I wonder what people think of Mazda's comments . . . The research Kunz cited mentioned a 95 kilowatt-hour battery pack. In comparison, Mazda's cutesy
MX-30 electric car sports a 35-kWh battery pack."
https://www.cnet.com/roadshow/news/mazda-electric-cars-batteries-range-mx-30/
From the article:
- "With 35 kWh, the MX-30 should go 130 miles." - My 18.6 kWh, BMW i3-REx achieves an EPA rated 72 miles. Double both and you get 37.2 kWh and 144 miles, which makes the Mazda seem like my 2014 BMW i3-REx.
As a backup for our Standard Range Plus Model 3, the smallest one, the BMW i3-REx works. Replacement cost with another used, BMW i3-REx is in the $18-22k range. If I were to replace the BMW with a new car, I would go with a +300 mile, Long Range Model 3 or perhaps a Model Y. If another Tesla were forbidden, a Hyundai Kona (50 kW) or Ioniq (100 kW) might work but fast DC charging using Electrify America and EVgo, would be slow, expensive, unreliable, and in Dixie, unobtanium.
I am not a CO{2} puppet and remain
very suspicious of claims about CO{2} from battery manufacturing. There are multiple LiON chemistries and manufacturers but these are never identified in the lay reports. The last 'paper' I read was a 2012 Swedish paper that made claims not backed by data observations. We can use a 'rule of thumb' that the CO{2} generated is proportional to the cost per kWh since it takes energy to make any LiON battery:
So doing 'back of the envelope' math, 176 / 707 ~= 25% of the 2012 CO{2} per kWh. Yet too often we see bald-faced claims, not backed by a credible study, that batteries generate a large amount of CO{2}. There is another basis of estimate (BOE).
If we take $176 per kWh and split the energy cost with materials and labor, we come up with ~$80 of energy cost per kWh. Then using recent
USA energy sources:
- 35.2% - Natural gas (117 lbs/million BTU) ($14.71/million BTU)
- 27.5% - Coal (205 lbs/million BTU) ($10.18/million BTU)
- 19.4% - Nuclear (0 lbs/BTU) ($10.18/million BTU*)
- 16.9% - Renewables (0 lbs/BTU) ($10.18/million BTU*)
(*) I'm using coal cost, the minimum to guesstimate of these costs.
Given the USA average commercial rate of $0.11 per kWh, we can now estimate how much CO{2} comes from $80:
- $80 / $0.11 ~= 727 kWh
- 35.2% * 727 ~= 256 kWh natural gas * 3412 ~= 873,500 BTU
- 27.5% * 727 ~= 200 kWh coal * 3412 ~= 682,400 BTU
For estimation, thermal power plants are roughly 33% efficient (low efficiency case):
- 873,500 / 33% ~= 2,646,970 BTU -> 310 lbs CO{2}
- 682,400 / 33% ~= 2,067,879 BTU -> 424 lbs CO{2}
- ~734 lbs CO{2} per battery kWh
So let's have more 'back of the envelope' fun:
- 19.6 lbs CO{2} per gallon of gas -> 37.4 gallons of gas per battery kWh
- 22.38 lbs CO{2} per gallon of diesel -> 32.75 gallons of diesel per battery kWh
There are enough ***-umptions to take more than a pallet of toilet paper to clean up. But this was never intended as a definitive study but to bring things into perspective. On day zero, an EV will start with a CO{2} load equivalent to 32-38 gallons of diesel or gasoline. Typical Tesla batteries come in these sizes:
- ~50 kWh (mine) -> 1,638-1,870 diesel-gas gallons
- ~75 kWh (larger Model 3) -> 2,457-2,805 diesel-gas gallons
- ~100 kWh (Model S/X) -> 3,275-3,740 diesel-gas gallons
But this initial load is incorporated in the purchase cost. As an operator, my CO{2} cost is ~1/3d to 1/4th the cost per mile. Others have done more detailed modeling:
As an owner:
- Full power at lights - I reach the speed limit first.
- Very low noise, no oil changes, no brake pads, no exhaust
- 1/3d to 1/4th the cost per mile that I pay
- I don't care about manufacturing CO{2}
Bob Wilson
ps. Tesla battery costs are reported less than $100/kWh or 100 / 176 ~= 57% lower. Woot Woot!
