Re my 79: natural gas [or other fuels in general] (which can come from renewable sources [I guess that’s technically not ‘natural gas’ (?) although in some cases it’s natural and also a gas’] … [is] better than electricity for low temperature heating (though solar preheating should generally be used too, depending a bit on location).
Actually for any heating, except where economics dictate otherwise and/or where heat pumps may be used; heat pumps can make electricity from fuel more efficient than direct use of same fuel for some low temperature heating applications, depending on the COP. Of course you can use the fuel directly for heat+electricity (via combustion + mechanical conversion or TPV or thermoelectric device …, or via fuel cell). Solar PV ‘cogeneration’ has a temperature constraint, the best temperature depending on the economics of heat vs electricity needs; higher temperatures would typically reduce the PV efficiency, though it would tend to be more efficient than a non-hybrid system. But really what is best depends on economics – what if (with all externalities properly accounted) solar PV advances to become (including competition for roof and land space) so cheap that it just doesn’t make sense to ever use fuel even for high temperature purposes? Or what if the economics of storage and transport/transmission and are such that fuel makes sense in some places and times and electricity at other places and times for the same application? It’s quite possible (well, not the solar PV … so cheap … never use fuel, but the more general concept).
…, also , there may be a comfort and familiarity issue for gas vs electric stove top ranges. Energy and economics aside, I personally prefer electric. But that type of issue doesn’t come up so much when it comes to HVAC and water heating, because you’re not interacting with the flames so directly during normal operation.
/Obviously/ there is no single mitigation policy in no single country (or region) that can significantly reduce global emissions. However
– There are many cost-effective, global mitigation options that can significantly reduce emissions. A lot of these are in buildings but more efficient cars (which are available) are also a good option
– Efforts in the US, EU & Japan /across all sectors/ to reduce emissions will have an impact on global emissions, because these countries combined emit a lot
– If you want China to take you seriously, then the US (in particular) better do something about climate. that’s political reality
– Finally, and most importantly, there are available energy technologies that could significantly decarbonise global electricity. Concentrated solar is extremely promising, and will (experts say) be as cheap as coal in a decade. CCS is challenging, but at least technically possible. Onshore wind (the US has rather large wind resource) is cheap. Expanding the market for these technologies will reduce costs and, ultimately, these technologies will not need state support
Clearly, we have the technological solutions to significantly reduce emissions (whether we can reach 450ppm is another question, but probably, just about). People who say “It’s not economic” seem a bit odd to me, as the best economics say it’s cheaper to mitigate than adapt, and the economy is a tool to improve the lives of humans.
John E. Pearsonsays
100 Hank said: perhaps your perl wizard could do something with killfile .
Hank: Thanks for the info. I’m betting she’s not gonna be jumping up and down to take on any new projects now that she’s 8 months pregnant. (Jumping up and down has gotten pretty difficult for her.) I’m going to fiddle around some on my own with greasemonkey.
CMsays
John #107,
Good call — wizards are subtle and quick to anger, particularly when eight months pregnant.
Everyone,
Got a poster you can’t stand? Feel like spewing fire every time the troll posts another worthless rant? Your Christmas spirit wearing thin? There is a remedy.
The following killfile bookmarklet should work in Firefox. Greasemonkey users can probably adapt it, so they don’t have to click a bookmark every time they reload.
Installation: You may be able to drag <a href="javascript:l=document.getElementsByClassName('comment');for(i=0;ithis link to your bookmarks folder. If that doesn’t work, make a new bookmark with the above as the location, changing any curly quotes back to straight quotes.
Usage: Replace \A. Troll\ with the name of any poster you can’t stand. Multiple names must be separated by a pipe \|\. \Jim B\ will match both \Jim Bullis\ and \Jim Bouldin\ — be careful. Periods (\.\) must be backslash-escaped (\.\) as in the example.
Peace on Earth, and good will to men…
:)
CMsays
Oops, that came out really wrong, but the code is nearly usable. Again, change three sets of curly quotes to straight quotes, and if you have a period in the poster name (“A. Troll”), use a backslash before the period (WordPress ate it).
An important disagreement I have with you concerns your incorrect sense of how electric power sources are selected to feed into the grid. Only when there is reserve capacity of sources cheaper than coal will these be the sources that respond to new loads.. (Of course government can over-rule sound economic decisions by power planners.) Until then, the fact that coal will be the actual basis of marginal response changes some of your generalizations about what is the cheaper among heat generating systems.
I think we also see economic factors differently.
For a person who is demonstrably competent in energy conversion physics, what do you think about public policy that repeals the Second Law of Thermodynamics and defiles the First, that being the EPA insistence that one kilowatt of heat makes one kilowatt of electricity at the input plug of an electric car? Not only is this offensive to science, it seriously misguides public policy in practical ways.
And Furry Herder, you help me explain the harm of the EPA chicanery, and also make a valid challenge to me about getting my car ideas going. There is reduced incentive for trying to sell vehicles that are actually efficient when public perception is distorted by such a rating system. Who needs an efficient car when you get 99 mpg out of a Nissan Leaf, which is nothing at all about energy efficiency? This Leaf would get around 33 mpg if it carried its own gasoline engine and operated as a well designed hybrid like the Prius. The industrial system does not function to encourage improvement of products if the market system is distorted by false information. Getting the public to change their attitude toward cars is difficult under any circumstances.
Where you say, “When will it become more profitable to grow these forests to sequester C than it is to do something else with the land and water?’, you make an important point for discussion.
I argue, with more conviction than most here would seem to agree with, that our energy based industrial system, economy, and all that goes with it in our developed world can not afford to put a large penalty on the use of coal. That makes the forest option the more atrractive way to use land and water, and it would be a way for us all to provide the infrastructure needed for our present way of life.
I do not defend for a minute a number of bad choices in the way we have wasted resources, spent money, and such, but I do see a present danger in the state of our economy. As it stands, here today, there is a need for a rational course of action. Setting things up for people to do productive work is the highest need we have right now.
By the way, as our Furry friend reminds me, there would be nothing better for my car project than to have very high priced energy as a fundamental part of our economy. But getting a car project going through a depression situation is not worth it.
“”Post-Partisan Power” — How a Limited and Direct Approach to Energy Innovation Can Deliver Clean Cheap Energy, Economic Productivity, and National Prosperity October 13, 2010 at 4:59 AM”
“The first thing to say about the climate negotiations – meeting soon in sunny Mexico – is that they’re teetering at the edge of what, back in the day, we used to call a “legitimation crisis.” ….
Which, actually, is an odd turn of events…. midway through the cycle of negotiations (Copenhagen 2009, Cancun 2010, South Africa 2011) that will determine the shape and direction of the post-Kyoto climate regime. What happens now matters, particularly because, all else being equal, the eventual end of the economic crisis will be accompanied by another rapid rise in global emissions. …
…
… There are extenuating circumstances in today’s America, where the “tea party” – a corporate-funded creature of self-satisfied, self-destructive, flat-earth libertarianism – has emerged to oppose even climate science, let alone international solidarity. It’s an heartily unwelcome development, and it almost makes a good excuse. Moreover, there’s plenty of competition for the role of the world’s leading climate spoiler. …
Issues abound, and it’s hard to know who to forgive for what….”
CMsays
Jim #113, where does the EPA say that? You’ve probably told us before, but I’ve avoided earlier “car wars” on this site, so I missed it. (I’ll probably sit this one out too — but I’m still curious about your source.)
“Our goal is to accelerate the transition to a world where all 6.5 to 9 billion of us can enjoy secure, free, prosperous, and fulfilling lives on an ecologically vibrant planet.”
Sure, Uh-huh. Good luck with that. All of the evidence I am looking at indicates quite the contrary to me. But that’s just my ‘opinion’.
Quoting Michael Shellenberger :
“The Death of Environmentalism: Global Warming Politics in a Post-Environmental World.”[1] The essay argues that environmentalism is conceptually and institutionally incapable of dealing with climate change and should “die” so that a new politics can be born.”
Sure. Uh-huh. Politics can save us. From a ‘consultant’ and ‘self publicists’ no less.
Sorry, Hank, it’s new age drivel. We need hard technological solutions, in my humble opinion. These guys are totally status quo,
Your link is informative. They say all the right things about objectives, education and innovation.
Their objective to develop economic solutions is recognition of the current political reality.
Their interest in education is laudable, but it appears that things are not in a good way in the world of energy science, as I demonstrated in my #113. Education is not likely to be productive of innovative thinking where government laws over-rule physics.
The general call for innovation based on misconceptions about how innovation happens is not inspiring. This is a long subject, but in the end, innovation is achieved by people thinking differently than those devoted to the status quo. And this different thinking is only useful if it is based on penetrating insight into the problem at hand, which requires a process of critical questioning. We have discovered here in realclimate discussions how the people who ‘are the box’ react to thinking ‘outside the box’.
For quick reference, a gallon of gasoline puts out 33.7 kWhr of heat. In this example it takes 34 kWhrs of electrical energy to push the car 100 miles and the EPA declares this to be equivalent to 99 MPG. This demonstrates that the EPA formula is based on a pretension that this work can be done by heat that can be produced from a gallon of gasoline.
Please supply a source, to provide both detail and context, for your statement that:
… the EPA insistence that one kilowatt of heat makes one kilowatt of electricity at the input plug of an electric car…
Patrick 027says
Re Jim Bullis – assuming your numbers are correct, then I agree, the EPA rating is stupid.
from http://en.wikipedia.org/wiki/Gasoline
(gasoline density = 0.71 to 0.77 kg/L,
35 MJ/L ~= 132 MJ/gal (US) ~= 36.6 kWh/gal (US) (higher heating values)
implies 45.5 to 49.3 MJ/kg, setting aside sig figs and the possible energy per unit volume variations)
I don’t think it undermines the potential for electric vehicles to be helpful; it requires working on the energy source problem at the same time (we agree there, I think).
But how should an equivalent rating be done?
The efficiency of the power supply – power output is one part, then there’s the CO2 emissions of the power supply, then there’s the work done per passenger/cargo * mile…
Where the sticker indicates emissions, there should not be a single mark, there should be several (coal, gas, nuclear, hydro, wind, solar (CSP, PV, ?), geothermal, US average power supply, US average power supply at night, US average power supply during day, projected US average power supply with climate policy, without climate policy) …
Because there are some components associated with gasoline-powered vehicles that are not found in purely EV and vice versa (with PHEV and HEV being …), it’s not enough to just compare the engine efficiency with the power plant efficiency (with adjustment for different emissions per unit fuel energy); the efficiency of the battery and motor to wheel vs the transmission etc.
“EVs emit no tailpipe pollutants, although the power plant producing the electricity may emit them. Electricity from nuclear-, hydro-, solar-, or wind-powered plants causes no air pollutants.”
(not quantified and placed on sticker as one may like, but they’re not exactly saying power plants don’t exist)
Back to the first point – 20 % efficiency for ICE car – I assume this is a more efficient engine with additional losses in the (car’s) transmission. Assuming perfect plug to battery efficiency, the 75 % battery to wheel efficiency multiplied by 30 % power plant and (grid) transmission (can be lower or higher) gives a fuel conversion efficiency of 22.5 %, so the EV could beat the ICE car, but not by a huge margin (using 35 % plant+grid efficiency gives ~= 26.3 %). So if the power plant is, on average, coal, then that wouldn’t be an improvement.
…
Patrick 027says
But
What if the power plant is not coal-powered? And you say it will be coal, but that’s not necessarily true; it depends on the policies we have (and hydroelectric and nuclear are baseload, too; wind can be available at night, … other stuff about electric transmission and storage and flexible charge times).
…
Patrick 027says
…
Meanwhile, what if the ICE is not running on gasoline? The choice is not limited to gasoline vs electricity (if it were then it will have to be electricity in the end, and at least you have the possibility
…
Patrick 027says
…
of relatively clean electricity that is not much more expensive); it may turn into biofuel, and those have some problems,
…
Patrick 027says
…
too (would compete with your sequestering forests, among other things)
…
Patrick 027says
…
– except, of course, we can’t in fairness
…
Patrick 027says
…
assume biofuels will continue to be as they are now if we are not assuming the same of electricity (cellusose
…
Patrick 027says
…
(cellulose crop residues, manure, landfills, sewage (there’s paper in there, too!),
…
Patrick 027says
…
algae, spoiled food and food scr-aps – residential (coffee grounds, banana peels, and the napkins and liners we leave crumbs on)
…
Patrick 027says
…
and upstream (olive pits, peanut shells, etc.), so let’s keep the engine around awhile – not necessarily in all cars, but in some fraction of them, to maintain strategic technodiversity.
Of course it may turn out that most of the biofuel ends up devoted to winter heating needs (low latitude people could sell their biofuel to the extratropics), due to the seasonal distribution of solar power (and it may be easier to take renewable CH4 and put it into the existing natural gas distribution system rather than to make it into fuel for transportation – again, it’s not all about the thermodynamics of a few things) – But what if the ICE or (P)HEV car is a cogeneration plant? Well, maybe it will be to some extent just by using the car in winter in middle-to-high latitudes, although the car’s own greenhouse effect plus body heat of passengers reduces that need somewhat.
But more on that point: what is the advantage of continuing to depend on ICE’s (or depend more on ICE’s in PHEVs and less on the P part) for the sake of cogeneration of heat? Is the heat produced while the car is in use to be stored and transfered to the building later, or is it only that heat produced by the car while parked that is used by a building? If it is the later, this could be accomplished just by making the building’s furnace/fuel cell cogeneration, or having cogeneration fuel power plants upstream. I realize of course that you might save money and resources by reducing the number of engines involved and trying to get the most out of one of them, but I’m not sure you can depend on having a car around to heat a building – yes, you can store heat energy – I would think more easily in a building than in a car (both good and bad for your concept) – but I suspect you’ll generally want buildings to have their own complete HVAC and water-heating systems anyway (which can generally have solar preheating at least, and maybe geothermal storage in addition to the building’s own thermal mass); meanwhile, if the engine is running so much more, will it need more maintanence? How much maintanence cost can be saved using the P of a PHEV more than the H (as in ICE)? I also realize that there is a turnover rate of cars that makes it is some ways more convenient to change the car than to change buildings and power plants and set up new steam/hot water distribution systems – but if you are going to start transfering heat from cars to buildings, you’ll have to change the buildings anyway.
One way to address these issues is to put a price on emissions and then just let whatever happens happen. Of course, markets are not always so ideal and we may want some additional public policies and funding (R&D, and D and D, targeted incentives, buidling codes and other mandates, reworking the structure of utilities and the grid to take advantage of opportunities).
Remember that a tax on emissions is not just a drain of money and resources, it is also a revenue source. Assuming a convex PPC (not necessarily true) and efficient market (a useful approximation at least in some ways but obviously not a precise description (ever bought a house with a tulip?)), there must be some overall economic cost to such action, not including gains by reducing negative externalities (which would be realized more in the future), but I don’t think it would have to be as big as the tax itself (I think ClimateProgress had a post on that issue). Farthermore, stating that we can’t do this because we won’t do this or because it will cost too much – well, will we plant those forests, will we buy your cars? Will we ever do anything?
There is no validity to such a comparison. The efficiency of an electric motor is the energy conversion after conversion that was done to get heat into electrical energy to charge the battery.
Then we get the fake statement using the incompleteness of ‘internal combustion engines’ designation. Yes, there are sloppy internal combustion engine, many in fact, that get 20% efficiency in converting heat to mechanical energy. But there are also ‘internal combustion engines’ that do far better, in fact, common diesels have long done 35% and Toyota Prius gasoline engines have been measured (by Argonne) to convert at 36% to 38% efficiency.
And your analysis is generally correct, but you incorrectly assume that the 20% efficient automobile represents a reasonable standard. The Toyota Prius is far better, and so is the Ford Fusion Hybrid. If you are comparing electric vehicles to the sloppy 20% old type cars with the electric vehicles, electric vehicles win, but not by a factor of three like the EPA sticker would have us believe.
Here is where some further caution is needed. Hybrid vehicles, if well designed, can make a big improvement in both CO2 emissions and in the amount of oil used. Making the same hybrid into a plug-in will cause the CO2 impact to worsen, some. But it will do much to reduce dependence on oil; but it will do this by shifting to coal.
The oft quoted NRDC-EPRI study by Mark Duval et al. was dedicated to making the case for plug-ins, but their Fig. 5-1 shows the misleading half truth on which the .gov statement you quoted is based. (I am not at a computer where I can get this easily.)
It is a further argument that I make that the electric vehicles will be useful in shifting from oil to coal, but they will at best be of mixed benefit when it comes to CO2 emissions. However, because of the EPA misguidance, we will likely find that the ease of making a car look good in MPG by electrification will take away incentive to improve vehicle efficiency in more fundamental ways.
This rating system is likely going to be the cause of opportunity lost.
If one worked out an equivalent based on the heat input to the heat engine making the conversion from heat to mechanical energy, whether it be the heat engine at the central power plant or the heat engine carried in the automobile, a reasonable result would be possible. Since we are looking for overall heat input, it would be fair to include compensation for delivery and processing of fuel, but this does not change much. Roughly though, the heat input for electric cars would be triple that of the EPA assumed electric power heat equivalent.
If government interceded and made coal prohibitively expensive, then it could be said that natural gas would be a fuel of choice, and in that case a different equivalent would be valid. Roughly, it would be double that assumed by the EPA. For this case, CO2 would be somewhat reduced over the hybrid, though to varying degrees depending on the type of heat engine used. (See Fig. 5-1 of that NRDC-EPRI study by Duval)
Hope this is useful. Also, please see discussion by Patrick 027 and myself that follows.
flxiblesays
JimBullis – If you insist on including the heat energy loss cost of electricity generation in the figures for battery powered vehicles, then why don’t you also include the cost/fuel use in supplying the gasoline for the ICE vehicle? What’s the efficiency of digging the oil sands, turning it into barrel petro, transporting it to a refinery near you and then delivering the gasoline to your fueling station?
For quick reference, a gallon of gasoline puts out 33.7 kWhr of heat. In this example it takes 34 kWhrs of electrical energy to push the car 100 miles and the EPA declares this to be equivalent to 99 MPG. This demonstrates that the EPA formula is based on a pretension that this work can be done by heat that can be produced from a gallon of gasoline.
I utterly fail to see how you arrive at this conclusion, or why you would think that heat has anything to do with the EPA’s logic. Quite honestly, it looks like you simply made it up.
Can you provide something other than your own personal inference? A link to an explanation (by the EPA) where the EPA says they followed your presumed heat-does-the-work logic to arrive at their mileage equivalence?
With that said, as to your point, my query, and the rest of the discussion… it’s way, way OT.
But as far as electric vehicles go, it’s very simple. The only choices are gas, fuel cell and electric. Gas means CO2, and is limited to a single, dwindling fuel source (well, okay, you might work synthetics and biofuels in there, but I doubt that will ever work for the entire planet). Fuel cells are not yet viable.
So all that is left is electric. If the vehicles are electric, then the actual source of the power is more flexible, and can change over time, and control of emissions is localized. Electric vehicles offer options, gasoline exacerbates AGW, wand fuel cell basically means wait, do nothing, and risk the technology never becoming viable.
Patrick 027says
Re 137 flxible – to be fair, not all petroleum is currently derived that way; the petroleum supply is one of the single biggest consumers in the U.S. today, but if the EROEI is something like 10/1 (? http://www.theoildrum.com/node/3810 – but does this include refining?), you can still reasonably approximate 1 MJ sold fuel ~= 1 MJ petroleum from ground (in the same way that the synoptic-scale extratropical wind above the boundary layer is generally approximately geostrophic) (though worth pointing out that renewable sources like PV and wind can beat that, when they’ve been criticized for being far less). But a valid concern at least going forward. On that note, the EROEI of some (not all) biofuel makes it more of an energy conversion technology.
Re Jim Bullis – are the 35 % (diesel) and 36 – 39 % (HEV) efficiencies specifically for the ICE? If so then they can’t be so easily directly compared to the fuel to wheel efficiency. How much of HEV efficiency is directly dependent on the EV part – aside from regenerative breaking, which (I would think) shouldn’t affect mpg hwy so much? Or could simply updating ICE technology bring the entire fleet’s fuel consumption significantly down? I’ve heard that a potential advantage of EV’s would be the opportunity to have a seperate electric motor for each wheel, which would improve efficiency – could that be incorporated into a HEV and would that make any significant difference?
Once upon a time, I recall reading or hearing that at 55 mph, a car’s power usage was equally divided between working against rolling resistance (proportional to speed) and working against air resistance (proportional to speed squared). So if got the drag area of a car and the mpg we could figure out just what the efficiency is, though changes in design probably alter the speed at which the two power sinks are equal.
PS a point about government policy – given the fuel economics of pure ICE’s vs non-P HEV’s verses PHEVs, it might be that without any government intervention, PHEV’s will eventually dominate and they will be powered mainly through the P and not the H. So to avoid the calamity you are warning about, you may want to support a tax on CO2eq or some other way to increase the price of coal power, if not to get PHEVs powered by the sun and wind etc, at least to prevent them being powered by coal.
Patrick 027says
… of course, even given 10:(1+refining transport etc.?) EROEI for gasoline, this is assuming the rest of the petroleum continues to find other purposes, so that the whole of each barrel is used. But I wouldn’t expect that to be a big problem. It used to be that gasoline (or its precursor?) was a waste product of the petroleum industry.
Patrick 027says
… oh, but the rolling resistance would include losses between ICE and wheel, wouldn’t it? Or is it only the viscosity of the tires that equaled air resistance at 55 mph? I really don’t know. Any good websites to explain this?
Patrick 027says
http://www.fueleconomy.gov/feg/atv.shtml
– appears to show a non-HEV car with an ICE near 18.2 + 2.2 + 17.2 = 37.6 % efficiency. Reminds me: HEV’s would reduce idling losses as well as breaking losses. Is this diagram for city driving? (I’d guess it must be, for that much idling) (accesories should be a smaller fraction at higher speeds, as they tend to be proportional to the time people are in the car, right?). This car has only a bit over 12.6 % of the gasoline’s energy going to the wheels. Eliminating idling and assuming proportions stay the same, this should be a bit less than doubled, bringing it near 20 %.
It seems like, aside from idling and regenerative breaking, there isn’t much overall difference among pure ICE cars, HEVs, and PHEV’s in the overall fuel to movement conversion efficiency, then (except for the range in power plant efficiencies). Maybe some advantage to be gained from changing or eliminating the drivetrain? (PHEV with 1 motor per wheel?).
Patrick 027says
… I wonder what the politics of climate change will be like in x0,000 (or xx0,000) years when the next ice age comes – will CO2eq earn a credit instead? Or will we let nature take it’s course (great opportunity for science, documentary film makers and photographers/artists tired of the same-old Holocene and Anthropocene subject matters (caution – you can’t go home again – sort of)? Also, with CO2 being long-lived (in so far as atmospheric perterbation ppm goes), would CH4 emissions be encouraged after a supervolcanic eruption?
Or sooner, when the Sahara gets wet again (maybe not this time around the Precession cycle due to small eccentricity ?, but eventually)…
Stevesays
Just encouraging you guys to keep on keepin on! Your work is vital, the planet desperately needs you!
thanks for the source. I think I’d agree that the sticker is potentially misleading. However, the 34 kWh = 1 gallon comparison is obviously meant to compare the efficiency of the respective engines in making use of the power supplied at the plug or pump, in units consumers will be familiar with (mpg). And that’s fine by itself, it’s just not meaningful as a guide to CO2 savings.
I think it’s worse that the right-hand side of the sticker declares CO2 emissions to be zero. The small writing makes it clear that this refers to tailpipe emissions only, but how many people will understand what that means? And“tailpipe emissions” have nothing to do with the actual carbon footprint of an EV; since CO2 is not a local pollutant, it’s a meaningless measure, I think.
But the mpg comparison makes it easy to do some back-of-envelope calculations of the CO2 savings from moving to electric vehicles, without having to get into all the details you and Patrick are discussing.
If gasoline gives 19.4 pounds = 8.8 kg CO2 per gallon (EPA), then an average U.S. passenger car (22.6 mpg) or a new vehicle (32.6 mpg) (BTS, *) emits 390 g or 270 g CO2 per mile, respectively. If U.S. power generation gives 1.341 pounds = 0.608 kg CO2/kWh (national average output rate, including fossil and non-fossil sources, EIA, 1999 figures); then an electric car that goes 99 miles on 34 kWh emits ~ 210 g CO2 per mile on a U.S. average. The effect of switching to this electric car, then, is a 46% reduction in CO2 emissions per mile traveled, if you’re giving up your average American car, or a 22% reduction relative to the fuel-efficient new car you might have bought.
This accords well with the Wikipedia statement that “With the current U.S. energy mix, using an electric car would result in a 30% reduction in carbon dioxide emissions.”
David Millersays
In #133 Jim misleads us again….
The link and quote from .gov is a further insult to physics, as well as a deliberate attempt to mislead to promote electric vehicles:
I think you’re projecting there Jim…. You don’t like what they say and so ascribe ill intentions and motive where none are really necessary.
There is no validity to such a comparison. The efficiency of an electric motor is the energy conversion after conversion that was done to get heat into electrical energy to charge the battery.
Yes, exactly.
Then we get the fake statement using the incompleteness of ‘internal combustion engines’ designation. Yes, there are sloppy internal combustion engine, many in fact, that get 20% efficiency in converting heat to mechanical energy. But there are also ‘internal combustion engines’ that do far better, in fact, common diesels have long done 35% and Toyota Prius gasoline engines have been measured (by Argonne) to convert at 36% to 38% efficiency.
You’re bending the numbers again Jim. You complain about the EPA comparing apples and oranges, then you go ahead and do the same thing.
Comparing the peak engine efficiency in any engine to the typical output in a real world auto is not a fair comparison.
If you’ve looked into efficiency at all, Jim, you must know that all engines have a peak efficiency point. ICE’s will be most efficient around the peak of their torque band and 80% power. When one accounts for typical power requirements, accessory drag, and adds the power train in one necessarily gets a much lower number than 35-40%.
And your analysis is generally correct, but you incorrectly assume that the 20% efficient automobile represents a reasonable standard. The Toyota Prius is far better, and so is the Ford Fusion Hybrid. If you are comparing electric vehicles to the sloppy 20% old type cars with the electric vehicles, electric vehicles win, but not by a factor of three like the EPA sticker would have us believe.
But you’re complaining about the EPA taking one extreme for comparison while you insist on taking the opposite extreme. IF – and only if – the extreme you insist upon (that coal or the like is the source used to charge the battery), you’re right in your analysis.
There are, however, many other sources of electricity. If the batteries for the (PH)EV are charged with power from wind, hydro, solar, or nuclear then essentially no CO2 is released for that energy. If one of the first three is used then essentially no heat is wasted, heat you insist on including in the comparison. If the electricity is produced with a co-generation system where the waste heat is used then the original heat source is essentially converted into electricity at more than 90% efficiency. If natural gas is the original source, up to 60% of the original energy can wind up in the batteries.
So the real answer, Jim, is “it depends”. It’s not a simple black and white issue like you try to paint it.
There are two other factors worth noting.
First, I think our ability to generate more electricity with which to power our transportation greatly exceeds our ability to create more liquid fuels. The CO2 impact of new electrical generation should be much less than that of developing alternative liquid fuels. Wind and solar are coming on strong; oil has probably peaked and alternative liquids (tar sands, GTL, CTL, biofuels) are expensive and dirty. These are things worth considering: will there be affordable liquid fuels for any vehicle at the end of a 20 year life? Will there be affordable electricity in 20 years with which to charge your (PH)EV ? I know which I’d be more likely to bet on.
Second, if your WonderCar really reduces energy requirements, there’s no reason it couldn’t use electric power. IE, if you can drop the energy requirements by 80% it would be easier than ever to power electrically. Then you could get 1000 mpg the way the EPA measure it:)
The effect of switching to this electric car, then, is a 46% reduction in CO2 emissions per mile traveled…
… as long as energy production maintains that 210g CO2 per mile average. But as energy production shifts to cleaner sources, that number has the potential to improve further, where there is no such possibility (outside of improved gas mileage) for the internal combustion engine. So the use of just some renewables (and nuclear) combined with electric cars could cut easily alter this savings by a factor of two or more. Beyond this, I would have to believe that carbon capture technology would be easier and more efficient at a coal or gas turbine electric plant than individually on millions of vehicles.
I’ll say it again… electric vehicles open a host of options which simply are not available to an internal combustion fleet of vehicles.
I’d also argue that the 32.6 mpg figure for current cars is high. Far too many vehicles are driven primarily in congested traffic with a lot of idling, inefficient speeds, and frequent stops and starts. Actual fuel efficiency is never as good as those numbers state.
I did, I do, and it counts. The losses you mention are what I categorized as corrections to be applied after the far larger effects of heat engine losses are accounted for.
Generally, the heat lost in these up front activities simply adds to the heat input. Thus, for a reference where the gallon of gasoline would have 33.7 kWhr of heat, and for 33% efficiency, this would put out 11.2 kWhr of mechanical energy, the efficiency would be (11.2 / ( 33.7 + 6.8 ))%. Thus, it would be appropriate to rate the heat engine at 25% efficiency. Note especially though that the heat thrown away is 22 kWhr and the up front heat loss correction is 6.8 kWhr, so the importancr of the heat thrown away by the heat engine is significantly more. And it makes no sense to rate vehicles without including it.
Electricity produced from coal probably follows this fairly well, since coal transportation has to be similarly accounted for. However, the efficiency of the electric distribution and motor knocks it down some more. Both kinds of car require mechanical linkages that lose a modest amount, but they balance out roughly.
The EPRI NRDC reference (link is in my #135 above) takes this into account though they do not provide details of their methodology. The motivation was so strongly in favor of the plug-in that we can assume that they did not cheat against the plug-in side of things.
ps, with Firefox 4 betas, Greasemonkey and Killfile nightly builds work fine.
Here’s a more balanced mashup of Jen Sorensen’s cartoon, restoring the politico vs. politico of the original:
http://i53.tinypic.com/2po49di.png
Re my 79: natural gas [or other fuels in general] (which can come from renewable sources [I guess that’s technically not ‘natural gas’ (?) although in some cases it’s natural and also a gas’] … [is] better than electricity for low temperature heating (though solar preheating should generally be used too, depending a bit on location).
Actually for any heating, except where economics dictate otherwise and/or where heat pumps may be used; heat pumps can make electricity from fuel more efficient than direct use of same fuel for some low temperature heating applications, depending on the COP. Of course you can use the fuel directly for heat+electricity (via combustion + mechanical conversion or TPV or thermoelectric device …, or via fuel cell). Solar PV ‘cogeneration’ has a temperature constraint, the best temperature depending on the economics of heat vs electricity needs; higher temperatures would typically reduce the PV efficiency, though it would tend to be more efficient than a non-hybrid system. But really what is best depends on economics – what if (with all externalities properly accounted) solar PV advances to become (including competition for roof and land space) so cheap that it just doesn’t make sense to ever use fuel even for high temperature purposes? Or what if the economics of storage and transport/transmission and are such that fuel makes sense in some places and times and electricity at other places and times for the same application? It’s quite possible (well, not the solar PV … so cheap … never use fuel, but the more general concept).
http://www.nukees.com/comics/nukees20101124.gif
…, also , there may be a comfort and familiarity issue for gas vs electric stove top ranges. Energy and economics aside, I personally prefer electric. But that type of issue doesn’t come up so much when it comes to HVAC and water heating, because you’re not interacting with the flames so directly during normal operation.
Hot Rod – Suggest you read the Stern Review, if you haven’t done so already.
and IPCC AR4 WG3 Summary for Policymakers. http://www.ipcc.ch
/Obviously/ there is no single mitigation policy in no single country (or region) that can significantly reduce global emissions. However
– There are many cost-effective, global mitigation options that can significantly reduce emissions. A lot of these are in buildings but more efficient cars (which are available) are also a good option
– Efforts in the US, EU & Japan /across all sectors/ to reduce emissions will have an impact on global emissions, because these countries combined emit a lot
– If you want China to take you seriously, then the US (in particular) better do something about climate. that’s political reality
– Finally, and most importantly, there are available energy technologies that could significantly decarbonise global electricity. Concentrated solar is extremely promising, and will (experts say) be as cheap as coal in a decade. CCS is challenging, but at least technically possible. Onshore wind (the US has rather large wind resource) is cheap. Expanding the market for these technologies will reduce costs and, ultimately, these technologies will not need state support
Clearly, we have the technological solutions to significantly reduce emissions (whether we can reach 450ppm is another question, but probably, just about). People who say “It’s not economic” seem a bit odd to me, as the best economics say it’s cheaper to mitigate than adapt, and the economy is a tool to improve the lives of humans.
100 Hank said: perhaps your perl wizard could do something with killfile .
Hank: Thanks for the info. I’m betting she’s not gonna be jumping up and down to take on any new projects now that she’s 8 months pregnant. (Jumping up and down has gotten pretty difficult for her.) I’m going to fiddle around some on my own with greasemonkey.
John #107,
Good call — wizards are subtle and quick to anger, particularly when eight months pregnant.
Everyone,
Got a poster you can’t stand? Feel like spewing fire every time the troll posts another worthless rant? Your Christmas spirit wearing thin? There is a remedy.
The following killfile bookmarklet should work in Firefox. Greasemonkey users can probably adapt it, so they don’t have to click a bookmark every time they reload.
javascript:l=document.getElementsByClassName(‘comment’);for(i=0;i<l.length;i++){void(n=l[i].getElementsByTagName('cite')[0].textContent);if(n.match(/A. Troll/)){void(l[i].textContent="(ignored)");}};
Installation: You may be able to drag <a href="javascript:l=document.getElementsByClassName('comment');for(i=0;ithis link to your bookmarks folder. If that doesn’t work, make a new bookmark with the above as the location, changing any curly quotes back to straight quotes.
Usage: Replace \A. Troll\ with the name of any poster you can’t stand. Multiple names must be separated by a pipe \|\. \Jim B\ will match both \Jim Bullis\ and \Jim Bouldin\ — be careful. Periods (\.\) must be backslash-escaped (\.\) as in the example.
Peace on Earth, and good will to men…
:)
Oops, that came out really wrong, but the code is nearly usable. Again, change three sets of curly quotes to straight quotes, and if you have a period in the poster name (“A. Troll”), use a backslash before the period (WordPress ate it).
105 Patrick 027
An important disagreement I have with you concerns your incorrect sense of how electric power sources are selected to feed into the grid. Only when there is reserve capacity of sources cheaper than coal will these be the sources that respond to new loads.. (Of course government can over-rule sound economic decisions by power planners.) Until then, the fact that coal will be the actual basis of marginal response changes some of your generalizations about what is the cheaper among heat generating systems.
I think we also see economic factors differently.
For a person who is demonstrably competent in energy conversion physics, what do you think about public policy that repeals the Second Law of Thermodynamics and defiles the First, that being the EPA insistence that one kilowatt of heat makes one kilowatt of electricity at the input plug of an electric car? Not only is this offensive to science, it seriously misguides public policy in practical ways.
And Furry Herder, you help me explain the harm of the EPA chicanery, and also make a valid challenge to me about getting my car ideas going. There is reduced incentive for trying to sell vehicles that are actually efficient when public perception is distorted by such a rating system. Who needs an efficient car when you get 99 mpg out of a Nissan Leaf, which is nothing at all about energy efficiency? This Leaf would get around 33 mpg if it carried its own gasoline engine and operated as a well designed hybrid like the Prius. The industrial system does not function to encourage improvement of products if the market system is distorted by false information. Getting the public to change their attitude toward cars is difficult under any circumstances.
63 Patrick 027
Where you say, “When will it become more profitable to grow these forests to sequester C than it is to do something else with the land and water?’, you make an important point for discussion.
I argue, with more conviction than most here would seem to agree with, that our energy based industrial system, economy, and all that goes with it in our developed world can not afford to put a large penalty on the use of coal. That makes the forest option the more atrractive way to use land and water, and it would be a way for us all to provide the infrastructure needed for our present way of life.
I do not defend for a minute a number of bad choices in the way we have wasted resources, spent money, and such, but I do see a present danger in the state of our economy. As it stands, here today, there is a need for a rational course of action. Setting things up for people to do productive work is the highest need we have right now.
By the way, as our Furry friend reminds me, there would be nothing better for my car project than to have very high priced energy as a fundamental part of our economy. But getting a car project going through a depression situation is not worth it.
Thanks for picking up on these issues.
108 CM
And good will to you as well, sir.
Let’s test the validity of one of my most basic points.
Good ladies and gentlemen, please answer the following question:
How much heat energy does it take to produce one kilowatt-hour of electric energy at the input plug of an electric vehicle?
If you support the EPA and answer “one”, kindly get your own blog and cease being in the cheering section here.
I will explain why you are disqualified to comment here in a later comment.
http://thebreakthrough.org/blog/2010/10/postpartisan_power.shtml
“”Post-Partisan Power” — How a Limited and Direct Approach to Energy Innovation Can Deliver Clean Cheap Energy, Economic Productivity, and National Prosperity October 13, 2010 at 4:59 AM”
http://www.ecoequity.org/2010/11/the-cancun-setup-one-year-after-copenhagen-and-counting/
“The first thing to say about the climate negotiations – meeting soon in sunny Mexico – is that they’re teetering at the edge of what, back in the day, we used to call a “legitimation crisis.” ….
Which, actually, is an odd turn of events…. midway through the cycle of negotiations (Copenhagen 2009, Cancun 2010, South Africa 2011) that will determine the shape and direction of the post-Kyoto climate regime. What happens now matters, particularly because, all else being equal, the eventual end of the economic crisis will be accompanied by another rapid rise in global emissions. …
…
… There are extenuating circumstances in today’s America, where the “tea party” – a corporate-funded creature of self-satisfied, self-destructive, flat-earth libertarianism – has emerged to oppose even climate science, let alone international solidarity. It’s an heartily unwelcome development, and it almost makes a good excuse. Moreover, there’s plenty of competition for the role of the world’s leading climate spoiler. …
Issues abound, and it’s hard to know who to forgive for what….”
Jim #113, where does the EPA say that? You’ve probably told us before, but I’ve avoided earlier “car wars” on this site, so I missed it. (I’ll probably sit this one out too — but I’m still curious about your source.)
Re : Post Partisan Power.
Quoting the ‘Breakthrough Institute :
“Our goal is to accelerate the transition to a world where all 6.5 to 9 billion of us can enjoy secure, free, prosperous, and fulfilling lives on an ecologically vibrant planet.”
Sure, Uh-huh. Good luck with that. All of the evidence I am looking at indicates quite the contrary to me. But that’s just my ‘opinion’.
Quoting Michael Shellenberger :
“The Death of Environmentalism: Global Warming Politics in a Post-Environmental World.”[1] The essay argues that environmentalism is conceptually and institutionally incapable of dealing with climate change and should “die” so that a new politics can be born.”
Sure. Uh-huh. Politics can save us. From a ‘consultant’ and ‘self publicists’ no less.
Sorry, Hank, it’s new age drivel. We need hard technological solutions, in my humble opinion. These guys are totally status quo,
[edit – please stop with the sniping]
114 Hank Roberts
Your link is informative. They say all the right things about objectives, education and innovation.
Their objective to develop economic solutions is recognition of the current political reality.
Their interest in education is laudable, but it appears that things are not in a good way in the world of energy science, as I demonstrated in my #113. Education is not likely to be productive of innovative thinking where government laws over-rule physics.
The general call for innovation based on misconceptions about how innovation happens is not inspiring. This is a long subject, but in the end, innovation is achieved by people thinking differently than those devoted to the status quo. And this different thinking is only useful if it is based on penetrating insight into the problem at hand, which requires a process of critical questioning. We have discovered here in realclimate discussions how the people who ‘are the box’ react to thinking ‘outside the box’.
116 CM
Sorry you would sit this out since it directly relates to how global warming will progress.
The new sticker can be seen at:
http://www.wired.com/images_blogs/autopia/2010/11/Nissan_LEAF_FE_LABEL.jpg
For quick reference, a gallon of gasoline puts out 33.7 kWhr of heat. In this example it takes 34 kWhrs of electrical energy to push the car 100 miles and the EPA declares this to be equivalent to 99 MPG. This demonstrates that the EPA formula is based on a pretension that this work can be done by heat that can be produced from a gallon of gasoline.
110, 113 (Jim),
Please supply a source, to provide both detail and context, for your statement that:
Re Jim Bullis – assuming your numbers are correct, then I agree, the EPA rating is stupid.
from http://en.wikipedia.org/wiki/Gasoline
(gasoline density = 0.71 to 0.77 kg/L,
35 MJ/L ~= 132 MJ/gal (US) ~= 36.6 kWh/gal (US) (higher heating values)
implies 45.5 to 49.3 MJ/kg, setting aside sig figs and the possible energy per unit volume variations)
from
http://www.treehugger.com/files/2010/11/nissan-leaf-electric-car-gets-99-mpg-rating-epa.php
from picture of actual EPA rating sticker:
99 mpg equivalent (106 city, 92 hwy)
100 mi/ 34 kWhe ~= 3 mi/kWhe
99 mpg / (36.6 kWh/gal gasoline) ~= 3 mi/kWh gasoline
Yikes!
I concur with your analysis here.
I don’t think it undermines the potential for electric vehicles to be helpful; it requires working on the energy source problem at the same time (we agree there, I think).
But how should an equivalent rating be done?
The efficiency of the power supply – power output is one part, then there’s the CO2 emissions of the power supply, then there’s the work done per passenger/cargo * mile…
Where the sticker indicates emissions, there should not be a single mark, there should be several (coal, gas, nuclear, hydro, wind, solar (CSP, PV, ?), geothermal, US average power supply, US average power supply at night, US average power supply during day, projected US average power supply with climate policy, without climate policy) …
Because there are some components associated with gasoline-powered vehicles that are not found in purely EV and vice versa (with PHEV and HEV being …), it’s not enough to just compare the engine efficiency with the power plant efficiency (with adjustment for different emissions per unit fuel energy); the efficiency of the battery and motor to wheel vs the transmission etc.
…
…
http://www.fueleconomy.gov/
– http://www.fueleconomy.gov/feg/evtech.shtml
“Electric motors convert 75% of the chemical energy from the batteries to power the wheels—internal combustion engines (ICEs) only convert 20% of the energy stored in gasoline.”
and also
“EVs emit no tailpipe pollutants, although the power plant producing the electricity may emit them. Electricity from nuclear-, hydro-, solar-, or wind-powered plants causes no air pollutants.”
(not quantified and placed on sticker as one may like, but they’re not exactly saying power plants don’t exist)
Back to the first point – 20 % efficiency for ICE car – I assume this is a more efficient engine with additional losses in the (car’s) transmission. Assuming perfect plug to battery efficiency, the 75 % battery to wheel efficiency multiplied by 30 % power plant and (grid) transmission (can be lower or higher) gives a fuel conversion efficiency of 22.5 %, so the EV could beat the ICE car, but not by a huge margin (using 35 % plant+grid efficiency gives ~= 26.3 %). So if the power plant is, on average, coal, then that wouldn’t be an improvement.
…
But
What if the power plant is not coal-powered? And you say it will be coal, but that’s not necessarily true; it depends on the policies we have (and hydroelectric and nuclear are baseload, too; wind can be available at night, … other stuff about electric transmission and storage and flexible charge times).
…
…
Meanwhile, what if the ICE is not running on gasoline? The choice is not limited to gasoline vs electricity (if it were then it will have to be electricity in the end, and at least you have the possibility
…
…
of relatively clean electricity that is not much more expensive); it may turn into biofuel, and those have some problems,
…
…
too (would compete with your sequestering forests, among other things)
…
…
– except, of course, we can’t in fairness
…
…
assume biofuels will continue to be as they are now if we are not assuming the same of electricity (cellusose
…
…
(cellulose crop residues, manure, landfills, sewage (there’s paper in there, too!),
…
…
algae, spoiled food and food scr-aps – residential (coffee grounds, banana peels, and the napkins and liners we leave crumbs on)
…
…
and upstream (olive pits, peanut shells, etc.), so let’s keep the engine around awhile – not necessarily in all cars, but in some fraction of them, to maintain strategic technodiversity.
Of course it may turn out that most of the biofuel ends up devoted to winter heating needs (low latitude people could sell their biofuel to the extratropics), due to the seasonal distribution of solar power (and it may be easier to take renewable CH4 and put it into the existing natural gas distribution system rather than to make it into fuel for transportation – again, it’s not all about the thermodynamics of a few things) – But what if the ICE or (P)HEV car is a cogeneration plant? Well, maybe it will be to some extent just by using the car in winter in middle-to-high latitudes, although the car’s own greenhouse effect plus body heat of passengers reduces that need somewhat.
But more on that point: what is the advantage of continuing to depend on ICE’s (or depend more on ICE’s in PHEVs and less on the P part) for the sake of cogeneration of heat? Is the heat produced while the car is in use to be stored and transfered to the building later, or is it only that heat produced by the car while parked that is used by a building? If it is the later, this could be accomplished just by making the building’s furnace/fuel cell cogeneration, or having cogeneration fuel power plants upstream. I realize of course that you might save money and resources by reducing the number of engines involved and trying to get the most out of one of them, but I’m not sure you can depend on having a car around to heat a building – yes, you can store heat energy – I would think more easily in a building than in a car (both good and bad for your concept) – but I suspect you’ll generally want buildings to have their own complete HVAC and water-heating systems anyway (which can generally have solar preheating at least, and maybe geothermal storage in addition to the building’s own thermal mass); meanwhile, if the engine is running so much more, will it need more maintanence? How much maintanence cost can be saved using the P of a PHEV more than the H (as in ICE)? I also realize that there is a turnover rate of cars that makes it is some ways more convenient to change the car than to change buildings and power plants and set up new steam/hot water distribution systems – but if you are going to start transfering heat from cars to buildings, you’ll have to change the buildings anyway.
One way to address these issues is to put a price on emissions and then just let whatever happens happen. Of course, markets are not always so ideal and we may want some additional public policies and funding (R&D, and D and D, targeted incentives, buidling codes and other mandates, reworking the structure of utilities and the grid to take advantage of opportunities).
Remember that a tax on emissions is not just a drain of money and resources, it is also a revenue source. Assuming a convex PPC (not necessarily true) and efficient market (a useful approximation at least in some ways but obviously not a precise description (ever bought a house with a tulip?)), there must be some overall economic cost to such action, not including gains by reducing negative externalities (which would be realized more in the future), but I don’t think it would have to be as big as the tax itself (I think ClimateProgress had a post on that issue). Farthermore, stating that we can’t do this because we won’t do this or because it will cost too much – well, will we plant those forests, will we buy your cars? Will we ever do anything?
http://www.skepticalscience.com/economic-impacts-of-carbon-pricing.html
122 Patrick 027
The link and quote from .gov is a further insult to physics, as well as a deliberate attempt to mislead to promote electric vehicles:
http://www.fueleconomy.gov/
– http://www.fueleconomy.gov/feg/evtech.shtml
“Electric motors convert 75% of the chemical energy from the batteries to power the wheels—internal combustion engines (ICEs) only convert 20% of the energy stored in gasoline.”
There is no validity to such a comparison. The efficiency of an electric motor is the energy conversion after conversion that was done to get heat into electrical energy to charge the battery.
Then we get the fake statement using the incompleteness of ‘internal combustion engines’ designation. Yes, there are sloppy internal combustion engine, many in fact, that get 20% efficiency in converting heat to mechanical energy. But there are also ‘internal combustion engines’ that do far better, in fact, common diesels have long done 35% and Toyota Prius gasoline engines have been measured (by Argonne) to convert at 36% to 38% efficiency.
And your analysis is generally correct, but you incorrectly assume that the 20% efficient automobile represents a reasonable standard. The Toyota Prius is far better, and so is the Ford Fusion Hybrid. If you are comparing electric vehicles to the sloppy 20% old type cars with the electric vehicles, electric vehicles win, but not by a factor of three like the EPA sticker would have us believe.
Here is where some further caution is needed. Hybrid vehicles, if well designed, can make a big improvement in both CO2 emissions and in the amount of oil used. Making the same hybrid into a plug-in will cause the CO2 impact to worsen, some. But it will do much to reduce dependence on oil; but it will do this by shifting to coal.
The oft quoted NRDC-EPRI study by Mark Duval et al. was dedicated to making the case for plug-ins, but their Fig. 5-1 shows the misleading half truth on which the .gov statement you quoted is based. (I am not at a computer where I can get this easily.)
It is a further argument that I make that the electric vehicles will be useful in shifting from oil to coal, but they will at best be of mixed benefit when it comes to CO2 emissions. However, because of the EPA misguidance, we will likely find that the ease of making a car look good in MPG by electrification will take away incentive to improve vehicle efficiency in more fundamental ways.
This rating system is likely going to be the cause of opportunity lost.
122 Patrick 027
If one worked out an equivalent based on the heat input to the heat engine making the conversion from heat to mechanical energy, whether it be the heat engine at the central power plant or the heat engine carried in the automobile, a reasonable result would be possible. Since we are looking for overall heat input, it would be fair to include compensation for delivery and processing of fuel, but this does not change much. Roughly though, the heat input for electric cars would be triple that of the EPA assumed electric power heat equivalent.
If government interceded and made coal prohibitively expensive, then it could be said that natural gas would be a fuel of choice, and in that case a different equivalent would be valid. Roughly, it would be double that assumed by the EPA. For this case, CO2 would be somewhat reduced over the hybrid, though to varying degrees depending on the type of heat engine used. (See Fig. 5-1 of that NRDC-EPRI study by Duval)
122 Patrick 027
Here is the link to the Duval study:
http://mydocs.epri.com/docs/public/000000000001015325.pdf
120 Bob
Link you requested is at my #119
Hope this is useful. Also, please see discussion by Patrick 027 and myself that follows.
JimBullis – If you insist on including the heat energy loss cost of electricity generation in the figures for battery powered vehicles, then why don’t you also include the cost/fuel use in supplying the gasoline for the ICE vehicle? What’s the efficiency of digging the oil sands, turning it into barrel petro, transporting it to a refinery near you and then delivering the gasoline to your fueling station?
136 (Jim),
I utterly fail to see how you arrive at this conclusion, or why you would think that heat has anything to do with the EPA’s logic. Quite honestly, it looks like you simply made it up.
Can you provide something other than your own personal inference? A link to an explanation (by the EPA) where the EPA says they followed your presumed heat-does-the-work logic to arrive at their mileage equivalence?
With that said, as to your point, my query, and the rest of the discussion… it’s way, way OT.
But as far as electric vehicles go, it’s very simple. The only choices are gas, fuel cell and electric. Gas means CO2, and is limited to a single, dwindling fuel source (well, okay, you might work synthetics and biofuels in there, but I doubt that will ever work for the entire planet). Fuel cells are not yet viable.
So all that is left is electric. If the vehicles are electric, then the actual source of the power is more flexible, and can change over time, and control of emissions is localized. Electric vehicles offer options, gasoline exacerbates AGW, wand fuel cell basically means wait, do nothing, and risk the technology never becoming viable.
Re 137 flxible – to be fair, not all petroleum is currently derived that way; the petroleum supply is one of the single biggest consumers in the U.S. today, but if the EROEI is something like 10/1 (? http://www.theoildrum.com/node/3810 – but does this include refining?), you can still reasonably approximate 1 MJ sold fuel ~= 1 MJ petroleum from ground (in the same way that the synoptic-scale extratropical wind above the boundary layer is generally approximately geostrophic) (though worth pointing out that renewable sources like PV and wind can beat that, when they’ve been criticized for being far less). But a valid concern at least going forward. On that note, the EROEI of some (not all) biofuel makes it more of an energy conversion technology.
Re Jim Bullis (again)
http://www.skepticalscience.com/renewable-baseload-energy.html
Re Jim Bullis – are the 35 % (diesel) and 36 – 39 % (HEV) efficiencies specifically for the ICE? If so then they can’t be so easily directly compared to the fuel to wheel efficiency. How much of HEV efficiency is directly dependent on the EV part – aside from regenerative breaking, which (I would think) shouldn’t affect mpg hwy so much? Or could simply updating ICE technology bring the entire fleet’s fuel consumption significantly down? I’ve heard that a potential advantage of EV’s would be the opportunity to have a seperate electric motor for each wheel, which would improve efficiency – could that be incorporated into a HEV and would that make any significant difference?
Once upon a time, I recall reading or hearing that at 55 mph, a car’s power usage was equally divided between working against rolling resistance (proportional to speed) and working against air resistance (proportional to speed squared). So if got the drag area of a car and the mpg we could figure out just what the efficiency is, though changes in design probably alter the speed at which the two power sinks are equal.
PS a point about government policy – given the fuel economics of pure ICE’s vs non-P HEV’s verses PHEVs, it might be that without any government intervention, PHEV’s will eventually dominate and they will be powered mainly through the P and not the H. So to avoid the calamity you are warning about, you may want to support a tax on CO2eq or some other way to increase the price of coal power, if not to get PHEVs powered by the sun and wind etc, at least to prevent them being powered by coal.
… of course, even given 10:(1+refining transport etc.?) EROEI for gasoline, this is assuming the rest of the petroleum continues to find other purposes, so that the whole of each barrel is used. But I wouldn’t expect that to be a big problem. It used to be that gasoline (or its precursor?) was a waste product of the petroleum industry.
… oh, but the rolling resistance would include losses between ICE and wheel, wouldn’t it? Or is it only the viscosity of the tires that equaled air resistance at 55 mph? I really don’t know. Any good websites to explain this?
http://www.fueleconomy.gov/feg/atv.shtml
– appears to show a non-HEV car with an ICE near 18.2 + 2.2 + 17.2 = 37.6 % efficiency. Reminds me: HEV’s would reduce idling losses as well as breaking losses. Is this diagram for city driving? (I’d guess it must be, for that much idling) (accesories should be a smaller fraction at higher speeds, as they tend to be proportional to the time people are in the car, right?). This car has only a bit over 12.6 % of the gasoline’s energy going to the wheels. Eliminating idling and assuming proportions stay the same, this should be a bit less than doubled, bringing it near 20 %.
It seems like, aside from idling and regenerative breaking, there isn’t much overall difference among pure ICE cars, HEVs, and PHEV’s in the overall fuel to movement conversion efficiency, then (except for the range in power plant efficiencies). Maybe some advantage to be gained from changing or eliminating the drivetrain? (PHEV with 1 motor per wheel?).
… I wonder what the politics of climate change will be like in x0,000 (or xx0,000) years when the next ice age comes – will CO2eq earn a credit instead? Or will we let nature take it’s course (great opportunity for science, documentary film makers and photographers/artists tired of the same-old Holocene and Anthropocene subject matters (caution – you can’t go home again – sort of)? Also, with CO2 being long-lived (in so far as atmospheric perterbation ppm goes), would CH4 emissions be encouraged after a supervolcanic eruption?
Or sooner, when the Sahara gets wet again (maybe not this time around the Precession cycle due to small eccentricity ?, but eventually)…
Just encouraging you guys to keep on keepin on! Your work is vital, the planet desperately needs you!
Jim (#199),
thanks for the source. I think I’d agree that the sticker is potentially misleading. However, the 34 kWh = 1 gallon comparison is obviously meant to compare the efficiency of the respective engines in making use of the power supplied at the plug or pump, in units consumers will be familiar with (mpg). And that’s fine by itself, it’s just not meaningful as a guide to CO2 savings.
I think it’s worse that the right-hand side of the sticker declares CO2 emissions to be zero. The small writing makes it clear that this refers to tailpipe emissions only, but how many people will understand what that means? And“tailpipe emissions” have nothing to do with the actual carbon footprint of an EV; since CO2 is not a local pollutant, it’s a meaningless measure, I think.
But the mpg comparison makes it easy to do some back-of-envelope calculations of the CO2 savings from moving to electric vehicles, without having to get into all the details you and Patrick are discussing.
If gasoline gives 19.4 pounds = 8.8 kg CO2 per gallon (EPA), then an average U.S. passenger car (22.6 mpg) or a new vehicle (32.6 mpg) (BTS, *) emits 390 g or 270 g CO2 per mile, respectively. If U.S. power generation gives 1.341 pounds = 0.608 kg CO2/kWh (national average output rate, including fossil and non-fossil sources, EIA, 1999 figures); then an electric car that goes 99 miles on 34 kWh emits ~ 210 g CO2 per mile on a U.S. average. The effect of switching to this electric car, then, is a 46% reduction in CO2 emissions per mile traveled, if you’re giving up your average American car, or a 22% reduction relative to the fuel-efficient new car you might have bought.
This accords well with the Wikipedia statement that “With the current U.S. energy mix, using an electric car would result in a 30% reduction in carbon dioxide emissions.”
In #133 Jim misleads us again….
The link and quote from .gov is a further insult to physics, as well as a deliberate attempt to mislead to promote electric vehicles:
I think you’re projecting there Jim…. You don’t like what they say and so ascribe ill intentions and motive where none are really necessary.
http://www.fueleconomy.gov/
– http://www.fueleconomy.gov/feg/evtech.shtml
“Electric motors convert 75% of the chemical energy from the batteries to power the wheels—internal combustion engines (ICEs) only convert 20% of the energy stored in gasoline.”
There is no validity to such a comparison. The efficiency of an electric motor is the energy conversion after conversion that was done to get heat into electrical energy to charge the battery.
Yes, exactly.
Then we get the fake statement using the incompleteness of ‘internal combustion engines’ designation. Yes, there are sloppy internal combustion engine, many in fact, that get 20% efficiency in converting heat to mechanical energy. But there are also ‘internal combustion engines’ that do far better, in fact, common diesels have long done 35% and Toyota Prius gasoline engines have been measured (by Argonne) to convert at 36% to 38% efficiency.
You’re bending the numbers again Jim. You complain about the EPA comparing apples and oranges, then you go ahead and do the same thing.
Comparing the peak engine efficiency in any engine to the typical output in a real world auto is not a fair comparison.
If you’ve looked into efficiency at all, Jim, you must know that all engines have a peak efficiency point. ICE’s will be most efficient around the peak of their torque band and 80% power. When one accounts for typical power requirements, accessory drag, and adds the power train in one necessarily gets a much lower number than 35-40%.
And your analysis is generally correct, but you incorrectly assume that the 20% efficient automobile represents a reasonable standard. The Toyota Prius is far better, and so is the Ford Fusion Hybrid. If you are comparing electric vehicles to the sloppy 20% old type cars with the electric vehicles, electric vehicles win, but not by a factor of three like the EPA sticker would have us believe.
But you’re complaining about the EPA taking one extreme for comparison while you insist on taking the opposite extreme. IF – and only if – the extreme you insist upon (that coal or the like is the source used to charge the battery), you’re right in your analysis.
There are, however, many other sources of electricity. If the batteries for the (PH)EV are charged with power from wind, hydro, solar, or nuclear then essentially no CO2 is released for that energy. If one of the first three is used then essentially no heat is wasted, heat you insist on including in the comparison. If the electricity is produced with a co-generation system where the waste heat is used then the original heat source is essentially converted into electricity at more than 90% efficiency. If natural gas is the original source, up to 60% of the original energy can wind up in the batteries.
So the real answer, Jim, is “it depends”. It’s not a simple black and white issue like you try to paint it.
There are two other factors worth noting.
First, I think our ability to generate more electricity with which to power our transportation greatly exceeds our ability to create more liquid fuels. The CO2 impact of new electrical generation should be much less than that of developing alternative liquid fuels. Wind and solar are coming on strong; oil has probably peaked and alternative liquids (tar sands, GTL, CTL, biofuels) are expensive and dirty. These are things worth considering: will there be affordable liquid fuels for any vehicle at the end of a 20 year life? Will there be affordable electricity in 20 years with which to charge your (PH)EV ? I know which I’d be more likely to bet on.
Second, if your WonderCar really reduces energy requirements, there’s no reason it couldn’t use electric power. IE, if you can drop the energy requirements by 80% it would be easier than ever to power electrically. Then you could get 1000 mpg the way the EPA measure it:)
145 (CM),
… as long as energy production maintains that 210g CO2 per mile average. But as energy production shifts to cleaner sources, that number has the potential to improve further, where there is no such possibility (outside of improved gas mileage) for the internal combustion engine. So the use of just some renewables (and nuclear) combined with electric cars could cut easily alter this savings by a factor of two or more. Beyond this, I would have to believe that carbon capture technology would be easier and more efficient at a coal or gas turbine electric plant than individually on millions of vehicles.
I’ll say it again… electric vehicles open a host of options which simply are not available to an internal combustion fleet of vehicles.
I’d also argue that the 32.6 mpg figure for current cars is high. Far too many vehicles are driven primarily in congested traffic with a lot of idling, inefficient speeds, and frequent stops and starts. Actual fuel efficiency is never as good as those numbers state.
> and frequent stops and starts.
Regenerative braking makes city driving more rather than less efficient for electric vehicles. http://www.google.com/search?q=regenerative+braking+fuel+economy+city+highway
137 flxible
I did, I do, and it counts. The losses you mention are what I categorized as corrections to be applied after the far larger effects of heat engine losses are accounted for.
Generally, the heat lost in these up front activities simply adds to the heat input. Thus, for a reference where the gallon of gasoline would have 33.7 kWhr of heat, and for 33% efficiency, this would put out 11.2 kWhr of mechanical energy, the efficiency would be (11.2 / ( 33.7 + 6.8 ))%. Thus, it would be appropriate to rate the heat engine at 25% efficiency. Note especially though that the heat thrown away is 22 kWhr and the up front heat loss correction is 6.8 kWhr, so the importancr of the heat thrown away by the heat engine is significantly more. And it makes no sense to rate vehicles without including it.
Electricity produced from coal probably follows this fairly well, since coal transportation has to be similarly accounted for. However, the efficiency of the electric distribution and motor knocks it down some more. Both kinds of car require mechanical linkages that lose a modest amount, but they balance out roughly.
The EPRI NRDC reference (link is in my #135 above) takes this into account though they do not provide details of their methodology. The motivation was so strongly in favor of the plug-in that we can assume that they did not cheat against the plug-in side of things.
#145 CM
You say, “I think it’s worse that the right-hand side of the sticker declares CO2 emissions to be zero.”
And I completely agree with you. I just had not gotten to that yet.