Rat
Well-known member
There have been several different threads or posts about how much it costs for the power to run a Leaf, but they all suffer from being too technical and not taking into account rate structure and other factors like usage patterns besides the car charging. With two PG&E bills to go off of now I think this way is simpler for most people and more accurate.
1. Compare your current electric bill (cost only) to the same month last year. Mine went up $21 for June, $24 for July. I got the car June 4 so these are pretty consistent.
2. Use Carwings or the odometer to determine your total driving distance for the month. I've been driving about 350 mi./mo.
3. Divide the $ from step 1 by the miles in step 2 and you have your cost in dollars per mile (or actually, cents per mile).
That's all there is to it. For me I drove about 700 mi. for a total increase in electric cost of $45 so the cost is about 6.4 cents per mile. Obviously this is just for the electricity, and does not take into account other factors. If you charge at work or pay for electricity elsewhere then you need to account for that separately, but for those of us charging exclusively at home and without solar this works. There's some inaccuracy because other factors may account for some of the difference from last year, like weather, vacations, etc. but after a few months those things average out.
From my electric bill I can determine that overall my average cost per Kwh is about 25 cents. My car used 129.4 Kwh during that period. If I multiply the two I get $32.35 of electricity used by the Leaf, or about 4.6 cents per mi. Why is this less than the way I just explained it above? Because the added electric consumption from the Leaf charging has pushed me from Tier 2 rates to higher Tier 3 rates, which are applied by the utility to all usage at any time of day, not just the periods when I charge. In effect by charging the Leaf I push up my costs for running the refrigerator, TV, oven, lights, etc. So the engineer's or scientist's logical approach of computing Kwh and applying rates is misleading. This is especially so if they logically use the rates from off-peak since they are charging during off-peak hours. That's only 5.6 cents per Kwh for Tier 1 here. The problem is that you aren't charging at Tier 1 rates if you have other usage, which everyone does (although if you have solar you may keep that usage off the utility's grid and stay in Tier 1). Energy usage is marginal, like taxes. If your ordinary non-Leaf usage is near the top of Tier 2, charging the car at night pushes you into Tier 3 not only for the off-peak charging, but for all times of day, at least for PG&E customers and other utilities that have baseline rates and higher rates for usage above that. So the bottom line is just divide dollars increase on electric bill by miles driven; that's your true cost, no spreadsheet needed.
1. Compare your current electric bill (cost only) to the same month last year. Mine went up $21 for June, $24 for July. I got the car June 4 so these are pretty consistent.
2. Use Carwings or the odometer to determine your total driving distance for the month. I've been driving about 350 mi./mo.
3. Divide the $ from step 1 by the miles in step 2 and you have your cost in dollars per mile (or actually, cents per mile).
That's all there is to it. For me I drove about 700 mi. for a total increase in electric cost of $45 so the cost is about 6.4 cents per mile. Obviously this is just for the electricity, and does not take into account other factors. If you charge at work or pay for electricity elsewhere then you need to account for that separately, but for those of us charging exclusively at home and without solar this works. There's some inaccuracy because other factors may account for some of the difference from last year, like weather, vacations, etc. but after a few months those things average out.
From my electric bill I can determine that overall my average cost per Kwh is about 25 cents. My car used 129.4 Kwh during that period. If I multiply the two I get $32.35 of electricity used by the Leaf, or about 4.6 cents per mi. Why is this less than the way I just explained it above? Because the added electric consumption from the Leaf charging has pushed me from Tier 2 rates to higher Tier 3 rates, which are applied by the utility to all usage at any time of day, not just the periods when I charge. In effect by charging the Leaf I push up my costs for running the refrigerator, TV, oven, lights, etc. So the engineer's or scientist's logical approach of computing Kwh and applying rates is misleading. This is especially so if they logically use the rates from off-peak since they are charging during off-peak hours. That's only 5.6 cents per Kwh for Tier 1 here. The problem is that you aren't charging at Tier 1 rates if you have other usage, which everyone does (although if you have solar you may keep that usage off the utility's grid and stay in Tier 1). Energy usage is marginal, like taxes. If your ordinary non-Leaf usage is near the top of Tier 2, charging the car at night pushes you into Tier 3 not only for the off-peak charging, but for all times of day, at least for PG&E customers and other utilities that have baseline rates and higher rates for usage above that. So the bottom line is just divide dollars increase on electric bill by miles driven; that's your true cost, no spreadsheet needed.
