Home / Uncategorized / Total Cost of Ownership Calculator Assumptions
The PGR Calculator was built on the following platform of assumptions:
| Constant Inputs[3] | |
| Price of Electricity | $0.11/kWh |
| BTUs per Gallon of Gasoline | 125,000 |
| BTUs per Gallon of Diesel | 139,000 |
| BTUS per Barrel of Oil | 5,800,000 |
| Well to Pump Efficiency of Gas | 79.8% |
| Well to Pump Efficiency of Diesel | 83.7% |
| Duration of Car Payments | 5 yr |
| CO2 Equivalent Emissions of Electricity | 684 g/kWh |
| Well to Wheel CO2 Equivalent Emissions of Gasoline | 11,500 g/gal |
| Well to Wheel CO2 Equivalent Emissions of Diesel | 10,700 g/gal |
Generation Mix Assumed
In order to calculate the CO2 equivalent green house gas emissions relating to electricity use, the following generation mix was assumed:[4]
| Electricity Generation Mix and Power Plant Emissions Factors (g/kWh) | ||||
| Power Plant | Generation Mix | CH4 | NO2 | CO2 |
| Residual Oil | 2.7% | 0.009 | 0.004 | 833.9 |
| Natural Gas | 18.9% | 0.030 | 0.012 | 504.8 |
| Coal | 50.7% | 0.012 | 0.011 | 1084.0 |
| Biomass | 1.3% | 0.041 | 0.117 | 1086.0 |
| Nuclear | 18.7% | 0.000 | 0.000 | 0.0 |
| Other (wind, hydro, geothermal) | 7.7% | 0.000 | 0.000 | 0.0 |
| Totals | 100% | 0.313 | 0.009 | 681.6 |
| CO2 Equivalent Multiplier | 25 | 298 | ||
| Total Emissions (g/kWh) | 684.72 | |||
Multipliers of 25 and 298 were used for CH4 and NO2 emissions respectively.
CO2 equivalent green house gas emissions of Gasoline and Diesel use were calculated using the Argonne National Laboratory’s GREET figures:
Emissions from combustion of Gasoline (g CO2eq/gal): 8,909
Well to Pump Emissions of Gasoline (g CO2eq/gal): 1,800
Total[5] (g CO2eq/gal): 10,709
Emissions from combustion of Diesel (g CO2eq/gal): 9,802
Well to Pump Emissions of Diesel (g CO2eq/gal): 1,653
Total[6] (g CO2eq/gal): 11,455
Subsidies
Federal subsidy figures were calculated based on the kWh battery capacity of plug-in vehicles: $2500 + $417 x each kWh of battery capacity in excess of 4 kWh up to a maximum of $7500.
Car Payments
Car payments for each vehicle are made on an annual basis over 5 years.
Monthly lease payments are calculated as 1.5% of the MSRP.
Barrels of Oil Used
Vehicle barrels-of-oil use is estimated based on a vehicle’s use of gas and diesel. Oil used for the production of electricity is not considered.
Barrels of oil saved are calculated using the following formula:
= Gallon of Gas or Diesel used x (BTU per Gallon of Gas or Diesel / Well to Pump Efficiency of Gas or Diesel) / BTU per Barrel of Oil
Driving Profiles
The three driving profiles effectively weight PHEV annual fuel consumption and annual xEV electricity consumption. The consumptions are weighted by the percent charge sustaining and percent charge depleting. The first profile assumes 10% and 90%, the second assumes 40% and 60%, and the third assumes 80% and 20%.
[2] Top 10 Best Selling Vehicles of 2008 based on U.S. News Rankings & Reviews:
http://usnews.rankingsandreviews.com/cars-trucks/daily-news/090107-The-Ten-Best-Selling-Vehicles-of-2008/
[3] Taken from the ANL GREET 1.8.
[4] Taken from the ANL GREET 1.8. Sheet: Electric, Lines: 15-29.
[5] Calculation based on ANL. GREET 1.8. Sheet: Vehicles. Line: 46 and GREET 2.8. Sheet: TEC Results.
[6] Calculation based on ANL. GREET 1.8. Sheet: Petroleum, Line: 191.
How can we add OKA NEVZEV to your calculator comparator ?
Posted by Miro Kefurtq November 3rd, 2009 at 10:32 pmMany, if not most people in California use up their cheap rate electricity so additional use of electricity, as would be an EV, costs $0.27 per kWhr. If the “transportation rate” is applied it means that the cost will be charged to the public.
If real economic thinking is applied, it will be realized that the consequence of an EV will be the use of coal to make the electricity. Where there is available coal fired capacity, the choice will be obvious. Where limits are placed on coal so that more natural gas is used, the upward pressure on natural gas prices will cause more use of coal in places where such limits are not imposed.
One might hope this was not true, but just looking at the rate offered to night time users should suggest that a very cheap fuel will be used for electricity at such times. Why would that not be coal?
Posted by Jim Bullis, Miastrada Co. March 23rd, 2010 at 10:54 pmHi Jim, we understand that adding many EVs will certainly make some places dirtier, but as the grid gets cleaner, so do these cars. If the EVs are incentivized correctly to charge at night, they are using power that is already available and it is far cleaner and more efficient to run EVs off of coal-generated electricity than ICEs off of gas or diesel. Additionally, in California only 1.1% of electricity is generated using coal. Additional baseload caused by EV demand would probably come from hydro and nuclear.
Posted by admin March 24th, 2010 at 12:40 pmHi Admin,
Thanks for the response to my comment. This can be an important discussion.
I hope, as you do, for a really good future world where electric power is made without fossil fuel. However, there are some difficulties in getting there.
Running an EV off of coal generated electricity is somewhat better from a CO2 point of view than running it directly from gasoline, maybe better than diesel but definitely worse than running it off a well designed gasoline hybrid such as the Prius. See the NRDC-EPRI study Fig. 5-1 for the detail on this.
I try to stay away from the “cleaner-dirtier” words since these do not reasonably represent CO2, which is by itself as benign and clean as things can get, but is a huge problem in its global effect.
It might not be a bad thing for us to pay extra in California so that we can burn very little coal here. But it seems like not such a good policy when you realize that on a global basis it could actually have a negative effect, meaning that the use of more natural gas here simply leads to use of more coal elsewhere due to the balancing effect of the natural gas market. Our use of more use of natural gas drives the price of that fuel upwards, and that causes others to make decisions that use less of it; and this means of course that they would use more coal.
Unfortunately, the supposed increase in night time load (”baseload” is not a good term) can not be supplied by hydro or nuclear. First, these are completely tapped out; nuclear in California runs at full tilt regardless of anything and hydro is not capable of responding due to limitations not easily surmounted.
I add that hydro might be better used as a peaking source for daytime short term needs. It also could be very meaningful in combination with wind, where its flexibility is used to fill in where wind fails. There seems to be an idea going that EVs would have some ownership claim to hydro electric power, but this is really something of a fast trick by our PUC and Energy Commission. There is something quite disturbing in knowing that very cheap power is made available at night by making hydro power available, when a far higher use of that hydro power can rather easily be made available for peaking power needs.
Sorry to sound strident about the way things are done, especially since I have the same objectives as you do. I think that we tend to go about fixing things in the wrong way.
You might wonder what I think would be better? RMI has been strongly advocating efficiency which is much more appropriate. I go much further with efficiency than RMI, since I know that aerodynamics for vehicles is far more meaningful than the more timid approaches put forward by RMI.
At the risk of being accused of self promotion, you can get an idea of my approach (not a product) at http://www.miastrada.com.
Posted by Jim Bullis, Miastrada Co. March 25th, 2010 at 8:01 pmHi again Admin,
I try to be complete. You used the word efficiency, so something must be said on that point.
Some, very well respected authority seems to be seriously in error on the subject of electric vehicle physics. Electricity is not a fuel; it can be measured in terms of energy, but it is really only a carrier of energy. It has to be generated using a heat engine. If the efficiency of such a heat engine, such as coal, being 32% in the USA on average, is taken into account,the “efficiency” efficiency of an electric motor system comes more in line with that of a motor vehicle that carries its own heat engine. By counting the energy transfer efficiency of the electric motor as something that can be compared with the heat engine efficiency of an engine, we get very wrong results. In fact, the EV is artificially made to look three times better than it is. By the way, a clue to the correct thinking might be noticed in the fact that the proper terminology is that an electric motor is a “motor” and an ICE is and “engine.”
Posted by Jim Bullis, Miastrada Co. March 25th, 2010 at 8:14 pmIn my previous on the 24th at 8:01 I provided no link to the NRDC-EPRI study that I referred to, so here it is: http://mydocs.epri.com/docs/public/000000000001015325.pdf
Figure 5-1 carries my point about CO2 from electric vehicles, even though it is directly addressing plug-in hybrids that work as hybrids about half the time. The bar labeled “old coal” represents coal systems that provide most of our power production from fossil fuels, and a large reserve capacity as well. The yellow part of that bar is the CO2 for the electric part of the car operation. For an all electric car, that would need to be doubled, and the lower red bar would need to be deleted.
As I discussed before, in reacting to new loads, electricity production does not respond proportionately to its status quo ratios of the “mix”; instead, the response is determined by reserve capacity and relative cost advantages within that limitation If it can be agreed that coal will be the fuel used to respond to new loads, clearly, for CO2 reduction, we would be much better off to stick to a good hybrid and forget the next step of the plug-in operation.
Of course, some day things could be different. However, the IEA put out a report before Copenhagen which showed aggressive conversion to renewables and EVs at a future time point, but there was still a substantial component of coal systems in the production of electricity. Thus consider that every EV that might be eliminated at that point, would directly reduce use of coal. As I recall, they used the year 2030 for this study data point.
Thus, it seems that a big shift to EVs should not start yet.
Posted by Jim Bullis, Miastrada Co. March 26th, 2010 at 10:20 am