"EV's simply move the tailpipe to Coal" Answer

The green revolution gave us a reprieve. But exponential population growth is unsustainable, and fossil fuel reserves are limited. Sooner or later the bubble will burst.

It is noteworthy that bubbles always burst, and until they do, just about everyone believes the bubble will go on forever. The population-energy-carbon boom is a bubble, and it will burst. I pray most fervently to the FSM that it happens after I've lived out my life and have died a peaceful, natural death of old age. I am not hopeful.

Note that energy efficiency comparisons are not the only reason to switch from non-renewable fossil fuels to renewable electricity. Another reason is the terrorism tax. Another is the balance of trade deficit. Another is climate change. Another is non-carbon pollution. Another is noise pollution. (ICEs are noisier than electric motors, and some ICEs are disgustingly loud.) Another is the disastrous pollution of oil spills on land and sea. There are probably many more reasons.

Evan: Do you really expect to get 5 M/kWh from your Model S? I mostly see 3 to 4 for existing EVs, though I don't remember what the prototype Aptera got. I still think your arguments above are valid, but I think that 30 miles on 6 kWh is overly optimistic.

 

Chogan took the time to explain in detail here: http://priuschat.com/forums/environ...-move-tailpipe-coal-answer-4.html#post1408044

In particular read points 4 and 5.

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yeah but you would not get the full 6kWh out of it. That is not including transportation, exploration and other costs..

This reminds me a hoax from the days of past, which convinced that eating ice-cream will result in negative energy surplus. If you take # of kW needed to heat 1oz of ice cream convert it in calories it is actually higher then # of calories in said ice-cream.

Turned out that food calories are indeed the kilo-calories, so the estimate was off by order of 3.

The majority of gasoline energy goes into cracking. Cracking is exothermic self sustaining; sans the small losses all energy used is energy produced. If it were to convert to electricity there would be less then 50%

Amicus Plato, sed magis amica veritas

 

This is misleading at best. The fact that the reaction is exothermic is neither hear nor there, as it does not increase the total chemical energy available from the petroleum. What is relevant, of course, is the conversion efficiency for generating electricity, but that enters into the equation regardless of the fuel source, assuming we are talking about burning fuel.

Tom

 

First, yes, the 6kwh, or as the doe says 4 -7.5 kwh of energy is mainly in the oil, and this must be converted to electricity if it is to to run your car.

Unfortunately there is also extraction costs. On many wells this cost is low, but when we talk about sustainability, we need to consider that easy oil is harder to find. So in some cases we get oil from oil sands, and this uses a great deal of natural gas.

This amounts to millions of electric miles of natural gas being used. That worst cyclic steam stimulation has over 500 kwh of natural gas per barrel. I'll leave it to you to fix the figures and decide if that should be divided by the 19 gallons of gas or 45 gallons of refined product, but either way you will have more than 10kwh of natural gas, and over 5kwh of electricity if burned in a cc power plant.

We are also building gas to liquids plants, which today are about 58% efficient in turning natural gas into diesel or gasoline.

But the big idea is, if we don't convert off of gasoline, we can not substitute and build more efficient power to transportation.

Actually if we didn't need the gasoline and diesel, we would not get the low quality hydrocarbons. I agree with the lack of free energy. But imagine we took all that money that went to import oil, 1/2 of the trade deficit, and built combined cycle gas and wind and solar. Looking only at efficiency today will not get us to sustainability.

Yes the payoff or penalty is down the road. 50 years from now 50 mpg will not seem sustainable.

 

In the US today, per capita electricity generation is about 9,000 kwh a month. Talk about unsustainable !!

EVs are an appliance, not a source solution.

Conservation and efficiency leave enough money to capitalize the clean energy for the remainder. Will it happen ? Nah. Our informed yuppies will continue the energy gluttony with coal and despair that the money that stayed domestic was squandered on climate change damage control.

 

beg to disagree. While the total amount of energy is reduced due to losses, the amount of usable energy (yield) increased as they are able to convert up 80% crude to gasoline.

I cannot find info on cracking losses, but it would not surprise me to find out the overall efficiency x2-3 more then conversion to electricity, esp if you count real time non-peak load, distribution losses, etc. So in reality the electric equivalent would not be 6kWh, less, alot less

 

The first law of thermodynamics tells us otherwise. The total amount of chemical energy in the petroleum is not increased by cracking. I don't think you are actually making this claim, but it would be easy to misconstrue given the wording.

The yield of gasoline is increased by cracking, which is the whole reason for doing it. However, the petroleum stock feeding the cracking process is not waste material. If it were not needed for gasoline, it and the energy used for cracking would be used in some other process. We don't get to count it as free. Using it to generate electricity is one option; not the best option, but a good example given the EV vs gasoline discussion.

I believe I previously stated exactly that, so we are in agreement. The electric equivalent is reduced by losses, but it is not zero. The energy used for cracking is not without cost.

Regardless, burning petroleum to make electricity is not the best use of petroleum. It is too valuable for that. How we should use petroleum could be the topic for many future threads.

Tom

 

Efusco,

I am not sure I know what your argument is, but maybe you think that burning petroleum to make electricity is a smart thing ?
It does have one advantage: the pathway of discovery, extraction, and delivery to the power plant or refinery is identical, so we can start our analysis with a mythical 2.44 gallons of petroleum that arrives in the Houston dock. 1.22 gallons turns left in the pipeline and heads to the refinery for eventual ICE auto use, while the other 1.22 gallons turns right in the pipeline and goes to the power plant.

Left - hand turn (liquid fuel):
18% of the source energy is used by the refinery: 1.2*.88 = 1 gallon of liquid fuel is transported to an auto tank, and in the case of the Prius, transports the car 50 miles by EPA test conditions.

Right - hand turn (electricity):
1.22 gallons of petroleum is ~ 34 * 1.22 = 41.5 kwh of source energy
32% becomes electricity = 41.5 * .32 = 13.28 kwh electric energy
10% of the electricity is lost at the plant (DOE) = 13.28 * .9 = 11.95 electric energy
7% of the electricity is lost in transmission (DOE) = 11.95*.93 = 11.115 kwh electric energy remaining
LEAF ....
90% of battery energy makes it to the wheels = 11.115 * .9 = 10 kwh
At this point it is obvious that the LEAF is going to have to hit 200 wh/mile wall-wheel to match the Prius. NOT gonna happen.

ok, now a slight detour to talk about miles/kwh. We tend to use EPA results for the LEAF, assuming this is an apples to apples comparison since we used EPA numbers for the Prius, but the assumption is flawed because EPA does not include cold weather conditions in testing. An ICE car is a combined heat and mechanical plant every cold day of the year, while the LEAF's central power plant is not. Judging by the results of Volt owners last winter, 450 - 500 wh/mile plug - wheel is typical in cold weather, and I estimate the national average as 3 months of winter a year. Weighted, this works out to (360*9 + 475*3)/12 = 4665/12 = 388.75 wh/mile. I'll also note parenthetically, but not include in the analysis, the common report of the EV driver who drives fast(er) and more aggresively because their oil consumption guilt has been "solved."

10 kwh/ 0.388 kwh/mile = 25.7 miles for the LEAF.

Like Chogan says, feel free to massage assumptions so that the Prius only goes 45 miles, or the LEAF makes it to 30 miles. No matter what you do, I think the unescapable conclusion is that EV is no panacea -- for anything. Certainly not climate change, certainly not pollution, and even the economic argument is wobbly since you buy $ 10-20k of foreign batteries per car. I still like the national security argument myself, but it does require us to accept a toxic swamp of coal by-products in our neighbor's back-yards.

I am fascinated too. By the absurdity that anyone would think that an inefficient central power plant (compared to the Prius) combined with transmission and charging losses, compounded by cars dragging around extra weight, is somehow progress. For anyone keeping track, just the AC/DC charging losses into the battery about equal the refinery losses.

 

Cyclo- cracking big molecules to small ones is endo-thermic, if nothing else is going on. But you do get some volume gain, subtract from that mass losses to create heat-of-cracking and you are breaking even volume-wise (ballpark number). Overall recovery is very good as you say, but of course, Internal Combustion Engine is only, what, 30% recovery? So there is your loss.

If you burn oil to convert to elec at 40-50% (high efficiency), but EV elec engine is maybe 70% net efficient so you are breaking even in this example. Problem in USA we like to use 30% efficient (cheapest possible) coal plant technology so now you are better off with gaso (carbon basis-if coal is high is your local power mix).

Based on this reasoning, right now EV should be considered carbon neutral on the national average, but EV diversifies auto fuel mix away from oil-dependence to more coal, gas, solar, wind etc.

USA used to make a whole lot of its electricity from oil. This is sort-of what some EVangelists are implying could be done. In the 1970's when oil prices went up, it made no economic sense to make electricity from more expensive oil, so the utilities quickly shifted from oil to coal. This USA shift to coal represented a huge reduction in USA oil dependence, at the time, in response to formation of OPEC.

 

If you shift the goalposts from:

1) fueling today's Prius with today's average oil, compared to fueling a Leaf from today's grid,

to

2) fueling today's Prius with the least-efficient technology for extracting today's dirtiest oil now, compared to a fueling a Leaf from the grid 50 years in the future,

then you may get a different answer.

Given how slowly the grid is de-carbonizing (about 1% per year reduction in C02/KWH), I think the first question is relevant to evaluating the benefits of buying electric transportation today. My PHEV Prius is never going to have to run purely on dirty unconventional oil, and it's never going to be able to charge from the far-future grid. If the grid improves (likely) but hybrids don't (unlikely), and all we're left with is unconventional oil (likely, eventually), then cost/benefit ratio will shift. And when my current ride wears out, I'll re-assess based on how things look then, over the expected life of the car.

 

No straw-man intended. I wrote out the pathway step by step to show the fallacy in concluding that refinery energy costs somehow validates EVs run on coal.

Earlier I wrote life-cycle and confused you. Is pathway a clearer term ?

Combusting coal is dirtier than combusting petroleum, hands down. So unless coal mining and delivery to the power plant is at least 100% less energy intensive and 100% less polluting than the equivalent petroleum steps, no improvement in the pathway is gained but the car is sure damned expensive.

Your 1/10000 argument is weak. The additional inefficiency from electric not having a CHP outlet is about a 10% further loss.

I love change for the better. Coal based EVs need not apply. Honestly, I think thoughtful people like Corwyn and Chogan who are EV advocates readily admit that EVs today are an immediate waste of resources and dirtier than a Prius. Their stance appears to boil down to an opinion (hope?) that Burgeoning EV market will drive clean energy. I find no justification for this position, in fact all I see is ineffective subsidy.

Fossil fuel consumption will decrease for one reason only: cost. The cost can be either supply constraints or regulatory.

 

If the price charged for petroleum bore any relation to its full cost, we'd have switched eons ago. The only way gas or coal looks cheaper than renewably-generated electricity is by ignoring a significant portion of the cost. Supply and demand have only minor effects in comparison. This particular subsidy has been very effective at keeping the price of gas artificially low.

 

^^ Hyo, I could not agree more. Thus the regulatory aspect, which to me means charging for cost externalities.

 

Subsidies for renewably-generated electricity are even higher. Solar PV without subsidies is 10 times more expensive than electricity from coal.

 

This defines 'subsidy' far too narrowly, and ignores subsidies for coal. The costs of electricity from coal include pollution, habitat destruction, and increased medical costs, to name a few. Subsidies are social and environmental, not just cash. Unless the comparison includes ALL the costs, it's not valid.

If the prices we paid - for everything - at least covered the costs (again, not just the cash part) then we would know the harm we are doing, and change our ways. I've no doubt most people will almost always choose the cheaper item, but we're not being given sufficient information to make informed purchasing decisions.

 

Well yes, I think it is important to look at the field from different perspectives. If we simply ask what is the average non-oil energy used to refine a gallon of gasoline, we will get one answer, and it is yours and different than the OP's answer since that article confused energy with electricity.

But we are not sitting on a static field, and the goal posts of sustainability for oil are moving to unconventional sources. These sources will only increase in the future, so as your ICE car ages more of the gasoline will come from these sources. Now in the oil sands they can shift to nuclear or wind and become less carbon intense in extraction, but it still takes a great deal of energy. I am not sure what the proper number method of accounting, but you can see from a marginal cost basis energy needed and environmental damages increases from gasoline.

The other side of the field is moving also. Where I live there is a strong push for plug-ins. The teslas, leafs, volts are being charged from from a grid that is much cleaner than average, and planners think that we will add enough wind that it will be the primary source for night recharging on the smart grid. Different regions are moving more slowly, but the volt and leaf buyers on this forum use a great deal of alternative energy and a fairly small amount of coal. The grid is very slowly decreasing its coal use, and quickly adding natural gas and wind. Should we burden just the electric drivers for the old energy plants, and pretend the cleaner energy goes somewhere else? I think you do agree that we should clean up the grid faster. If you keep 30% of energy use petroleum which is getting dirtier how do you clean it up?

Let me get a couple of things out of the way. First congratulations on having a PHEV, you already have reduced your petroleum footprint, which reduces demand on unconventional oil. Second, I think its a real straw man, pro massive oil use argument to care only about co2. That is really moving the goal posts and ignores the other issues about oil, and seems to go along with coal is worse than gasoline. Your ability to charge in a greener way than using gasoline is definitely regional, but I would be surprised if you can't within the next 5 years charge it with a tiny carbon footprint, although it may cost you extra. I'm not telling to you shift from phev to ev. I am saying it is good for a number of reasons to develop a variety of phevs and bevs today as well as clean up the grid. The longer we wait the harder it will be to reduce pollution and sustain the standard of transportation we are accustomed to.