This section was created so that users do not need prior knowledge of which EV models are available. If they have an idea of what they are looking for in a car, based on the information provided, they can fill out this section according to their wants and needs.
This is a followup to Step 1, and allows the user to select which vehicles to compare in the rest of the tool. The models that come up in the drop down list are only those that fit all of the criteria selected in Step 1. The information provided for each vehicle’s cylinders, engine, and transmission is taken from the Fuel Economy Guide.
The purpose of Step 3 is to specify factors that affect driving and fuel usage based on the user’s location and driving habits. The default values are explained below, but to obtain the most accurate outcome of fuel usage and cost, users are allowed to change the inputs.
When a user enters their zip code, it supplies the following local information:
$$Total\ annual\ miles\ = (daily\ mi) * (\frac{days}{week}) * (\frac{weeks}{year}) + long\ distance\ mi$$
This step was created to teach anyone interested in purchasing an EV about charging, and to gather information about what their charging habits would look like in order to estimate their electricity usage. It is especially important if one of the selected powertrains is a PHEV to know how much of the daily mileage would run on electric. If both powertrains selected are HEVs, then this step does not apply, because HEVs do not need to be plugged in.
$$time\ driving\ before\ battery\ needs\ recharging = \frac{0.8* rated\ electric\ range}{daily\ miles}$$
If the user is planning on charging while at work or any other place outside of the home, this will also be factored into the total cost of electricity. If the box for “Yes” is not checked, then this does not change anything. If “Yes” is checked:
This chart is similar to the chart found in the Vehicle Cost Calculator tool. There are a few differences, including the first year price and the option of viewing the total cost of ownership without taking out loans.
The following are variable names and their corresponding description for the use of Step 5. Further calculations used to solve for each value are shown in a chart below the main calculations that are put into the graph. Sources are included in the appendix at the bottom of this page.
Variable  Variable Description  Value  Source 

DF  discount factor  0.87  1 
TM  tires and maintenance cost 
for ICE,HEV, and PHEV: 5.38 cents/mile for BEV: 4.1 cents/mile 
2, 3 
ILR  Insurance, License, Registration  $1,616  4 
GC  gas cost  starts with annual gas cost, increases each year with an escalation rate of 1.8  see Step 6 Fuel Cost Calculations below for annual cost, source 5 for escalation rate 
EC  electric cost  starts with annual electric cost, decreases each year with an escalation rate of 0.3  see Step 6 Fuel Cost Calculations below for annual cost, source 6 for escalation rate 
DP  Down Payment  10%  7 
LP  Loan Payment  6% annual interest  8 
FTI  federal tax incentive  Varies based on model  9 
yr  year  1  15 
For the purpose of these calculations, we refer to all gasoline engine models by their powertrain  internal combustion engine, or ICE.
If “Yes” is checked for the vehicle to be financed, the firstyear costs include the initial down payment, fuel costs, loan payment, insurance, license and registration, and the tax incentives for BEV and PHEV are factored out. If “No” is checked, then the down payment and loan payment are replaced with the full price of the vehicle.
ICE & HEV firstyear cost:
$$1^{st}\ yr\ [\$] = \frac{(TM+ILR+GC_{1}+DP+LP)}{DF}$$
PHEV firstyear cost:
$$1^{st}\ yr\ [\$] = \frac{(TM+ILR+GC_{1}+EC_{1}+DP+LP)}{DF}  (FTI_{PHEV})$$
BEV firstyear cost:
$$1^{st}\ yr\ [\$] = \frac{(EV\ TM+ILR+EC_{1}+DP+LP)}{DF}  (FTI_{BEV})$$
The vehicle is set to be financed for 90% of the initial cost, with a 5year loan at 6% interest rate. For years 2 through 5, the annual cost of ownership includes the loan payment, insurance, license and registration, with an escalation factor applied to gasoline and electricity prices.
ICE & HEV years 2–5 cost:
$$n^{th}\ yr\ [\$] = \frac{(TM+ILR+GC_{n}+LP)}{DF_{n}}$$
PHEV years 2–5 cost:
$$n^{th}\ yr\ [\$] = \frac{(TM+ILR+GC_{n}+EC_{n}+LP)}{DF_{n}}$$
BEV years 25 cost:
$$n^{th}\ yr\ [\$] = \frac{(EV\ TM+ILR+EC_{n}+LP)}{DF_{n}}$$
For the remaining years, the annual cost is the sum of the upkeep of owning a car: tires, maintenance, insurance, license, registration, and fuel costs. If “No” is checked for the vehicle to be financed, then years 2 through 5 will be the same as the following:
ICE & HEV years 6–15 cost:
$$n^{th}\ yr\ [\$] = (TM+ILR+GC_{n})$$
PHEV years 6–15 cost:
$$n^{th}\ yr\ [\$] = (TM+ILR+GC_{n}+EC_{n})$$
BEV years 6–15 cost:
$$n^{th}\ yr\ [\$] = (TM_{BEV}+ILR+EC_{n})$$
The table below shows where each variable comes from and how they are first calculated for use in the equations above.
Variable  Calculation 

Discount factor 
$$discount\ for\ n^{th}\ year = 1.0087^n$$

Tires/maintenance cost 
$$= \frac{5.38}{100}+(total\ annual\ miles)[\$]$$

EV tires/maintenance cost 
$$= \frac{4.10}{100}+(total\ annual\ miles)[\$]$$

Gas escalation rate 
$$rate\ for\ n^{th}\ year=1.018^n$$

Electricity escalation rate 
$$rate\ for\ n^{th}\ year=0.997^n$$

Down Payment  $$=0.10*(price\ of\ vehicle)$$ 
Loan Payment 
$$=0.232 * 0.9 * (price\ of\ vehicle)$$

Fuel (gas) cost 
$$1^{st}\ yr\ cost = (\frac{\$}{gal})*(\frac{annual\
miles}{MPG})$$
$$n^{th}\ yr\ cost= (1^{st}\ yr\ cost)*(Gas\ escalation\
rate)$$
For example:
$$2^{nd}\ yr\ cost=(1^{st}\ yr\ cost)*(1.018^2)$$

Electricity cost 
$$1^{st}\ yr\ cost=(\frac{cents}{kWh})*0.1*(\frac{annual\
miles}{100}*\frac{kWh}{100\ mi})$$
$$n^{th}\ yr\ cost= (1^{st}\ yr\ cost)*(Elect.\
escalation\ rate)$$
For example:
$$2^{nd}\ yr\ cost = (1^{st}\ yr\ cost)*(0.997^2)$$

This is the final step for the tool, and it displays the outcome of all the inputs leading up to this. First, the annual gas usage, fuel costs, and GHG emissions are given. Second, to further exemplify how driving an EV can save money, a chart is included showing daily savings from driving an EV compared to a gasoline engine powertrain based on driving speed. In the calculations below, the conventional gasoline vehicle is referred to by the powertrain – internal combustion engine (ICE).
Gasoline usage [gallons] – this is calculated differently depending on the powertrain. The values used in the calculations are from driving factors and miles per gallon equivalent (MPG(ge))(10). Driving factors are calculated from the inputs in Step 3, and MPG(ge) is the rated combined fuel efficiency from the Fuel Economy Guide. Annual miles is based on the daily driving habits, and how many days in a year the user input for their daily mileage to occur.
$$annual\ miles= daily\ miles\ * \frac{days}{week}*\frac{weeks}{year}$$
Powertrain  Gasoline Usage Calculation 

ICE/HEV 
$$Gas\ Used\ [gal]=\frac{(annual\ miles + long\
distance)}{MPG_{comb.}}$$

PHEV 
PHEVs are calculated more in depth because they use both gasoline and electricity, and the annual consumption of each fuel depends on the electric range of the vehicle and the user’s long distance and daily driving. The electric range is from the ratings at fueleconomy.gov. For the purpose of the next table on Fuel Costs, this section will also provide calculations on PHEV electricity annual usage (El. Used). These calculations take into account a 20% depletion of the rated electric range because of outside factors such as weather and aggressive driving. Daily Driving:If 80% electric range > daily mileage and we assume the vehicle is charged at home every night: $$Gas\ Used\ [gal]= 0$$
$$El.\ Used\ [kWh]=\frac{annual\
miles}{100}*\frac{kWh}{100\ mi}$$
If electric range is less than daily mileage: This part also depends if “Yes” was checked for workplace/other public charging in Step 5, which would mean the battery gets recharged during the day and more electricity is used than gasoline. If “Yes” is checked and 80% electric range >1/2 daily mileage: We assume that the battery is recharged enough halfway through the day’s driving, and there is enough power to run on electricity through out. $$Gas\ Used\ [gal]= 0$$
$$El.\ Used\ [kWh]=\frac{annual\
miles}{100}*\frac{kWh}{100\ mi}$$
If “Yes” is checked and electric range is less than 1/2 daily mileage: We assume that the battery can cover a fraction of half the day’s driving, and gasoline will be used for the rest until recharged.
$$Gas\ Used\ [gal]= (1  \frac{0.8* electric\
range}{0.5* daily\ miles})*\frac{annual\ miles}{MPG}$$
$$El.\ Used\ [kWh]= (\frac{0.8* electric\ range}{0.5*
daily\ miles})*\frac{annual\ miles}{MPG}*\frac{kWh}{100\
mi}$$
If “Yes” is not checked, there will be no recharging during the day, so the PHEV can run on electricity for a fraction of the entire day’s drving.
$$Gas\ Used\ [gal]= (1  \frac{0.8* electric\
range}{daily\ miles})*\frac{annual\ miles}{MPG}$$
$$El.\ Used\ [kWh]= \frac{0.8* electric\ range}{daily\
miles}*\frac{annual\ miles}{MPG}*\frac{kWh}{100\ mi}$$
Long Distance driving:
For longdistance travel, we assume that all city miles are on electricity, while all highway miles are on gasoline:
$$El.\ Used\ [kWh]=\frac{kWh}{100\ mi.} *Long\
Distance*\frac{(\%City\ miles)}{100}$$
$$Gas\ Used\ [gal] = \frac{Long\ Distance * (\%Highway\
miles)}{MPG_{comb.}}$$
The total Gas Used and Electricity Used in a year is the
sum of the daily travel and longdistance travel usages.

BEV  $$Gas\ Used\ [gal]= 0$$ 
Fuel Costs (gas and electric) [$] – this is also calculated differently depending on which powertrain, because the different powertrains are fueled by either gas, electric, or both. These calculations include the gas and electric prices from Step 3, total annual mileage and MPG for powertrains running on gasoline, and kWh/100 miles for powertrains running on electricity. kWh/100 miles is taken from fueleconomy.gov.
Powertrain  Fuel Cost Calculation 

ICE/HEV 
$$Fuel\ Cost\ [\$] = (\frac{total\ annual\
miles}{MPG_{comb.}}) * \$/gal$$

PHEV 
PHEVs are calculated differently because they use both
gasoline and electricity, and the total cost is for both
fuel types combined, based on the equations for gas usage.
$$Fuel\ Cost\ [\$] = (Gas\ Used)*\frac{\$}{gal}+(El.\
Used)*\frac{\$}{kWh}$$

BEV 
$$Fuel\ Cost\ [\$] =( total\ annual\ miles)*
\frac{\frac{kWh}{100\ mi}}{100}*\frac{\$}{kWh}$$

GHG Emissions [kg] – emissions are counted as the sum of both upstream and tailpipe emissions, listed on fueleconomy.gov. For EVs, total emissions can be found at Beyond Tailpipe Emissions; our tool uses the national average.
Powertrain  GHG Emissions Calculation 

ICE/HEV 
$$GHG\ [kg]=(tailpipe+upstream)[\frac{g}{mi}]*(
annual\ mi)*0.001$$

PHEV 
$$GHG\ [kg]=(tailpipe+upstream)[\frac{g}{mi}]*(
annual\ mi)*0.001$$

BEV 
$$GHG\ [kg]=(upstream)[\frac{g}{mi}]*(
annual\ mi)*0.001$$

This graph compares the two alternative powertrains to the selected ICE vehicle. The yaxis shows the amount of money saved in a day based on the xaxis, which shows driving speed. The calculations are derived from the hours spent driving in a day, MPG(ge), electric range of EVs, and fuel prices. These are the initial assumptions made:
Starting at 100% urban driving, this is decreased by 5% for each point until reaching 0%. The following calculations are made for each point:
$$calculated\ MPG_{comb.}=100/(\frac{\%urb\ miles}{MPG_{city}}+\frac{100\%urb\ miles}{MPG_{Hwy}})$$
$$MPH = 100/(\frac{\%urb\ miles}{19.7\ MPH}+\frac{100\%urb\ miles}{57.9\ MPH})$$
City and highway MPG are from the Fuel Economy Guide. For PHEVs and BEVs, the efficiency used is the MPG or MPGge, also from the Fuel Economy Guide. At 100% urban miles, the combined MPG(ge) equals the rated city MPG(ge), and at 0% urban miles, the combined MPG(ge) equals the rated highway MPG(ge).
For PHEV and BEV powertrains, the kWh/100 miles is set based on the above calculated MPG and their Fuel Economy rated values. This is used to estimate the amount of kWh used in a day.
$$calculated\ \frac{kWh}{100\ m}=rated\ \frac{kWh}{100\ m}*\frac{rated\ MPG_{comb.}}{calculated\ MPG_{comb.}}$$
For PHEVs, the electric range is also necessary to determine how much driving is spent on electric compared to gasoline, with both contributing to the cost of driving.
$$Electric\ Range = (Rated\ Electric\ Range) * \frac{rated\ kWh/ 100\ m}{calculated\ kWh/100m}$$
Next, gallons or kWh by day are computed using the above values and the daily driving time (in hours per day). This is done differently for each powertrain. The miles driven/day equation below affects the PHEV fuel used.
$$\frac{miles\ driven}{day} = MPH_{calculated}* \frac{hours\ driven}{day}$$
Powertrain  Fuel Used per Day 

ICE/HEV (gal/day) 
$$\frac{gal}{day} =
\frac{MPH_{calculated}}{MPG_{calculated}} * \frac{hours\
driven}{day}$$

PHEV Can run on either gas or electric (gal/day or kWh/day) 
If (miles driven/day) is less than electric range:
$$\frac{kWh}{day} = \frac{hours}{day} * calc.
\frac{kWh}{100\ m} * \frac{MPH}{100}$$
$$\frac{gal}{day} = 0$$
If (miles driven/day) is greater than electric range:
$$\frac{kWh}{day} = calc.\frac{kWh}{100\
mi}*\frac{range_{calculated}}{100}$$
$$\frac{gal}{day} = \frac{(MPH * \frac{hours}{day})
range_{calculated}}{MPG_{calculated}}$$

BEV (kWh/day) 
$$\frac{kWh}{day}=(MPH)*\frac{\frac{kWh}{100\
mi}_{calculated}}{100\ mi}*\frac{hours}{day}$$

Gallons and kWh are converted into dollars with the price of gasoline and residential electricity in Step 3 – which is then translated into savings when the amount from the EV powertrain is subtracted from the ICE amount.
Powertrain  Savings per Day ($) 

ICE/HEV 
$$\frac{\$}{day} = ([\frac{gal}{day}]_{ICE} 
[\frac{gal}{day}]_{HEV})*\frac{\$}{gal}$$

PHEV 
$$\frac{\$}{day} =
([\frac{gal}{day}]_{ICE}*\frac{\$}{gal}) 
([\frac{gal}{day}]_{PHEV}*\frac{\$}{gal} +
[\frac{kWh}{day}]_{PHEV}*\frac{\$}{kWh})$$

BEV 
$$\frac{\$}{day} =
([\frac{gal}{day}]_{ICE}*\frac{\$}{gal}) 
([\frac{kWh}{day}]_{BEV}*\frac{\$}{kWh})$$

To make it relevant to the user’s location, the graph also shows the average speed for their location, taken from Step 3. The default value for this is derived from NHTS09, but users could also have changed this during Step 3.
The following table lists the sources of information in the table found in Step 5.
Source Number  Variable  Source Description 

Step 5  
1  Discount factor  Assumed value based on the current national average return on a 5year CD (http://www.bankrate.com/cd.aspx) 
2  Tires and maintenance  American Automobile Association (AAA), "Your Driving Costs, 2010 Edition 
3  BEV tires and maintenence  AAA maintenance reduced by 28% based on: DeLuchi and Lipman, 2001, An Analysis of the Retail and Life Cycle Cost of BatteryPowered Electric Vehicles, UCDavis Institute of Transportation Studies, http://escholarship.org/uc/item/50q9060k 
4  Insurance, license, and registration  Average of 5 vehicle classes – small sedan, medium sedan, large sedan, 4 x 4 SUV, minivan; 5 averages within +/−12% of grand average 
5  Gasoline price escalation rate  EIA, Annual Energy Outlook, 2011, Table A3, Transportation section 
6  Electricity price escalation rate  EIA, Annual Energy Outlook, 2011, Table A3, Transportation section 
7  Down payment  AAA, Your Driving Costs, 2010 Edition 
8  Loan payment  AAA, Your Driving Costs, 2010 Edition 
9  Federal tax incentive  Qualified PlugIn Electric Drive Motor Vehicles section of the IRS code (IRC 30D) 
Step 6  
10  MPG(ge) city/highway/combined  Fuel Economy Guide 