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The mpg confusion

Filed under: — gavin @ 23 September 2008 - (Español) (Français)

What reduces emissions more?
A. Someone swapping their old SUV (which gets 12 miles per gallon) for a hybrid version (18 mpg) or
B. someone upgrading their 25 mpg compact to a new 46 mpg Prius?
(ignore for a minute manufacturing issues or driving habits and assume the miles driven are the same).

The surprising answer (for those who don’t work it out) is A. It’s easy enough to see why this is the case. If the driving distance is 100 miles, then for case A the saving in fuel used (and hence emissions) is 100/12-100/18 = 2.8 gallons, while for B, you have 100/25-100/46 = 1.8 gallons. The confusion arises because people like to think linearly about numbers, not inversely, and so tend to assume that a similar change in mpg has a similar impact on fuel usage. This is not however the case – improvements in efficiency at the low end of the scale are much more useful at reducing emissions. This is actually a very general point – when trying to raise efficiency it is always sensible to start with the least efficient processes.

This confusion got some attention a couple of months ago after a piece that was published in Science by Larrick and Soll. They tested peoples instinctive reactions to changes in mpg numbers and found that people very often got it wrong, leading to less than optimal decisions. They also tested a different way of giving fuel usage information (the number of gallons used per mile), and since this is linear in emissions, people made the correct judgment much more often (it’s worth noting that the standard in most of Europe is already litres per 100 km). Rewritten in those terms, the choices above become:

A. Someone swapping their old SUV (which takes 8.3 gallons to go 100 miles) for a hybrid version (5.6 gallons/100 miles) or
B. someone upgrading their 4 gallons/100 miles compact to a new 2.2 gallons/100 mile Prius?

Much easier, right? The authors of the Science piece are trying hard to get US manufacturers and the EPA to switch over from mpg to this new standard (though they prefer gallons/10,000 miles). It all seems eminently sensible to us.

356 Responses to “The mpg confusion”

  1. 251
    Dave Rado says:

    Re. cheap solar cells, concentrating solar thermal power (CSP) is already cheaper than nuclear and if it were invested in properly, it would be competitive with coal within 20 years or so according to some peer reviewed studies. There is a good article about it ere. One of the scientists who have published about it, Dr. Franz Trieb, wrote to me in November 2007:

    Dear Dave,

    You will find all relevant information in the quoted studies.

    The article – at least my portion – is not about solar (photovoltaic PV) cells but on concentrating solar thermal power (CSP). This technology does not store electricity as it produces and stores heat for operating conventional steam turbine power stations. Two 50 MW plants are presently build in Spain with storage capacity for 8 hours night-time operation, a 64 MW plant was recently commissioned in Nevada, U.S. A total of 415 MW is on the grid world wide.

    The collectors continuously track the sun (for the concentration of direct sunlight) and therefore they can be put in a protective position if a sandstorm comes up. Those plants are operating since 20 years in the Californian Mojave desert and have survived sandstomes, hailstormes and twisters. The biggest plant there has 150 MW capacity. Strange thing that this is fairly unknown as those plants are on the grid since the mid eighties of the last century.

    High voltage direct current (HVDC) transmission is expected to loose about 10 % from Morocco to Germany, as an example. This technology is running world wide since the 1970ies. It will add about 1-2 c/kWh to the electricity generation cost which will be about 4-5 c/kWh in the medium and long-term. The cost of CSP comes done with production volumes, about 10-15% each time the installed capacity doubles (this in fact is true for most technical devices, but not for fossil fuels, as they are no technical devices but limited resources).

    The collectors replace fuel in conventional power plants, today at a cost equivalent to about 50-60 $/barrel fuel oil (that means they are already cheaper than oil!!). A pre-requisite for achieving equivalent costs of 15 $/barrel after 2020 will be the expansion of installed capacity, that means that people must start acting and stopp talking. That’s what the Algeriens finally did and I can only congratulate them for this, because talking another 10 years about possible problems (like most politicians did for the past ten years) will not solve them and will delay the moment when 15 $/barrel can be achieved for exactly the same time span (that’s in fact the major uncertainty).

    Our numbers have been published in Sustainability Science (Springer) and by the Club of Rome ( in its Whitebook to the European Parliament that will be released on November 28, both thoroughly peer reviewed.

    At the trans-csp website you’ll find several useful links for more information.

    Best regards

  2. 252
    Dave Rado says:

    Also, re. CSP, see here.

  3. 253
    Rod B says:

    Matt, sidebar to your side note (240): But Gore’s 100% in 10 becomes even more important now that he is going to terrorize coal-fired plants, or whatever falls under his call for “civil disobedience”.

  4. 254
    Rod B says:

    Mark (243) It was actually Watson of IBM in the late 40s I think that predicted a use for about 6 computers (back when they took a whole building). I think it wasn’t until a NYC librarian explained how she would use one that the bulb lit up.

    No doubt the growth of computer technology is astounding. Thanks to material science and chemical engineers with a little help from physicists and electronic engineers ;-) .

  5. 255
    matt says:

    #244 RichardC:

    Yeah, well good luck with that. I first had this discussion in 1982, as part of a debate in high school. Nuclear was too dangerous, the japanese had perfected the high mileage car, people were installing solar hot water heaters in their backyard, some were still wearing sweaters at the request of the Carter administration, and Michael Stipe of REM was convinced Reagan was an idiot governor out to blow up the world.

    Man, good thing we’re past all that and that history never repeats. But you keep your blueprint handy…I’ll check back with you in 10 years to see how we’re doing. By then, France will make us all look like CO2 gluttons.

  6. 256
    Martin Vermeer says:

    What you’re all ignoring is that the bottleneck for replacing the existing power infrastructure is not the time it takes for one plant to come online, but the investment needed, in money, work, and raw materials, to replace a complete infrastructure.

    A power plant has a depreciation lifetime of something like 30-50 years. Replacing all or most existing plants with something new — nuclear, concentrating solar, wind, OTEC, a mix — is going to take that amount of time, if you want to do it without closing down perfectly good plants, a major destruction of capital. That’s why you won’t see more than 50% or so by 2030, even if we get our act together now, even for currently available technologies.

    Suggesting that nuclear can somehow short-circuit this (and that CSP, e.g., somehow can not), is less than honest and simply not true. What is true is that decisions we take — or start to take — now, will determine the power mix we will have a few decades from now.

  7. 257
    Eli Rabett says:

    Basically this argument about mpg or liters per 100 km is trash because it assumes that the number of miles driven is inelastic.

  8. 258
    Anne van der Bom says:


    JCH, why do these regulations exist?

  9. 259
    Anne van der Bom says:

    #244, RichardC:

    The US version is deliberately made less efficient. Those sold in Japan get far better mileage.

    Where did you get that information from? I never heard that before. I know two things:
    1. The Japanese version has a larger fuel tank. So yes, you get more miles on a tank.
    2. The Japanese tests for assessing fuel economy yield lower consumption on all cars, but are especially favourable to hybrids. You can not compare the Japanese ratings to the US or European ones.

  10. 260
    dagobert says:

    #248 – Anne van der Bom
    I’m afraid you missed my point entirely. It’s not just about building new plants but about keeping the ones already running. We’re currently phasing out nuclear not because the plants are about to break down but because of political decisions tailored for those who grew up with the ‘nuclear is bad’ feeling.
    And even today, solar could in theory power the world – let alone in ten years – but it requires a whole new grid and ways to store and distribute the energy far more effectively than we can do it today. Yes, there are a number of ideas out there how it could eventually be done if only this and that would happen. But the mere fact that it may be possible doesn’t automatically make it the best way to go. I linked to a study somewhere above in this thread that details very optimistically how to get to a mere 20% renewables with technology that does not have to evolve and even that is slow and ineffective compared to simply building nukes – no matter whether it takes 10 or 20 years to establish a new one. Look at France. If we’d all have an energy mix like they have, we might not even be here talking about AGW at all.

  11. 261
    Mark says:

    Martin, you’re right, but windfarms and solar panels are quicker to start generating an ROI for at least two reasons:

    Half built, the farm can still generate (heck, as long as you have one windmill or panel).

    They can be distributed over many sites, making finding a site less critical. You can’t build a nuke facility without the right amount of land and the right permission and so on. You can put a panel on your business roof, or a windmill in your farm.

  12. 262

    I think there is a misapprehension about the Japanese vs. the American Prius. If I read the the Edmonds article correctly, the differing economy figures are purely artifacts of measurement methodologies, not “tuning.”

  13. 263

    Re: #219:

    “If you have 6 people going to the same place, do they take a compact and a prius (4+2.2 = 6.2 gal/100) or one hybrid SUV (5.6 gal/100)”

    Under current BAU, they generally take 2 SUVs, 2 mid-sized sedans, 1 compact, and one hybrid.

    (Captcha seems to think we should look at steam: “Whitcomb baby”)

  14. 264

    walt bennett writes:

    grant me the proposition that AGW science is in its relative infancy,

    “AGW science” is older than quantum mechanics. Do you doubt that your PC works?

    Specifics: The greenhouse effect was discovered by Fourier in 1824. The major greenhouse gases in the Earth’s atmosphere were identified as water vapor and carbon dioxide by Tyndal in 1859. The first quantitative estimate of global warming under doubled carbon dioxide was made by Arrhenius in 1896.

  15. 265

    I wrote:

    there’s little research going on to disprove AGW for the same reason that there’s little research going on to disprove relativity or evolution. Once something is that well established, people don’t usually waste time reinventing the wheel. The fact that you don’t understand this says more about you than about the allegedly politicized science.

    walt bennett replied:

    You simultaneously missed and made my point. Thanks again.

    And mine appears to have sailed over your head. Do you really think evolution is shaky because biologists aren’t looking for ways to overturn it? Or that relativity is doubtful because scientists don’t spend a lot of effort on trying to “break” it? There comes a point when trying to disprove something that’s passed every test for over a century becomes useless and stupid. There are other things to do in science.

  16. 266

    matt writes:

    Side note: A commercial that has been running on US TV is “We Demand 100% Renewable Energy In 10 Years.” This is from an Al Gore group. I can’t begin to stress how counterproductive these types of ads are, because they give everyone the impression it’s indeed possible but that an evil force is preventing it. Shame.

    It is possible in ten years. It might be difficult and expensive and require some kind of massive, world-shaking government program, but it is not impossible in the sense that faster than light travel is impossible.

  17. 267

    JCH writes:

    Ten years [to build a nuclear plant] is because of regulations. If they would just deregulate we can have some subprime plants in less than one year.

    Just leave off the containment structure. That’ll speed things up a lot!

  18. 268
    dagobert says:

    #244 RichardC
    “Man, I just told you how transportation can be reduced by 66%. License the Prius technology. *poof* the fleet goes from 25 mpg to 75 mpg. The US version is deliberately made less efficient. Those sold in Japan get far better mileage. I’m saying that the US version could be nudged towards the Japanese way. All it takes is the desire – no new nuttin required. Instead of 94 MPG the Japanese one gets, we can settle for 75 MPG.”
    Sorry, but this is completely and utterly wrong. The only “deliberate” efforts to make US versions of cars “less efficient” were made due to the bad fuel quality in your country. Most modern cars don’t have any special US components at all, since they adapt to fuel quality automatically.

  19. 269
    Jim Eager says:

    Re: JCH @250: “Ten years is because of regulations. If they would just deregulate we can have some subprime plants in less than one year.”

    Not to mention a few subprime catastrophic failures.

    prescient reCaptcha: week controls

  20. 270
    Rod B says:

    BPL (265), Walt doesn’t need my help (…neither does anybody else, I suppose, but that’s another story… :-P ), but from his assertion that scientists are not looking at or considering negatives, you try to refute it, but instead agree with it (in part) but say it makes sense since no scientist in his right mind would look for negatives in fully established AGW, or evolution, or relativity. ‘Course others here have strongly asserted that scientists are salivating over the prospect of finding a disproving theory to make a name for themselves. I wonder which it is…

  21. 271
    Dave Rado says:

    dagobert wrote in #260:

    And even today, solar could in theory power the world – let alone in ten years – but it requires a whole new grid and ways to store and distribute the energy far more effectively than we can do it today.

    That is not true in the case of CSP.

  22. 272
    RichardC says:

    202 Dagobert said “renewables need a considerable share of their full capacity as backup and their net contribution will always be compromised by the losses from running conventinal plants far from their sweet spots or by switching to fast reacting backups like gas turbines”

    Weather forecasts, tide charts, etc, give a long lead time. It’s easy to crank up only the most efficient backups. Plus, transportation fuel production and water pumping stations can trim the sails.

    220 Dick, the backup is already embedded, so there is only the cost of keeping it alive.

    225 Larry, exactly. It seems that bringing up one wedge just makes the denier say that it isn’t the entire solution so should be discarded. They’re forgetting it is a system.

    233 Dagobert, yep, we’ll need energy at night, but with a world-wide super-conducting backbone, Chinese sunshine can power your nightlight (you said in 100 years.) And again, tides, wind, solar, and a few others all have different periods. We’re talking about the sum of all of them, spread across as wide a geographic area as the current backbone allows efficient transmission. Even 1000 km does wonders for load smoothing. I just don’t see your point about nuclear. Dropping load through efficiency changes the ball game. Renewables can be used to retire non-hybridized nukes and fossil fuel plants. It’s kind of like the refineries argument, “We need more refineries!” Uh, no, we need far fewer refineries, just better MPG. That’s the key disconnect here. Some think demand will go up, others see an easy path to drop demand, save money, and increase wealth. So to whose dream do we build the infrastructure?

    236 Walt, “Please define “current threat”, and then please describe how the science underpinning that threat is “well established.” In what year did it become well established? When did it cross that threshold?” Easy, the current threat is methane outgassing from the Arctic ocean and it became well established a week ago. You also asked about contrarian research. There’s been a lot of it. Cloud feedbacks, for one. All of the studies attempting to discredit AGW have failed miserably. Most studies have this, that, or the other speculations, so attempting to disprove AGW is built right in. The one that gets the headline is the one that bears fruit. Doesn’t mean the study didn’t delve into all three.

    238 Deb, my condolences. Yep, the owner of an SUV is kinda stuck. That’s free market capitalism. Ya gots to live with your choices.

    250 JCH “Ten years is because of regulations. If they would just deregulate we can have some subprime plants in less than one year.” Egad, that’s one scary post. Yeah, let’s build sub-prime nukes. We can fund them with sub-prime l*ans!

  23. 273
    RichardC says:

    259 Anne 268 Dagobert, I was talking programming, not components, though some components are different, like the “electric only” button that Europeans get.

    “While the current Prius posts a class-leading 35.5 km/liter in Japan’s 10.15-mode fuel cycle (equal to 83.5 mpg in the U.S.), Toyota’s reported target with the third-generation Prius is a stellar 40 km/liter (94 mpg) in the same cycle.

    Hold the champagne, however. Japan’s 10.15 mileage cycle is now an old system, far from relevant to global standards, and especially kind to hybrids. (The cycle enables hybrids to run on electric-only power for extended periods, which helps deliver wondrous fuel-mileage numbers.)”

    The US cars are tuned for battery durability while Japanese cars are tuned for efficiency. It’s a marketing choice, and it is a REAL difference, NOT an artifact of testing. North American Priuses are dang difficult to keep in electric mode. (Trust me, I’ve spent many an hour trying to keep my foot just right to not get the stupid program to unnecessarily turn on the gas engine.)

  24. 274
    Dave Rado says:

    Re. Rod B, #270, it’s pretty straightforward really. Scientists constantly analyse evidence (data). If in the course of doing so they came across any that appeared to contradict a mainstream theory, then being sceptics in the true sense of the word, they would first try to find flaws in their own analysis or data. If they couldn’t find any, they would certainly publish a paper about it. Once the paper had been published, other scientists, being sceptics in the true sense of the word, would also try to find flaws in the paper’s analysis or data. If they couldn’t do so, the theory would eventually be modified. That’s how science works and always has.

    Recent example: Christy’s papers on tropospheric temperatures based on satellite measurements, which were eventually found after several years to be based on flawed calculations.

    Scientists do not ask for a grant in any field of research to find data that will either support or contradict any theory – that isn’t and never has been how science works. Science, unlike law advocacy, isn’t about starting with a desired conclusion and then trying to find evidence that might support that conclusion. It is about starting with the evidence and then forming conclusions that are supported by that evidence. You appear to be asking for scientists to do the former (act like legal advocates) rather than the latter, but to do so would be a corruption of science.

    On the other hand a number of scientists (Soon, Singer, Michaels, and more recently Spencer and Christy) who once had decent reputations as scientists have indulged in your form of advocacy by cherry picking data in order to support a desired conclusion in the context of climate change, and have destroyed their scientific reputations in the process, although it has made them heroes in the non-scientific denialist community.


  25. 275
    Dave Rado says:

    Why so much focus on the Prius? The Honda Insight electric/petrol hybrid has far better mpg ratings than the Prius, and unlike the latter, it gets much better ratings even than compact diesels.


  26. 276
    dagobert says:

    I think our main difference when it comes to nuke vs. renewables is the perspective of what we believe is ‘doable’ and what isn’t. You assume or at least hope that entire societies can turn on the spot quickly and I believe they can’t. To be honest I just don’t have the optimism anymore. I wish you were right (not just in terms of energy but generally) and I was wrong but since I’m more of a pessimist I’m afraid its the other way round (kind of a catch 22, come to think of it ;) ). Anyway. When I look at the options, when I look at what we achieved in Germany with efforts already considered far too great by a majority and with a political party probably impossible in the US and certainly impossible in China, when I look at what additional efforts we’d have to make just to get renewables up to one 5th and then compare it to France and think of carbon in 50 years, I’d still go for nukes.
    You are right about different software for different markets. Not only for the Prius, btw. If you’d buy a Prius III in Japan and import it, you’d probably not notice much of a differnce though and more likely than not, your Japanese Prius would even consume slightly more when driven under American conditions. My bet would be a maximum difference of 2-3 percent either way. Remember: mileage is the one silver bullet the Prius has. They don’t go and blow a huge 94 vs. 78 (or whatever) difference out the window for better reliability. So lets settle on “almost” all of the difference is a testcycle artifact.
    I wasn’t aware that the US Prius doesn’t have an EV-button like the ones sold here. I played a lot with it during my first drives with Priuses but the effect isn’t really what you might expect. It makes some sense when, i.e. you know a longer slope follows and there will be plenty of speed to recuperate so you can use up the battery fully (perhaps Toyota considers Americans not capable of memorizing the topology of their daily commute or whatever) but after a while you don’t really bother because the difference is minimal unless you travel a lot at very slow speeds in very hilly terrain and had plenty of time to work out a perfect strategy. Hybrids should couple the recuperation strategy to the route-finder. That could know when it’s going up or down and should make more of a difference but its also a very complex system to introduce into a car and will take some time to develop properly.

  27. 277
    Walt Bennett says:

    Re: #272


    I just loved that answer! Nice belly laugh, thanks. I just want to clarify that I am not interested in “discrediting” AGW. In fact, since I started asking these questions, I have come to learn that I am not alone and that RC, CA and other places are robustly kicking the tires of some of the conclusions. So, that reassures me somewhat.

    I can accept the fact that almost every single member of this discussion group wants to believe that IPCC and Dr. Hansen have it basically correct. Funny that Hank accuses me of beliefism when there is ample proof that the general tone of this board is to blindly accept anything that comes from sources who have similar sympathies.

    I have no quarrel with that approach, as far as it goes. My concern is more in the overall sense that we as a planet are being asked to act, to act soon, and to disrupt a century of progress in unproven ways with unknown results, for potentially invalid reasons. And of course, how do we ever get everybody to act in common, anyway? And how do we know what technologies may emerge in the next decade or two?

    I would, if I were you, worry about my own bias when you make the statement “All of the studies attempting to discredit AGW have failed miserably.” I sure see bias in that statement, not to mention subjectivity (which I suppose is a prerequisite for bias).

    I’m done contributing to this OT thread, and I thank all those who came along for the brief ride. I got my answer in two ways: (1) there is a strong “shut up and go away” bias among those who fancy themselves up-to-speed on the current state of the science; (2) there was an eery echo of silence from those “on the inside”, leaving me to wonder: are they worried that I had a point?

    It’s a fair conclusion to draw.

  28. 278
    Anne van der Bom says:

    #260, dagobert

    You wrote in 233:

    However my main point remains: if we need to act now, nuclear is the way.

    That definitely suggests building new plants, not merely extending the life of existing plants. Sorry if I missed something.

    but it requires a whole new grid and ways to store and distribute the energy far more effectively than we can do it today

    Are you seriously suggesting that we need to throw it all away and build something completely different? How does solar electricity differ from coal electricity that it can not be transported through the cables we now have? We need to adapt the grid, mainly increasing its capacity. This is business as usual for energy companies, they have been expanding it all the time. And why must the grid become the far more effective? As far as I know the grid is very effective. It gets all the energy needed in the right place at the right time. I do not see what is exactly wrong with our current grid that makes it unsuitable for renewables. Can you be more specific?

  29. 279
    Anne van der Bom says:

    #275, Dave Rado:

    Look up the sales numbers for the Insight and Prius and you’ll have your answer.

    The Insight is irrelevant. The Prius is a car that people actually want and buy. Why? Most people have a family, and the Insight only seats 2.

  30. 280
    Rod B says:

    RichardC (272), “…a world-wide super-conducting backbone”??? I’ll bet Radio Shack has to back order it.

  31. 281
    Rod B says:

    Dave (274), what you describe is the well-accepted ideal, which Walt (and, in part, me) is saying might not be happening in practice. In fact the vast preponderance of scientific is directed to hoped-for outcomes, though mostly this is a benign process that doesn’t change the scientists’ objectivity. I don’t do and haven’t done this specifically, but I would wager that a researcher looking for a mega-thousands dollars and mega hours of National Labs and/or DOE supercomputer time to disprove AGW has one helluva worse time than any protagonist, though this is way beyond what is being looked for. More to the point, I would wager a scientist with a grant to, say for example, explore global warming cause and effects on oceanic currents and arctic ice, and at the end had little to report on that objective because he/she had found something that looked like an anomaly so instead researched that because it was scientifically interesting, is going to have an uphill battle getting his grant renewed. Naturally most scientists will not pursue that interesting anamoly, at least very much. What I would say (and I think Walt, too) is that this seems, from an outsider’s view, to have become very strong and prevalent in climate science. Unless he/she has other protection and funding (University tenure maybe…) a scientist chasing his negative anamoly in climatology will likely not only lose his grant but be put in the stocks, strung up and/or lose certain important body parts.

    For my part, this is a problem, but a minor problem and not real troublesome. To your question, I’m not really asking scientists to do anything.

  32. 282
    Anne van der Bom says:


    I live in Europe. I have to be careful too for the ICE not to kick in, but it is not difficult below 60 km/h. How far will the car let you deplete the battery, down to 5 bars, 4, 3? I can quite easily let it run on electricity until there are only 4 bars left and with some difficulty, 3. Is that different from your car?

  33. 283
    Rod B says:

    Anne (278), I offer a thought. Current power plants are built relatively close to the consumption sink. Wind and solar plants predominately will be built where consumers aren’t. They’re already looking at a $3-4B transmission facility just to get the planned N. Texas ~$12B wind farm’s electricity to just Dallas and other large Texas, Oklahoma and N. Mexico (predominately) consumer areas. Second, there has to be a complex grid expansion and control system emplaced to interconnect current sources and maybe (far out) storage systems. Doable, but not while you’re sipping your morning coffee ;-) . (That’s a hippie’s “far out” not a map maker’s.)

  34. 284
    dagobert says:

    #278 Anne van der Bom
    I would like to refer you again to this paper:
    The main problem as I see it is the way the grids are structured today. They do rely very much on backbones connecting the main consumer areas with the main production areas. The paper is for Germany only and the main enhancements to the grid it describes necessary for 20% renewables (mostly wind) are new backbones connecting the windy areas in the north with the south where there is more consumption and more production from conventional plants due to denser population and more industry. The backbones are required for both – backup in case of too little wind to satisfy the northern requirements as well as feeding into the south to enable usage of the energy if the north requires less than the turbines provides in case of stronger winds. Now this is for one fifth of our energy from wind and the fifth is not stable but averaged out over a year. There will be days where there is close to zero wind (this is a small country so it will look different for the US) and in that case, conventional backups have to kick in.
    I think the closer you get to 100% from any single, unreliable source (wind or solar) the more problematic this gets. Think of a wind-band going across the US from west to east with, say, 20% of maximum usable windspeed on its front and back and the main band with maybe 80% in the middle and 400 miles wide. (Is this a realistic scenario? I don’t know). Then the installed capacity would already have to be almost 4 times that of the consumption in order to work at all with no reserves whatsoever. The same is more or less true for solar. The two combined whould be little better and in any case, you’ll have situations where almost all of the energy required in one area would have to be drawn from another area which is currently not the case. If all plants in the atlantic region would break down today, I doubt very much that the midwest plants could just jump in, even if they had the capacity, because the backbones don’t carry that load.
    And all of that doesn’t include energy storage yet, which is a completely different topic.
    Yes, it can probably be done. But its a huge project. Far greater than keeping the nukes and far greater than building new ones. Finland currently builds a new EPR-reacto in Olkiluoto and is all over the press because it’ll cost more than 4.5 billion euro compared to the 3 billion originally planned. A bargain in comparison, I think. Has anybody ever tried to seriously tailor a 100% renewable concept for the US that really includes all associated cost? I’ve been looking but couldn’t find anything I’d consider realistic (maybe just my bias – but if you know a good source, please let me know.)

  35. 285
    RichardC says:

    Anne, it is always hard, even with 8 bars, especially above say, 30kph. Another factor in the USA is acceleration. By kicking in the engine whenever need is perceived to be possible, the relatively slow Prius gains a bit of oomph. It would be nice if there were a user-controlled switch to pick the program; Japanese, European, or North American, but that might make the battery warranty too expensive. It’s 100k miles here, and with wide-open spaces in the USA, going any lower wouldn’t do. What is it in Europe?

  36. 286
    matt says:

    #284 dagobert: Has anybody ever tried to seriously tailor a 100% renewable concept for the US that really includes all associated cost? I’ve been looking but couldn’t find anything I’d consider realistic (maybe just my bias – but if you know a good source, please let me know.)

    Go check out to see the plan. It’s a massive, but very professionally produced PDF, so it took some time to download. Most could probably just download the accompanying xls and monkey with the numbers themselves as it’s a lot smaller. They are the same organization that demands we be on 100% renewables in 10 years. Their proposal is actually quite detailed, and gives a yearly breakdown of the migration costs, technology mix, expected efficiency increases, materials cost, economic winners and losers, upgrades required to the grid, surveys on public opinion that will ensure a quick path to acceptance (so we don’t run into the folks on Marthas Vineyard fighting against wind turbines again).

    Just kidding. They do have some t-shirts you can buy, though. And you can vote that it’s time to end our addiction to fossil fuels. And you can also join the facebook social network. And this is good, because we know that hope is the #1 ingredient in all this. The same thing that got man to the moon!

  37. 287
    matt says:

    #279 Anne van der Bom: The Insight is irrelevant. The Prius is a car that people actually want and buy. Why? Most people have a family, and the Insight only seats 2.

    Honestly, who really needs a car with 4 seats? My car has only two, and seldom is the other one filled up. And if I needed a third seat, I could just rent a car with 3 seats for the day. I don’t understand this mentality in which everyone has to have a car with 4 seats even though 95% of the time only one seat is filled.

    If you have a really efficient 2 seater, then a family of four can still be moved, it just takes two extra trips. Sure that’s not super efficient, but it doesn’t have to be done all the time.

    It’s that kind of gluttonous thinking that has gotten us to the point we’re at today. PLEASE THINK, SHEEPLE! YOU ARE KILLING GAIA!

  38. 288
    Anne van der Bom says:

    #287, matt:

    If you have a really efficient 2 seater, then a family of four can still be moved, it just takes two extra trips.

    Realism is certainly not your strong point. Calculus isn’t either. Two extra trips? More like four! Suppose I want to make a trip to the beach. The beach is only half an hour away. I would have to drive the distance between my house and the beach five times in the morning (three to the beach and two return trips to pick up the next passenger) and five more in the afternoon. I would be shuttling back and forth for 5 hours that day. Add an extra hour for each child. Not much time to enjoy the sun & sand. And another detail, you can not leave young children alone, and that’s what you’re forced to do in your scenario.


    If you are that fanatic, why do you bother with cars at all? An Insight kills gaia at a 20% slower rate than the Prius.

  39. 289
    Anne van der Bom says:

    #283 RodB & #284 dagobert,

    I have never contended that we do not have to adapt, augment the grid. But suggesting we need to, sort of, go back to the drawing board like dagobert suggests is exaggeration.

    Dagobert, what you are describing in #284 proves my point exactly. A new backbone must be added from the North sea and Baltic sea to the Ruhrgebiet. That is augmenting the grid, not building a completely new one. The cost for this (look at page 14 of the report you linked to) is estimated to be 0.025 cent /kWh. Yes, that is like sipping your morning coffee.

    Demand fluctuates, powerplants are not infallible. Keeping the grid stable under those circumstances is what the energy companies have to do every day. Nothing new*) has to be invented, it’s just more of the same.

    Dagobert, you are correct to mention regulating power. That is where the real challenges are. The grid will be just fine.

    Lastly, these electricity guys have decades to do this. When will Germany achieve 100% renewables? 2070? That means the Germans have more than half a century to do it. Think about what the German grid was like 50 years ago, and how much different and larger it is now. Ask yourself: was that such a gargantuan effort?

    *) A good storage solution would be most welcome.

  40. 290
    mark says:

    Matt thinks he’s being clever by using sarcasm.

    But he’s right. This is why smart cars (that look utter pants) are selling any models at all. Because they are well cheap, well effective and easy to drive.

    A four seater is also popular because you can (if uncomfortably) seat four or five people in it.

    An SUV is popular because… well, I don’t really know. Superiority complex? Genetic abnormality? Dunno. Willy-waving maybe (and you can do that as a woman too, its a cross-gender failing).

  41. 291
    Anne van der Bom says:

    #285, RichardC:

    From what you describe, indeed, it seems the American Prius is programmed differently.

    The hybrid components are guaranteed for 160.000 km or 8 years. Seems to be the same as in the US.

  42. 292
    Guy says:

    #277 – Walt, I haven’t the first clue how you arrived at your conclusions. I (and I suspect many others) simply think you don’t understand how science works – coincidentally well explained by Dave in #274. You seem to have satisfied something or other to yourself, but don’t kid yourself that you have to anyone else! And you’ve never answered the logic as to why when the overwhelming scientific consensus says “we must act right now”, this is of lesser practical importance as to the extreme minority opinion that “well, we might be ok for a bit so lets wait 30 years for some really great tech”.

    By the way, the inference of the “conspiracy of silence” from the contributors here is entirely bogus, and certainly not a “fair conclusion to draw”. I’ve been asking for public comment by the RC contributors on Hansen’s CO2 target of 350ppm for weeks, and no-one has said a thing. I’ll admit, a fanciful conspiracy theory even crossed my mind that things were much worse than RC admit and they were too conservative to admit it. I wonder which way the conspiracy lies re Hansen, then? Or maybe – just perhaps – the RC contributors are rather busy and bored of answering the same questions from us great unwashed again and again? (cough, ahem, self-defence – I still think they haven’t answered the 350ppm target, or at least why a specific target is, in Gavin’s words, “irrelevant”).

  43. 293
    dagobert says:

    #286 matt
    Believe it or not. I honestly went there and looked for the xls ;)
    (Failed to see the irony at first… found the t-shirts, though.)

    #285 RichardC
    It’s 160k km (or eight years) on the hybrid components here in Germany. Even with the EV mode activated, the ICE kicks in at 55 km/h. As with all hybrids, driving electrically isn’t always the best option. One has to minimize the phases where the ICE charges the batteries while trying to maximize the phases where the battery loads during breaking or rolling downhill. Using up the battery if there’s no slope or breaking coming up and you don’t need the extra power is counter productive.

  44. 294

    walt bennett writes (in his usual, charming fashion):

    the general tone of this board is to blindly accept anything that comes from sources who have similar sympathies.

    Do you know what psychologists mean by “projection?”

  45. 295
    dagobert says:

    #289 Anne van der Bom
    I am persistently not disputing that it ‘can be done’. Now if you believe there is ‘nothing new’ and that ‘the grid will be just fine’ you can surely also quote or name a study showing in detail how, what it would cost and what kind of energy storage will be required to get there.

  46. 296

    Re: 290: “An SUV is popular because… well, I don’t really know.”

    Luckily, the tense is now incorrect in this sentence!

  47. 297

    I’m not sure if this has been said already, but let’s think about this way: the car buyer sells her/his present car. Then we’ll have 3 cars althogether on the roads in both cases.

    If the one who switches the compact for a Prius sells his compact car, someone else will be able to save fuel compared to her/his present vehicle. As a result, you’ll have 1 old gas guzzler and 2 fuel savers on the roads.

    If the one who switches her/his old SUV for a hybrid version, you’ll still have the old SUV on the market. As a result, you’ll have 1 old gas guzzler, 1 gas guzzler hybrid and a compact on the roads.

    Combined fuel consumption for those 3 cars is less when more people who already have fuel efficient cars switch to even more fuel efficient cars.

    Anyway, I’m really glad we use litres per 100km system in Finland. That mpg thing is crazy.

    PS. My 8 year old smart fortwo cdi gets 69 mpg in combined drive. 76 on highway if you drive ~ 50 mph.

  48. 298
    Ike Solem says:

    #292- “(cough, ahem, self-defence – I still think they haven’t answered the 350ppm target, or at least why a specific target is, in Gavin’s words, “irrelevant”)”

    Let’s consider timescales and maybe that will help.

    First, we have the past century’s climate change due to the buildup of infrared-absorbing gases in the atmosphere, mainly CO2 from fossil fuel combustion and deforestation, but also methane CH4 and nitrous oxide N2O. That is the sum of the “momentum” built in (mostly heat build up in the oceans) and the current forcing.

    Second, we have the transient climate response, as calculated by modern climate models. This is the famous sensitivity calculation, which involves, as inputs, two things. First is the rate of increase of IR-absorbing gases, (1% per year, say), and second is the 2X CO2 point, or the 560 ppm point. The number that comes out is the global average temperature change at 2X CO2 for that particular climate model ensemble.

    That is a transient estimate, meaning that the planet will continue to warm after that, even if atmospheric CO2 is stabilized at 2X CO2.

    Third, when equilibrium is reached under the 2X CO2, it appears that all the world’s mountain glaciers would be gone, most of the ice caps would be melted, sea level would be tens of meters higher, the permafrost might be gone, ocean circulation would be very different, most likely, with widespread regions of anoxia and acidity – a very different planet. How long would that take? Something like 200-2000 years, apparently. The transient (climate sensitivity) response is a far more dependable number.

    So what is the equilibrium climate response to 350 ppm CO2? That’s a very tricky question, far more difficult than the 2X CO2 sensitivity estimate. This is where the paleoclimate studies are most dependable, and they point to an Earth like that of >3 million years ago, before the most recent glacial cycles began.

    There are already unavoidable climate changes in progress which must be adapted to – drought, heat waves, weather pattern changes, as well as the resulting effects on agriculture, disease, and the migration of human, plant and animal communities.

    So, any specific target is not going to be safe – changes are unavoidable, and unpleasant surprises are likely. Thus, if you were at 350 ppm, you might still want to see that level go back down to the pre-industrial level, on the principle that stability is best when it comes to your atmosphere. The only way to do that would be to eliminate the use of fossil fuels entirely, while also doing a lot of biochar-based soil carbon sequestration.

    We are of course going in the opposite direction today:

    “CO2 emissions accelerate 400% as world turns to dirtier fuels, September 26, 2008”

  49. 299

    A small documentary on the Dutch TV this week showed an Opel P-1 experimental car (refurbished in 1973) that got a mileage of 373 mpg (0.6 liter/100 km). It’s supposedly not entirely roadworthy as is, but it does show what’s possible when engineers put themselves to the task. But then nothing is done with it…
    I blog about it here

    Also noteworthy is a new electric car soon to be on the road, the Think City ( It looks like it’s a similar size as the smart car (and as such many times cheaper than the Tesla Roadster)

  50. 300
    Jim Eager says:

    Re matt @287: “I don’t understand this mentality in which everyone has to have a car with 4 seats even though 95% of the time only one seat is filled.”

    Well, if one is spending several thousand dollars on 1-1.5 thousand kg of metal and plastic, does it not make sense that one should purchase a vehicle that offers the most efficiency and the most utility? A two-seater can never safely carry more than two people, plus it is severely limited in cargo capacity. If one is only using the car for a one or two person weekday commute, or operating a courier service, then a 2-seater may be the most efficient vehicle. But if one is using the vehicle as a family vehicle for multiple uses a 2-seater seems like an inefficient use of metal and plastic, and dollars, to me.

    “If you have a really efficient 2 seater, then a family of four can still be moved, it just takes two extra trips.”

    Make that two extra round trips.