The mpg confusion

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 comments on this post.
  1. Ray Ladbury:

    Walt Bennett, While I sympathize with your disgust at the political, ideological (and consequently nasty) debate we see raging, I think that your perspective is somewhat clouded by the fact that you are observing it from the outside. The thing you have to remember is that there is a concerted effort by powerful interests to hoodwink the public. As with all such anti-science efforts, scientists respond with outrage and with practical efforts (like RC) to educate the public. Yes, these efforts are politicized. Politics is how things get done among people, as evidencedby the word’s very derivation. The contributors to this board do not benefit from their efforts other than by correcting the flood of disinformation being heaped on the public. The mistake you are making is that you are equating the battle between disinformation and education with the science. They are different. If you go to a conference, the scientists are still motivated by trying to understand the mysteries of climate. They are still motivated by curiosity, frustrated by difficulties in undersanding and dedicated to overcoming those difficulties. The debate over the role of CO2 does not rage there because among scientists, that’s known science. The denialists don’t publish. They don’t do science. So, on the one hand we have the sideshow of the debate, which is over the most settled science. In the main ring, though, climate scientists are still doing their jobs as they always have. Some few of those are motivated counter disinformation and engage the forces of anti-science. The majority, however, are no more politicized by this debate than are paleontologists by the storms surrounding the blathering of creationists. Pay more attention to the main event, and you will be better equipped to hold your own in the side show.

  2. dagobert:

    #192 Matt
    40% in 30 years is, IMHO, impossible or at least wouldn’t be effective. True, we do have 14% here in Germany but even the most optimistic forecasts which are halfway realistic don’t see more than 20% by 2015 and that will require significant alterations to our current grid topology and tripling of our current backup capacity from 2.000MW to almost 7.000MW. The problem with renewables other than biomass is that, unlike conventional power plants, they can’t be run according to requirements and consumption but scale output depending on external factors entirely unrelated to consumption. So unless somebody comes up with a clever new idea to store electricity effectively, 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 (and all the problems associated with that). So while renewables are a good idea and should be exploited wherever it makes sense, they won’t save the world unless energy storage is revolutionized real soon. Personally I don’t see how anybody can call for immediate action because of AGW and dismiss nuclear in hope of the electric car and a wind-powered world.

  3. Walt Bennett:

    Re: #189


    I used to believe we should have confidence in detailed projections. I now know better.

    Please do not mistake me for a convert to denialism. I asked a straightforward question: what science is being undertaken in an effort to break AGW theory? Are we looking for data which does not conform to theory? Are we following up on odd observations? Is anybody even trying to put together a project to confirm/deny the potential for negative feedbacks to draw down CO2 or lengthen the time before such a drawdown would be necessary?

    I have said all I intend to say on this OT topic, unless and until a member of s science organization takes the time to understand my question and respond. Either such work is being done or it is not. My intent is to glean an answer from somebody who is in a position to know. From the outside looking in, what seems to have happened is that AGW science is now in the process of being used to bolster a political point of view.

    I don’t know how in the world we could see what Dr. Hansen has been doing for the last several years, and not at least ask that question.

    Re: #190


    It works like this: all of the AGW-related climate science projects seek to find evidence of AGW where they expect to find it. Melting ice, for example. If the ice is melting: AGW! If the ice is not melting: we have an explanation: oscillations or unusual events or actually warming causing cooling, and so forth.

    I believe there is good climate science going on, so let me say that “all” is too strong a word. What I really mean is: all climate science is viewed through the AGW prism anymore. The science becomes politicized as soon as it is published. How this affects what projects are chosen and funded, how they are carried out, and how their conclusions are framed, are all legitimate questions in such an atmosphere.

    More to the point: my outside-in observation is that we are now in a headlong rush to “prove” the case. My concern is that this is not “what science is all about.” In fact, it’s the opposite of what science is all about.

    Just look at how many posts here in RC deal with the ongoing effort to “prove” that data falls into one of two categories: (1) it supports AGW theory; (2) it does not (yet) reveal how it supports AGW theory, and here’s why.

    This has got to be the most perfect theory ever, to be treated with such certainty. I remind you that I do not challenge basic AGW theory. I am merely asking a question: have we attached hypotheses and suppositions to the theory when the evidence for them is not strong enough to rise to that level?

    Re: #193
    My concerns are simple: if we are in a headlong rush to prove a scientific scenario in order to justify broadly disruptive political acts, we are increasing the likelihood that we will miss something that will change everything.

    I was specific: nailing down sensitivity and searching for potential negative feedbacks. If we are wrong by even a little on either of those, if could make all the difference. Did you see me say “stop planning! Stop projecting!” No. We must always plan and project. But answer me this: what purpose do we serve if we do not at the same time constantly challenge those projections? It sure would suck if we spent all that time and money planning for an outcome that was never actually going to happen. We may even miss a chance to plan for another outcome that may be of more potential harm. Point being: we don’t know what we don’t know. We have to remain vigilant and open minded. We don’t know this planet near as well as many, many, many people seem to think we do.

    Re: #194
    If that was meant for me: I raise my hand as being a skeptic, as you point out, of all information. I accept nothing, certainly not anymore, until I’ve studied it. I’ve learned the hard way that a lot of things get said with nothing much to back them up. That happens, if you will allow the term, on both sides.

    You evidently have not read much of what I’ve written in the past. That was my point. You don’t seem to have the understanding that Hank, for example, has, that I have been a warmist all along and I am still a warmist. I’m the annoying warmist who asks the questions that piss off everybody else.

    Re: #198

    Thanks for making my point that we have a tendency to think we are done asking questions.

    Re: #199

    The way you phrased that question indicates that you missed my point entirely. Perhaps you could read my posts again and gain a better understanding.

  4. Rod B:

    Guy (193) et al, it will likely prove insignificant (I guess) but the fact that 1998 was the warmest in 10 years deserves more than the equivalent of brushing off a gnat. Doing things like that (including actually denying it) has raised reasonable criticism before. Just an observation.

  5. Dave Rado:

    Rod B, #204, have you ever heard of the difference between weather and climate? 1998 was an El Nino year and 2007 was a La Nina year – that’s weather, not climate.

    Also have no never heard of linear regression and trend analysis? One does not ever measure any trend in any field of study by drawing a straight line between two points in a graph containing many peaks and troughs; that measures noise, not trends. One has to use trend analysis to measure trends, and if one does so, one finds that the trend is still warming.

    Finally, some measurements show 2005 to have been hotter than 1998 in any case.

    I’m not sure whether you’re uninformed or just disingenious?


  6. Walt Bennett:

    Re: #@01


    Please do not misunderstand. I am not, as you characterize me, “disgust(ed) at the political, ideological (and consequently nasty) debate we see raging”. Not at all. As I said, I can and do easily dismiss most denialist rebuttals to AGW. I have gotten pretty good at spotting junk, and when I’m not sure, I have reliable sources to help me sort it out.

    You say there is good science going on behind the scenes. By definition, that would be skeptical science. I am asking the question: examples, please? What have we encountered recently which might cause us to adjust climate sensitivity; to challenge the veracity of models versus observation; to explore potential negative feedbacks?

    Just some examples of robust science which is not agenda driven to “prove” AGW.

    Just a couple, is all. I’m really looking for evidence of a certain point of view.

    The discourse to this point serves to prove my original point: it’s increasingly difficult to even ask these questions.

    Dr. Hansen, perhaps the country’s if not the world’s pre-eminent climate scientist, has spent the last two years pushing an agenda. Specifically: no more dirty coal plants. He must know the social impact of such an idea. He must realize what he is saying.

    Who wouldn’t be tempted to draw the conclusion that we know all we need to know about the dire consequences which will ensue if we do not follow Dr. Hansen’s advice?

    How can such a situation not influence those who practice the science, who respect and admire Dr. Hansen? Who wouldn’t want to be the one to conduct the experiment or record the observation that helps him make his case?

    All I see around me lately are exactly such efforts. Consciously or not, climate science seems to be moving in lock step to “prove” AGW. My very legitimate question remains: how hard are we trying to break it?

    It’s not the politicizing of the debate that concerns me. What debate isn’t political in some way? Rather, it’s the perception I am developing, that the science itself has become politicized, about which I express my curious concern.

    I am still “on the reservation.” I still believe “CO2 = bad” when it comes to destabilizing climate. What I want to know is that this hasn’t been elevated to a legend, where we simply accept it and do not question it. It seems to me that often along the course of human history, we become certain of something we are completely wrong about.

    To me, science and certainty are not supposed to be too closely related. Is that the state of climate science today? My eyes have me wondering.

    So, perhaps counter-intuitively, I’d be more inclined to believe the dire projections if we occasionally announced that we had lowered sensitivity or discovered new negative feedbacks, injected them into the models and come up with a new scenario. When we seem to be on a one way track, the question comes, to my mind at least: have we narrowed our focus? From a science perspective, that would strike me as a very dangerous portent.

  7. matt:

    #195 Mark Will you believe the numbers or, if they don’t prove you right, will you demand more proof?

    If you are going to cite numbers from a government agency, then of course I cannot demand more proof and I’ll accept them as they are. I think Germany leads here, and they won’t hit 40%. In any case, we will take that number and move to step 2, which is to figure out how much we must reduce consider India and China are coming on line, and what will provide the remainder of the needed energy. As I’ve noted before, you know where I’m going: 90-95%, and nuclear. There’s no trap here. It’s just getting you to ack reality.

    Seriously, you’ve typed an amazing number of words instead of answering the simplest question for a progressive energy thinker. And that is: What credible % of the world’s energy can come from renewables in 20 years????

    If you can’t or won’t answer that, then I’m done.

  8. matt:

    #202 dagobert: 40% in 30 years is, IMHO, impossible or at least wouldn’t be effective. True, we do have 14% here in Germany but even the most optimistic forecasts which are halfway realistic don’t see more than 20% by 2015 and that will require significant alterations to our current grid topology and tripling of our current backup capacity from 2.000MW to almost 7.000MW.

    I agree with you. Unfortunate, there is a group that will not support nuclear, and will not tolerate continued CO2 emissions. They think this position will force the world to renewables. As you note, this isn’t realistic. And unfortunately, by adding fuel to the anti-nuclear fire, and by touting and endless array of unproven renewable sources of energy, they give the perception to many other like-minded invidiauls that it’s indeed possible to dramatically reduce CO2 without nuclear.

    The end result is decision making paralysis by our leaders, and once decision stop being made, the status quo (coal + oil) is forced to GROW otherwise we face outages.

    I think the most sound approach right now is to put a plan into place to get to a non-trivial % of renewables in 20-30-40 years, build nuclear like crazy right now, and we we learn more about renewables, target the phase-out of nuclear. Germany is quite sane in that regard.

    On the transportation side, the world consumes 20-30B of oil per year, or 475B gallons of gasoline a year. A $0.01/gallon tax would generate about $5B/year for a world-wide staged XPrize type award for key innovations and breakthroughs. Job #1 should be batteries or other energy storage.

  9. matt:

    #197 BPL: Nuclear reactors and coal-fired power plants do not achieve 0.9999 reliability.

    Indiviually of course not. Collectively they do. We had a major wind storm in the PacNW a few years back, and we had no power for 8 days. So, it’ll be a long, long time before we see 4 9’s again.

    My point was this: too often people look at the peak output of a wind turbine and figure it does that 24x7x365. It doesn’t come close. To achieve a useful constant supply, an enormous amount of redundancy is required to get the nameplate rating…40 or 60X in some cases when you look over an entire year.

  10. dagobert:

    #208 matt
    I don’t think “sane” is the right word. They are phasing out nuclear und replace it with coal. After the next elections next year this may change but right now it looks very much like a “no-nuke-no-co2” catch 22. We are of course closer to Tchernobyl than you are, but that’s true for the UK and France, too. And they keep running nukes.

  11. Ray Ladbury:

    Walt, First, if you look at any theory, there will be some propositions that are relatively more certain than others. In climate science, one of the least uncertain propositions is the sensitivity of CO2. It pretty much has to lie between 2 and 4.5 degrees per doubling of CO2. That’s something we really can’t break without breaking all of climate science–and since climate science has proven pretty reliable, what purpose would that serve? Climate science is a pretty mature science, and in mature sciences most progress takes place gradually rather than by “breaking” the models that work.

    The antrhopogenic causation of current warming follows pretty much directly from that–unless, there is some magical effect that limits the effect of CO2 above 280 ppmv. If you buy that more CO2 means more warming, then you have to start asking what sorts of effects that could have. Now here things are more uncertain–even the question of how to proceed is uncertain. Do we require demonstration of great risk or do we proceed cautiosly and try to limit risk while we try to better understand it.

    You seem to be arguing that there is a confirmation bias in climate science. I think you are wrong. Overturning the current theory would be the key to fame and glory for any scientist who managed to do it. What you are responding to is the fact that the current threat is predicated on very well established science.

  12. Mark:

    You have said that the changes can’t be done.

    How about you put those figures of yours in there first and how you came about them?

    PS you’ve never accepted figures in the past (except by saying “those aren’t the figures I’m interested” which is kind of accepting them but immediately dismissing them).

  13. RichardC:

    191 – Matt, I summed 181’s numbers. You’re looking for a breakdown? Sure.
    1) What % of alt energy (marginal CO2 emissions) is possible in 2030

    By using the military budget to build wind power and a backbone to deliver it, about 90%. Wind is $3 a watt at current production levels (assuming 30% capacity factor – wind doesn’t always blow) . 20 years would be plenty to replace our electric grid and most other power needs with wind.

    2) What % of savings can we achieve through conservation

    Amory Lovins says getting rid of most energy use at a negative cost is easy. He’s the best environmental economist around. I’ll conservatively say we can save 66%. Combine the two factors – 90% of supply with wind and 33% new need, and it’s patently obvious that using any fossil fuel is stupid at best, suicidal at worst.

    3) What % do you believe we need to cut our CO2 to avert AGW assuming RoW comes on line and wants to produce at our current rates

    120% or so. We have to get back to 300 ppm pronto. Thanks for letting me assume the rest of the world will also reduce CO2 emissions by 120%. Again, that’s doable. The USA is the only country that can initiate the military –> energy conversion.

    4) What do you propose to generate the remainder of the needed energy you noted in 1)

    Uh, we have plenty of excess power, given Amory’s stuff and wind. There is no more needed so this question is baseless. We just need the willpower to realize that marching tin soldiers isn’t as important as saving the planet. Remember “One Tin Soldier?”

    Your bit about the Prius is off. Toyota’s reported target with the third-generation Prius is 94 mpg with the Japanese cycle without plug-in. Yep, if one tunes the car differently, one gets different results. Since it is doable and a current technology, I’d say it is a valid measure. Comparing the Smart “car” to the Prius is almost as bad as comparing a motorcyle to a full-size car.

    192 – Matt, there is no country on the planet that is dedicated to renewables. $1 a watt for wind is a simple fact ($3 given 1/3 capacity factor), and the available funds can replace the USA’s electrical grid with wind in 20 years. Your argument seems to boil down to, “Since nobody has gotten serious about reducing CO2 emissions, it’s impossible to reduce CO2 emissions.”

    193 Guy, not true on sea ice. The Arctic ice has hit a new record low in volume. Extent is only two of three dimensions. As I posted before, the volume is far lower in 2008 than 2007. Here’s the link again:

    209 Matt, that’s the beauty of wind. Reliability of essentially 100% is guaranteed because each generator is stand-alone. The backbone needed to deliver it across different wind-belts is all that lacks.

  14. Lawrence Brown:

    A few calculations show that increasing our fuel economy standards will pay big dividends in reducing foreign oil imports.

    If the average mileage of cars and SUVs in the US is about 22 miles/gallon and the average car travels 12,000 miles/year, then
    the average vehicle uses 12,000/22~ 545 gallons/year. If the US fleet consists of about 180 million cars and SUVs,
    then, 180 million x545=~98,180 million gallons per year or (dividing by 365 and 42gals/barrel) gives us 6.4 million
    barrels per day/(mbd) used by cars and SUVs.

    .If we were to double our mileage to 44 mpg then, 12000/(44)x180/(365×42)=3.2 million barrels/day consumed. The savings on imports amounts to 3.2 mbd. If we’re currently importing about 12 million barrels per day, then the percentage is
    3.2/12 ~ 27 %. Well worth achieving.

    If we go further and raise our average to 50 mpg then the average use per vehicle would be 12,000/50~ 240 gallons/year.
    Then following the same procedure we’d consume 240x 180 million /(365×42)=~2.8 million barrels per day.

    The difference of how much lesss oil we’d have to import is 3.6 millions barrels per day. In this case we’d cut our imports by 3.6/12 =.3 or 30 percent! This would make us a lot less dependent
    on the Persian Gulf Emirates.

  15. dagobert:

    #213 RichardC
    “Comparing the Smart “car” to the Prius is almost as bad as comparing a motorcyle to a full-size car.”
    Yes, that’s true. I only braught it up to set the Prius claim into perspective. 94 mpg is 2.5 l/100km and the Prius will not come even close to that with any cycle but the Japanese one. We can bet if you like, but I think my 3.6 l/100km will be very close even with EPA rating. I don’t really know what to say about the rest of your post. If you really suggest the US should convert most of their defense budget to an environmental marshall plan, I’m all for it. If you suggest this is realistic, I’d ask you to get real.
    As far as wind power is concerned, you may want to take a look at this:
    It must be said that this is a very optimistic study that did lead to a lot of criticism because of that and I’m afraid the English version is just a summary – but you may get an idea about how difficult it is to create a grid powered by renewables even to just a fifth of its capacity – let alone 100%. It may be possible some time far in the future but I thought we need CO2 reduction now and not when dreams come true.

  16. Hank Roberts:

    > I’d be more inclined to believe

    Walt, you really went from disbelief to belief, and you should have stopped with the science instead.

    Why come here wishing aloud as though there weren’t good science being done, when you can look it up for yourself and find out you’re wrong?

    You’d be a lot happier if you used the search tools, read some journal articles, and checked footnotes and references. Instead you seem to have fallen for the bogus claims from the PR sites and been fooled.

    Here, take the words directly from your long posting above.
    Put them into Google Scholar.

    Mind you this is not the only information, it’s just an example to encourage you to look for yourself, instead of declaiming you need help to “believe” something that you can find out for yourself:

    Example — just one example — the first hit from the search:

    … Greenland and Labrador seas during 1901–1984 and their relation to an interdecadal Arctic climate …
    LA Mysak, DK Manak, RF Marsden – Climate Dynamics, 1990 – Springer
    … occurred in the 1960s are described in relation to the GSA, and a new negative feedback loop that could sustain interdecadal Arctic climate oscillations …
    Cited by 127

    Read the citing papers:

    There’s plenty more there. When you come here parroting stuff from the PR sites claiming there’s no scientific work going on yaddayadda, — when it’s so easy to falsify that claim — you’re acting like you forgot to learn how science is done. Don’t “believe” — look.

    Try it. It’s enlightening. Look stuff up. Ask good questions. Search.

  17. David B. Benson:

    Kevin McKinney (200) — We need to sequester 10–12 GtC per year until the CO2 concentration is sufficiently small. The carbon could come from tresstrial biomass or from Azolla; perhaps sequestering CO2 via some form of CCS will prove economic.

    The main point, however, is that we need to start now. This is a large scale project!

  18. JCH:

    At the rate we are slowing down, the United States could be in compliance with Kyoto by Christmas.

    The Republican shepherds of the economy have just had their way with the sheep.

  19. Will:

    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)

  20. Dick Veldkamp:

    #209 (Matt) Back up capacity of wind turbines

    There are always fluctuations in electricity consumption in the grid, even if there are no wind turbines at all. So you need back up capacity in any case.

    Roughly speaking 20% wind power can be added to a grid without additional back up (example: Denmark). For higher wind penetration there is a cost in extra back up, estimated to be USD 0.02 per kWh. This number is small because output of wind turbines is not perfectly correlated i.e. the probability that ALL wind turbines produce nothing simultaneously is low. In extreme cases you can also solve the problem by being clever, say by combining with hydro power.

    Note by the way that even if you needed 100% backup, you would still save tonnes of fuel (and CO2) whenever you used wind power.

  21. Guy:

    #206 – Walt, I have no problems with awkward questions. I’m just not sure I find your questions awkward! Take “looking for negative feedbacks”. Someone correct me if I am wrong, please, but I’d be staggered if climate scientists are scouring the earth “looking” for positive feedbacks, and not bothering to consider negative ones. That doesn’t sound much like science to me. How I kind of assume it works is that they are looking at everything that might affect climate one way or the other – clouds, methane releases, solar oscillations… everything. Some of these processes are positve, some negative. Why do you have the view that scientists are only “looking” for positive ones?

    I’m similarly baffled by your assumptions re James Hansen. It seems (unless I misunderstand) that you think he is on a political crusade to be political. You don’t seem to entertain the notion of the basic, logical scientific case he makes, which necessetates a political response – the basic numbers say that coal must be phased out in order to get emissions down. Period. Is there a serious scientific challenge to his science… the numbers? No. I see a lot of reticence to follow in his political footsteps by other scientists, but I’ve not read any real attempt to question the actual science.

    Otherwise, what Ray said in #201!

  22. Dave Rado:

    Re. Will, #219, that logic might work for a hire car (although even then you could hire a far more fuel efficient 6-seater than an SUV), but it doesn’t work when making purchasing decisions, unless the vast majority of the trips you make are carrying 6 passengers.


  23. Rod B:

    Ray (210), your characterization and description of climate scientists at work hardly presented a rebuttal to Walt’s accusation. That they are excitedly scurrying around trying to hone the details and fill in some blanks is a non sequitur to Walt’s charge.

  24. Rod B:

    Dave (205) says, “…1998 was an El Nino year and 2007 was a La Nina year – that’s weather, not climate.” Good gnat swat.

    Dave also says, “…have [you] never heard of linear regression and trend analysis?” Yes, ad nauseam in “Once More Into The Bray” of July in RC. It was much more than a gnat swat and thrown under the bus for the period being discussed as being downright embarrassing. But I offer this as a gentle observation only. NO BODY wants to resurrect that tar baby.

  25. Larry Coleman:

    I don’t get it. I’ve read these postings, in some cases reread them, and have concluded that those who claim that this reduction in CO2 or that reduction cannot be accomplished within 20 years or 50 years, or whatever…those people are unaware of some reasonable ideas out there that directly refute their claims. Or at least bring their claims into question.

    For example, here is a link to a 4-year-old article on “stabilization wedges” by Socolow and Pacala. They describe a wide variety of strategies for keeping our CO2 emissions at the current level, or lowering them, using current technologies. If people are going to say it can’t be done, they tell us why S and P’s approach is not possible. We might not have the will, very possibly don’t, but that is a different claim than saying that it cannot be done.

    A second example is strategies found in the second highest-rate site on GW (after this one) found at by Joe Romm. Joe thinks we can do it without nuclear and certainly nuclear is an expensive option, probably an unacceptable one to utilities without federal guarantees.

    Anyone who wants to discuss future energy options should know what these guys are proposing. Many of the claims in this thread are belied by what Socolow, Pacala and Romm have shown it feasible. Again, we might not have the will, but we certainly won’t if we don’t even know the possibilities…and we certainly won’t if we maintain it cannot be done when it can. There seems to be a lot of reinventing the wheel going on here.

  26. matt:

    #213 RichardC: ..various comments…

    Alas, you’ve tried with some numbers, so let’s see where we go.

    Current installation costs on wind is about $1500/KW of NAMEPLATE rating. The 1/3 factor you cite drives that cost up by 3X. But that 1/3 factor is even further derated when you consider reliability (see Archer and Jacobson, “Supplying baseload power…”, Nov 2007)

    The demand in the US will be around 4.5T KWH in 2020. Using your 1/3 figure, you will typically see 50% of the time the generator is generating more than 1/3 the nameplate, and the other 50% of the time, it’s generating less. To get wind power with 92% reliability, about that of a coal plant, you are typically at 1/12 of nameplate rating if you can interconnect a large number of sites together. The cited article looked at 19. The chart is Figure 3. So, sharpening the numbers a bit more, 1TW of nameplate * 0.12 * 0.92 * 24 * 365 / 1000 = 967B KWH. For the 4.5T KWH, we’d need 4.7TW of nameplate. At $1500/KW, that’s $7T. Not including thousands of miles of copper and easement rights to wire it all together.

    Quick check: The US military budget is $500B for 2009. Assuming we could spend ½ that instead of that on wind, it’d take 28 years of military budget to pay for wind. You are close on that.

    Next is the logistics. I won’t go into detail there. Read “High Wind Penetration Impact on US Wind Manufacturing Capacity and Critical Resources” by Laxson et all at NREL. They outline a plan, based on increases in manufacturing and raw material production, to get our wind generation to 20% by 2030. Surprise, but fiberglass, copper and rare earth magnets are a challenge. Not insurmountable at a 20% target. But potentially marketing upsetting (meaning none of the above economics hold) if the US + EU is aiming for 100% in 20 years. We’ve seen cost of wind go up since 2005 based on copper prices alone.

    Summary: you are alone in thinking we’ll have appreciable (>50%) wind power in 20 years. We could have a lot. But there are limits to what can practically be achieved. Taking a chunk of the military budget and assuming we’ll use it to pay for wind installation is arbitrary. Why not take welfare or medicare or education? Sure, the cost of a military is wasted if you don’t use it, but if you need it and don’t have it…

    You and Amory believe we can reduce our consumption by 66%. Wonderful. Do you have anything else? I’ll take this to mean you don’t have a proof point here. Historically humans have done a % or two per year, for a few years, and then they’ve crept back up into positive territory.

    Given the materials challenges on 100% wind, and the sheer logistics challenge of building 600,000 200 ton windmills….and combine that with the unprecendented conservation effort that requires substantial pains over 20 years to achieve…this just isn’t going to happen. You absolutely see no value in nuclear?

    PS. Is your assertion that the 2010 Prius will get 100/45 = 2.2 times better than the 2009 Prius, which gets EPA 45 MPG HWY? Won’t happen. Things don’t improve that fast.

  27. Mark:

    matt #226, I see you’re doing the “these aren’t the figures I wanted” speil.

    Where are your figures to prove your assertion (remember that 30 years ago 6 computers were considered the total world market for computers. How many we got?)

  28. Mark:

    Will #219

    And do you take your wife and kids (and do you HAVE four kids?) to work each day? Or are you driving to work in a six seater on your tod?

  29. Barton Paul Levenson:

    dagobert writes:

    renewables (which we dream of and play with but which aren’t about to make a significant difference on a global level for at least another 50 years – if ever).

    Sez you. They’re already making a dramatic difference in some countries, like Denmark and Germany. And the “if ever” comment is especially dumb. You think a hundred years from now nobody will know how to make cheap photovoltaic cells? I think that will only be true if civilization collapses.

  30. Barton Paul Levenson:

    dagobert writes:

    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 (and all the problems associated with that).


    If we build energy storage systems in large quantities that will bring down the price through economies of scale. Some government has to step in and subsidize building such facilities. There are a thousand ways to store energy, and any one of them will become practical when we start mass-producing them — flywheels, compressed air, pumping water uphill, storage batteries, etc. Some solar thermal plants achieve nearly 24/7 operation because they store excess heat in molten salts and use it to power the turbines at night and in bad weather. And of course, when the sun isn’t shining, you’re likely to have more wind, and vice versa.

  31. Barton Paul Levenson:

    walt bennett #203

    Look, I hate to tell you this, but 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.

  32. Barton Paul Levenson:

    matt writes:

    Using your 1/3 figure, you will typically see 50% of the time the generator is generating more than 1/3 the nameplate, and the other 50% of the time, it’s generating less.

    You’re assuming the median is the same as the mean. Note that wind power production is proportionate to the cube of velocity, not velocity:

  33. dagobert:

    #229, Barton Paul Levenson
    “They’re already making a dramatic difference in some countries, like Denmark and Germany. And the “if ever” comment is especially dumb. You think a hundred years from now nobody will know how to make cheap photovoltaic cells? I think that will only be true if civilization collapses.”
    Depends on what you call ‘dramatic’. Our (German) carbon footprint per person far outweighs that of our French neighbors. True, we do have a lot more industry but at the end of the day it comes down to France using much more nuclear than we do. Our 14% renewables with an optimistic outlook at 20% don’t help when you introduce new gas and coal plants to back it all up.
    I agree that in 100 years, we will probably have really cheap and highly effective solar cells. But in 100 years we’ll also have energy consumption during the night, we’ll have the need to distribute energy and we would have the need to store it. I also agree that my ‘if ever’ statement was dumb. I take it back. However my main point remains: if we need to act now, nuclear is the way. And in the future (when all these cheap solar cells are on the market and we found a revolutionary way to store energy effectively), all these wonderful achievements will have to compete with fusion und new types of reactors. CO2 neutral energy will be possible either way in the future but the fastest way to significant reduction will be something already proven, something that doesn’t require new grid-topologies and something that doesn’t require storing energy.

  34. Kevin McKinney:

    It occurs to me that a principle stated by a Guy Gavriel Kay character is has become relevant to the debate on how we cope with our energy dilemma today. The principle is that when there are limited possibilities for paths to survival, it is adaptive to presume that those pathways are possible.


    –It is possible to materially improve our outcomes vis a vis climate by:
    *increased deployment of renewables
    *judicious use of nuclear power (which, IMO, would require more attention to the long-term storage issue)
    *conservation (which would require commitment and education, as well as better incentive structures)

    Vigorous pursuit of all of the above is essential, and the “counsels of despair” don’t help this.

    Realistically, the question of *which* mix of these and other tactics is best is of course important, but this is most likely to be emergent, not predicatable a priori. (Just as the Manhatten project pursued multiple technologies for concentration of U235–it was essential to succeed, and unknowable a priori which method would work.)

  35. Martin Vermeer:

    Barton Paul Levenson #230:

    There are a thousand ways to store energy

    And then there’s number 1001: transport energy over large distances using high voltage direct current. 3% loss over 1000 km — which happens to be the synoptic scale of weather systems, and a few times that is what separates the population concentrations in Europe and North America from their future desert areas. And you can bury the cables or put them underseas. And if the copper runs out, use alumin(i)um…

  36. Walt Bennett:

    Re: #211

    You write “climate science is a pretty mature science”. I would grant you that proposition if you would grant me the proposition that AGW science is in its relative infancy, especially in consideration of the fact that we haven’t seen this before.

    You write “unless, there is some magical effect that limits the effect of CO2 above 280 ppmv”. Why does it have to be magical? It could simply be “unknown at this time.”

    You write: “Do we require demonstration of great risk or do we proceed cautiosly and try to limit risk while we try to better understand it.” I am all for proceeding cautiously.

    You write “You seem to be arguing that there is a confirmation bias in climate science.” No, I am beginning to sense a confirmation bias in AGW science. It’s a natural enough reaction to, for example, the complete disgust with which most of the skeptic community greets another Mann study. Who wouldn’t get defensive?

    You write: “What you are responding to is the fact that the current threat is predicated on very well established science.” 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?

    Re: #216

    You write: “Walt, you really went from disbelief to belief, and you should have stopped with the science instead” and then go on to imply repeatedly that my position is “belief-based”, akin to “faith-based”. and so I must retract the comment that I made, that you remember me from before.

    My initial position was belief-based. I liked Al Gore! He seemed quite earnest and well informed. I came to really like Dr. Hansen. He’s been at this most of his life! It’s his dedicated passion! I was all about belief when I started. I have evolved. I thought you knew that about me.

    I do in fact read and study and compare conclusions. That’s why I have this current view that there is in fact, to borrow Ray’s term, a confirmation bias in AGW today. How about this unscientific observation: not a single one of you has even accepted my premise long enough to discuss. You dismiss, out of hand, that AGW science could have a confirmation bias. Well, what makes you so sure? You cited a study and a list of search returns. I would ask you: what recent study are you aware of which has affected IPCC projections (or NASA, Hadley or NOAA projections) regarding time lines? Is the policy locked in while the science is not? What’s your impression?

    Re: #221

    I agree with you in general. There is no bias within science projects themselves. My concern is more that a bias exists within science organizations, which is then passed on to policy makers and the public. AGW Science is trying very hard these days to “get in the game” with regard to social policy.

    As you may or may not know, I consider Dr. Hansen to be a modern day hero. I almost always trust what he says. But the simple fact that he carries such stature, creates a ripple effect. When he talks, the climate science community perks its ears. To whatever extent there is a tendency, today, to look for confirmation, it can only be made stronger in the wake of Dr. Hansen’s agendized public stance. In other words, now more than ever it seems that AGW science is attempting to directly infulence public policy. How can that not lead to questions regarding bias?

    Re: #231

    You write: “Look, I hate to tell you this, but 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.”

    You simultaneously missed and made my point. Thanks again.

  37. Walt Bennett:

    Just as an aside, it is continually frustrating to attempt to do actual research and keep running into subscription walls. I do not understand how the results of publicly funded research can be withheld unless I pony up some cash.

    I was researching Walker, Hays, Kastings (1981) A NEGATIVE FEEDBACK MECHANISM FOR THE LONG-TERM STABILIZATION OF EARTH’S SURFACE TEMPERATURE, to see who has cited it and in what context, and I simply cannot get at most of those cites.

    By the way, Dr. Hansen seems to never have cited this paper.

  38. Deb:

    What you didn’t mention is the cost to the family who is going to get a horrible trade in value on their SUV, which then raises the cost of to the family…while they take out extra to cover that Prius, thus costing the difference or more in what they WOULD have paid for in gas.

    While I’d love to trade my SUV in for a more fuel efficient vehicle, I can’t afford this extra expense. I’ll just pay that $10 more at the pump, and try to drive less.

  39. Rod B:

    Mark (227), you have to go back at least 60 years to find the 6 computer forecast.

  40. matt:

    #227 Mark: I see you’re doing the “these aren’t the figures I wanted” speil.

    Where are your figures to prove your assertion (remember that 30 years ago 6 computers were considered the total world market for computers. How many we got?)

    No, I’m asking you to provide a reliable agency with some level of responsibility that agrees with you. No more, no less.

    And great read (cited above) about the challenges of broadly deploying wind:

    That paper, combined with the Archer paper I cited, and the widely available cost data (pick your source), allows you to recreate my numbers if you wish.
    Read it, and afterwards if you really believe 100% in 20 years is possible, then there’s no more to discuss I guess. But if you come to the conclusion that less than 50% is probable in 20 years, then what do you want to backfill that with? Business-as-usual (coal, etc) or nuclear?

    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.

  41. matt:

    #233 dagobert: However my main point remains: if we need to act now, nuclear is the way. And in the future (when all these cheap solar cells are on the market and we found a revolutionary way to store energy effectively), all these wonderful achievements will have to compete with fusion und new types of reactors. CO2 neutral energy will be possible either way in the future but the fastest way to significant reduction will be something already proven, something that doesn’t require new grid-topologies and something that doesn’t require storing energy.

    100% agree and well put. If you care about CO2 reduction TODAY, nuclear is surest and quickest path out.

  42. Mark:

    re: 241

    ‘cept it takes 10 years to make one.

    Hardly “today” is it.

  43. Mark:

    Rod, 239. Maybe. Thought it was about the time of the start of the Apple Mac.

    What power of computer did we have on the desktop 20 years ago? IBM/AT? 30kflops? 200kflops?

    What we got on our desk today?

    2Gflops? 3Gflops?

    10,000 fold increase in 20 years.

  44. RichardC:

    215 dagobert – I agree that there is little chance for the new Prius to be tuned as it is in Japan, nor much hope that the US military budget will be used to fight the real enemy – climate change. But back to fantasy… (I’ll use Matt’s excellent post as a sounding board)

    226 Matt, I get $1 a watt, a bit lower than your figure, and assuming large-scale construction, it should drop to $0.80 or so. Just a guess, and you’re right, costs can go up instead due to supply constraints and profiteering too.

    Your US military budget is way off. It doesn’t include the DOE military spending nor the three wars going on. Wiki says $900 billion, not counting depreciation of equipment nor future costs of keeping all those brain-damaged limbless kids fed and housed and prostheticized (Prosthetics are getting wicked cool and $expensive$) for sixty years each. As to half the military budget, no way, I’m assuming 90%. That’s $810 billion a year. Keep all the personnel, just change the mission to fighting climate change and dependence on foreign fuel. So kids still get the military experience and all the good things about the military stick around. Can’t Patriotism be used for building stuff?

    No, I used wind as an example (sorry for not making that clear). I’d say Solar thermal, Solar PV, wind, etc etc. As Barton said, Wind and Solar make a grand Tag-team.

    The power plant of the future has a nuclear front end. A HUGE box with TREMENDOUS thermal mass that has a safe multi-stage meltdown process – Seeds melt, reducing power drastically with no damage (just re-seed), main body partially melts with no damage, reducing power (again, reseed) – depleted uranium liner partially melts, killing process with minimal damage – Steel and concrete outer box remains intact. (Normally, just reseed; could have piping damage or whatnot, so box could need rebuilding) No controls are needed because it uses decline in temperature with increased load instead of control rods to reduce power at decreased load. The thermal mass keeps the temps from dropping (or rising) too rapidly. Totally opposite of the way it’s done now. The reason it works is because the fossil component “tops up the temperature.” When renewables are peaking or demand is slack, then the nuke can provide sufficiently hot water to run the generators. No fuel rods are needed, no control rods, no expensive safety systems. A nice big compartmentalized box (different stuff goes in different places to keep the reaction going – mix it together and it goes cold). When load increases is needed, crank up the coal or gas and increase power. The CO2 exhaust goes to algae or food beds and grows stuff. Excess power is converted to transportation fuel with whatever technology desired. (Coal –> CO2 –> algae –> diesel and alcohol, for example)

    With $810 billion dollars of “found” money, it’s easy. The reason the military budget is the one to use is because there is no logical need to have a military stronger than the strongest on the planet. Dropping the US military budget by 90% leaves the US as number one, with the next group of powers mostly staunch allies. Nobody could beat NATO, even if the US didn’t exist. Thus, your “if you need it” argument is flawed. There is no possible “need it” scenario. The “US interests” the US military protects is oil. Everything else, we could just ignore.

    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. Yep, maybe slightly more or less, but essentially 66% reduction. (Small cars would get better mileage, and the 2010 Prius is seriously large) Insulation, solar hot water, LED and fluorescent lights. This stuff isn’t “way out”, it’s here now. I’ve built near-zero-carbon housing. It’s not rocket science, and it would be a waste of bandwidth to say much more than “read some Amory Lovins, then decide.”

    As to nuclear, see above. I see it as essential in a hybrid system, and totally stupid as stand alone. Stand alone requires too much money, invites proliferation, is somewhat dangerous, and creates waste. In a hybrid system, it’s a cheap box, can’t be proliferated, is totally safe, and creates no waste.

  45. Martin Vermeer:

    Walt #237: Walker, Hays, Kastings (1981)

    Are you aware that this is about deep geological time?

    Yes those paywalls are irritating, but this one isn’t going to help you in your fishing expedition :-)

  46. Jim Bullis:

    The global warming problem is solved. The GM “Volt” will reduce emissions due to personal car transportation by 75%. (I am being sarcastic.)

    The article of interest:

    Volt could break 100 mpg ceiling if EPA approves

    The Chevrolet Volt could get at least 100 mpg.
    General MotorsThe Chevrolet Volt could be on its way to being the first mass-produced vehicle rated at 100 mpg or more.

    To ensure that happens, General Motors is asking the EPA to declare the Volt an electric vehicle for regulatory purposes. GM spokesman Rob Peterson said the California Air Resources Board has given the Volt preliminary certification as an electric.

    A government rating of more than 100 mpg would give GM invaluable marketing ammunition and would be a boost for company compliance with fuel economy standards. Peterson confirmed the request today.

    Loops vs. formulas

    Normally, a vehicle is run on an EPA test loop, consisting of both city and highway driving, to measure tailpipe pollutants and provide data for calculating fuel economy. But for electrics, which have no emissions, the government uses a Department of Energy mathematical formula to translate energy use into some equivalent of miles per gallon of gasoline.

    Using that formula, the limited-production all-electric Tesla Roadster, for example, gets rated at 244 mpg for the government’s corporate average fuel economy program. Tesla officials say they look forward to being able to sell the fuel economy credits they will accumulate, even with limited sales.

    The Volt is a plug-in electric hybrid, which GM calls a “range-extended” electric. Due on the market in late 2010, the Volt will be designed to go 40 miles on all-electric power. Then a small internal combustion engine would kick in to extend the range.

    It appears unlikely that the government test loop could be used to accurately measure Volt emissions and fuel economy.

    Removing all doubts

    Simply declaring it an electric would remove any doubt.

    But one government official, who insisted on anonymity, said declaring the Volt an electric would not paint a true picture. If a motorist forgets to plug in one night, then the car would run the next day using the 1.4-liter gasoline engine to generate all the electric power for the drive motor.

    Peterson said if the Volt is certified as an electric vehicle, engineers could then optimize the powertrain’s calibration for testing against that classification.

    The Society of Automotive Engineers would not classify the Volt as an electric vehicle. SAE defines a hybrid as having two energy sources, such as gasoline and electricity. The Volt has both.

    GM has not said how many miles per gallon the Volt would deliver when it is running on its gasoline engine. But the size of the Volt’s fuel tank and the range GM says the vehicle can travel points to a gasoline-only fuel economy of between 35 and 50 mpg after the car’s first 40 miles on pure electric power.

    And :
    Jim Bullis writes:
    How can we have come to a point where we believe that changing the category of a car can make it more fuel efficient? I answer my own question: By allowing the EPA to use bogus mpg calculations for electric cars. There three levels of bogosity. First is to completely ignore the energy represented by the electricity. Second is to inappropriately calculate the electric energy as if it dropped into the wall socket from the sky. (Actually it mostly connects to a trainload of coal.) And third, there is a special factor for electric vehicles that is a goodness factor that has nothing to do with anything except political lobbying by electric car interests. (As I recall, this was written into regulations in 2001.)

  47. Hank Roberts:

    Must every topic here become a nuke-antinuke repetition?

    You know how long conservation takes, it’s quickest; you know how long major construction takes.

    Pasting in debating points just derails actual discussion. Please.

  48. Anne van der Bom:

    @matt, dagobert,

    You seem to be very convinced that nuclear offers CO2 reduction TODAY. How much time does it take to build a nuclear plant? From the first draft proposal until the first kWh is fed into the grid? 10 years? Wow that is fast. How much time to build the nukes needed to replace, say, 20% of generating capacity? 20 years? 30 maybe?

    I think you are being a bit too optimistic about the speed at which we can build nuclear capacity. I really do not see the timescale differ that much from that of introducing alternative energy sources. To get a substantial contribution, it’s a matter of several decades for both options. No, nuclear does not offer CO2 reductions TODAY.

    On the other hand, dagobert, to say that cheap solar cells are 100 years away is so pessimistic, I’d call it completely unrealistic. 100 years ago we had electric light. Now you have a 100 MIPS device in your pocket. Cheap solar cells (< 1$/W) are less than 10 years away. They’ll be flooding the market while those nuclear plants are still in some stage of construction.

  49. Jim Bullis:

    A little more background re #246
    It is indeed discouraging to see the SAE rule J1711, March 1999 where they assert in effect that electricity falls from the sky into the plug:

    “– Electric only—Composite fuel efficiency including charger losses for a plug-in HEV when
    operating in all-electric mode, in miles driven per kWh of electricity. This is converted to
    miles per gallon of gasoline on an energy equivalent basis using 33.44 kWh/gallon of
    gasoline (determined in the FCT test).”

    This is in epri doc published in 2001

    No wonder our American auto industry needs help. Maybe the recent $25 billion could be used to set up Freshman physics classes for the “designers.”

    Then look at the DOE, where they understand thermodynamics, but are subject to political influence, such that they apply a “1/0.15” advantage to electric vehicles because it gives “consistent treatment with other alternative—” and they seem to be directed to promote electric vehicles. This rule was set in July 2000.

    See Federal Register July 2000:

    Corruption is corruption, well meaning or not.

    I had thought that SAE and govt. standards meant something.

    The fact is that about 2/3 of the heat produced to make electrical or mechanical energy, wherever the heat engine is, is thrown away.

  50. JCH:


    Ten years is because of regulations. If they would just deregulate we can have some subprime plants in less than one year.