AutoblogGreen

1. Ok, so let's say you live in California drive your Prius mostly in town or in the burbs, 12000 miles a year. Let's say you manage 50mpg on the stock vehicle. At $3.50 a gallon, you're using 240 gallons/year at cost of $840/year.

Now let's say you spend an extra $15k for the 7kWh supplemental pack. Let's further assume that your duty cycle is such that you really do end up paying as much as you would without plugging in to the grid but averaging 100MPG, i.e. 120 gal/yr or $420.

Ignoring net present value considerations and assuming the price of gasoline will not change, you're looking at an ROI horizon of $15000/$420 = 36 years, i.e. three times the vehicle's life expectancy.

This illustrates why plug-in retrofits are not a scalable solution and therefore, of little value to either the individual or society as a whole. For the $15000, you could equip perhaps 30 cars with a factory-installed option of a stop-start system plus intelligent alternator (cp. BMW efficient dynamics, Citroen C2/3/4 etc) Fuel savings: ~5% in combined-cycle driving.

Now, lets assume you decide to spend your $15k one a tax-deductible donation to a charity that subsidizes the purchase of new vehicles that feature this option. Let's also say that qualifying models must achieve at least 35MPG combined cycle even without it, the CAFE target the House has voted for in 2020. Your identity will be revealed to benefactors if you so wish.

In a single year, these 30 vehicles will save roughly 5% * 30 * 12000 / 35 = 514 gallons of fuel, over 4x the amount you would save by upgrading your Prius to 100mpge! The tax deduction (worth ~$4000-5000) more or less compensates you for forgoing your own savings at the pump. The only fly in the ointment is that very few manufacturers currently offer the described option on their vehicles, but that may change before long.

Now tell me, what would give you greater bragging rights: driving around in a modded Prius that gets 100mpge or philantropy that achieves over 4x the impact?

Posted at 1:15PM on Dec 11th 2007 by rgseidl

2. "The small system costs around $8,000 "



Cripes! Have these folks lost their minds?

Share your car with one person once a week (AKA car pool) and you will have more impact on the environment, CO2, global warming, etc.) than any hybrid will ever have. And think of the nice conversation you get as well!

Posted at 2:49PM on Dec 11th 2007 by Dad

3. "Now tell me, what would give you greater bragging rights: driving around in a modded Prius that gets 100mpge or philantropy that achieves over 4x the impact?"

Drive in the modded hybrid ;-)!!!!!! It is all about image, style over substance of course.

Posted at 2:49PM on Dec 11th 2007 by Dad

4. I agree with 'Dad', besides the plugin-hype we should not forget where else we can save energy. The principle reduce, reuse, recycle also applies to driving. Lots of emissions could be saved by simply not even taking a car. I know this is not the solution as most of us are in love with cars, and many depend on the car to get to/from work etc. And for those a green car is a good thing. But to be an environmentally responsible person, you do not need a hybrid car...
http://www.ecocarforum.com

Posted at 3:12PM on Dec 11th 2007 by maileco12

5. While the cost is high, I think it is very unrealistic to be making comparisons between the Prius and a modified Plug-in Prius.

First, these companies are in the business to sell their technology, and saving gasoline is a secondary goal. If it is possible to sell people a 7 kwh pack for $100 and they still make money, they will sell it. The limiting factor right now is the logistics and investment.

Second, breaking down costs like this is somewhat irrelevant. If cost is the ONLY reason why one buys a car, then why buy a NEW car at all? If saving fuel is the goal, then why buy just compare cars, why not involve other factors like scooters and e-bicycles? The argument can go on with infinite variations.

The point is that the market for plug-ins is a new frontier. In order to claim your piece of the pie, businesses have to start somewhere. This is not just about modding a Prius for "green creds" but about Nilar wanting to sell their products to a receptive audience.

Posted at 4:35PM on Dec 11th 2007 by Charles S

6. @rgseidl
I think it's important to note that these people aren't out to save money (although you are right that we should warn pp who are looking to save money to consider other options), nor are they out to continue using gas in their conversions. I think most would want to use their cars as an EV most of the time until practical EVs begin to be avaliable. This high initial cost is also because these are still low volume batteries. These prices can be halved pretty quickly. Look at 5kWh li-ion pack from a123 with cost of $12k, and that's with more expensive nano lithium cells. Then there is the whopping 56kWh pack from Tesla at a cost of $20k (honestly I don't believe it either, but that's what they quote a replacement pack would cost). These are prime examples of "early adopters" who are going to help drive down battery cost until they are feasible for EVs.
Your calculations assume gas prices never rise and assume that there are start-stop devices avaliable now in the US and assume that charities exist that subsidizes purchases of vehicles with specific specs. In short it amounts to waiting around until these things are implemented. These early adopters are putting money out of their pockets to spur development in automotive battery packs. We are already seeing results with GM pushing for the Volt. The development in battery technology in this rush for PHEVs can only help in making a practical EV a reality.
Honestly, people can easily blow $10k more on a car for a better badge, or for more performance, or more luxury, and none of those save you any money at all. I don't see the problem with people blowing money for better mileage and better technology in our future.

Posted at 5:17PM on Dec 11th 2007 by jake