>Which produces less CO2 emissions, the Toyota Prius or the Toyota Echo? According to Treehugger, the Prius wins out, but just barely. The Prius emits only 104 gm of CO2 per km driven, whereas the Echo emits 117 gm per km – treehugger.com. However, they point out that the Prius weighs slightly more than the Echo and attribute that weight to the amount of steel used in the car (which they admit is debatable – it could be the large battery). In any case, whether it is steel or battery components, more materials are used in the Prius. As an example, making a ton of steel produces half a ton of CO2 which means and additional 145 kg of CO2 were admitted during the making of the Prius (if you attribute the additional weight to extra steel). Divided by the difference in emissions while driving, one has to drive 6,930 miles before the Prius drives ahead. That isn’t much but let this be a lesson in looking at the “greeness” of a product from start to finish – something we fail to do on a regular basis in this country. There are a lot of hidden environmental costs in automobiles as well as most other products. In this case, you may be paying for those costs in the Prius. It is about $15,000 more expensive than the Echo.