Oddly enough, most cars that are considered green are diesel. Why? Because the ‘green’ factor of a car generally focuses on two factors, it’s CO2 emissions / km driven, and fuel efficiency.
Unfortunately, we are only comparing the green factor at the consumer end of the transaction. It would be prudent to compare all factors when determining which cars are the most eco-friendly. These unconsidered factors include:
- all emissions, not just CO2
- gas vs diesel refining costs
- battery disposal
Soot. This is the biggest non-CO2 emission as a result of burning diesel. Although diesel outputs less CO2 per km driven in general, it outputs MUCH more soot (up to 10x) because emissions standards are not yet as strict as that of gasoline burning engines. This should change by 2009 when diesel engines must meet the same output requirements as that of gasoline, but for now, the soot output can be brutal.
Refining costs. Did you know it takes 25% more oil to generate diesel than it does to generate gasoline? While diesel is generally thought of as more fuel efficient per litre by approximately 33%, this savings is simply pushed up the chain. 33% more mileage comes from 25% more oil, thus in reality diesel is approximately 8% more efficient when we consider it in terms of oil, not cost per litre. Weird huh?
Battery disposal. What happens to the batteries when their lifespan is over? It turns out that Toyota uses batteries that are recyclable, include a phone number and a $200 ‘bounty’ on each of their batteries to encourage returning them to recycling facilities. I’m not sure how other auto manufacturers handle the battery disposal, but Toyota seems to have a great solution here.
So, although this doesn’t cover everything and doesn’t provide all of the answers, it does bring a few other factors into play when deciding to go for a green car.
And yes, this is part of my ‘pre-green car purchase’ research. The prius is the #1 pick so far, as I drove one for a week in los angeles on business. Interesting car, but please.. turn the LCD off to prevent crashes! It’s very distracting!