It is reported that the production of a small car such as that shown in Figure 8.23 (mass 1,000 kg) requires materials with a total embodied energy of 70 GJ, and a further 25 GJ for the manufacturing...

It is reported that the production of a small car such as that shown in Figure 8.23 (mass 1,000 kg) requires materials with a total embodied energy of 70 GJ, and a further 25 GJ for the manufacturing phase. The car is manufactured in Germany and delivered to the US show room first by sea freight (distance 10,000 km), followed by a heavy truck over another 1,500 km (Table 6.8 of the text gives the energy per metric ton km for both). The car has a useful life of 10 years, and will be driven on average 20,000 km per year, consuming 2 MJ/km. Assume that recycling at end of life consumes 0.5 GJ but recovers 25 GJ per vehicle.

Make an energy-audit bar chart for the car with bars for material, manufacturing, distribution, use, and disposal. Which phase of life consumes the most energy?

The inherent uncertainty of current data for embodied and processing energies are considerable—if both of these were in error by up to 20% either way, can you still draw firm conclusions from the data? If so, what steps would do the most to reduced life-energy requirements?