So what is your carbon footprint?

nahi would think the environmental forum would be more appropriate, since you don't have a pip, and some others commenting don't, and other ev's are being brought up.

 

That's correct. However... Comparing the carbon intensity of electricity to the carbon emissions of a Prius isn't apples to apples since it's ignoring all the energy/carbon it took to discover/extract/transport/refine/and transport again the oil/gas conventional vehicles use.

Gasoline and Oil

Producing gasoline requires ~5-6kWh of electricity/natural gas that could be turned into electricity. So, right off the bat, just by not using gasoline, you've freed up enough electricity/natural gas to generate electricity to take most EVs ~20-24 miles. At that point, then you can look at the carbon required to take you the next ~26-30 miles, and compare that to the carbon a Prius emits driving 50 miles.

Or... You can just add the carbon from producing the gallon of gas to the Prius tab and compare them that way, but you can't compare carbon intensity of electricity, which AFAIK includes everything needed to generate that electricity, to mpg, since that doesn't include the carbon released to make that gallon of gas.

 

^^^ I do not believe it takes 5-6 kWh of electricity to make 1 gallon of gasoline. That is based on misleading calculations. Remember, a barrel of oil doesn't just make gasoline. It makes gasoline and a whole bunch of other products. The energy use is to produce all those products.

 

Hey bisco, can I suggest you quote at least part of the message you are responding to?

 

of course you can!

 

apparently you
didn't read post #6 or its link ... but what the heck, our logic falls on deaf ears -

really? . . . how many kWh's do you think it takes to run air craft carriers around the Persian Gulf to prevent the consequences of us being there in the 1st place .... or the kW's to run hospital's lung cancer/respiratory treatment centers needed due to fossil fuels / petrochemicals side effects, etc, etc. or do those kWh's not count against the usable remainder either ? .....
.

 

argh!!! you're right, i had no interest in the posts, just the forum. great minds think alike!

 

In addition to old data, I also dislike the very large aggregation zones, so it is not really representative of the local area.

My zip code produces the exact same results as all the test zips I entered across Washington, Oregon, Idaho, Montana, Utah, even parts of Nevada and Wyoming. And the results are vastly different than shown in my local utility's annual 'Fuel Mix' report.

 

It's not strictly ~5-6kWh of electricity, it's some electricity plus some natural gas, which can be used for electricity. I think it's more natural gas than electricity, but the basic idea is that if you took the electricity used directly, and used the natural gas to generate electricity instead of using it as on site power for extraction and feedstock for refining, you'd get ~5-6kWh/gallon of gas.

Fully Charged Discusses Electricity Use By Fossil Fuel Refining

 

My wife and I are angels
Across all categories, we consume about 1/2 of the locals.

I'd like to consume about 10%, but renting limits my options.

I don't think that is quite right.

Think of source energy: If you start with ~ 40 kWh of oil, after processing you end up with ~ 33.5 kWh of petrol

 

The figures are from the state of CA in the early 2000s, so there might be variations depending on location, but it's more or less accurate. Refining efficiency is also part of the higher carbon footprint of oil, but a larger part is direct consumption of electricity and natural gas in extraction and refining (most as a feedstock).

Very roughly, if we start with 40kWh of oil (1 gallon), we need an extra ~5-6kWh of electricity plus the electricity equivalent of natural gas (~55% conversion efficiency IIRC). That's why 25+% of the emissions associated with driving are from production of gasoline.

http://www.transportation.anl.gov/pdfs/TA/273.pdf (page 3)

Refinery efficiency is generally pretty high, usually at 90% or better, but all those additional natural gas and electricity inputs are why 25% of gasoline's emissions are associated with production.

https://greet.es.anl.gov/files/hl9mw9i7

Do you have a link to that? ANL lists 25+% of auto emissions as being from fuel production (in my last post).

 

Yep.

This is why it is also a nice rule of thumb to say that of every ~ 40 kWh oil, 33.4 kWh make it into petrol. The conversion used to be 17% lost IIRC, but EPA has apparently bumped it up to 18%. Perhaps to account for shale oil ?

 

"Electric plant efficiency..."

Care to define "electric plant", I'm not sure what you are talking about.
Electric motors??

 

I was thinking he meant something like in a hydro dam set of generators. Like in transmission loss to the end user.
.