Calculating car ownership costs (enviro costs too!)

Should be? The inclusion of environmental costs can be seen as an act of social responsiblity, or as an anticipation of future taxes/charges that will/should be in place. This tool makes it easy to build scenarios with different environmental costs: say a $0.50 per gallon carbon tax or a a $4.00 per gallon carbon tax

Thus, the best use of this tool is to compare costs under different scenarios? For example, what if gas prices jump? What if air pollution demands a large gas tax? What if electricity prices fall?

Time variables:	Time horizion:	Discount rate:

Fuel costs

Gas Costs

Electricity Costs

Gas price / gallon

electricity price /kwh

Enviro cost of gas / gallon

Enviro cost of electricity /kwh

Toggle display of the environmental costs worksheet ...

x Environmental fuel costs worksheet

Gasoline

Electricity

CO2 cost / gallon

CO2 cost / kwh

Toggle display of Co2-tax worksheet ...

x CO2-tax worksheet: Convert tax per ton of CO2 to gallon and kwh costs

What is the cost per ton of CO2
Note that for a ...	the pounds of CO2 is	(in tons per ..)	Click button to use this per unit CO2 cost.
gallon of gas		0.00950
a kwh		0.000685

Air polution cost / gallon

Air polution cost / kwh

Resource cost / gallon

Resource cost / kwh

per gallon enviro costs: 0

per kwh enviro costs:0

...

Green energy faction: 0

Green energry Cost/kwh: 0

Toggle display of green energy variables worksheet

x Green energy variables worksheet: Are you producing any green electricity(i.e.; using photovoltaic panels) ...

PV fraction		What fraction of your electricity is from green sources (i.e.; photovoltaic panels).
PV cost/kwh		What is the cost, per kwh, of this electricity

Full gas price per gallon:

4.00

Full electricity price per kwh:

0.15

Environmental-costs of building a car variables

Gallons per lb of normal car

Toggle display of build costs worksheet

x Environmental costs of building a car worksheet

btu/gallon of gas	113500
btu used per pound of car
Normal car:		(gallons per pound: `0.28)`
Hybrid car:		(gallons per pound: `0.34)`

Gallons per lb of hybrid car

Miles you drive (this is assumed to apply to all cars -- your choice of new car will not effect your driving habits)

Short trip miles

Toggle display of short trip miles worksheet ...

x Short trip miles worksheet: compute your yearly short trip (city) miles ...

Workdays:	Daily commute distance (round trip):	Workdays per year:	Your yearly commuting distance (in city traffic): 5000
Non-workdays (weekends, etc):	Typical city miles driven (shopping trips, etc):	Non-workdays per year:	Your yearly non-commuting distance (in city traffic): 2000

Note: these variables are also used to compute the pct of miles driven in EV mode

Long trip miles

Current car long trip miles

Set to 0 if you will NOT be keeping the current car

Maintenance cost variables
For mileage range	0 to 36k	36k to 60k	60k to 100k	100k to 150k	greater then 150k
Repair costs per mile
Insurance costs per year

Specs of your current car (miles driven per year: 12000)

Current car: Name: Current mileage:

EV variables 0 0

Short trip mpg Short trip gallons: 350 Yearly short trip costs: 1400

Long trip mpg Long trip gallons: 100 Yearly long trip costs: 400

current car long trip miles gallons: 67 costs: 270

average mpg: 25 Yearly fuel costs: 2070

Maintenance costs

For year ...	1	2	3	4	5	6	7	8
For year ...

Specs for new cars (miles driven per year: 12000)

Alternate car 1:

Name:

Price:

Weight:

Is this car a ...

Hybrid?

Electric?

EV range stMiles EV: 0 (0%)

miles per KWH Short trip KWH: 0 Yearly short trip electricity costs: 0

Short trip mpg Short trip gallons: 175 Yearly short trip costs: 700

Long trip mpg Long trip gallons: 75 Yearly long trip costs: 300

average mpg: 25 Yearly fuel costs: 1270

Maintenance costs

For year ...	1	2	3	4	5	6	7	8
For year ...

Alternate car 2:

Name:

Price:

Weight:

Is this car a ...

Hybrid?

Electric?

EV range stMiles EV: 0 (0%)

miles per KWH Short trip KWH: 0 Yearly short trip electricity costs: 0

Short trip mpg Short trip gallons: 175 Yearly short trip costs: 700

Long trip mpg Long trip gallons: 75 Yearly long trip costs: 300

average mpg: 25 Yearly fuel costs: 1070

Maintenance costs

For year ...	1	2	3	4	5	6	7	8
For year ...

Alternate car 3:

Name:

Price:

Weight:

Is this car a ...

Hybrid?

Electric?

EV range stMiles EV: 0 (0%)

miles per KWH Short trip KWH: 0 Yearly short trip electricity costs: 0

Non-EV short trip mpg Short trip gallons: 140 Yearly short trip costs: 560

Long trip mpg Long trip gallons: 60 Yearly long trip costs: 240

average mpg: 25 Yearly fuel costs: 1070

Maintenance costs

For year ...	1	2	3	4	5	6	7	8
For year ...

Alternate car 4:

Name:

Price:

Weight:

Is this car a ...

Hybrid?

Electric?

EV range stMiles EV: 0 (0%)

miles per KWH Short trip KWH: 0 Yearly short trip electricity costs: 0

Non-EV short trip mpg Short trip gallons: 140 Yearly short trip costs: 560

Long trip mpg Long trip gallons: 60 Yearly long trip costs: 240

average mpg: 25 Yearly fuel costs: 1070

Maintenance costs

For year ...	1	2	3	4	5	6	7	8
For year ...

Why?	If you think of the electricity needed to power the car as "marginal", then you are buying all of it from the utility: so pvFraction=0. But if you think of using your "average cost per kwh", so as to not differentiate how you use it, then pvFraction= `kwh/yr pv production` divided by `total yearly electricity use`

Assumptions:	You charge the battery every night, but only at night. That is: you don't charge the battery at work. If you do charge the battery elsewhere regularly, you can accomodate this by increasing the value of the EV range variable. You can't have percentage greater than 100%. This means that if your short trips are always less thann your EV range, you just won't be using the full capacity of the battery. The battery is used just for short trips. That is, we assume that on long trips the battery impact is small -- which means that we assume that long trips are all under gasoline.

Your current car.

The current car is special. You can ..

Not buy a new car, and use this current car all the time
Buy a new car, and keep the current car. For example, you might keep it for long trips with lots of luggage, or for use by guests/kids.
Buy a new car, and get rid of the current car. If you do this, you should adjust the price of the new car (to account for trade in value of your current car).

Note that setting te current car long trip miles to 0 means get rid of the current car.

Is this car a hybrid? Is this car electric?

Check these buttons if the car is a hybrid, or if the car has electric (plug in) capabilities.

If you check hybrid, the production costs are modified.
If you check electric, you will then set a few more variables (such as the range, and miles per kilowatt hour) for this car.

Environmental fuel costs

The several categories of environmental fuel costs should contain guesses as to the "non-market" costs of using energy resources. This includes co2, other air pollution, and resource depletion (i.e.; costs of maintaining military)

Environmental costs of building a car

The values in this worksheet are use to estimate the gallons of gas to build a car. More precisely, the full car cost table uses an estimate of the energy required to build a car. This estimate is converted to gallons of gas, and the environmental costs of this quantity of gasoline is used as the environmental costs of building a car.

To do this, a btu per pound of car value is used. Two values should be specified: one for normal cars, and one for hybrid cars.

Default values, that are derived from averages across all cars, are provided. Note that this is used for all cars, all that matters is whether the car is a hybrid or not (and the weight of the car). By the way, electric cars will have similar features as hybrids (large batteries).

Notes:

the btus per gallon of gasoline is used, and is displayed. You can't change that!
After changing the btus per pound, a gallons per pound is computed. You can copy that number to the appropriate field.
That is, it will not be automatically used.

Maintenance costs

Maintenance costs means all yearly costs that are not fuel costs. Actually, what is of greatest interest are the costs that are not constant across cars. Thus, registration fees and liability insurance can be ignored. Examples of interesting costs are repair costs and equipment insurance, since these can vary across cars (especially across cars with different mileage). For example: older cars require more repair dollars, but less equipment insurance.

A value for each year (up to the years specifiedin the time horizion variable) should be specified.

You can auto fill these values. Auto fill uses the maintenance cost variables, which are combined with the predicted mileage of a car.

Note: auto fill will estimate maintenance costs of both the new car, and the current car (if you chose a current car long trip miles greater than 0)

Maintenance cost variables

The maintenance cost variables are used to auto-fill maintenance costs for a car. These variables do not vary across cars. Instead, they are combined with the expected mileage a car will have at the beginning of a year.

You will fill in a range of values, that are for a range of miles. At the beginning of each year, the mileage for a car is computed, and then the matching range is found. The repair-costs-per-mile, and the insurance-for-year, for this range are then used. Note that the insurance costs are constant, while the repair costs depend on the miles driven per year.

Typically, one expects the per mile repair costs to increase with mileage (since high mileage cars need more frequent main down more often). One might also expect insurance costs to drop (say, because you increase the deductible as the car ages).

Note: we recommend ignoring costs that do not vary across cars. This includes liability insurance, registration fees, and some regular maintenance.

Car	Purchase and maintenance	enviro build cost	Fuel costs	Total cost

Yearly fuel cost comparisons

Full cost of ownership, over time (8 years)