Parts C and D please! Thank you Biomass can be used to create ethanol fuel. It can also be used to generate electricity, that can then be used to charge electric vehicles (EVs). In this problem, you will determine whether ethanol or electricity can provide a higher biomass‐to‐wheel efficiency. Assume that one hectare of cropland can produce 14 tons of dry switchgrass per year and that dry switchgrass has an energy density of 15 MJ/kg. a. Each ton of dry switchgrass can be processed to produce 73 gallons of ethanol. Ethanol has an energy density of 92 MJ/gallon. Assume that the internal combustion engine (ICE) is 23% efficient in converting fuel energy to useful work at the wheels (motion). With what efficiency is biomass energy delivered to the wheels in this ICE car? b. Alternatively, each ton of dry switchgrass could be used directly to generate electricity, and this electricity could in turn be used to operate an EV. Assume that a biomass‐fueled power plant has a first law efficiency of 28%. There is a 7.5% loss for transmission and distribution of electricity from the power plant to the car charging station. The motor plus battery is 88% efficient in converting electrical energy delivered from the chargingstation to mechanical work. With what efficiency is biomass energy delivered to the wheels in this EVICE car? c) According to the above analysis regarding these two uses of biomass for transportation, if we are concerned about utilizing biomass resources most energy efficiently, should we use biomass to generate electricity or should we use it to produce liquid fuels? While this analysis is useful and illustrative, many important factors are left out. Explain twoshortcomings of this simplified analysis. Assume switchgrass is used to produce ethanol for use in 100% ethanol‐fueled vehicles. How much land (in km^2) would be required for switchgrass production to provide enough ethanol to meet the fuel demand of all cars the United States? Assume 264 million cars traveling an average of 13,000 mi/year with an average fuel economy of 24 miles/gallon ethanol.

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Asked Dec 3, 2019
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Parts C and D please! Thank you
 
Biomass can be used to create ethanol fuel. It can also be used to generate electricity, that can then be used to charge electric vehicles (EVs). In this problem, you will determine whether ethanol or electricity can provide a higher biomass‐to‐wheel efficiency. Assume that one hectare of cropland can produce 14 tons of dry switchgrass per year and that dry switchgrass has an energy density of 15 MJ/kg.
 
a. Each ton of dry switchgrass can be processed to produce 73 gallons of ethanol. Ethanol has an energy density of 92 MJ/gallon. Assume that the internal combustion engine (ICE) is 23% efficient in converting fuel energy to useful work at the wheels (motion). With what efficiency is biomass energy delivered to the wheels in this ICE car?
 
b. Alternatively, each ton of dry switchgrass could be used directly to generate electricity, and this electricity could in turn be used to operate an EV. Assume that a biomass‐fueled power plant has a first law efficiency of 28%. There is a 7.5% loss for transmission and distribution of electricity from the power plant to the car charging station. The motor plus battery is 88% efficient in converting electrical energy delivered from the charging
station to mechanical work. With what efficiency is biomass energy delivered to the wheels in this EVICE car?
 
c) According to the above analysis regarding these two uses of biomass for transportation, if we are concerned about utilizing biomass resources most energy efficiently, should we use biomass to generate electricity or should we use it to produce liquid fuels? While this analysis is useful and illustrative, many important factors are left out. Explain two
shortcomings of this simplified analysis.
 
Assume switchgrass is used to produce ethanol for use in 100% ethanol‐fueled vehicles. How much land (in km^2) would be required for switchgrass production to provide enough ethanol to meet the fuel demand of all cars the United States? Assume 264 million cars traveling an average of 13,000 mi/year with an average fuel economy of 24 miles/gallon ethanol.
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Expert Answer

Step 1

 

(c)

It is more efficient to use biomass to generate electricity and hence shall be adopted.

The two drawbacks can be:

  • Pollution is higher than when the biomass is converted to liquids.
  • The cost of installation and the expenditures need to be analyzed to make a better benefit.
Step 2

(d)

The number of cars = 264 million = 2.63×106

Average distance travelled = 13000 mi/yr.

Fuel economy = 24miles/gallon

Step 3

The fuel requi...

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13000 x2.64x10gallons/yr = 143x10igallons/yr 24

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