As I wrote last week the environmental impact is not a health issue alone. Below, I allow the scope to be broadened to cover also energy use and carbon dioxide emissions. The total scope now coinceedes with the European Directive on “Promotion of clean and energy efficient vehicles” Read about the directive here
When we compare the scope to the total life cycle impact we can conclude that now only raw materials from the production are missing in the total life cycle impact of the bus. The raw materials contribute by less than 10% of the total environmental impact of the bus, when the recycled materials are subtracted.
The graph shows the cost savings for society as compared to a bus fleet of 150 buses, where 10 buses are from each year 1995-2009.
If a rule is introduced to not accept buses older than 10 years. I.e. the fleet will have 15 buses from each of the years 2000-2009. The society will gain € 290 000 each year in decreased environmental cost. While if we compare to a new fleet of 150 buses the yearly saving would be € 940 000. And, a hybrid bus fleet containing 150 Volvo “7700 Hybrid” buses would decrease the environmental load by some € 2 100 000 on a yearly basis.
The conclusion from the excercise is that not only health benefits are achieved but substantial cost savings can be gained by swithing to newer buses or to the Volvo hybrid bus.
The pay-back on the investment for the latter is about 5 years!
The emission performance of the buses has improved a lot the last 20 years. The gradual decrease of the emissions from Euro I to Euro V, that will be introduced in a few weeks, has contributed to the improved air quality in our cities.
In many areas the bus fleet is of varying age. The old buses cause increased cost for society in many ways (health, hospitalisation, absence from work, acid rain, corrosion etc.).
Knowing the impact we now ask: How old should we allow the buses to get before we should replace them?
To calculate the environmental load of hazardous emissions I have been using the key values of the public procurement directive. The result is plotted in the graph below. In the first column you will find the environmental load of a bus fleet where the age of the buses is evenly distributed from 1995 to 2009, 10 buses purchased each year giving a total of 150 buses. In the second column the bus fleet is not allowed to have any buses older than 10 year giving 15 buses each year distributed from 2000 to 2009. In the third column all 150 buses have Euro V status and in the last column we compare to a fleet with hybrid buses.
The environmental cost for society for the bus fleet that is distributed over 15 years exceeds € 900.000 each year. For the case where the fleet is distributed over 10 years we find that the cost decrease to some € 650.000. For the operator that invests in a Volvo 7700 Hybrid bus fleet the yearly cost for society for the impact of the hazardous emissions will be €120.000. To invest in new hybrid buses will improved the health and bring an economical benefit for the society.
In the next blog I will include the cost for carbon dioxide and energy use in the calculation to show total cost efficiency for society.