Our stock 1995 Subaru Imprezza chassis converted to electric uses .250 kWhr per mile at 60 MPH. Same weight as a Prius and worst aero. Most EVs will get pretty close to our energy use. IMHO, your electric number is 4 times too high.

Cliff
http://www.ProEV.com

This is so dumb…CO2 is the CLEAN exhaust you dummies.

Other commenters have been correct in noting that in order to really calculate the CO2 impact of a vehicle that’s ever connected to the power grid, you must also know the CO2 profile of the power generation plants there too. The CO2 released by electrical utilities is not zero. Nor is the CO2 released by a hybrid vehicle burning diesel or gasoline to generate electricity for it’s own use. This EPA regulation is much more driven by politics than science. As if that’s a surprise.

But with CO2, who knows? How many cars have a CO2 gauge?

Wouldn’t CO2 production be linear with fuel consumption?

Absolutely not. When an internal combustion engine is run under less than perfect conditions -which is most of the time -it loses fuel and heat efficiency.

Engine efficiency is complicated by a lot of variables, including load, gearing, wind, etc… one of the reasons for using a electric motor driven by a generator driven by a diesel engine (like a diesel/electric train or submarine does) is that you can run the petro-fueled IC engine at its peak efficiency on a constant load.

The electric motors in such a system, by contrast, reach 100% torque from a dead stop and don’t suffer (as much) from variable loads… they also can be “run backwards” when braking or going downhill to generate storable electric energy, while petro-fueled engines do not create gasoline or diesel fuel under any circumstances.

As you start your car, warm it up, brake, idle, accelerate, etc. your CO2 output is guaranteed to vary, (and different engine configurations will behave differently) and it won’t be linear with fuel use.

Good question, Guysmiley!

PS: Most modern cars have sensors in the exhaust system.

http://en.wikipedia.org/wiki/Oxygen_sensor#Function_of_a_lambda_probe

But how to account for, in terms of CO2 emissions, whether the electricity you use in your car came from a thermo-electric plant (lots of CO2 generated) or from a nuclear plant (no CO2 generated)?

I bought my Prius in 2002 mostly because of the 90% reduction in tailpipe emissions. It’s got well over 100,000 miles on it now, and still going strong with nothing but routine maintenance.

Of course, I’m also laughing my way to the bank, since I’ve been getting 47 mpg (until recently when I switched to different tires, and still getting 42).

I assume this does not supplant the requirement for also listing mileage? (Which really ought to be reported in gallons per mile, not the inverse.)

How is “miles per gallon” less fudgy than “CO2 per mile”? Wouldn’t CO2 production be linear with fuel consumption? Or are they taking into account CO2 released by electric power generation? In that case, what if my electric co. is 100% wind/hydro/nuke?

Yes but the car will only have one co2 number, so I wonder how they get this “ideal” figure.

As an aside the CO2 ratings have been used in the UK for years, first because it drove company car tax rates, then later the main road tax for every car. Trust me when I say that they have become very important, and have indirectly driven MPG upwards (smaller engine, less CO2, less tax). Every year I have seen the car companies try like mad to improve the engines to lower CO2, and introduce special ecoflex models, else they loose sales as people chase lower taxes.

The company car tax has been around ages so its been driving the market for quite a while, the main car tax based on CO2 is quite new, but already its also driven older inefficient vehicles off the road, things like thirsty MPV’s cost a bomb to tax, so their second hand value has dropped to near zero.

Main road tax rates here(second table), if you want a scare:
http://www.direct.gov.uk/en/Motoring/OwningAVehicle/HowToTaxYourVehicle/DG_10012524

It’s important that specious statistics be averaged evenly across heterogeneous populations, so we can broadly distribute tiny quantities of guilt for things we may or may not be responsible for.

They would have to know your zip code where you charge the batteries to understand the environmental/CO2 impact.

Honestly, if you live in the Northeast US, you are most likely being fueled over 50% by burning coal nearly any time of day. Anywhere else, and you are still probably doing much of your charging overnight, which is mostly fueled by baseload generation (mostly coal and nuclear, but also hydro and wind). Even if you buy “green” power, you still get the same mix as everyone else, though you can feel better about providing additional economic incentives to generators to build green generation.

The best way to clean up the CO2 and other emissions from coal-fired generation right now is to build more nuclear generation – it is emission-free. There isn’t enough hydro to do the job (with current technology), wind is too variable to power more than about 20% of a reliable grid, and solar is still too expensive/variable. We can and will figure out the waste problem with nuclear, and the safety issues are generally a thing of the past.

Doubly so because it gets rid of the inverse number effect that afflicts mpg. See articles like http://www.sciencedaily.com/releases/2008/06/080619142118.htm to explain how that leads to poor judgment.

Well then it wouldn’t really be a fuel standard, it would be an environmental impact standard.

Unless you consider things like coal a “fuel.”

A large percentage of our electricity comes from fossil-”fuels,” so I think there is at least a little justification for this.

The calculation would be a bit fuzzy, but there are advantages: if we continue to employ more things like solar and wind (like they’re predicting), your car will perform better as it ages!

The MPG rating exists to give us an idea of the cost to drive our cars. It really should be the $$ per mile rating.

I don’t think consumers care that much about a CO2 per mile rating. Otherwise, there wouldn’t be so many SUV’s and trucks on the road. We want to know what our cars COST to drive, and so what we really need for electrics, pluggable hybrids, and alternative-fueled cars is a rating that correlates distance driven with the cost to purchase the energy or fuel for that vehicle.

What we really need are 3 total figures: the MPG on gas, the range on battery only, and the Kilowatts per mile cost when running on battery.

So you might see this on a car like the Volt:
40 miles electric only at 1.1 KWH/mile.
40 MPG highway on gasoline
60 MPG city gasoline/electric mixed

This is only slightly more complicated than the current city/highway EPA MPG estimates we currently have to deal with, and it actually shows that a pluggable hybrid might cost more to operate on electric than we think.

In fact, assuming my numbers aren’t completely wonky, it’s possible that this hybrid actually costs MORE to drive when running on power from the wall: Electricity in my area costs somewhere around 15-20c per kilowatt hour, and a car that gets 40MPG highway only costs 7.5c per mile when gas is $3/gallon. Of course, the 1.1KW/mile figure may be high… it might be half of that on a small, light chassis, but even then, the pluggable hybrid isn’t actually saving any real money.

That’s not to far-fetched, either. Some of my friends are seeing higher electricity bills this year than last year over the same time period – nearly double. At that price, we figured out that it’s actually cheaper to run a generator than to buy power from the electric company. One friend of mine is seriously considering installing a diesel generator and a transfer switch for just that reason.