I had some time this weekend to do an analysis of GHG emissions under different scenarios of driving the ICE on hot days to try to add extra life to the Leaf Battery. Very interesting results. Data was taken from the Lifecycle Analysis done for CARB by UCLA:drees wrote:Regardless - driving the stinker during the hottest two months of the year when air quality is typically at it's worst seems to defeat a lot of the purpose of the LEAF - especially when out on the "glide path" the difference in capacity between EOL at 10 vs 12 years is minimal.
http://www.environment.ucla.edu/media_I ... rh-ptd.pdf" onclick="window.open(this.href);return false;
I took the following estimates from that study:
CO2 equivalents emitted to manufacture Leaf = 9,000 kg / 1.5 batteries assumed manufactured to get full matching life = 6,000 kg per battery
ICE vehicle CO2 equivalents emitted per mile = 60,000 kg / 180,000 miles = 0.33 kg per mile
--Assume that Leaf battery lasts 8 years under "normal" use, but would last 10 years if not driven in extremely hot climates for 8 weeks in summer. We can thus allocate 750 kg CO2 equivalents per year of use of the battery. If two years are saved, about 1500 kg CO2 would be saved
--my commute is 160 miles per week, so 8 weeks would be 1280 miles, which would be 422 kg CO2 extra emitted per year by taking the ICE vehicle
--over 8 years, the ICE vehicle would emit 3,379 kg CO2 equivalents extra to save the Leaf battery for 2 years longer life.
Thus driving the Leaf all the time would mean an extra 1500 kg CO2 would have to be emitted to build a new battery for the Leaf to last the two more years (allocated 2/8 = 1/4 of CO2 emissions to get 2 years of life from the new battery). However, in order to get that savings one would have to emit the extra 3,379 kg CO2 by driving the ICE vehicle. The break even point would be if one could gain 2 years extra life of the battery by driving the ICE vehicle only 3.5 weeks out of the year.
Conclusion: given the assumptions above it is better for the environment from a CO2 emissions standpoint for me to drive the Leaf all the time. Serious food for thought.