Miles per year: 12,045 (33 miles every day)
Assumed Efficiency: 250 AC Wh/mi
Annual Consumption: 3,011 AC kWh
Required DC System Rating: 1.88kW (@1600 kWh/yr/kW DC)
Assumed System lifetime: 20 years

Est Upfront Cost: $13,174 (assumed $7/W installed)
Util Rebate: -$5,646
AZ Tax Rebate: -$1,000
Fed Tax Rebate: -$3,952
System Net Cost: $2,576

Low Fuel Offset Estimate: 5,236 gallons (vs. 46mpg)
High Fuel Offset Estimate: 10,950 gallons (vs. 22mpg)
Est 20 Year Av Gasoline Price: $2.73 ($2/gal, increasing at 3% per year)
Est Value of Offset Fuel: $14,294 – $29,893
Break Even Point: <5 years - <2.5 years
Annualized ROI: ~23% – ~53%

This analysis is for the solar alone. It does not include the cost of the conversion, or premium for a factory PHEV.

Our company 3Prong Power Inc. has a conversion that allows you to turn the motor off completely and drive around town up to 50mph as an electric vehicle only until you run out of battery power. The engine never comes on in this mode. Right now the mileage I get on my commute to work (admittedly less than 10 miles from my house) is infinity miles per gallon.

The car takes 5 kwh per charge so if I charge it every work day, it would be 1300 kwh per year for communting. As a practical matter, I don’t commute by car every day, in fact, in summer I rarely use the car because it is easy to commute by bike and the exercise is great. So the car charging essentially comes “for free” from the extra we would normally give back to PG&E. The original payback time for the solar array was something like 15 years, it would be interesting to calculate how that changes when I can displace 20 mi of gasoline per commute. I calculated that the plug-in displaces something like 66% of the CO2 the car would normally generate, it would be great to get that up to 80% with something like an ethanol conversion, but that looks to be tough since nobody markets a CARB-approved ethanol kit for the Prius.

Regarding practicality of charging, I’ve strung an extension cord from a 110v/15amp socket to the front of the garage (I originally wanted a plug in the floor that would come up on a spring, but the cost of installing that was too big for one car). The cord is on a mechanical timer that goes on between 11 PM and 5 AM when power is cheapest. By the NetMetering tariff, PG&E pays about 3x for power in summer during 11 AM and 6 PM because that’s when they have air conditioning peak load, so I don’t want to charge it then. The car takes about 5 hr to fully charge, but it is about 2/3 to 3/4 charged within a couple of hours. I wanted a 220v charger too for faster charging but Hymotion only supplies the conversion with a 110v charger because – kind of like the original Toyota Prius commericals about not having to plug it in – they were concerned about consumer acceptance. What would help more than anything else is to have the opportunity to charge the car when it is sitting around parked somewhere, like in the company parking lot or downtown in a garage, though of course the power in that case wouldn’t be from solar panels.

Hope that helps.

jak

You say solar is clean? Do you know how much chemical waste is created to make those panels?
I am not opposed to electric cars, just to people who put on blinders, ignoring the costs. The best answers involve a mix of technologys to achieve efficient use of resources.

In addition to using gasoline efficiently, the important thing a PHEV can do that an ordinary hybrid cannot is use electricity as a fuel to displace gasoline. This is not as important today as it will be soon, as, to avoid climate and energy security calamity, we must move toward an 80% reduction in greenhouse gas emissions from 1990 levels by 2050, which ALL NEW vehicles will therefore have to reach by 2035. We can’t grow enough biofuels for hybrids to do this, but with vehicles mostly powered by renewable electricity we can! And we must begin down the curve of volume production and lowered costs NOW to have a prayer of getting there.

A well-designed PHEV of any size or vehicle type can displace 35-50 gallons of gasoline per kilowatt-hour of battery capacity per year. This assumes that its battery is fully depleted once a day. Therefore, tailoring a PHEV’s All Electric Range (AER) to each driver’s daily routine is economically important, as the best cost-benefit is attained when the battery is fully depleted, or nearly so, between each charge.

However, most of an auto’s criteria emissions occur, and around 2 miles’ worth of gasoline is wasted, with each cold start — so an AER tailored to each consumer (e.g. via battery size options) to be just long enough to make routine daily driving all electric would likely provide the best overall economic optimization. Of course, once electric propulsion is common, battery prices will be on a downward curve and the sweet spot will lean increasingly toward electricity.

Another point is that it may be best to focus electrification efforts on the larger vehicles that eat up the most gas — SUVs and trucks of all sizes — as well as work to entice people toward buying and driving only as large a vehicle as they really need.

Aren’t plug-in hybrids touted for far more than **that**?

Read Doug Korthof & Pablo’s comments.