Fully Charged - Test Drive of the Nissan Leaf

[rmay635703]

Originally Posted by NeilBlanchard

The details I would like to learn:

* How many kWh is used by a refinery (and how many therms of natural gas, too) in a day/week/month/year.

* How many gallons of gasoline are produced in a day/week/month/year.

* What percentage of the total output is gasoline vs the other products; and the proportion of the input energy used to make those other products.

...to arrive at an average kWh + therms embedded in each gallon of gasoline.

Also just as important what type of pollution is being freed from the crude in the form of liquid, solid and gas based pollutions. (remember the type of crude plays a role in that)

Also the type of crude massively effects efficiency, Cradle to grave gas isn't very efficient, location, drilling, extraction, filtration, transportation, cracking (refining), transportation, additive package, transportation, you.

I would estimate US based refineries choose the type of "crude" very carefully and likely there is preprocessing going on outside our country because not all crude is light and sweet without impurities.

[user removed]

I live about 15 miles from a Nuke power plant.

regards
Mech

[04_Sentra]

Originally Posted by RobertSmalls

The issue is that Llewellyn has developed a near-religious belief that shuttering refineries will by itself be sufficient to power a fleet of electric cars. I have not found data to support that thesis. In fact, I have provided sufficient data in other threads to refute it.

I’ve never worked through it myself so here goes:
Looking at the Process Fuel Use in table 1, we have to throw out LPG, Fuel Oil, Still Gas, Coke, and Other because are Refinery outputs that are feed back in as process fuels or in the case of “other” we don’t know what they are. Purchased steam is a tough one. It is probably made from waste heat, which then we can neglect it but if natural gas is used to make the steam then we have assign an energy value to it. I just don’t know one way or the other. There are a lot of refinery inputs in Table 2 but I think that we should neglect those too because if we’re going to use crude and others to make electricity to power EVs then we should just make gasoline to power ICEs.

That leaves us with Natural Gas, Coal, and Electricity from Table 1:
So, if you can believe the internet then it takes 10 cubic feet of Nat Gas to produce 1kWhr of electricity, and 1.2 lbs of coal to produce 1kWhr (I found other figures too but tried to aim for the midpoint.)
From Nat Gas: 71.05TWhr
From Coal: 0.0717TWhr
Electricity: 42.682TWhr
Total: 113.8037TWhr
If an EV gets 300Whr/mile it can travel 379 billion miles.

From table 2 we can calculate Gasoline production of 131 billion gallons.
Average mileage for US fleet passenger cars is 22.6mpg so can travel almost 3 trillion miles. Dang… so shutting down the oil refineries won’t provide enough electricity to power EV the same number of miles.
Of course this is only looking at the energy input to the refinery. It’s neglecting getting crude from the well to refinery and from refinery to pump. It also neglects the environmental impact of oil spills, down stream refinery pollution, etc, which other people have discussed on this thread.
I’m still very proEV. They should be an important part of the transportation solution. Gasoline should be used more efficiently too.

[euromodder]

Dunno about the US, but European companies of any significant size have to do quite detailed carbon-reporting (result of the Kyoto agreement).
What goes in, what comes out.
Includes energies, end- or intermediate products, waste.

I don't know wether this information is publicly available, but it exists.

[NeilBlanchard]

The electricity (and a lot of natural gas too) that gets used to refine petroleum has to be added to the carbon footprint of the resulting gasoline and diesel. So if you were to use it directly to power EV's (or natural gas burning vehicles), then you are using much less carbon, since you use no oil. And, there are many other steps that add to the carbon footprint of oil other than refining...

And 300Wh/mile is a fairly inefficient EV -- 150 to 200Wh/mile (or even lower) is possible. And even our low efficiency generation plants are much more efficient than are ICE's. So, with oil the carbon footprint is very complex and things add up quickly. With electricity, even right now, there is much lower carbon used per BTU than for gasoline -- and it is possible to generate electricity from renewable energy sources, so it can be virtually carbon free.

So, shutting down refineries doesn't power the EV's for as many miles, but those miles are essentially "free" because that carbon is not used to refine the gasoline. If you replace the total miles with more electricity, then the total carbon is lower because of the higher efficiencies of generators and electric motors vs the ICE's you would be replacing. In other words, if you put the energy into electricity, you get more work and/or use less carbon than you do with petroleum.

For example, my plug-in electric lawn mower can run for an hour of heavy duty work for between 0.38kWh and 0.47kWh. This converts to 0.01118 gallons to 0.01382 gallons of gasoline PER HOUR of operation! That is 0.178 - 0.22 cups of gasoline per hour. A gasoline powered lawn mower would probably burn at least 1 pint in an hour, which is 9-11X more.

[RobertSmalls]

Originally Posted by 04_Sentra

If an EV gets 300Whr/mile it can travel 379 billion miles.

From table 2 we can calculate Gasoline production of 131 billion gallons.
Average mileage for US fleet passenger cars is 22.6mpg so can travel almost 3 trillion miles. Dang… so shutting down the oil refineries won’t provide enough electricity to power EV the same number of miles.

These figures are in good agreement with the 90.x% efficiency figure given by the DoE.

I’m still very proEV. They should be an important part of the transportation solution. Gasoline should be used more efficiently too.

I am pro-electrification (though I think short range PHEVs make better sense than EVs, certainly in the near term), but I am far more strongly pro coal phaseout. Actually, if EV adoption goes too smoothly, there goes the gas price crunch which I'm hoping will awaken the masses to the importance of good energy policy. I really hope we never see a cheap, coal-fired SUV, but it looks like it's on the way.

[RobertSmalls]

Neil,

Even accounting for the inputs of refining and distribution, I arrived at 16KWh = 1gal in terms of CO2. Coal is dirty stuff, as you're breaking only C-C bonds and forming only CO2. HC's are better because you're breaking mostly C-H bonds, and your primary waste product (dihydrogen monoxide) is a very short lived GHG.

Originally Posted by NeilBlanchard

And 300Wh/mile is a fairly inefficient EV -- 150 to 200Wh/mile (or even lower) is possible. And even our low efficiency generation plants are much more efficient than are ICE's. So, with oil the carbon footprint is very complex and things add up quickly. With electricity, even right now, there is much lower carbon used per BTU than for gasoline -- and it is possible to generate electricity from renewable energy sources, so it can be virtually carbon free.

22mpg is an extremely inefficient gas-burning vehicle, yet that's what people buy. 300Wh/mi at the wall is more like 250Wh/mi at the battery, which is pretty ordinary. Give it a few months, and we'll see what the EPA says the Leaf and Volt can do with a KWh.

So, shutting down refineries doesn't power the EV's for as many miles, but those miles are essentially "free" because that carbon is not used to refine the gasoline. If you replace the total miles with more electricity, then the total carbon is lower because of the higher efficiencies of generators and electric motors vs the ICE's you would be replacing. In other words, if you put the energy into electricity, you get more work and/or use less carbon than you do with petroleum.

This is terribly incorrect. Total carbon is comparable because electricty is far more carbon-intense per MJ than gasoline. Unsurprising if you understand that on the other end of the power lines is a heat engine that, sadly, is probably about 35% efficient. We can do better.

[NeilBlanchard]

The heat engine in each car averages about 18-20% efficiency.

[rmay635703]

Originally Posted by RobertSmalls

Neil,

This is terribly incorrect. Total carbon is comparable because electricty is far more carbon-intense per MJ than gasoline. Unsurprising if you understand that on the other end of the power lines is a heat engine that, sadly, is probably about 35% efficient. We can do better.

??? Even in the 1960's efficient power generation was VERY important and costs were considered high from an industrial standpoint as a result
Even inefficent coal plants run very efficiently compared to an ice typically in the 35-40% area, china's newest plants operate at 44% efficiency. Other plants running on diesel and natural gas tend to be above 45% due to the cost of fuel with the most efficient units a tad over 50%.

If there was enough demand and push I believe it would go even higher nearing the theoretical maximum which is somewhere around 59% with full recovery in place.

A lot of people foo foo me but they don't seem to realize how inefficient the normal driving cycle really is, most drivers are cars only about 5% eff. due to the motor operating in poor eff. range and due to poor habits. Although some ICE engines approach 25% they rarely operate in that narrow region for more than a few seconds during the normal driving cycle. I have always believed a series hybrid ev would be more efficient than a standard ICE if the motor were a single speed 40-50% eff. turbine type, even with losses it would still do better than a typical driving cycle which spends a lot of time in very very inefficient areas of the motor torque band.

That isn't to say these same drivers with electric or series hybred would do much better but at least they would have regen.

Cheers
Ryan

[RobertSmalls]

Originally Posted by NeilBlanchard

The heat engine in each car averages about 18-20% efficiency.

Yep, and it still maths out as I mentioned. Though a Prius or an Insight is more like 30-40% efficient.