Some time ago, I wrote about how we are very bad at making cost vs. benefit decisions and illustrated it with the cost benefit of hybrid vehicles and later with the total energy consumption of hybrids. If you enjoyed those discussions, you might be interested in real test between a BMW and a Prius conducted by the London Times.
UK Top Gear did a comparison with BMW M3 vs Prius (http://www.youtube.com/watch?v=wq9ilgw1plc), BMW seems better at fuel consumption, but the conclusion is how you drive makes the difference.
Interesting video. Of course the Prius is designed to do better in stop and go driving. I imagine it would have done significantly better if they were driving through town for an hour. The London Times specifically took a route that would have some city driving to help make the test more fair.
The comparison you link to is pretty meaningless for US readers.
According to the BMW USA website, they don’t offer any vehicles with estimated MPG above 28 while Toyota estimates 46 MPG. 18 MPG is a pretty huge difference.
More interesting is that Europe has a much higher average fuel economy. 44 mpg vs 24 mpg in the US.
@Mitch – Also you have to keep in mind that the numbers the use are for Imperial gallons which is larger than a US gallon. And with diesel costing more than gasoline, the BMW might not be any cheaper to operate. According to BMW the diesel engines are supposed to be available in the US this year. BMW isn’t the only automaker with diesel engines. I know of people with diesel VW mid sized cars who get 50 to 60 MPG when driving carefully.
Regarding better fuel economy in Europe, I have been told that the US regulations for emissions actually push the MPG down. I don’t know exactly what is involved, but I’ve heard that cars that get 50 MPG in Europe only get 35 in the US because of additional equipment that is required to met EPA regulations.
When we are talking about CO2 it is the prius who wins with a difference of about 10%;
BMW 11,50 kgCO2/imp gallon x 10,84imp gallon=124,62kgCO2
Prius 9,89 kgCO2/imp gallon xx11,34imp gallon=112,18kgCO2
When we are talking about CO2, it is pretty deceiving to leave out the construction CO2 costs. I believe the CO2 construction costs for the Prius are much higher than average because of how the batteries are made. (The BMW manufacturing process may produce just as much CO2.)
This is a very difficult thing to calculate because it involves looking at the process for every part over the entire supply chain.
The other really big thing to consider is how many miles the car will be driven over its lifetime. BMWs generally last a very long time (I have one that is 22 years old that is still in good shape) and diesel engines are often capable of going 400,000 to 800,000 miles from what mechanics tell me.
In 10 years, I bet you’ll see a much higher percentage of BMWs than Prius that were manufactured in 2008 still on the road.