Monday, June 8, 2009

Doing the math - what transportation mean is really good for the environment?

The University of California has published a scientific report to compare different transportation means and their specific energy consumption and greenhouse gas emissions. What is new in this report is that they also included the energy spent to provide the infrastructure, i.e. rails, roads, airports, maintenance services, and so on. And of course the effort of building the vehicle was included as well. The authors also assessed the typical load of the different vehicles and therefore can show the "cost" per person transported. If you now look at the key chart they produced you will have some surprises. The worst polluter is the urban diesel bus that is half empty and travels fairly big distances. Pickups also look pretty bad, especially when they run on gasoline. Best is the city bus that is heavily loaded (many would say overloaded) with people and covers the centers. Large aircrafts are actually much better than you wouold assume, this is because they don't need a lot of infrastructure. And what about the conventional gasoline sedan, the car we all use? Well, it's sort of in the middle field, better than the SUVs of course, but clearly worse than most of the public transport vehicles. Of course the picture would look much different if you would take cars like the Aptera or the Toyota Prius as reference. Modern optimized electrical or hybrid cars would certainly be better in comparison than small aircraft and could probably beat the light rail vehicles. What is interesting is the fact that building these vehicles, and the bigger they get the more relevant this is, produces quite a share of the overall greenhouse gas emissions. But on this topic I will post specifically during the coming days.

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