E85) 2 Use July 2019 Average US National Fuel/Energy Prices for this analysis Nala CNG) 5221 OCE Liquefied Gas 75DGE * Propane 52.83 Assume the following costs for a new bus: - Standard diesel transit bus - $400,000 - CNG transit bus - $450,000 - Electric transit bus - $750,000 Gasoline S alon Diesel $300 Source: A P R Assume the following major maintenance costs (ignoring tires, fuel, lubrication, etc. which should be similar for all buses) - Diesel and CNG buses need engine/ transmission rebuild at 7.5 years which costs $20,000 - Electric bus needs no engine/transmission rebuild, but new batteries at year 7.5 at cost of $50,000. Assume efficiencies for the internal combustion engines of the diesel and CNG transit bus to be 20%, the efficiency of the electric bus motor to be 60%, the efficiency of the electricity generation to be 35%, and the efficiency of the electricity grid to be 92%, and the efficiency of the batteries to be 96%. The carbon emissions coefficient for diesel fuel is 10.2 kg CO2/gallon and for natural gas is 54.6 kg CO2/thousand cubic feet (MCF). The average US electricity CO2 emission are 0.998 lb/kWh. Notes: *Compressed natural gas (CNG) is gas compressed to 3,600 psi, not compressed high enough for a liquid phase as is the case for liquified natural gas (LNG). This makes volume comparisons confusing, so CNG amounts are typically discussed in equivalent units of energy compared to gasoline or diesel. This is just a unit conversion. 1 Gallon of Gasoline Equivalent (1 GGE) is the typical way CNG is sold at public fueling stations. 1 standard GGE = 114,000 BTU (LHV or lower heating value) which equals 127 SCF (standard cubic feet). Alternatively, 1 Diesel Gallon Equivalent (1 DGE) is another conversion which accounts for the higher energy content of diesel (129,500 BTU) compared to gasoline. 1 DGE = 1.14 GGE. 1. How much diesel (gallons), CNG (standard cubic feet), and electricity (kWh) are used per year for each of these buses? 2. What is the fuel cost/mile ($/mile)? 3. Ignoring other maintenance costs since they are similar for each vehicle, what is the total cost per mile for ownership over the bus lifetime? 4. What is the overall energy efficiency (%) of the diesel vs. CNG vs. electric transit bus? 5. What are the CO2 emissions per year (short tons) for each type of transit bus? 6. What is the primary energy intensity (fuel input per passenger.mile traveled) for each of these types of vehicles (Btu/passenger.mile)? Remember to use primary energy for electricity. 7. For a gasoline car with a fuel economy of 23 miles per gallon, how many passengers, on average, are needed for the annual primary energy intensity (Btu/passenger . mile) to equal each of the 3 bus cases? 8. Do some additional research to qualitatively comment on the other air emissions (criteria air pollutants) for these vehicle technologies relative to each other and provide references to justify these comments. 9. Comment on how the assumptions of passenger load and carbon emissions from electricity in this assignment could change the results if specific data from local or regional transit systems was used