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New Study Suggests Flying Is Greener Than Driving

New submitter Desert Leap writes: The Washington Post reports a new study that suggests it is more environmentally friendly to fly rather than to drive. Analysis from the University of Michigan Transport Research Institute found that driving uses 57% more energy than flying per passenger mile. This is largely due to the number of occupied plane seats increasing while passengers per car decreased. Of course, "results may vary" for individual trips depending on many factors, such as distance flown (long flights are more fuel efficient) and the kind of car, and how many riders. One factoid is interesting: it takes 4,211 BTUs per person mile to drive. This number will fall as we switch over to electric vehicles. For example, a Tesla Model S takes about 1,100 BTUs per vehicle mile. Will future aircraft be able to also make the switch to electric?

280 comments

  1. What about a bus? by dunkindave · · Score: 4, Interesting

    Using the same logic, using a but or going by train is also more efficient since the many seats versus a couple is also true.

    1. Re:What about a bus? by dunkindave · · Score: 1

      Using the same logic, using a bus or going by train is also more efficient since the many seats versus a couple is also true.

      That should read using a BUS. Damn autocorrect.

    2. Re:What about a bus? by Anonymous Coward · · Score: 0

      Probably true, assuming the bus is carrying an efficient number of passengers. There is probably much better data available on flight utilization than bus utilization.

    3. Re:What about a bus? by oodaloop · · Score: 4, Funny

      I was about to ask how many seats you have in your butt.

      --
      Tic-Tac-Toe, Global Thermonuclear War, and relationships all have the same winning move.
    4. Re:What about a bus? by dbc · · Score: 0

      Actually, buses are terrible. They only run fully occupied during peak times, and transit companies don't pull the big buses and replace them with minivans during off-peak hours. So most bus miles are run with very light loads. On average, buses are far worse than cars for energy efficiency because of the low average load factor.

    5. Re:What about a bus? by bored_engineer · · Score: 1

      Your assumption is true for a loaded bus, but municipal busses, in all but a few cities, spend much more time travelling nearly empty than they do full. In an overall average, bicycles are the most efficient, while trains are a distant second. If I recall correctly, planes follow up trains, then cars, then busses with taxis being an absolute shit way to travel. (The class was some years ago, so forgive me if my memory has failed.) Interesting aside: The article presents this as new and surprising, but air travel was more efficient than travel by passenger cars when I took an "Energy in Transportation" class almost two decades ago.

    6. Re:What about a bus? by mrsquid0 · · Score: 3, Informative

      This depends where you are. In many cities buses run full regardless of the time of day. Even when ridership does decrease the reason that bus companies do not switch to minivans is that the most expensive part of operating a bus is the driver. Switching to smaller vehicles does not save a transit authority enough money to justify the logistical nightmare involved in changing vehicles while a route is in operation.

      --
      Just because you are paranoid does not mean that no-one is out to get you.
    7. Re:What about a bus? by killkillkill · · Score: 1

      Based on my limited experience, what you say is consistent with my observation of city buses but not cross-county line like Greyhound.

    8. Re:What about a bus? by Anonymous Coward · · Score: 0

      Jeezus Christ you don't change vehicles while the route is in operation, you'll fucking kill someone! You wait until the route has ended and then change vehicles before sending it out again. And regardless of what the most expensive part of operating the bus is, you should still save money where ever you can. You need to run this like a business and not the government.

    9. Re:What about a bus? by dunkindave · · Score: 4, Informative

      The comparison between planes and other modes of transit would be for longer-haul routes since planes do not provide inter-city transport. For longer routes, buses normally run fairly full. And for those that say buses aren't always full, I have been on a 737 plane between cities 1000 miles apart where there were only four passengers, including me, and on a flight to the far east where I had a row of five seats on a 747 all to myself for 12 hours.

    10. Re:What about a bus? by praxis · · Score: 5, Insightful

      On average, buses are far worse than cars for energy efficiency because of the low average load factor.

      On what data is this assertion based? I spent a few minutes seeing if such data exist. I could not find data to support your claim that buses are far worse.

      I found the following. A bus fuel efficiency is about 5 mpg [1]. That is with fifty-five passengers, which is the maximum capacity and therefore our lower bound. In my county, the average load-factor over all of 2012 was 479 million passenger miles divided by 44 million vehicle miles, or 10 passengers per mile.

      Our average fuel consumption over number of passengers then is 50 mpg, which is not far worse than cars for energy efficiency. In 2006, the average mpg of a private vehicle on the road was about 20 mpg. Even with two people in such a vehicle, the average-loaded bus is better.

      I did not dig very deeply; I was more trying to find your data and stumbled into data that seems to paint a different picture. It's quite possible that my data paints the wrong picture and you were using much more sound data, but because you did not provide it, I must ask for a citation now.

      Which data had you used?

      [1] http://www.nrel.gov/docs/fy00o...
      [2] http://metro.kingcounty.gov/am...
      [3] http://www.project.org/info.ph...

    11. Re:What about a bus? by dunkindave · · Score: 2

      Your assumption is true for a loaded bus, but municipal busses, in all but a few cities, spend much more time travelling nearly empty than they do full.

      Show me a plane that makes stops every few city blocks then we can accept your data as a fair comparison. Otherwise, stick to data about long-haul bus and train routes.

    12. Re:What about a bus? by grimmjeeper · · Score: 3, Informative

      I remember some years back that the Ford Excursion Diesel was rated one of the top most fuel efficient vehicles. The caveat was that you had to fill all 9 seats with people. If you did that, your economy per passenger was better than just about every car out there, even a Prius with a full passenger load. Of course, I would usually only see one or two people in them on the road so the real world figures weren't as good as that. But the point being made was that bulk transportation of people was more efficient than individuals driving cars.

      But that also underlines another point..

      We really didn't need another very expensive study to tell us the very obvious. Of course flying is more efficient than driving, so long as everyone is going from the same origin to the same destination on a direct flight.

      One of the things I'm pretty sure they didn't factor in was how far people had to travel to get to the airport before the flight and how far they had to travel to get to their destination afterwords, not to mention what type of transportation they used. Certainly, if you're driving from one airport to another the model holds true. But the farther away from the airport you are before and/or after your flight, the more the numbers can skew. And I'm pretty sure they don't factor in when you have to fly through a hub airport that takes you hundreds of miles out of your way. So if you got a deal on a United ticket and you have to fly from Iowa through Denver's hub on your way to Orlando, I'm pretty sure any fuel efficiency you would have gained on the airplane is negated by the fact that you're going something like 1,500 miles farther than you would have on the drive.

    13. Re:What about a bus? by Anonymous Coward · · Score: 0

      Yes. Here's a table for the US: https://en.wikipedia.org/wiki/...

    14. Re:What about a bus? by dbc · · Score: 1

      If you are up for it, search for information related to the Google self-driving car project. The data I saw was part of a presentation by one of their engineers at an IEEE RAS (Robotics and Automation Society) meeting that showed that in most cities, self-driving taxis would be a big efficiency win over buses, entirely because of low off-peak load factor.

      I didn't make it up, but I don't have a link.

    15. Re:What about a bus? by Anonymous Coward · · Score: 1

      I once took a Greyhound bus cross country, 3500km. Poor college student. I recommend that everyone try this to intelligently debate the pros and cons of the matter. Unfortunately intelligence is out of style in the US. Uninformed opinions matter more.

    16. Re: What about a bus? by Anonymous Coward · · Score: 0

      Why the hell are you insulting our uniformed patriots?

    17. Re:What about a bus? by praxis · · Score: 1

      I don't require a link, but perhaps a name of an engineer or a name of a study or which RAS meeting? I am not finding any of what you mention online. Perhaps my search terms are lacking, so anything else to go on?

    18. Re:What about a bus? by Austerity+Empowers · · Score: 3, Insightful

      Maintain an extra fleet of vehicles which need to be maintained and insured, at some % utilization. I'm not really sure this saves money.

    19. Re:What about a bus? by Wycliffe · · Score: 2

      Actually, buses are terrible. They only run fully occupied during peak times, and transit companies don't pull the big buses and replace them with minivans during off-peak hours. So most bus miles are run with very light loads. On average, buses are far worse than cars for energy efficiency because of the low average load factor.

      You're talking about city buses. You can't compare city buses with city to city buses. Chartered city to city buses run at or near 100% at
      all times just like alot of airlines. Chartered airlines are the same way. That's the reason certain getaway packages are so cheap. They sell
      every seat and know that every seat is sold and only leave when it's full unlike city buses and some airlines where they are running 12
      rounds a day whether someone is riding or not.

    20. Re:What about a bus? by Anonymous Coward · · Score: 0

      More accurately, how many Calories (kcal outside the US) are in your butt?

      Each capital-C Calorie is just short of 4 BTU's, which means that it takes approximately 1000 Calories per passenger per mile to drive (and the Tesla drops that to 275 Calories). How much would it burn to drive your muscles hard enough to move you a mile at highway speed? I'm betting it's WAY more than 1000 Calories. And then you have the medical bills for the pulled muscles and joint wear.

      What we need is a car that metabolizes cheeseburgers. OPEC could FOADIAF at that point.

    21. Re:What about a bus? by AthanasiusKircher · · Score: 2

      I found the following. A bus fuel efficiency...

      This is one of those arguments where the units can really change perception. I'm NOT trying to ignite one of those frequent Slashdot wars between those who say liters/100km is the best measure or mpg is stupid or whatever. I think various measures are better for various comparisons or circumstances.

      In this case, buses are traveling a fixed route, so the mileage is fixed. Buses are also frequently used for commuting fixed distances. Therefore, what we mostly care about is how much gas is used per unit distance, not how many units distance we could travel per unit fuel.

      Converting your stats to their reciprocal measurement gives:

      -- A bus fuel efficiency is about 20 gallons per 100 miles.
      -- Fuel consumption over number of passengers for buses is 2 gallons per 100 miles.
      -- Average mpg of a private vehicle is 5 gallons per 100 miles. With two people in a vehicle, that's 2.5 gallons per 100 miles per traveler.

      I draw your attention to the last statistic, since it's the place where things begin to look potentially misleading. If you use mpg, it looks like a bigger difference between bus and car: 40 mpg for two people in a car vs. 50 for a bus. But that's only a 0.5 gallon difference for a fixed route of 100 miles. Whereas if you were talking about a similar "difference of 10 mpg" between, say, your average 20 mpg single-driver vehicle and a 10 mpg SUV, that's 5 gallons extra for the SUV on the 100-mile route.

      Bottom line: mpg stats can be misleading when talking about gas consumption for fixed routes and distances (which are what buses are often used for). I'm not disagreeing with anything you said, only expressing numbers in a way that might make comparisons easier to evaluate in terms of fuel use.

    22. Re:What about a bus? by bored_engineer · · Score: 3, Informative

      Fair enough. I was working from memory, couldn't remember where intercity busses fit in the mix and was too lazy to try to find it. I stand corrected. The TRBs TCRP 79 reports the average energy consumption for intercity buses as 713 BTU/(passenger mile). As such, the revised hierarchy ought to be:

      1. 1. Bicycles,
      2. 2. Walking,
      3. 3. Intercity passenger busses,
      4. 4. Planes,
      5. 5. Long-haul passenger trains,
      6. 6. et c.
    23. Re:What about a bus? by ranton · · Score: 2

      On average, buses are far worse than cars for energy efficiency because of the low average load factor.

      The data I saw was part of a presentation by one of their engineers at an IEEE RAS (Robotics and Automation Society) meeting that showed that in most cities, self-driving taxis would be a big efficiency win over buses, entirely because of low off-peak load factor.

      Your two quotes above are very different assertions. You never said anything about comparing buses to self-driving taxis. Once we get self driving taxis I think anyone would agree they would be more efficient than buses. For one, nothing is stopping these self-driving taxis from being buses when loads are high enough or mini-smart cars when driving one person. When you don't have to worry about a human driver needing to make a living, who cares if a particular vehicle is only in service 2 hours per day? There are numerous efficiency gains to be gained from self driving cars that have nothing to do with cars inherently being more efficient than buses.

      --
      -- All that is necessary for the triumph of evil is that good men do nothing. -- Edmund Burke
    24. Re:What about a bus? by asylumx · · Score: 2

      I was about to ask how many seats you have in your butt.

      You only really need one.

    25. Re:What about a bus? by praxis · · Score: 1

      I agree that mpg is a poor metric for efficiency in passenger-miles. I used those, because that's what I found quickly and I did not want to put in the effort of conversion.

      My post was not meant to be a rigorous study. I was merely asking the poster to who I was replying for their data, because my cursory look for their data did not show anything even resembling what they were claiming.

    26. Re:What about a bus? by Anonymous Coward · · Score: 1

      You've never been to San Francisco, have you? Our buses are fully loaded all day long.

      But they're still pretty inefficient. The fleet averages about 8Mph. One day the bus was especially crowded and I decided to just walk the last mile. Despite having to go uphill the first third of the way, the bus only passed me about 2 blocks from my usual stop.

      And, yes, I usually walked to work at that time. Now I'm too far out to walk, and alternate between bussing and driving. The bus is so damned slow that I'm willing to part with over $250/month for parking (about 10 days per month) just to maintain my sanity. Sometimes I wish Chinese Communists would invade and build us a subway. I think the tradeoff might be worth it.

    27. Re:What about a bus? by praxis · · Score: 1

      Basically, I was attempting to show that a claim that bus efficiency [much less than] (not sure how Slashdot wants me to typographically represent less-than less-than) car efficiency needs some data because a quick dig showed that it was far, far closer. You exemplified this closeness by showing that on fixed-length trips they are even closer than I claimed.

    28. Re:What about a bus? by avandesande · · Score: 2

      Not to mention that an airplane is useless for traveling a handful of miles.

      --
      love is just extroverted narcissism
    29. Re:What about a bus? by AthanasiusKircher · · Score: 1

      You exemplified this closeness by showing that on fixed-length trips they are even closer than I claimed.

      Yes, precisely. That's why I said I wasn't disagreeing with your argument. I was just trying to clarify things a little.

    30. Re:What about a bus? by SillyHamster · · Score: 1

      Your two quotes above are very different assertions. You never said anything about comparing buses to self-driving taxis. Once we get self driving taxis I think anyone would agree they would be more efficient than buses.

      It's not obvious to me why self-driving taxis would be fundamentally different in energy efficiency compared to people driving their own cars.

    31. Re:What about a bus? by Anonymous Coward · · Score: 0

      If you use mpg, it looks like a bigger difference between bus and car: 40 mpg for two people in a car vs. 50 for a bus. But that's only a 0.5 gallon difference for a fixed route of 100 miles. Whereas if you were talking about a similar "difference of 10 mpg" between, say, your average 20 mpg single-driver vehicle and a 10 mpg SUV, that's 5 gallons extra for the SUV on the 100-mile route.

      They are identical, of course. The bus is 20% (or 25%) more efficient. Your "small" 0.5 gallon difference on a fixed route of 100 miles shoudl also be compared to the 2.5 gallons. Are you serious???

    32. Re:What about a bus? by Mr+D+from+63 · · Score: 2

      I found the following. A bus fuel efficiency...

      This is one of those arguments where the units can really change perception.

      I don't see why we should even be comparing efficiency. If emissions is the thing we care about then compare emissions, not efficiency.

    33. Re:What about a bus? by Anonymous Coward · · Score: 1

      How often does an airplane go where you want to go? Not very. Most trips are short distance with a good chance of multiple stops. Air transport planes are only efficient for long distance travel. The time delays of loading/unloading passengers and luggage, airport security screening, parking, and driving to/from the airport make it less practical to fly for short trips. If practicality is not important, walk. Airplane to car comparison is not meaningful for most of our travel. Airplanes are only useful to reduce the time it takes to travel long trips. On to next topic.

    34. Re:What about a bus? by Anonymous Coward · · Score: 0

      Well, at highway speeds you only need one minute to cover one mile. There is no way a human body will burn 1000 Calories in a minute unless by spontaneous combustion

      A strong cyclist can produce around 400W, i.e. 23 BTU/minute or about 5-6 Calories/minute, for an hour or more of continuous effort. I've read that extreme athletes and soldiers might consume double that, reaching almost 10 Calories/minute (actually, 15k Calories/day) under the most intense endurance activity scenarios like humping heavy equipment over mountains. However, a large part of that may simply be tissue repair rather than useful mechanical power.

      If we really want efficient cars, we have to go back to small and lightweight designs. We cannot carry around 4k lbs of metal per person.

    35. Re:What about a bus? by Headw1nd · · Score: 1

      They do. They are saving the money they would need to purchase, house, insure, and maintain a separate fleet of vehicles, plus depreciation. They are also maintaining capacity in case of an unexpected surge, say a party or club letting out. Not to mention that the end of the route is not necessarily the bus depot, so switching to another vehicle involves more driving time where no fares are being collected. There are cases where using smaller vehicles makes sense, but on a more ad-hoc basis.

    36. Re:What about a bus? by Anonymous Coward · · Score: 0

      How many BTU's does it take to get 1,000 BTU's to that Tesla?

      People seem to think that electricity magically gets installed in electric cars with no waste and no pollution.

      While people CAN install solar panels on their houses and charge from those, most people plug their cars into commercial mains, and use oil, coal, gas, or nuclear generated electricity, and there is loss during the delivery, too.

    37. Re:What about a bus? by Cochonou · · Score: 1

      I think you got your ordering wrong. From your source:
      The overall energy intensity of the intercity bus mode, which is measured in BTUs (British thermal units) per passenger-mile, is 713, compared with 2,441 for intercity passenger rail (Amtrak); 3,999 for certified air carriers; and 4,238 for public transit buses. Automobiles experience 3,671 BTUs per passenger-mile.

    38. Re:What about a bus? by wbr1 · · Score: 2

      It's powered by natural gas.

      --
      Silence is a state of mime.
    39. Re:What about a bus? by Anonymous Coward · · Score: 0

      On average, buses are far worse than cars for energy efficiency because of the low average load factor.

      The data I saw was part of a presentation by one of their engineers at an IEEE RAS (Robotics and Automation Society) meeting that showed that in most cities, self-driving taxis would be a big efficiency win over buses, entirely because of low off-peak load factor.

      Your two quotes above are very different assertions. You never said anything about comparing buses to self-driving taxis. Once we get self driving taxis I think anyone would agree they would be more efficient than buses. For one, nothing is stopping these self-driving taxis from being buses when loads are high enough or mini-smart cars when driving one person. When you don't have to worry about a human driver needing to make a living, who cares if a particular vehicle is only in service 2 hours per day? There are numerous efficiency gains to be gained from self driving cars that have nothing to do with cars inherently being more efficient than buses.

      Self driving electric recumbent bike is where it's at, with a cargo trailer if you need groceries/luggage to be carried. Should be up at about 200-500mpg equivalent.

    40. Re:What about a bus? by ray-auch · · Score: 1

      On average, buses are far worse than cars for energy efficiency because of the low average load factor.

      On what data is this assertion based? I spent a few minutes seeing if such data exist. I could not find data to support your claim that buses are far worse.

      Actually they are about the same - given an average car and average loading - but if your car is more eco than average or you carry more people it _will_ be a lot greener than bus.

      You can get complete data for calculating carbon footprint from here: http://www.ukconversionfactors... - choose all scopes and "business travel land" and "passenger vehicles" to get bus and car relative data. There are links to the methodology papers on that site as well - explains what data backs the figures e.g. https://www.gov.uk/government/...

      Average local bus (not london) by these figures is 0.11 and average car is 0.18 - but the bus is per passenger per km, and the car is per vehicle. Take an average car occupancy of 1.6 - see e.g. https://www.gov.uk/government/... - and the car is near enough the same as the bus per passenger km.

      Now, if you have a more eco car than average or carry more than 1.6 persons on average then your figure may vary. I have a 7 seater which is 170 g/km, to which (according to the methodology links) I should add 15% for the mfrs cheating the tests (actually it gets closer to spec than that) so say a round 200. That car is mostly used to carry at least 5 people, and almost always more than 1, so take a conservative load average of 3 and you have 66g/km or 0.066 vs 0.11 for a bus. That's a lot less. Many new small cars will be less than a bus even with single occupancy.

    41. Re:What about a bus? by ray-auch · · Score: 1

      If efficiency is emissions per passenger mile, then it is the right thing to compare - it tells you the relative emissions for moving the same number of people between the same points by different means of transport.

      If you want to just compare emissions, then you'll find that can make a much bigger difference by not going at all than by changing how you go - and indeed plenty of greens will argue that we should just travel less. This tends to miss the point that most people travel for a reason rather than just for the hell of it.

    42. Re:What about a bus? by BradMajors · · Score: 1

      Bicycles and walking are powered by very non-green energy sources. An engine that spews CO2 from one end and methane from the other end. Travelling by an electric car is much greener than walking.

    43. Re:What about a bus? by AK+Marc · · Score: 1

      I flew Christmas Eve in about 1993 from Boston to Dallas, and there were more flight attendants than passengers. "We are suspending all service on this flight. If you want something, just ask." Most everyone pulled up the armrests in the middle row, and laid across middle seats to sleep on the empty plane.

    44. Re:What about a bus? by bored_engineer · · Score: 1

      The paper I linked to is from 2002. The Washington Post article cited by the original submission reports that this newer research concludes that on average air travel uses 2,033 BTU/(passenger-mile), considerably better than the 1998 data in the TRB paper. (The WP article also reports average energy use of 4,211 BTU/(passenger-mile) average for travel in personal vehicles.)

    45. Re:What about a bus? by thegarbz · · Score: 1

      while a route is in operation.

      Assuming a perfectly always in operation route with a mythical bus that never needs to go back to the depot for a refuel. This isn't as big of a problem as you may think if the depots are placed strategically.

    46. Re:What about a bus? by thegarbz · · Score: 2

      Maintenance is based on distance traveled and as a result will cancel. Also buses use an incredible amount of fuel. They are stop start vehicles with incredible weight and huge engines.

      But don't take my word for it, look to cities where they already do this (last trip to Vienna I saw after a certain time many buses changed to minivans, many double buses changed to singles, and then after a later time the entire city's route system changed so only major arterials were serviced by buses and if you wanted to take a minor route you'd call a number and a minivan would come get you from one bus stop and drop you at another.

      Seemed to work there.

    47. Re:What about a bus? by speederaser · · Score: 3, Informative

      Bicycles and walking are powered by very non-green energy sources. An engine that spews CO2 from one end and methane from the other end.

      I don't know if you're being funny or serious, but that's a common misconception so I'll assume you're being serious. The CO2 and methane that we animals spew all came directly from the atomsphere through the food chain or through breathing. It's a closed cycle - plants and animals take CO2 from the atmosphere, store it a short while, then release it back into the atmosphere. That closed cycle is the gold standard of sustainability, pretty much the opposite of "non-green".

    48. Re:What about a bus? by Mr+D+from+63 · · Score: 2

      If efficiency is emissions per passenger mile, then it is the right thing to compare

      But they are not measuring emissions per passenger mile, they are measuring passenger miles per gallon. Two different things, particularly when they are using different fuels. If you don't care about emissions, then what it the point of the comparison to start with?

    49. Re:What about a bus? by mrsquid0 · · Score: 1

      Shutting down a route temporarily to change all the buses that are running along that route, then starting up the route again will cause tremendous disruption, not to mention the loss of business while the route is not operating. The (very) few transit systems that do this use live vehicle swaps. That is, they replace one vehicle with another at an end point of the route. This avoids the need to shut down the route,a and means that passengers do not have to transfer from one bus to another.

      --
      Just because you are paranoid does not mean that no-one is out to get you.
    50. Re: What about a bus? by stu72 · · Score: 1

      This is ludicrous. If your local bus company or transit agency has the authority to run like a business and run stick to profitable routes (higher density, straight lines) they will be plenty full and far more fuel - and most importantly - space efficient, than a car.

      If your local agency has a mandate from voters to run like a social service, providing transportation to all, regardless of location or profitability, then they won't be full or efficient, but then that's not what you asked the agency to do in this scenario.

      Studies like these are just sops to politicians and people living in areas where doing anything but driving is challenging, they convince them that 50 km grocery runs really aren't that ludicrous and hey, one day you'll fly 500 km to get your groceries and that will be more efficient thanks to "future tech"

    51. Re: What about a bus? by Anonymous Coward · · Score: 0

      Your calculations are a fair bit off. Any cyclist producing 400w for an entire hour will have burned well over 1000 calories per hour, multiples more than your 5-6 estimate. I personally have burned over 1000 calories per hour producing a steady average of only 230 watts.

    52. Re:What about a bus? by siliconsmiley · · Score: 1

      May I introduce... the five @$$ed monkey.

    53. Re:What about a bus? by Anonymous Coward · · Score: 0

      Absolutely correct. All mass transit is more green for society in aggregate. The car is supremely bad in every way because it's utterly dependent on cheap oil and not having any greenhouse effects of its waste "externalities" (aka exhaust).

    54. Re:What about a bus? by Anonymous Coward · · Score: 1

      Bicycles and walking are powered by very non-green energy sources. An engine that spews CO2 from one end and methane from the other end.

      I don't know if you're being funny or serious, but that's a common misconception so I'll assume you're being serious. The CO2 and methane that we animals spew all came directly from the atomsphere through the food chain or through breathing. It's a closed cycle - plants and animals take CO2 from the atmosphere, store it a short while, then release it back into the atmosphere. That closed cycle is the gold standard of sustainability, pretty much the opposite of "non-green".

      This is also a common conception. Obviously, there is a lot more CO2 involved in food production than just the CO2 captured by plants. This depends a lot on the type of food you use to fuel your body (meat being worse than cereals etc.). Production, processing, and transportation of food products all involve non-renewable CO2 sources, outside of the closed CO2 circle, which you have to factor in the CO2 budget of food consumption.
      I'm not saying that cycling and walking doesn't have lower carbon emissions, but food consumption in the modern world isn't automatically renewable just because plants take CO2 from the atmosphere.

    55. Re:What about a bus? by Anonymous Coward · · Score: 0

      479 million passenger miles divided by 44 million vehicle miles, or 10 passengers per mile.

      Passenger miles divided by vehicle miles is passengers per vehicle, not passengers per mile.

  2. Hasn't this always been true? by Anonymous Coward · · Score: 1

    Can you imagine 300 people driving from Seattle to Florida in separate cars?

  3. With REALLY Huge Fans... by avgjoe62 · · Score: 1, Insightful

    Will future aircraft be able to also make the switch to electric? Yes, of course. Electric driven propellers should do the trick.

    Of course, the size of the batteries needed will preclude carrying any passengers or cargo.

    --

    How come Slashdot never gets Slashdotted?

    1. Re:With REALLY Huge Fans... by NatasRevol · · Score: 3, Insightful

      That's not very forward looking....

      People said the same thing about cars & range.

      --
      There are two types of people in the world: Those who crave closure
    2. Re:With REALLY Huge Fans... by The+Grim+Reefer · · Score: 3, Interesting

      I would think it also depends on when the plane is flying. If it's entire trip is during daylight hours, and it's above the clouds as most larger aircraft flights are, then you may be able to use solar panels in place of the majority of the batteries. Plus you won't have to carry the weight (as much) in fuel.

      It's probably not a practical solution currently. But as efficiencies increase, it's at least feasible it may be at some point in the future.

    3. Re:With REALLY Huge Fans... by Rei · · Score: 2

      Of course, the size of the batteries needed will preclude carrying any passengers or cargo.

      There are already electric small airplanes that take a couple people.

      Airplanes are obviously the highest-hanging fruit for switching over to electric drive, but they're not impossible. On the pure electric front you're first going to see the current growth trend in small personal electric airplanes continuing and short-range business uses like crop dusting and the like grow. From there you'll move to the little short hop passenger flights between small regional airports, and then increasingly longer ranges and sizes.

      There's also hybrid jet technologies being researched, wherein you greatly simplify your jet engines by removing the turbine, and instead drive the compressor with electric power; the casing becomes the stator and the compressor the rotor of an electric motor. The moving part count is greatly reduced and there's far less resistance to the exhaust gases leaving the engine, meaning more power and better fuel efficiency.

      But actually, before all that, there's one electrification system that's just now hitting the market, but it's not where most people might think: the wheels. Jet engines are horribly efficient in running at low powers such as taxiing, and planes burn a lot of fuel just moving about and waiting to take off or heading to the gate - on a short flight a plane may burn 5-10% of its fuel just sitting on the ground. There are now small scale pilot projects out there that have battery-driven electric motors in the landing gear so that one doesn't have to waste all this fuel.

      --
      "...but Republicans plan to come back with a new plan, where they just slash the tires on all the ambulances."
    4. Re:With REALLY Huge Fans... by Shakrai · · Score: 2

      Aerospace is a huge hole in our plans for a carbon less energy future; you can replace fossil fuels with ships (nuclear) and transit (electric cars and trains) but I haven't seen any technology (real or imagined) that can do the job in aerospace. Short haul trucking is another hole that's going to be hard to fill, long haul can conceivably be replaced with trains but you're still going to need something to move goods from the rail network to their final destination.

      --
      I want peace on earth and goodwill toward man.
      We are the United States Government! We don't do that sort of thing.
    5. Re:With REALLY Huge Fans... by Rei · · Score: 1

      There's also some interesting side possibilities of airplane electrification being looked at. I read a research paper at one point which focused on the fact that electric propulsion scales down far better than other forms of aircraft propulsion; they investigated the possibility of having a number of micropropellers along the wing which are run at full power during takeoff and landing but not during level flight. The concept was that though they're not as efficient as the main propeller, they dramatically increase the lift and reduce the stall speed, so you can have aircraft lift off on very short runways or fly at very slow speeds without having to resort to normal VTOL techniques.

      --
      "...but Republicans plan to come back with a new plan, where they just slash the tires on all the ambulances."
    6. Re:With REALLY Huge Fans... by mlts · · Score: 1

      I wonder about airships. If we can build some that can handle the cargo of a larger plane, it takes far less fuel to keep those going than it does an average plane (mainly because an airship won't crash if the engines stop.) I can see those being quite effecient at moving cargo. Since they only go 20-60 mph (32-100 km/hr), they won't be replacing high speed rail... but airships require relatively little energy to operate compared to a plane which needs airspeed to maintain lift.

    7. Re:With REALLY Huge Fans... by Anonymous Coward · · Score: 0

      That's stupid. Just taxi with an electric tug-car. Why carry the weight of the electric motor system in the air where it isn't doing any good?

    8. Re:With REALLY Huge Fans... by mrchaotica · · Score: 1

      The answer to both of those issues ("green" fuels for aviation and trucking) is biofuel or synthetic (hydrocarbon) fuel. (FYI, we had an article here about the latter just a few days ago.)

      Nobody said we need to be "carbon-less;" it's sufficient to be "carbon-neutral."

      --

      "[Regarding the 'cloud,'] ownership was what made America different than Russia." -- Woz

    9. Re:With REALLY Huge Fans... by Rufty · · Score: 1

      Or you could just put a nuclear reactor on the plane. Or cut out the electric bit in the middle and go straight for a nuclear jet engine.

      --
      Red to red, black to black. Switch it on, but stand well back.
    10. Re:With REALLY Huge Fans... by fustakrakich · · Score: 1

      you're still going to need something to move goods from the rail network to their final destination.

      A long time ago, produce (mostly coal) was on underground light rail. There is no reason not to expand on that. Well, maybe one

      --
      “He’s not deformed, he’s just drunk!”
    11. Re:With REALLY Huge Fans... by jeff4747 · · Score: 0

      No, there isn't enough surface area to power a passenger/cargo aircraft via solar panels. That's why the plane currently attempting a 100% solar-powered flight around the world is a custom, ultralight airplane with zero passengers and basically zero cargo.

    12. Re:With REALLY Huge Fans... by bobbied · · Score: 2, Insightful

      Oh sure it is... The issue is ENERGY density.

      Aircraft are more efficient when the energy storage is lighter and smaller. Batteries are not lighter and smaller than liquid hydrocarbons that contains the same amount of energy. Not to mention that as you burn off liquid fuel, the aircraft weighs less and gets more efficient as a result.

      So, until batteries get small enough and light enough to have the same range with the same payload, liquid hydrocarbons will be the fuel of choice. I don't think we will be at that point for a LONG time yet as we are currently pushing the limits of battery technology to do a car, where weight isn't a big deal, at least as big a deal as it is in airplanes.

      --
      "File to fit, pound to insert, paint to match" - Aircraft Maintenance 101
    13. Re:With REALLY Huge Fans... by Anonymous Coward · · Score: 0

      You're not thinking outside the box.

      A really long extension cord would work just as well!

    14. Re:With REALLY Huge Fans... by hawkfish · · Score: 1

      That's stupid. Just taxi with an electric tug-car. Why carry the weight of the electric motor system in the air where it isn't doing any good?

      Do we really want the O'Hare runways to look like the LA freeway system at peak times?

      --
      You will not drink with us, but you would taste our steel? - Walter Matthau, The Pirates
    15. Re:With REALLY Huge Fans... by Qzukk · · Score: 4, Funny

      Please direct your attention towards the front of the cabin as our flight attendants demonstrate the safety features of this craft.

      In the event of pressure loss, an oxygen mask will drop from the overhead compartment. Please pull the mask to extend it completely and start the flow of oxygen, then place the mask over your nose and mouth and place the strap around your head to hold it in place. Put on your mask before helping children or others in need of assistance.

      In the event of power loss, bicycle pedals will extend from the floor of the cabin. Please pedal as if our lives depended on it

      --
      If I have been able to see further than others, it is because I bought a pair of binoculars.
    16. Re:With REALLY Huge Fans... by sonicmerlin · · Score: 1

      Actually the issue isn't just battery density. It may not be as long as you think before we get lithium air batteries with similar battery density to fossil fuels, but the problem with refueling time remains. You would need an impractically sized cable to carry the voltage required to "fast charge" a plane battery, and that would still be much slower than using a liquid fuel.

      I think hydrogen will eventually supplant fossil fuels in aerospace.

    17. Re:With REALLY Huge Fans... by Rei · · Score: 2

      The system is actually not that big. The batteries are small because, despite the weight of the plane, the distances traveled are very short; and electric motors pack a lot of power into a small package. Having it all built into the plane reduces ground delays, ground staff, and additional ground hardware. It's a "pushback and go" system, the pilot can move the instant he gets clearance to, he doesn't have to wait for anyone else. It's estimated to save about 2 minutes over using tugs, which may not sound like a much, but each flight at the gate represents about $100k worth of revenue, so squeezing an extra flight in every couple days is a lot of money.

      Ultimately they want to turn it into a fully automated airport traffic flow, where each plane moves from the runway to the gate and vice versa in a fully automated, optimized manner.

      --
      "...but Republicans plan to come back with a new plan, where they just slash the tires on all the ambulances."
    18. Re:With REALLY Huge Fans... by The+Grim+Reefer · · Score: 2

      And that's why I finished my post with the following: "It's probably not a practical solution currently. But as efficiencies increase, it's at least feasible it may be at some point in the future."

      Battery tech has also been improving recently. There's no reason that it may become much lighter in the future and a combination of PV and batteries may become practical. It's also entirely possible that PV will never reach the necessary efficiencies and batteries don't reach the energy density necessary. That's why I said "may" in both cases.

    19. Re:With REALLY Huge Fans... by Gordo_1 · · Score: 2

      Yeah it's true. Battery technology has a long way to go for flight. Non-production electric airplanes *could* be a curiosity in about 15 years, but we're probably closer to 30 years for truly viable electric aircraft... and that's assuming we ever get to the point where energy density of batteries are able to close in on the energy density of petroleum distillates.

    20. Re:With REALLY Huge Fans... by Anonymous Coward · · Score: 0

      Electric car range is still a HUGE issue.

    21. Re:With REALLY Huge Fans... by Anonymous Coward · · Score: 0

      Will future aircraft be able to also make the switch to electric? Yes, of course. Electric driven propellers should do the trick.

      Any chemical reaction, even one that takes place in batteries, requires an oxidizer and a reducer. Oxidizers have lots of protons, making them much heavier than reducers. For example, one kilogram of a light hydrocarbon fuel (gasoline/kerosene/etc) requires 3.5 kilograms of oxygen to burn it. Internal combustion engines have the huge advantage of not having to carry their own oxidizer. This is why batteries are heavy.

      Unless the airplane has solar panels or has fuel cells reducing atmospheric oxygen, making a long range fully electric airplane is extremely difficult. A Boeing 787 has a max takeoff weight of 557,000lbs with 244,000lbs of that as fuel. Its range is extremely reliant on using the densest energy storage possible. Hydrogen atoms that are attached to just enough carbon to make them liquid at STP is about the best we can do.

    22. Re:With REALLY Huge Fans... by catchblue22 · · Score: 2

      Will future aircraft be able to also make the switch to electric? Yes, of course. Electric driven propellers should do the trick.

      Of course, the size of the batteries needed will preclude carrying any passengers or cargo.

      I don't think that is necessarily true. One option is to build hybrid electrical airplanes. And if battery power density and durability continues to improve, I think you might be surprised what is possible if you fill the wings of an airplane with electrochemical cells. Elon Musk has speculated that electric airplanes might be possible if we go beyond the incremental improvements of the current players.

      --
      This and no other is the root from which a tyrant springs; when first he appears as a protector - Plato (423 to 327 BC)
    23. Re:With REALLY Huge Fans... by Jason+Levine · · Score: 1

      Let's assume that you had some sort of battery that could store the same amount of energy as a full airplane fuel tank and was light enough to not cause issues. Couldn't you standardize the batteries across aircraft, make the battery removable, and charge them in the airport between flights. So airplane lands, everyone disembarks, the flight crew (among other things) removes the depleted battery, puts in a fully charged battery, and then puts the depleted battery in the airport's charging system until it is fully charged and ready for use again. This would make time to get the airplane from low charge to full charge very low (as low as the "pop out old one, put in new one" takes).

      Such a system wouldn't work for cars because you don't want your average person ripping out his car's battery, but for planes you have a crew of trained mechanics checking the plane between each flight. Surely, they could handle this task.

      --
      My sci-fi novel, Ghost Thief, is now available from Amazon.com.
    24. Re:With REALLY Huge Fans... by Yoda222 · · Score: 1

      You speak about aerospace where you should probably speak about aeronautics. In the aerospace sector, people rely a lot on non carbon energy, except for the launch part. Of course a launch is a big energy consumption in a short period of time, but on the other hand the S/C will usually be used for 10+ years, running on solar energy. And more and more S/C use "electric" propulsion, where you have still a "fuel" of course, but most of the delta-V comes from electricity.

      There are some people who want to use renewable also for launches. Or at least it's a side effect of trying to simplify/reduce the launch cost. For example zero2infinity is planning to use balloon for launching rocket from high altitude, avoiding the dense atmosphere (even better, they use it) and the drag, and also starting from higher slightly reduce the delta-V.

    25. Re:With REALLY Huge Fans... by Grishnakh · · Score: 1

      You would need an impractically sized cable to carry the voltage required to "fast charge" a plane battery, and that would still be much slower than using a liquid fuel.

      Wrong. With planes, it'd be trivial to just swap out batteries at the airport. Aircraft aren't like cars owned by individuals. With aircraft, they're owned by large companies like Southwest or Delta, who have whole wings or even concourses, plus giant hangars, at every airport they have a presence at. If they actually had batteries sufficient for this task, they'd simply swap them out at each stop, just like they refuel and swap out the baggage right now.

      They're already talking about doing exactly this with cars, but with cars there's some problems with the idea. Battery packs aren't fungible like fuel; an old one doesn't work as well as a new one, they can develop problems and need repairs (like replacing individual cells), so if you swap out your brand-new $20K pack for a worn-out old one, you're in effect losing a lot of money. So they're coming up with ideas like leasing the pack when you get a swapped one, and later returning for your charged-up old pack which you own, but that's obviously problematic.

      All this goes away with aircraft, since the airline company and the company swapping packs at the airport are one in the same. When a Delta plane lands and docks at the jetway, Delta personnel will swap out the pack for another Delta-owned pack. Delta will manage all its own battery packs, so issues of who owns which pack and who's responsible if one develops problems all go away.

      Obviously, this discussion is academic since we certainly don't have batteries capable of storing the amount of energy needed for an electric airplane, but if some giant breakthrough in battery technology is made next year and all of a sudden, electric airplanes are totally feasible and completely capable of replacing modern jet-fuel-powered aircraft, the recharge time will NOT be a problem; they'll just swap batteries the way people do now for rechargeable power tools.

    26. Re:With REALLY Huge Fans... by bobbied · · Score: 1

      Do you know any aircraft mechanics?

      It's not like you could just replace a ton of batteries with your standard ramp worker, baggage thrower. It's hard enough to get them to close the doors properly, now you want them replacing batteries? Yea, you might do this, but I'm thinking the logistics of what you suggest might be a problem for a "for profit" airline.

      --
      "File to fit, pound to insert, paint to match" - Aircraft Maintenance 101
    27. Re:With REALLY Huge Fans... by cnaumann · · Score: 1

      The biggest advantage that liquid hydrocarbons have over conventional batteries is that you can use air as the oxidizer. The oxidizer is much, much heavier than the fuel. Think about it. For burning hydrogen, the oxidizer is 8 time the mass of the hydrogen. For burning carbon, the oxidizer is over 2.5 times the mass of the carbon.

      But you don't have to use conventional batteries to operate an electric vehicle. You could use hydrocarbon-air fuel cells.

    28. Re:With REALLY Huge Fans... by Grishnakh · · Score: 1

      No, it really isn't. The Tesla can already go over 200 miles per charge. Commuters don't need that much range.

      The key thing, which most people are just too fucking stupid to understand (including most Slashdotters I've noticed, in fact it seems to me that Slashdotters are far less able to understand this than the general public), is that you don't need an electric car to do everything a gas car does to make it viable. A Prius can't tow a boat, but that doesn't stop countless people from buying them and driving them daily. It's the same with electric cars; they're already perfectly viable as commuter vehicles. No, they're not great for road trips; that's why you use your other car for the road trip.

      Most families these days have multiple vehicles, so you have one electric car, and one gas-powered car. This isn't a foreign concept to countless married couples, where the husband and wife both have a car: the wife's car is nearly brand-new and expensive, while the husband's car is a 20-year-old piece of shit beater car. The wife uses her fancy car to get her nails done and go to the spa, while the husband drives his shitbox to work every day so he can afford the payments for the wife's car. So, now, the husband can get an EV for his daily commute and they can use the wife's Mercedes for road trips. The main problem with this, of course, is that EVs are still relatively expensive, and since the wife insists on spending most of the car budget on her car and not one red cent on the husband's car even though he spends so much time in it, there's no money for a $30K Chevy Spark or Nissan Leaf or similar low-end EV. But as EVs become more commonplace and older used ones become available, this will change, and husbands will be driving 10-year-old beat-up Leafs to work, and toiling in the garage at night to replace dead cells in their battery packs.

    29. Re:With REALLY Huge Fans... by NatasRevol · · Score: 1

      To a minority of cases.

      --
      There are two types of people in the world: Those who crave closure
    30. Re:With REALLY Huge Fans... by sonicmerlin · · Score: 1

      I think they would prefer to keep the battery compartment sealed from the external environment.

    31. Re:With REALLY Huge Fans... by Ichijo · · Score: 1

      To save even more weight and batteries, it would also help to use some sort of assistance (example 1, example 2) to get the craft above the clouds and much of the atmosphere before any electric propulsion is needed. A similar concept existed as far back as 1915.

      --
      Any sufficiently unpopular but cohesive argument is indistinguishable from trolling.
    32. Re:With REALLY Huge Fans... by blue9steel · · Score: 1

      There is much anger in this post.

    33. Re:With REALLY Huge Fans... by Anonymous Coward · · Score: 0

      Before you go off insulting people, you should learn the laws of thermodynamics yourself. You can't simply equate thermal energy with electrical energy. The first needs to go through a highly inefficient single-stage Brayton cycle heat engine, and the second would go through efficient electric motors. So your argument is off by a factor of about 3X. Maybe you're not quite so smart as you think you are.

    34. Re:With REALLY Huge Fans... by Anonymous Coward · · Score: 0

      I would think it also depends on when the plane is flying. If it's entire trip is during daylight hours, and it's above the clouds as most larger aircraft flights are, then you may be able to use solar panels in place of the majority of the batteries.

      Solar Panels with 25% efficient Cells would produce a maximum of 0.2kW per m^2 of area at noon at latitudes of 30..40 if mounted horizontally.

      A Boeing 747 has less than 600m^2 of wing area, so you could produce around 120kW or 160hp with the entire wing area. That's about 75% of the engine rating of the "Spirit of St. Louis" (166kW), whose 2.5tons Charles Lindbergh almost failed to lift off the runway when making his famous transatlantic flight.

      Do you think one, or maybe two of these engines if we account for extra cells on the fuselage, could power a 400 ton Boeing 747 flying at 600mph?

      Plus you won't have to carry the weight (as much) in fuel.

      No, that is not efficient either.

      600 m^2 of mono crystalline solar cells with a thickness of 0.3mm would weigh around half a ton. With a turbine and a generator, you could produce around 2000kWh out of 500kg of fuel, compared to around 800kWh produced by the solar cells during 6 hours of flight while the sun is sufficiently hight in its zenith.

      So even without the overhead for mounting and wiring the cells, this is a losing proposition.

      It's probably not a practical solution currently. But as efficiencies increase, it's at least feasible it may be at some point in the future.

      No, not on a planet with a gravitational constant of 1g and a maximum solar constant of 1,4 kW/m^2 - in an orbit around the equator ;-(

    35. Re:With REALLY Huge Fans... by bobbied · · Score: 1

      Seems to me that an internal combustion engine and a prop is the same thing as what you describe, at least in results. Hydrocarbons and air in, spinning prop, water and CO2 out. Why bother with all the fuel cell mess and complexity, just use what already works, 110 Octane Low Lead Aviation Gasoline....

      --
      "File to fit, pound to insert, paint to match" - Aircraft Maintenance 101
    36. Re:With REALLY Huge Fans... by AK+Marc · · Score: 1

      Wireless power. Just don't ask about the really long grounding wire.

    37. Re:With REALLY Huge Fans... by AK+Marc · · Score: 1

      There are trial systems for car batteries. You can change a car's batteries (for specific prototypes) resulting in an energy transfer rate faster than liquid fuel. You drive on a special changer, the old battery is disconnected and drops out the bottom, and a new one is fitted in place. I've seen the videos, so I'm sure you can google it.

    38. Re:With REALLY Huge Fans... by Anonymous Coward · · Score: 0

      In the event of a water landing, hold on to your seat cushion tightly as the lithium battery explosion will launch you to your final destination.

    39. Re:With REALLY Huge Fans... by Anonymous Coward · · Score: 0

      Have you looked at the size of the fuel tanks on a 737? It's 20 Metric tons.

      For a 747, it's 200 MT.

      Liquid fuel is trival to pump in a little bit at a time. So you can drive up a 10,000L fuel truck, and load it with one guy and a hose, and do that several times.

      Batteries have to be loaded in large packs. Assuming standardization, you're looking at having to have some sort of forklift device that can hoist up 5 MT or more battery packs into the aircraft, then make sure they have their contacts completely hooked up properly, etc.

      It's far, far, far more difficult to do something like that. It's one of the reasons that the "battery replacement" recharge stations for electric cars never took off. Which is simple: push a small hose into your tank and wait 5 minutes for it to fuel up, or figure out how to life 200lbs of battery into your car and get it hooked up right? Same principle with an airplane.

      Batteries for aircraft simply aren't tenable. You need some sort of fuel - liquid or gaseous, hydrocarbon or whatnot. Solids won't work, and trying to push electrons over some sort of line feed won't either.

    40. Re:With REALLY Huge Fans... by NatasRevol · · Score: 1

      You mean just like UPS/Fedex does on their planes with the large containers?

      --
      There are two types of people in the world: Those who crave closure
    41. Re:With REALLY Huge Fans... by NatasRevol · · Score: 1

      Assuming standardization, you're looking at having to have some sort of forklift device that can hoist up 5 MT or more battery packs into the aircraft, then make sure they have their contacts completely hooked up properly, etc.

      Just like UPS/Fedex do with their package containers?

      --
      There are two types of people in the world: Those who crave closure
    42. Re:With REALLY Huge Fans... by jeff4747 · · Score: 1

      And that's why I finished my post with the following: "It's probably not a practical solution currently. But as efficiencies increase, it's at least feasible it may be at some point in the future."

      Nope. There is a fixed amount of sunlight hitting the surface of the airplane. Well, more-or-less fixed - the sun's output varies slightly.

      There is not enough energy in that sunlight to power a passenger/cargo airplane. Even with 100% efficient panels.

    43. Re:With REALLY Huge Fans... by The+Grim+Reefer · · Score: 1

      Like I said, it may never happen. But if it comes to pass that rotten dinosaurs are no longer a viable option, we may launch big fucking computer tracked magnifying glasses into orbit to focus enough energy to make it possible. Or use orbital solar powered lasers, or microwave transmission. We could do the same from the ground, it's probably less likely to cook the general population if it's coming from the ground.

      Powered flight in heavier than air craft wasn't possible 150 years ago. Just look at all of the advances there have been in that time. Who knows what the next 150 years will bring.

  4. Masstransit is more energy efficient than personal by jellomizer · · Score: 5, Insightful

    Nothing really too new. If you take the bus and the bus is full you are more efficient for the work being performed.
    Most of the energy goes into moving the actual machine, only a small fraction goes into moving its content.

    That is why the Train shipping companies advertise 1 gallon of fuel, for 500 miles per Ton of goods.
     

    --
    If something is so important that you feel the need to post it on the internet... It probably isn't that important.
  5. This is stupid by pem · · Score: 5, Insightful

    Either compare flying a small plane to driving a car, or compare a huge bus to a plane.

    1. Re:This is stupid by Anonymous Coward · · Score: 2, Interesting

      Any forms of travel from point A to point B should be valid for study. If I have to travel alone 800 miles it's good to know the options for energy efficiency. Do I rent a fuel-efficient car? Do I simply fly? Do I hop on a bus? It doesn't nothing for me to only study the difference between vehicles of the same size.

    2. Re:This is stupid by Anonymous Coward · · Score: 0

      The other obvious problem with comparisons like this is that flying gets you to and from an airport. For most of us, that isn't the start and end of the journey, so flying is never the complete picture. Most of us still need to do part of the jouney by car, so to do a proper comparison, you really need to factor that in because it is significant: personally, I need to drive for an hour and a half to get to a major airport, so for any point-to-point journey it's never going to just be a flight on it's own.

    3. Re:This is stupid by houghi · · Score: 2

      It is called a train, not a huge bus. 300 people is about 6 busses.
      The TGV is about 300 people and does Amsterdam, Paris. Other trains are similar. Those should be better to compare with as they are direct competitors of planes.

      --
      Don't fight for your country, if your country does not fight for you.
    4. Re:This is stupid by avandesande · · Score: 2

      Actually small planes aren't that bad- you can get 20-25 mpg at a ground equivalent of 100 mph. Figure that you are going on a straight path and the economics look pretty good.

      --
      love is just extroverted narcissism
    5. Re:This is stupid by k6mfw · · Score: 1

      Either compare flying a small plane to driving a car,

      I remember seeing an advertisement in 1980s magazine comparing a small plane (Mooney I think) to a car:
      "Faster than a Porsche, fuel economy as a VW, luxurious as a Cadillac. It's the perfect car for business travel and yet it isn't a car at all."

      Article went on to say you don't have to worry about speeding tickets because when you fly you can go as fast as your equipment can do so. This seems such a distant world compared to these days. I also remembered browsing through Aviation Week looking at tables of small airplanes and helicopters, comparing range, payload, price, etc. Thinking about actually buying an airplane! When 1990s came along, poof! no more GA.

      --
      mfwright@batnet.com
    6. Re:This is stupid by BitZtream · · Score: 1

      Very true, it is worth nothing though that efficiency in the air is far more important financially than it is on the ground so while taking a bus is going to be WAY more efficient over all than flying or being the one person in the car you're driving ... Airplanes are typically more efficient than any land vehicle and we should actually try to be better at incorporating things the commercial airlines do into other mass transportation options

      With that said, fi that means we start using airlines for a guide to how the seats should be sized, I promise you the entire nation will just drive their own cars, in which case, it would be less efficient.

      --
      Persistent Volume manager for Kubernetes - https://github.com/dwimsey/openshift-pvmanager
    7. Re:This is stupid by bobbied · · Score: 1

      Either compare flying a small plane to driving a car, or compare a huge bus to a plane.

      Cessna 150's burn about 6-8 gal/hour depending on what you are doing. If you cruse at your most efficient RPM and lean the mixture, you can get about 80 MPH ground speed @ 7 gal/hour and carry 2 adults. This gets you about 11 MPG for the aircraft, or 22 Passenger miles/gal. (I may be wrong on my numbers but I'd be on the high side on fuel burn) Larger planes do better in the passenger mile and low wing aircraft with retractable gear which are more streamlined go faster on the same fuel burn and adding a constant speed prop and fuel injection gets you quite a bit more.

      My point here is that aircraft are not that bad compared to say an SUV, mini-van or pickup truck in terms of fuel efficiency.

      --
      "File to fit, pound to insert, paint to match" - Aircraft Maintenance 101
    8. Re:This is stupid by Anonymous Coward · · Score: 0

      I'll do so based on my personal numbers.

      a) going by my car. 1.5t empty, mixture of wagon and SUV (crossover), permanent all-wheel drive, 2.5l naturally aspirated gasoline engine. On the German autobahn she likes 20l/100km if I allow her to. That's average consumption, not peak during accelerations.

      b) going by my plane. Small 1t MTOM two-seater, 320 cubic-inch engine (very similar to the car, just bigger displacement and lower RPM - and technologically 50 years behind). At 28l/h she's doing 200km/h easily, that's 14l/100km.

      Hence, I can confirm the results of the study. Going by plane is more environmental friendly than going by car.
      (yes, I'm neglecting all sorts of facts, like what the car would drink going 55 or 65 mph (but that would be no real-live scenario), and that the plane needs leaded fuel, and produces pretty ugly exhaust gases, while the car produces mostly hot air.)

    9. Re:This is stupid by umafuckit · · Score: 1

      In Europe, yes, this is a useful comparison. In the US the train system is slow and crap and has poor coverage.

    10. Re:This is stupid by asylumx · · Score: 1

      It is called a train, not a huge bus. 300 people is about 6 busses.

      Buses. Yes, I know it's stupid, but that's how the English language determined that the plural of "bus" is spelled.

    11. Re:This is stupid by Anonymous Coward · · Score: 0

      Why not buy a less crappy car?

    12. Re:This is stupid by tweak13 · · Score: 1

      The Cessna 150 is a pretty terrible design. To be fair, it is really old and there have been a lot of advancements in aerodynamics, as well as in materials and construction techniques that make more efficient designs easier to make. A more modern two seat aircraft would get more like 150mph ground speed at 5 gallons per hour. That's 30mpg.

    13. Re:This is stupid by Anonymous Coward · · Score: 0

      Actually, no, both are accepted, though yours is the more popular:
      http://dictionary.reference.com/browse/busses
      http://grammarist.com/spelling/buses-busses/

    14. Re:This is stupid by Solandri · · Score: 1

      Either compare flying a small plane to driving a car, or compare a huge bus to a plane.

      No, you want to compare likely transportation alternatives. If you're going to go on vacation, a likely decision you'll face is whether to pay for airline tickets and fly, or pay for fuel (and possible rental) and drive. That makes the plane vs. car comparison completely valid. Same reason a car vs. bus comparison is valid for intra-city travel, even though you've defined them as being nothing like each other. In fact the bus vs. plane comparison is probably the least valid, since the vast majority of buses are used for intra-city mass transport, while the vast majority of planes are used for long-haul inter-city transport. So it's very rare (at least in a large country like the U.S.) for you to have to decide between taking the bus or taking the plane.

      Incidentally, I'm not sure why this is news. These types of comparisons have been done before. Trains win. Then planes, then cars, then buses, then way at the bottom are taxis (which is why "services" like Uber are a bad idea - you want to minimize the number of taxis driving around).

      Buses are rather interesting in that you'd think they'd score better than cars. But the fundamental problem you come across with mass transit buses is capacity vs convenience. You want to load each bus with as many people as possible to decrease its fuel consumption per passenger mile. But you also want to run the buses frequently so people aren't stuck waiting 45 minutes at a bus stop and instead decide to bum a ride from a friend or (worse yet) hail a cab. These conflicting demands mean you run the buses a lot more than would be ideal from an energy efficiency standpoint. Air travel avoids this problem by forcing people to adapt to the airline's schedule (other than a few shuttle services between well-traveled routes, and even those have mostly ceased service).

    15. Re:This is stupid by rsborg · · Score: 1

      Actually small planes aren't that bad- you can get 20-25 mpg at a ground equivalent of 100 mph. Figure that you are going on a straight path and the economics look pretty good.

      So you're only traveling between airports? What about commuting to/from the airport?

      --
      Make sure everyone's vote counts: Verified Voting
    16. Re:This is stupid by pem · · Score: 1

      No, you want to compare likely transportation alternatives. If you're going to go on vacation, a likely decision you'll face is whether to pay for airline tickets and fly, or pay for fuel (and possible rental) and drive.

      That's all well and good, but while you're making decisions, you'll also have to decide where you're going on that vacation. Maybe you decide to drive a couple of hundred miles, or maybe you decide to fly to Hawaii.

      These things don't happen in a vacuum -- well at least until the space plane becomes a reality -- so while it's entirely possible that, given the current infrastructure, if I want to get from point A to point B, flying may be more environmentally friendly, that's a marginal case. If all the planes disappeared tomorrow, what would that do to our energy consumption?

    17. Re:This is stupid by avandesande · · Score: 1

      I guess it depends where you are, in NM roads are sparse and sometimes geography gets in the way so in many cases a straight path can be significantly less. Most towns have small airports pretty close to them.
      There are many people here that commute Albuquerque to Los Alamos in small planes and it is a huge advantage in time and cost(at least fuel).

      --
      love is just extroverted narcissism
    18. Re:This is stupid by ebvwfbw · · Score: 1

      You're crazy. That aircraft is
      1) very expensive
      2) can carry about 300 lbs.
      3) isn't practical.

      I know, I spent about 2 years looking into them. There are a LOT of gotchas. Some very expensive gotchas.

      I own one of the best ones going. A 1950s Bonanza. I get 170 MPH at 11 GPH. I can carry about 950 Lbs. That includes fuel and I have a 3.5 hour range. Even so at best I'm 17 MPG. My very best I had a 150 Kts tailwind so about double that. Most other planes are MUCH worse. Especially if you have a twin.

  6. BTUs per mile? by Anonymous Coward · · Score: 0

    I'm the guy who always argues with the folks who say everything should be in metric, but these really are stupid units to use.
    Next up, gas mileage in rods per hogshead.

    1. Re:BTUs per mile? by Anonymous Coward · · Score: 0

      4,211 BTUs per person mile = 2760 newtons per person
      1,100 BTUs per person mile = 721 newtons per person

      Much more intuitive.

    2. Re:BTUs per mile? by fnj · · Score: 1

      Newton is a unit of force. BTU is a unit of energy. You should be using megajoules.

      1 BTU = 0.001055055853 MJ, or 1000 BTU = 1.055055853 MJ
      1000 BTU per person mile = 0.6555813132 MJ/passenger-km

    3. Re:BTUs per mile? by Anonymous Coward · · Score: 0

      You don't get it. GP took it a step further and turned J/m into N.

    4. Re:BTUs per mile? by Anonymous Coward · · Score: 0

      So a BTU is approximately a kJ? Sounds like a good shortcut to me.

      You metric twits don't understand just how little anyone cares about precision for quick estimates like this. It's not like we're sending this shit to the moon and need 28 digits of precision.

  7. Oh no by Anonymous Coward · · Score: 0

    All those idiots who were crying about bill nye flying on airforce 1 will have to find some more science to deny.

  8. Now Factor in... by Anonymous Coward · · Score: 3, Insightful

    Being Robbed by the TSA, Groped and Accosted, or Simply not allowed to fly at all because of your views on social media.
    I'd rather drive or walk...

    1. Re:Now Factor in... by thegarbz · · Score: 1

      I tried walking from Australia to Europe once. Made it 100m down the road and then thought I'd rather get fondled.

  9. to drive by Ubi_NL · · Score: 2

    > One factoid is interesting: it takes 4,211 BTUs per person mile to drive.

    do we all drive the same car? Is this a chevy suburban or a fiat punto?

    --

    If an experiment works, something has gone wrong.
    1. Re:to drive by Anonymous Coward · · Score: 0

      And what about two people in the car? Is it 8,422 BTU? Does the energy required by the car's weight get counted twice, or was it not counted in the first place?

    2. Re:to drive by NatasRevol · · Score: 1

      Apparently you haven't heard of averages.

      --
      There are two types of people in the world: Those who crave closure
    3. Re:to drive by Anonymous Coward · · Score: 0

      Let me guess: they used the average number of people in cars, and assumed that an average dominated by commuters (who obviously can't fly to work) applies for long road trips?

    4. Re:to drive by jfengel · · Score: 1

      Averages are clearer when the correct number of significant figures is used. It's not meaningful to give four significant figures for an average that's supposed to stand in for a wide range of values. At best it's really just an order of magnitude.

      And while I don't doubt the number, it does imply that they're not careful with their methodology, which makes it harder to put a lot of weight on it. It would have been better with just one or two digits of precision, or (if they wanted to spend the extra space on it) with a description of the range.

    5. Re:to drive by NixieBunny · · Score: 2

      I've heard of averages, but "4211 BTUs per person" is meaningless. I often drive either my 1958 V8 Chevy by myself, or my Prius full of 4 kids and me. Neither uses 4211 BTUs per passenger mile, or anywhere near it. Same thing with buses. In Tucson, buses often have 2 or 3 passengers. My Prius beats those by a lot. Commercial aircraft are the only vehicles that have a fairly consistent passenger mileage, because they are always full and all are designed to fly with about the same efficiency.

      --
      The determined Real Programmer can write Fortran programs in any language.
    6. Re:to drive by bobbied · · Score: 1

      That's mean to you buddy.... Or is that median.... (smile)

      --
      "File to fit, pound to insert, paint to match" - Aircraft Maintenance 101
    7. Re:to drive by Anonymous Coward · · Score: 0

      Could be mode.

  10. Nuclear planes by Anonymous Coward · · Score: 0

    Nuclear powered propeller planes would work.

    1. Re:Nuclear planes by Anonymous Coward · · Score: 0

      Hell of a lot easier to find the sunken wreckage too :)

    2. Re:Nuclear planes by Rei · · Score: 1

      Before ICBMs became a reality, nuclear-powered planes were significantly researched. Probably the craziest was Project Pluto, whose concept was to have an open to the air nuclear core inside a ramjet housing, acting as the heat source instead of combusting fuel. The unmanned craft was designed to be able to fly around for months at a time holding numerous atomic bombs. When given orders to attack it would have bombed Soviet cities... then with its cargo spent, continued the rest of its lifespan flying low over Soviet territory damaging everything its path with sonic booms and the radioactive plume spewing out the back. Then when finally shot down or out of power, it'd crash as a dirty bomb in Soviet territory.

      The engine was actually tested on a railcar, but there were way too many concerns about the craft, and the advancement of ICBMs just seemed a better route. Among the many concerns was that the US didn't want the Soviets to feel that they had to develop a similar such craft as a countermeasure.

      --
      "...but Republicans plan to come back with a new plan, where they just slash the tires on all the ambulances."
    3. Re:Nuclear planes by Anonymous Coward · · Score: 0

      Why are plane sonic booms more damaging than sonic booms from lightning?

      I've heard and have been close to dozens of sonic booms from aircraft (and the space shuttle), but have never experienced one that came close to the power of a lightning strike from .5km away.

    4. Re:Nuclear planes by Sique · · Score: 2

      Probably no, as about 10 inches of water shield nearly all radiation that comes from the wreck of the plane.

      --
      .sig: Sique *sigh*
  11. Carpool by hawguy · · Score: 1

    When I travel far enough to fly, I don't usually travel by myself, I'm usually on vacation with family or on a business trip with coworkers, so by adding just one person to the car, that makes driving and flying almost equivalent -- probably even moreso since I can drive from my house directly to my destination instead of driving 20 miles to the airport on one end, then another 30 miles on the other end.

    1. Re:Carpool by Anonymous Coward · · Score: 0

      Depending on the distance traveled adding just one person doesn't quite bring it to parity cost wise, when we looked at this option the cost in fuel was nearly that of the price of the two round trip tickets. Once you then add that we'd need to overnight at a hotel at least twice on the way there (24 hour drive) and then again on the way back that wiped out even the savings of not needing to rent a car at our destination. (Yes we could take turns over and over but eventually someone is going to be worn out, very cranky, and maybe crash the car.)

      Now if you have three or more people in the car it starts to save money, especially on a family trip with young kids who are going to be sharing the hotel room with you anyways.

  12. Al Gore by Anonymous Coward · · Score: 0

    So, who is going to be the first person to apologise to Al Gore for riding a private jet?

    1. Re:Al Gore by Anonymous Coward · · Score: 0

      PRIVATE jet. As in, you don't have 100+ people on it, so any per-passenger efficiency that an airliner would have doesn't apply.

      The "Al Gore's a hippy-crit 'cause he flies in one 'a dem fancy airy-o-planes, hyuck hyuck!" thing is stupid, yes, but for completely different reasons.

  13. Electric planes? by Anonymous Coward · · Score: 1

    They already exist - http://www.washingtonpost.com/news/morning-mix/wp/2014/06/02/meet-solar-impulse-2-the-solar-powered-plane-that-never-has-to-land/

    I don't think they'll ever be practical though, batteries are heavy, and they aren't fast enough.

    1. Re:Electric planes? by Anonymous Coward · · Score: 0

      "practical" is an understatement. Solar Impulse can only fly between 30 and 60 mph, despite its massive size (236') it can only carry a single passenger and requires extremely favorable conditions for takeoff.

    2. Re:Electric planes? by Rei · · Score: 2

      "Fast" is not an issue. Electric motors have a much better power to weight ratio than combustion motors, and li-ion batteries have no trouble feeding it. The reason things like solar impulse fly slowly is to reduce air resistance and thus minimize their power consumption needs.

      Batteries have advanced tremendously in the past several decades and show no signs of slowing down. The transition of air travel will be more difficult and longer in the making than that of ground travel, mind you.

      --
      "...but Republicans plan to come back with a new plan, where they just slash the tires on all the ambulances."
    3. Re:Electric planes? by Yoda222 · · Score: 1

      requires extremely favorable conditions for takeoff.

      If you can flight forever, who cares ? You only need to takeoff once.

    4. Re:Electric planes? by Anonymous Coward · · Score: 1

      Being able to fly forever isn't really much of an advantage for the purposes of transportation unless your beginning and destination are also perpetually in flight.

    5. Re:Electric planes? by Anonymous Coward · · Score: 0

      The problem with electric vehicles is that the amount of energy that can be stored in batteries given a certain volume or weight is quite a bit less than conventional fuels. Given that volume and weight is a big design consideration for most aircraft (as is refuel time for most commercial aircraft), yes, transition for air travel will take a while.

  14. Fly me... by gti_guy · · Score: 1

    "Fly me to the supermarket.... I need some milk."

    1. Re:Fly me... by Bruinwar · · Score: 1

      Walk.

      --
      SLOWER TRAFFIC KEEP RIGHT
    2. Re:Fly me... by blue9steel · · Score: 2

      What third world hell hole do you live in where they still build grocery stores within walking distance?

    3. Re:Fly me... by Anonymous Coward · · Score: 0

      What third world hell hole do you live in where they still build grocery stores within walking distance?

      Pittsburgh. It's pretty rough.

  15. Fly me... by gti_guy · · Score: 1

    "Fly me to the supermarket.... I need to buy some milk."

  16. Well then... by mitcheli · · Score: 1

    When are we going to do something about the price and make it more competitive to driving?

    --
    Select from tblFriends where interesting >= 4;
    1. Re:Well then... by Anonymous Coward · · Score: 0

      Flying is already cheaper than driving. How much more competetive do you want it?

  17. Time for a new plane by mysidia · · Score: 1

    That circles around towns lowering 'hooks' to grab people at designated points, pick them up, whisks them through the air aways -- without having to load them up into a cabin, and drops them off at their destination when they push their personal 'eject' button.

    1. Re:Time for a new plane by Rei · · Score: 1

      I'd have trouble being whisked around town dangling from a drone under my command without also being in a superhero costume.

      Seriously, in our modern age, how else would a superhero get around? A fast car? Pish.

      --
      "...but Republicans plan to come back with a new plan, where they just slash the tires on all the ambulances."
  18. Bus Logic by WoodburyMan · · Score: 2

    Since when has traveling by car and plane been comparable? For long distances, I suppose. I'm not going to drive between NYC and LA. But on a daily basis it is not. Compare Plane Travel to Boat travel maybe, especially cargo. Or compare planes to trains. Cars should be compared to buses. Same travel medium, more directly comparable. Most cities, at least near me, have moved to around 50% mix of hybrid buses and eco-diesel buses. With that the numbers would be interesting to see.

    1. Re:Bus Logic by Sique · · Score: 1
      From the beginning of both the plane and the car.

      You can always look at the options. Is it feasible to fly to the local supermarket? If you have a helicopter, maybe it is. Does it make sense? Except for the ego boosting factor, probably not. Is it possible to drive from New York to Paris, France? If you get your car on a freight ship, it is. Does it make sense? In most cases, not, except you want that car to be in Paris for some reason.

      So yes, flying and driving by car are comparable. In many cases, there is a clear winner. But in a lot of other cases, there are several factors to consider until the best option can be determined.

      --
      .sig: Sique *sigh*
    2. Re:Bus Logic by AthanasiusKircher · · Score: 1

      Since when has traveling by car and plane been comparable? For long distances, I suppose. I'm not going to drive between NYC and LA. But on a daily basis it is not.

      The issue, I imagine, mostly has to do with environmentalists' concern about the inefficiency of plane travel in general. Environmentalists tend to criticize speakers who jet around the world frequently for example. For another example, I've seen a number of conferences in recent years that have tried to encourage "remote participation" via Skype or some other video conferencing tools to avoid perceived waste for travel.

      For many such people, traveling medium-length distances by car has traditionally seemed the more "environmental" choice. They may not drive from NYC to LA, but they might drive between cities in the Northeast rather than fly if driving were "better for the environment." I think the common perception for decades among environmentalists is that "flying is always bad." TFA suggests that is probably an inaccurate generalization, though it's not a new observation.

  19. What about Infrastructure? by ichabod801 · · Score: 1

    Are airports more efficient than interstates in terms of infrastructure costs? And I read somewhere (Freakonomics?) that there are seven parking spaces per car in the U.S. Is that the same for airplanes?

    1. Re:What about Infrastructure? by bobbied · · Score: 1

      Are airports more efficient than interstates in terms of infrastructure costs? And I read somewhere (Freakonomics?) that there are seven parking spaces per car in the U.S. Is that the same for airplanes?

      Actually, there are about 5 airplanes per parking space, especially for commercial aircraft.

      On 9/11 I lived near Wichita KS's airport. They have about 4 gates, but we had over 20 large aircraft parked all over the place. The parking logistics where quite something to see, but it shows that we have a lot more commercial aircraft than gates to park them at.

      For light aircraft, they stay parked more than not, so the parking space to aircraft ratio is nearly 1 to 1, with there being more parking than aircraft.

      --
      "File to fit, pound to insert, paint to match" - Aircraft Maintenance 101
  20. Who uses BTUs by ender06 · · Score: 1

    Why does this use BTUs and not MJ or kWh? 4211 BTU = 4.44 MJ or 1.234 kWh. Real units.

    1. Re:Who uses BTUs by Anonymous Coward · · Score: 0

      Because those "real units" are metric. Americans deal in miles, pounds, and degrees Fahrenheit.

    2. Re:Who uses BTUs by Anonymous Coward · · Score: 0

      Don't forget libraries of congress.

  21. what gets poluted might matter by Anonymous Coward · · Score: 0

    Sure its more fuel efficient. But do we prefer our pollution injected directly into the stratosphere? Doesn't that have different effects than polultion at ground level?

    1. Re:what gets poluted might matter by Anonymous Coward · · Score: 0

      Isn't pollution bad no matter where its being deposited?

  22. Wow by Anonymous Coward · · Score: 0

    "future aircraft be able to also make the switch to electric"

    Wow, that statement is almost painful. NO, there is no chance of future commercial aircraft switching over to electric. There is simply no way to match the performance of a fuel driven turbine with an electric driven system even delving into theoretical technology that we know of. Small prop driven aircraft MAYBE, if there is some insane breakthrough in battery technology but not large aircraft.

    1. Re:Wow by Rei · · Score: 2

      Small prop driven aircraft, ALREADY.

      The market was almost nonexistent about five years ago but it's growing quite fast. Don't underestimate what the major and ongoing advances in motors, controllers, and batteries will bring in the future. There's many radically new technologies in the works to partially or completely electrify aircraft transportation, far beyond just electrically driven propellers.

      --
      "...but Republicans plan to come back with a new plan, where they just slash the tires on all the ambulances."
    2. Re:Wow by Anonymous Coward · · Score: 0

      As I said, small prop drive aircraft maybe. But all of the current ones run for 2 hours MAX under optimal situations and if you are very frugal with the throttle, if you push the throttle and if you're fighting headwinds they can deplete the batteries in 15 minutes and neither of those leave any reserve power. Your average Cessna can fly for 3-5 hours at 80% throttle and still have 30-45 minutes of fuel left for emergency situations.

    3. Re:Wow by tweak13 · · Score: 1

      Your link to mh-aerotools.de pretty clearly illustrates why this isn't going to be happening to commercial aircraft anytime soon. By making some fairly absurd assumptions about efficiency gains from changing aircraft design (and ignoring all aspects of aircraft design other than efficiency) you still need batteries that have 6x the energy density of modern technologies. Using some numbers that might actually be realistic and you'd need more like 10x the energy density.

  23. Re:Masstransit is more energy efficient than perso by Anonymous Coward · · Score: 1

    They need to define the "minimum cost", ie the part the doesn't change regardless of distance.

    For airplanes that would be takeoff and landing, as they have to do that no matter where they go or for what distance. Additionally it's usually the most energy intensive part of the flight (since they rarely fly at max speed/power). So determine that cost, and you can determine the minimum distance below which cars are more efficient (ignoring logistics for the moment).

    Another thing I find interesting, they say its basically a 2:1 ratio....so what about a full car? wouldn't that flip the relationship back in favor of the car and be more efficient than a plane?

  24. On other words by Anonymous Coward · · Score: 0

    I suppose that we are supposed to take a 737 to our daily job then??

    Let's re-arrange the deck chairs on the Titanic to make the band more comfortable, as global warming continues to beat down on us.

  25. "results may vary" by QuietLagoon · · Score: 1
    Yes, the results may vary.

    .
    Yet the study picked the best of air travel and compared it to the worst of road-based travel.

    I wonder how efficient it would be for me to fly from my house to the supermarket (a mile away), or any of the other numerous trips I make via automobile?

    Let me see, first I have to drive three miles to the nearest airport. Get in a plane. Take off. Land at the same airport. Then drive four miles to the supermarket.

    Yeah, that's more efficient than driving.

    1. Re: "results may vary" by Anonymous Coward · · Score: 0

      Stop trolling, energy efficiency questions obviously don't matter to a fat lazy asshole who drives a car for a 1 mi trip to the store.

  26. Show me the math on the Tesla. by dbc · · Score: 4, Insightful

    Show me the math for both ICE cars and Tesla, from well-head to road. Because generating electricity takes energy, and there are losses in the distribution system, and the charging systems are not 100% efficient either. Of course, getting oil out of the ground, refining it into gasoline, and moving the gasoline to refueling stations takes energy, too. Show me the end-to-end math, and then let's talk. A 4:1 advantage for the Tesla seems optimistic to me.

    I have the same gripe with calling Teslas "zero emission vehicles". They are not. They are "displaced emission vehicles". Of course, it is easier to control pollution at a single point, and pollution controls scale up quite well, so the overall emissions are less for a Tesla versus an ICE vehicle. But don't claim the emissions are zero, they are just someplace else. (And I will grant that there are benefits to simply displacing emissions -- the Los Angeles valley, for instance, is a bowl, and so pollution tends to hang around in the air for a long time certain months of the year. Displacing the emissions outside the bowl has it's own benefits.)

    1. Re:Show me the math on the Tesla. by amorsen · · Score: 2

      That would be pointless because practically no one uses oil to produce electricity. Electric cars tend to charge at night where the coal plants are running at very low power and low efficiency. An idling coal plant has a very high average pollution per kWh produced but a very low marginal pollution per extra kWh.

      Of course if it is a windy night the coal plants might just give up and shut down overnight, and then you really get your zero emissions.

      --
      Finally! A year of moderation! Ready for 2019?
    2. Re:Show me the math on the Tesla. by tomhath · · Score: 1

      practically no one uses oil to produce electricity

      But practically everyone uses natural gas and/or coal. so the point is well taken.

      Of course if it is a windy night the coal plants might just give up and shut down overnight

      You can't "just shutdown" a coal fired generation plant. What you can do is dump the excess power to ground.

    3. Re:Show me the math on the Tesla. by dbc · · Score: 1

      Not pointless -- convert everything to BTU's. The electricity has to come from somewhere. And there are distribution system losses, which for electricity are considerable. Show me BTU's end-to-end.

    4. Re:Show me the math on the Tesla. by jeff4747 · · Score: 1

      Coal plants can't idle. They're either running at or near capacity, or shut down. And they do not shut down overnight, because it takes about 3 days for them to get up to operating temperature. This is why coal power plants will sell electricity at a loss overnight.

      That's also why most coal power plants in the US are getting replaced with natural gas power plants. A natural gas power plant is basically a helicopter engine connected to a generator. You can throttle it up and down somewhat, and you can start it up in minutes instead of days. And thanks to the "wonders" of fracking, we have a lot of very cheap natural gas.

    5. Re:Show me the math on the Tesla. by Overzeetop · · Score: 1

      I would be skeptical as well, however the Tesla is very easy to check. From the top link on Google:
      "[the range of the Model S] 85 kWh battery pack is 265 miles"

        86,000Wh x 3.41 BTU/Wh / 265 miles = 1107 BTU per mile

      I'm going to say that their claim is "accurate" based on a very simplistic level. As you point out, there are efficiency losses in generation, transmission, and charging.

      Now, if you use the EIA rates (http://www.eia.gov/tools/faqs/faq.cfm?id=667&t=3) for power generation, it's more like 10 BTU/Watt, which puts the tesla up to 3300 BTU per mile (ballpark), and still doesn't include transmission or charging losses. Of course, whether you're burning coal for that 10BTU or allowing fissile decomposition for that 10BTU makes a pretty big difference in the type of pollution you're going to have as a byproduct. (that's another argument, of course).

      --
      Is it just my observation, or are there way too many stupid people in the world?
    6. Re:Show me the math on the Tesla. by radl33t · · Score: 1

      Your "well" distinction is just as arbitrary as the one you criticize. Why stop at the well? Fossil fuels are just a stop gap storage of extremely long geological processes that we are exploiting at an unsustainable rate. Eventually most of it comes down to solar energy for the earth system, or galactic/universal processes on larger scales.

      Compare a Tesla from a solar panel to the fossil fuel pathway of ICE starting from algae 300,000,000 years ago. They share the sun's photons as a common ancestor. I have a feeling the Tesla will show a significantly greater than 4:1 advantage to ICE......,

    7. Re:Show me the math on the Tesla. by Gordo_1 · · Score: 1

      Well, it all depends on where you're talking about. The thing electrics have going for them is that *if* you can move toward clean/renewable sources of electricity, then you're doing more than displacing pollution by going electric. For example in California, less than 10% of electricity comes from coal (http://energyalmanac.ca.gov/electricity/total_system_power.html) and almost half is natural gas, which is somewhat "cleaner" than gasoline, all factors in.

      And with solar on it's current growth trajectory (http://energyalmanac.ca.gov/electricity/electricity_generation.html) it could rival natural gas for top dog in as little as a decade.

    8. Re:Show me the math on the Tesla. by Ichijo · · Score: 1

      Show me the math for both ICE cars and Tesla, from well-head to road.

      The math is here, showing that where you drive is as important as what you drive. But as a sibling post notes, even this math doesn't count the energy required to produce gasoline from scratch.

      --
      Any sufficiently unpopular but cohesive argument is indistinguishable from trolling.
    9. Re:Show me the math on the Tesla. by Anonymous Coward · · Score: 0

      The car *is* zero emission in the same way a bicycle is, or are we going to start pointing out that riding a bike to work sometimes means the rider has to consume more food and that's also bad for the environment?

    10. Re:Show me the math on the Tesla. by Anonymous Coward · · Score: 0

      I have the same gripe with calling Teslas "zero emission vehicles". They are not.

      They are. The vehicle itself emits zero combustion byproducts or pollutants.

      Nobody is pretending there isn't any environmental impact from electric cars overall, but the day-to-day operation of the car is not the source of any environmental impact whatsoever. And last I checked, we were burning coal to generate electricity long before electric cars existed. The net increase in pollution is so close to zero as to be equivalent.

    11. Re:Show me the math on the Tesla. by Anonymous Coward · · Score: 1

      Why BTU's instead of normal units?

    12. Re:Show me the math on the Tesla. by Solandri · · Score: 1

      Show me the math for both ICE cars and Tesla, from well-head to road. Because generating electricity takes energy, and there are losses in the distribution system, and the charging systems are not 100% efficient either.

      Sorry for the repost. This is probably a better place for this.

      The 1100 BTU/mi figure is consistent with the efficiency of a ICE vehicle from crankshaft to wheels. It takes about 20-25 hp to push a ICE vehicle at 60 mph. So in an hour it will burn 53.7-67.1 MJ. Since it travels 60 miles in that hour, that works out to 0.89-1.12 MJ/mile. Or 848-1060 BTU/mile at highway speeds.

      If you factor in other losses for the Tesla, add in a 40% efficient coal plant generating the electricity, 97% transmission efficiency over high-power electrical lines, and 75% charging efficiency and the Tesla actually uses 1100 / (.4*.97*.75) = 3780 BTU per vehicle mile. So it's actually not much different from an ICE from an energy consumption standpoint. (There are discharge losses too, but since the 1100 BTU/mi figure was apparently derived from a 85 kWh battery and 265 mile range, the discharge losses are already included.)

      The vast majority of the reason an EV is cheaper to operate is because coal is so much cheaper than gasoline. Coal costs about $50 per ton. A ton of coal has approximately 24 GJ of energy. That's about 0.21 cents/MJ. Gasoline costs about $3/gallon, and has about 120 MJ/gallon, or 2.5 cents/MJ. For the same amount of energy, coal is an order of magnitude cheaper than gasoline, which gives the EV a huge advantage in terms of operating costs. This is not a bad thing - being able to transfer a cheaper but traditionally static energy source into use in a mobile application is an economic win. But don't confuse it for better efficiency.

      Yes you could argue that we can make electricity from renewables. But the vast majority of the cost of renewables is in the initial production of the turbine or PV panels. Operating costs are nearly nil (limited to maintenance). So for a fair comparison you then need to incorporate production and transport costs. At which point renewables lose because on a per Joule delivered basis, even with coal plants being only 40% efficient, coal is still cheaper than wind and solar power. (Wind is only about twice the cost of coal, so cheaper than gasoline, but I suspect solar would be about the same cost as gasoline.) You need to incorporate cost of harm done by pollution for renewables to pull ahead. (And even then, only hydro, wind, and geothermal. PV solar still has a ways to go.)

    13. Re:Show me the math on the Tesla. by bill_mcgonigle · · Score: 1

      and don't forget that most wealth is generated by engaging in activities with energy requirements.

      That Tesla 80D Insane Edition that I want takes $115K worth of economic profit to acquire, which in most industries requires 5-20x as much revenue. So over a million dollars worth of economic activity on average to just get that Tesla before you can drive it. Is that greener than a Fiesta?

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    14. Re:Show me the math on the Tesla. by Anonymous Coward · · Score: 0

      Show me the end-to-end math, and then let's talk. A 4:1 advantage for the Tesla seems optimistic to me.

      I can't give you end-to-end math, but I can give you some numbers that give a general impression. An internal combustion engine is ~20% efficient under typical usage patterns, and a coal power plant is ~33% efficient. (Gas power plants can be ~60% efficient, but most power doesn't come from them.) Electricity transmission, battery charging and an electric motor are all going to be ~90% efficient, so a coal-charged electric car is going to come out ahead of an ICE car (33*0.9*0.9*0.9 = 24 > 20), even if we ignore oil-drilling, gasoline refining and transportation. But I very much doubt that these losses are enough to reduce the ICE car to 1/4 of an electric car's efficiency.

      Two important factors I've left out. The first, assuming we're concerned with greenhouse gas emissions, is the CO2 emitted per Joule of enthalpy in the combustion of gasoline versus coal. I don't know which way this is likely to go ... call it a wash. The second is regenerative braking, which is a huge (factor of 2?) advantage in stop-start traffic - but hybrid vehicles get this advantage too, so it's only an advantage over conventional ICE vehicles.

    15. Re:Show me the math on the Tesla. by amorsen · · Score: 1

      Coal plants are certainly capable of throttling their output and using less coal. But if what you say was true, my point would only be reinforced: Marginal CO2 emissions by using an extra kWh at night would be zero, because the grid would otherwise have to stabilize by dumping electricity in resistors.

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    16. Re:Show me the math on the Tesla. by Anonymous Coward · · Score: 0

      [...] of extremely long geological processes that we are exploiting at an unsustainable rate.

      Long-term unsustainable. Naturally (without living things) there's near-zero oxygen in the atmosphere. This allows a very simple estimation: There's as much hydro-carbon matter available to burn as there's oxygen in the atmosphere to do so.

      Of course, oxygen-breathing beings like us will go extinct, and plants will love the CO2 enriched atmosphere. Later, the cycle is going to start anew...

  27. Yeah. by Anonymous Coward · · Score: 5, Insightful

    Flying costs a lot more, and involves a period of being completely at the mercy of the no-background-check employees of the TSA.

    I don't care if it is green. The TSA is horrible. Get rid of it, and I might fly again. Until then, I will spring for the road trip.

    1. Re:Yeah. by Anonymous Coward · · Score: 0

      Flying costs a lot more

      Not if the car is not packed. For a single person, driving the same trip is typically at least twice as expensive.

  28. Flying? by Anonymous Coward · · Score: 0

    The heck with flying. When are we going to get teleportation!

  29. Most electric cars are powered by burning coal ... by brainchill · · Score: 1

    Exactly how will switching over to electric power lower the # of BTUs required when what we're talking about here is switching over to a less efficient medium of energy transfer IE Continually shoving coal into a furnace to create heat that spins a turbine that produces electricity vs a single gallon of gas creating an explosion that could take you 50+ miles depending on the efficiency of your vehicle.

  30. I just flew in from Cleveland.... by lurking_giant · · Score: 1

    ...and boy are my arms tired!

  31. BTUs is one thing by fustakrakich · · Score: 3, Insightful

    I also value my time, which I don't want to waste on a 200 mile trip waiting in line, and security theater

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  32. per passanger mile is useless metric by u19925 · · Score: 1

    This is absolutely useless metric. How about taking your clothes to dry cleaner or doing grocery using a plane? Cars are efficient compared to planes for the purposes where cars are used. Sometimes I go from SF to LA and I rarely see another car with a single passenger. This is the case where a plane can replace cars but even in this case planes would be inefficient once you take into account 3 passengers per car, 90% plane occupancy and take off, landing and airport infrastructure energy usage (even with the most modern energy efficient aircraft). So on case by case basis, planes will almost always lose if they try to replace the cars. Vice versa, cars may lose if they try to replace planes in many cases.

    1. Re:per passanger mile is useless metric by Anonymous Coward · · Score: 0

      Yeah, I'm not feeling any better about my carbon footprint caused by the 500,000+ miles I've flown in the last eight years. Compare that to 135,000 km driven in the same time (ok, I do live in a big city and prefer to cycle).

    2. Re:per passanger mile is useless metric by Anonymous Coward · · Score: 0

      This is absolutely useless metric. How about taking your clothes to dry cleaner or doing grocery using a plane? Cars are efficient compared to planes for the purposes where cars are used.

      For grocery or taking my clothes to the dry cleaner, I don't need to take a plane, or a car. I just use two legs. (but I agree with the general idea of your post. Plane and car are not used for the same purpose)

  33. Re:Masstransit is more energy efficient than perso by amorsen · · Score: 1

    Most other forms of transport have no chance against a decent modern passenger car with 4+ passengers. Most passenger cars are comparatively light, well below 500kg per passenger, which is very hard to beat. They do that because there is hardly any wasted space. A bus needs a walkway and it has to be tall enough to stand in, and trains are just horrendously heavy. While rubber-on-tarmac is a bit wasteful compared to metal-on-metal, it is not that bad, and the lower weight helps a lot.

    Electric trains can sometimes play in that efficiency range, but it is tempting to make them faster and then the savings mostly evaporate. Cars are useful despite their lower speeds because of the time saved by almost going door-to-door.

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  34. Very myopic study by Anonymous Coward · · Score: 0

    High flying jets cause high clouds which in turn causes more heating of the atmosphere. https://earthdata.nasa.gov/featured-stories/featured-research/trail-contrails
    And electric cars are actually more damaging to the environment in total that modern gasoline burning cars due to the significant environment damage cause just making the batteries.

    1. Re:Very myopic study by Yoda222 · · Score: 1

      "“When you consider all of the man-made radiative forcing and all the changes we’re making that can affect climate, contrails are one of the smaller effects, compared to carbon dioxide and other emissions,” Spangenberg said. “Globally, you would have to increase the contrail effect by roughly 100 times to get the same effect as all of the anthropogenic carbon dioxide in the atmosphere.”"

  35. Re:Masstransit is more energy efficient than perso by Anonymous Coward · · Score: 0

    Agreed. Well, with a train you also don't have the rolling resistance of soft rubber tires (if power were cut, a train would roll a hell of a lot longer than any truck).

    I remember reading that a plane needs a much smaller engine to get much faster than a car. What was it? Like a 50HP one to get up to 150mph vs whatever a car would need? Whatever the exact number, a plane ultimately just has a lot less pushback in forms of various forms of friction and resistance than a car does. It's just fighting the air and in a (hopefully) streamlined form. A car is fighting the air in a less than optimized form (the bottom is generally not contoured at all) plus the ground.

    Ah, if we only could have some type of personal hybrid quadrocopters for landing and takeoff that converted to gliders.

  36. BTUs? by JBMcB · · Score: 1

    Why is energy here measured in BTUs? I've usually seen total energy use expressed in Watts, especially in the mechanical realm.

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    1. Re:BTUs? by Gramie2 · · Score: 1

      Maybe because Watts are a unit of power, not energy. This is a U.S. report, so they tend to use Imperial units. 4,211 BTU works out to 4.4 MJ (MegaJoules). In Chrome I didn't even have to finish typing in "4211 BTU in Joules" before it gave me the answer.

    2. Re:BTUs? by JBMcB · · Score: 1

      I'm sorry I forgot to put the /h after Watt.

      Seriously, I've never seen mechanical energy expressed in BTUs, and I'm in the US. I know a few automotive engineers and they use W/h when calculating engine efficiency.

      --
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    3. Re:BTUs? by sl3xd · · Score: 1

      The thing is average Americans don't use BTU's either. MegaJoules are every bit as abstract and unfamiliar.

      The only things I see in "everyday" use for the BTU: Cooking stoves and window air conditioners -- things you don't buy or compare often. . In both cases, it's not "meaningful" other than a higher number is more powerful.

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    4. Re:BTUs? by radl33t · · Score: 1

      it isn't common, but it is correct in this unit system. It is often replaced in favor of W (kWh) when dealing with electrical systems. IMO, its more irritating and prone to error when multiple unit systems are used simultaneously. kWhs are not used here probably because they likely deal with source fuel & combustion calculations, which is expressed in the US as BTUs or in SI as Joules. Watt hours are a contrived unit anyway, I don't know why anyone would make efficiency calculations using them when the final answer is dimensionless and they would just be adding a needless constants into their equations.

      by the way, the unit is watt*hour
      Power*time = energy.

    5. Re:BTUs? by Anonymous Coward · · Score: 0

      W/h is not an unit of energy, it's a rate of change in power. You probably want to say W.h

    6. Re:BTUs? by Anonymous Coward · · Score: 1

      I'm sorry I forgot to put the /h after Watt.

      That would've only made you twice as wrong. Watts are already Joules per second, a rate of energy consumption. Watts per hour would be "Joules per second per hour", or the rate at which the rate of energy consumption changes.

      You forgot to put the *h after Watt. That would then give you Joules times the number of hours per second, which is at least a measure of energy. Of course, you could just use Joules instead, as it's considerably less convoluted.

  37. Re:Masstransit is more energy efficient than perso by rwa2 · · Score: 1

    Not just that, there are a LOT of efficiencies that airplanes can take advantage of that are just not available to ground transportation. For distances above ~400 miles, air freight can be more efficient than even a freight train for hauling just about anything with a higher value per pound than rocks and gravel.

    * gas turbine engines can reach peak thermodynamic efficiencies of ~50% around 30,000 feet, where the intake air is coldest but not too thin. Any combustion engine running at surface conditions can do maybe 20 - 30% efficiency tops.
    * air at 30,000 feet is still thin enough to greatly reduce drag compared to ground transportation. Only the vacuum tube trains like Elon Musk's "Hyperloop" will be able to beat that ... at enormous expense.

    Not to mention all of the "bonus efficiencies" not related to lower ton-mile/fuel costs that you get "for free"
    * Time is money, and air freight also happens to be the fastest mode of transportation. It actually takes more fuel to cruise slower than the design cruise speed of Mach 0.84 or whatever.
    * just need an airport with a mile or two of runway at each end, no other infrastructure needs to be built between point A and point B
    * lots of old used passenger airplanes are refurbished for freight for relatively cheap at the end of their passenger service life
    * lots of excess airport capacity at night when the passengers aren't flooding them

    The "distances above 400 miles" is a pretty significant caveat, of course... that's roughly the break-even point for the extra fuel you need to get your cargo airplane up to 30,000 feet so you can save enough fuel during cruise/descent.

    Also, with electric batteries and brushless motors also gradually approaching 50% efficiency (when taking advantage of regenerative braking), ground transportation kinda has a shot at achieving gas-turbine-like energy efficiency... at sufficiently slow speeds to keep drag down.

    I highly recommend this book:
    http://mitpress.mit.edu/books/...

  38. It's a Complex World by firewrought · · Score: 2

    While interesting, this study is also sort of meaningless for making any sort of policy decision. I take far away vacations because the plane makes it possible. If planes weren't an option (due to price or policy), then I would shift to taking vacations closer to home (with maybe 1 trans-Atlantic cruise to explore Europe late in life), and my business travel would shift to teleconferencing. Would the resulting environmental footprint be better or worse? Hard to say. And presumably train usage would (after a few years of infrastructure investment) boom under this scenario, changing things again...

    There are too many variables interacting for this study to "prove" anything.

    --
    -1, Too Many Layers Of Abstraction
  39. What about the soot by waterford0069 · · Score: 1

    Purely energy wise, maybe, but what about the soot?

    I recall hearing that one of the issues with flying is the amount of soot that is left in the upper atmosphere by a jet. The net result being that flying across North America (NY - LA) caused more greenhouse warming than driving an SUV for a full year (say 20,000km). The very black soot put out over the flight (cumulatively) causes more warming than the exhausts from the SUV (which for various reasons is not exhausting all that soot)

    1. Re:What about the soot by FooAtWFU · · Score: 1

      I'm curious where you heard that, because my understanding had been that those upper-atmosphere particulates mitigated against global warming (mildly), much like the volcanic eruptions which periodically cause cold winters.

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    2. Re:What about the soot by waterford0069 · · Score: 1
    3. Re:What about the soot by waterford0069 · · Score: 1

      And much more so for con-trails vs. soot :

      http://en.wikipedia.org/wiki/E...

    4. Re:What about the soot by tweak13 · · Score: 1

      I had heard the same thing, that particulate matter in the atmosphere had a cooling effect.

      Usually when people are complaining about soot from airplanes, it's that we're dumping it on all the people living in the departure path of major airports. Which does seem to be a legitimate health concern.

  40. My research contradicts these results... by Anonymous Coward · · Score: 0

    Once I read this report, I decided to verify it with my own research project: I decided to compare the fuel usage between flying a plane from New York to London and driving a car from New York to London.

    At first glance, it seems obvious - since cars don't float they obviously win as they can't make the trip (no fuel used at all), but further investigation reveals the truth.

    I simply drove my car onto a ship, went to England, then drove from the port to London; the car hardly used any fuel at all.

    This conclusively proves that it is more efficient ('greener') to drive from New York to London than to fly.

  41. Quit yer bitchin' by Anonymous Coward · · Score: 0

    Complimentary luggage sorting and a free handjob with every flight, I always say!

    1. Re:Quit yer bitchin' by Anonymous Coward · · Score: 0

      Wear a kilt while flying. Both of the times I've done so since the TSA's creation I could have been smuggling a beach ball between my knees and they wouldn't have found it.

  42. Commercial air travel is actually pretty green. by Karmashock · · Score: 1

    At least from the perspective of it being very efficient. Planes burn a lot of fuel but they also complete their task very quickly.

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    1. Re:Commercial air travel is actually pretty green. by BUL2294 · · Score: 1

      Except there's one major problem with commercial air travel... With airline consolidation comes a reduced number of direct routes. This is where I think the authors' analysis falls flat. I believe they only considered direct routes in their comparisons. This is how one would travel in a car between cities. But with planes, hubs, and airlines' asinine pricing policies (e.g. I've seen Chicago to NYC direct round trip costing $100 more than Chicago-(Atlanta)-NYC), I think much of the BTU savings is actually negated if they were to take actual travel plans vs. "perceived" ones.

      Cities like Cleveland, which used to be a hub for Continental, went from numerous direct flights to most places in the country (and even internationally) to an abysmal few. If you didn't want to fly through a city or wanted to take a direct flight, you used to have MORE choices (e.g. use a different airline) as recently as 5 years ago. So, airline consolidation has made this worse--where if you don't live in a hub city (Chicago, Denver, Atlanta, NYC, etc.), then you are much more likely to not get a direct flight--using more fuel & "BTUs" in the process...

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    2. Re:Commercial air travel is actually pretty green. by Karmashock · · Score: 2

      The problem with your theory is that the primary cost to airlines IS fuel and they set up those routing systems to maximize the fuel economy of the whole network.

      The issue is the big jumbo jets when full of passengers are pretty much as efficient as it gets. Planes get less efficient per person as they get smaller.

      So the concept is that you have small planes FULL of people traveling to the nearest hub, then you have as many people as possible moved from Hub to Hub via a jumbo jet. And then finally you have any final leg of the trip handled by a smaller plane.

      The per person fuel economy would be lower if you had a small plane go directly from point A to point B over a long distance.

      Again, as evidence, the airlines cite fuel as their largest operating cost and it is in their interest to maximize the per passenger fuel economy because that translates directly into per passenger profit.

      The market is really quite good at managing these things. I don't know why people have such little confidence in it. You can see the effect of the market in streamlining things throughout our economy all the time.

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    3. Re:Commercial air travel is actually pretty green. by jonwil · · Score: 1

      If that was true, airlines wouldn't be changing any number of routes from having a few flights a day on big airplanes to having many flights a day on smaller planes.

    4. Re:Commercial air travel is actually pretty green. by Karmashock · · Score: 1

      They generally don't put people on lots of smaller planes if they have bigger planes they can fill. I don't know what you're talking about.

      Sometimes they might run out of the big planes and then they'll retask the smaller ones. But the bigger planes are much more efficient on a per passenger level for fuel economy.

      Do you want me to quote engineering specs at you for these planes or do you want to concede that I am correct and stop contradicting people that are right?

      Sorry... I find that annoying. :D

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  43. Re:Most electric cars are powered by burning coal by jeff4747 · · Score: 2

    Electric traction motors are far more efficient than ICEs. That's why diesel locomotives don't actually connect the diesel engine to the wheels. The diesel engine generates electricity, which turns electric traction motors.

    Same with the really big earthmoving equipment - those gigantic dump trucks down at the strip mine are using electric traction motors powered by diesel generators.

    Why don't we do this in cars? Space and complexity.

    So what's the point of all electric cars? It separates the energy generation from the energy consumption, allowing flexibility in the energy generation. That coal plant you decry is a lot more efficient than an ICE. And other electricity generation sources have other benefits. The problem has been getting the power from the power plant to the car so that you can use electric traction motors.

  44. Electric aircraft is like a sub with a screen door by Anonymous Coward · · Score: 0

    It is going to be more efficient to power a jet directly with a turbine engine than to burn natural gas via turbine, covert the motion of the turbine into electricity, send the electricity hundreds of miles, convert the electrical energy into chemical energy via charging the battery, reverse the process again convert chemical energy back into electrical energy, then finally convert the electricity into motion again. Each step of an energy conversion wastes energy. Jet engines are already quite efficient into converting fuel into thrust, much more so than a piston engine.

    There is also the problem of the power to weight ratio. The power to weight ratio for an electric powered aircraft is going to be lower than a turbine engine. That means more energy is going to be wasted keeping the batteries/motors aloft lowering the passenger capacity of the aircraft.

  45. Renewable and Nuclear Power by Roger+W+Moore · · Score: 4, Insightful

    I have the same gripe with calling Teslas "zero emission vehicles". They are not.

    True, but unlike petrol driven cars they could be. Both renewable and nuclear power power are zero carbon methods of generating power and while renewable has issues with cost, limited locations and variability if it were supplemented by nuclear we could significantly reduce greenhouse gas emissions. In fact if you charge your Tesla in France then 75% of that power comes from nuclear so you might not be zero emission but you will be getting close.

  46. Re:Masstransit is more energy efficient than perso by radl33t · · Score: 1

    any recent data to suggest that cars have bested are better than trains recently? I imagine aerodynamic losses per person is a greater handicap than friction for passenger vehicles (or greater advantage for trains).

  47. Re:Masstransit is more energy efficient than perso by Anonymous Coward · · Score: 0

    I don't actually agree that speed necessarily means a loss of efficiency.
    rather I do think that speed itself is another factor with its value.

    that is, I think that oftentimes the "efficiency question" itself is often too simplistic, too two-dimensional, and we could stand to expand it to account for other factors that have their own value, such as speed.

  48. Re:Most electric cars are powered by burning coal by Overzeetop · · Score: 1

    Even the most inefficient modern coal plants are significantly more efficient than an internal combustion engine.

    The added bonus of electric cars is that, as the power generation shifts to less polluting sources (we hope), the electric car will become less polluting over time. The ICE powered car, however, will likely decrease in efficiency and increase the amount of pollutants it expels over time.

    As for coal power, most of the electric cars in the US are located in CA, OR, and WA. Those states are primarily powered by natural gas, hydro, and nuclear power plants. Less then 15% of their energy comes from coal.

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  49. Re:Most electric cars are powered by burning coal by alen · · Score: 1

    what about that huge battery? Tesla's weigh more than similar gasoline sized cars because of the battery

  50. Re:Masstransit is more energy efficient than perso by fnj · · Score: 1

    Any combustion engine running at surface conditions can do maybe 20 - 30% efficiency tops.

    Better than that. There are internal combustion engines which reach 50% at sea level. The Wartsila-Sulzer RTA96-C 108,920 hp marine diesel exceeds 50%. Heck, even the TDI diesel engine in my 1999 Golf tops out at very close to 40%. The LM-2500+ gas turbine, a derivative of the CF6 which powers some 747s, adapted for shaft output, is over 39%.

  51. BTUs? Okay. by Anonymous Coward · · Score: 1

    My Nissan Armada seats 8 and gets 19mpg on the highway, give or take (yes, fully loaded with 8 people, it still gets 19 on average).

    That's 152 person-miles per gallon.

    That's 736 BTU per person-mile fully loaded, or 5895 BTU per person mile solo. The only people who feel like they are sitting in an airplane are those in the third row, too. I usually just stuff the smallest people back there.

  52. What was used for energy basis? by Anonymous Coward · · Score: 0

    Did they include all the energy to run the airport and air traffic control? I'm thinking not.
    Did they include the energy consumed taking people to/from the airport to home or destination? Probably not.

  53. Re:Masstransit is more energy efficient than perso by Yoda222 · · Score: 1

    The energy consumption of a takeoff depend on the mass of the plane at that time (I think), so for a given plane with a given number of passenger, it's not exactly independent of the distance. (more fuel needed for longer distance, bigger take off mass)

  54. Re:Most electric cars are powered by burning coal by fnj · · Score: 1

    Electric traction motors are far more efficient than ICEs. That's why diesel locomotives don't actually connect the diesel engine to the wheels.

    You are high. The diesel engine turns fuel into mechanical energy. If you change that mechanical energy into electricity and then back into mechanical energy, there is no way that could give you more efficiency than a simple mechanical transmission (which is typically well over 90% efficient). The reason for the electric transmission is flexibility. It does away with a big honking clutch and a multi-speed gearbox and gives you very smooth transition from standstill to forward motion.

  55. but flight trips 100x longer than car trips by peter303 · · Score: 1

    I agree that in terms of emissions commericial flight miles are close to car miles. However I usually fly much further than I drive per trip or over a year. That jacks up my carbon contribution considerably.

  56. Re:Masstransit is more energy efficient than perso by allawtterb · · Score: 1

    While your point may be true about moving people, the weight of what is being moved is less than the device doing the moving, it doesn't apply necessarily for moving freight by train. For moving typical goods, say by intermodal transport, the goods can easily exceed the weight of the unloaded train (including locomotives). When you get to moving heavier material, say iron ore, the material can weigh more than the 5 times that of the unloaded train.

  57. Great by Anonymous Coward · · Score: 0

    Now Al Gore the rest of the hyper-rich greenies have an excuse for taking their private jets everywhere! Thanks!

  58. bus industry claims it is most efficient by peter303 · · Score: 1

    I thought train travel was until I poked around the web.

    www.buses.org/files/ComparativeEnergy.pdf

  59. Cheap planes encourage longer travel distances by Anonymous Coward · · Score: 0

    Because flying is so efficient in terms of time it encourages and stimulates people to travel thousands of miles. The relative efficiency with regard to CO2 emissions would have to be insanely optimized in order for it not to be a problem. It is not.

  60. This is an old study! by Anonymous Coward · · Score: 1

    That's really old news. I read something similar 20 years ago. The question is why hasn't aircraft fuel efficiency improved in twenty years?

    So if you fill up your car (4 or 5) people, then you have quadrupled the efficiency pr. person compared to driving alone and thus getting double mileage compared to flying.
    Further benefits are: No TSA, No waiting, instant change of route and no even more hours of waiting and eating overly expensive mediocre food.

  61. Flying to work? by mveloso · · Score: 1

    Flying to work isn't really a very practical commuting method, because my 747 won't fit in any of the spaces. Plus, what would I do with the crew?

    1. Re:Flying to work? by blue9steel · · Score: 1

      Replace them with H1B contractors that you could hire and lay off twice a day?

  62. No it doesn't more efficient by Solandri · · Score: 1

    One factoid is interesting: it takes 4,211 BTUs per person mile to drive. This number will fall as we switch over to electric vehicles. For example, a Tesla Model S takes about 1,100 BTUs per vehicle mile.

    No it doesn't. 1100 BTU (0.322 kWh) is the energy consumption from the battery to the wheels. You need to include the entire energy generation chain to get a fair comparison. Add in a 40% efficient coal plant generating the electricity, 97% transmission efficiency over high-power electrical lines, and 75% charging efficiency and the Tesla actually uses 1100 / (.4*.97*.75) = 3780 BTU per vehicle mile.

    The vast majority of the reason an EV is cheaper to operate is because coal is so much cheaper than gasoline. Coal costs about $50 per ton. A ton of coal has approximately 24 GJ of energy. That's about 0.21 cents/MJ. Gasoline costs about $3/gallon, and has about 120 MJ/gallon, or 2.5 cents/MJ. For the same amount of energy, coal is an order of magnitude cheaper than gasoline, which gives the EV a huge advantage in terms of operating costs. This is not a bad thing - being able to transfer a cheaper but traditionally static energy source into use in a mobile application is an economic win. But don't confuse it for better efficiency.

    Yes you could argue that we can make electricity from renewables. But the vast majority of the cost of renewables is in the initial production of the turbine or PV panels. Operating costs are nearly nil (limited to maintenance). So for a fair comparison you then need to incorporate production and transport costs. At which point renewables lose because on a per Joule delivered basis, even with coal plants being only 40% efficient, coal is still cheaper than wind and solar power. (Wind is only about twice the cost of coal, so cheaper than gasoline, but I suspect solar would be about the same cost as gasoline.)

  63. Fights for the last spot by YoungManKlaus · · Score: 1

    I am pretty sure, both trains and busses have lower footprints, esp. if you consider that its trivial to run trains from renewable sources (as they normally run on electricity). Also the study probably forgets to include the fuel it takes me to get to the airport, which is often a considerable amount (eg. for me it would mean driving nearly 80km per direction).

    1. Re:Fights for the last spot by Anonymous Coward · · Score: 0

      Yup, it's a pointless statement to make - air travel is certainly more cost-effective in *some* circumstances... but not all.
      I'd be willing to bet that the 15 minute walk from my house to the train, 30 minute train ride *south* to the connecting station, and then 1hr train ride *north east* to the state capital would be more energy efficient (per passenger) than me driving there, and while I don't know about fuel for a local small plane, there's a 10 minute drive to the local small airport, charter a flight with a private pilot or small carrier (?) out... I'm betting that'd cost more in time and money than either train or car (or bus even). I can drive there in an hour, anytime I want - train or bus I have to wait for certain schedules, and small plane I really have no idea (never really considered it). Plus of course, depending on where I need to get to when I get there, might toss in the cost/time of another bus or cab ride (Greyhound or train there to a central station doesn't necessarily get me to where I need to be).

      Then again, travelling 1000s of miles across country, I'm sure an hour to the closest airport for larger planes, and a 4-5hr flight across country, is definitely faster and cheaper than trying to drive it in my own car (counting that in my car I'd need a few hotel rooms as well along the way). ... and then on the other side of all of that, if I drive I probably don't have to worry about being blasted with scanner radiation and/or hassled and/or potentially cavity-searched by the TSA, or having my luggage lost, probably won't have to give up passwords to my laptop or be considered a "potential terrorist", etc. That alone might be worth $200 and more wasted energy. :-P

  64. Re:Masstransit is more energy efficient than perso by Anonymous Coward · · Score: 0

    The TDI engine *design* in your 1999 Golf tops out at a *maximum theoretical efficiency* close to 40% (~37-38%) while running in it's most efficient load/speed range. There's a rather significant difference between said maximum theoretical efficiency, and the maximum efficiency in practice. And that's not even getting into the actual average efficiency in practice.

    Your Golf still only manages to pull 15-20% efficiency from tank to road, because of various losses (transmission, friction, etc.) and the fact that it spends so little of its time running in it's most efficient speed/load range.

  65. BTUs? Are You Frickin Serious? by 0xG · · Score: 1

    British Thermal Units? What century are you living in?

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  66. Re:Most electric cars are powered by burning coal by Anonymous Coward · · Score: 0

    Perhaps true for plain old diesel-electric, but once you introduce hybrid battery storage, you open many avenues for further efficiency gain. You can reduce the size of the generator set to sustained output levels while using the battery for short-term peak outputs (instead of sizing it for peak outputs). You can start and stop the generator set and keep it close to peak efficiency modes rather than idling or cruising at partial load. And you have a place to store regenerative braking energy instead of always having to use friction brakes.

  67. It gets even better by kamapuaa · · Score: 1

    Planes show an even greater advantage for me, as when I drive a car I tend to throw cigarette butts and plastic bottles out the windows, and they pollute the side of the road.

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    1. Re:It gets even better by koan · · Score: 1

      So basically you're a pig that actually thinks smoking is a good idea?

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  68. Hmm by koan · · Score: 1

    Once, a long time ago, I read an article stating that flying was the 2nd most dangerous mode of travel, (1st was motorcycle) but the author stressed it depends on how you look at it.
    Miles travelled, or per trip.

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  69. Self driving for the win. by Anonymous Coward · · Score: 0

    Give me a reasonably priced Tesla sized car with a full autopilot and I'll never fly again. After dinner you hop into the car and set your destination, watch a movie/read a book, and then go to sleep. 8-9 hours later you wake up after the car has been driving 70mph all night. Sure that won't get me from coast to coast in a night, but it would be good enough for most. Ramp that up to something the size of an RV then you could travel non-stop until you got where you are going. It would only take 3-4 days to go coast to coast. The bonus no jet lag.

  70. Military by Etherwalk · · Score: 1

    Aerospace is a huge hole in our plans for a carbon less energy future; you can replace fossil fuels with ships (nuclear) and transit (electric cars and trains) but I haven't seen any technology (real or imagined) that can do the job in aerospace. Short haul trucking is another hole that's going to be hard to fill, long haul can conceivably be replaced with trains but you're still going to need something to move goods from the rail network to their final destination.

    Not to mention tanks.

    And the combination of domestic heating and electricity demand. Politicians are afraid of building nuclear plants, and green energy projects aren't getting us anywhere near where we need to be.

  71. difference in accuracy vs precision by recharged95 · · Score: 1

    Cool, I guess flying will easily get me to the corner of 14th and Pennsylvania Ave. Really, the exact corner...

    Really, all this shows it that the more precise location you need to be in, the more energy you'll use. Sure, flying may theoretically get you closer, but if you factor in the infrastructure required vs a dirt road, it's more expensive (today's street cost a lot for robustness.

    Goes with my mantra: More precision == more effort (i.e. cost in this case). Applies to pretty much everything.

  72. The driver by Etherwalk · · Score: 1

    And there are tons of other costs. What is the difference in cost to manufacture? Amortized over the mileage travelled? Are you driving your own car (and avoiding the need for a driver) and are you including the bus driver's carbon usage as a carbon cost?

  73. Does it Take into Consideration? by wisnoskij · · Score: 1

    Does it take into consideration that on any plane trip you have to drive to and from the airport?

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  74. Re:Masstransit is more energy efficient than perso by amorsen · · Score: 1

    DSB (Danish Railways) has a table on http://www.dsb.dk/om-dsb/dsbs-... saying that their long-distance trains do 33g CO2 per person km. Regional trains are considerably worse. Modern cars should hopefully do better than 133g per km.

    Urban trains do better because people are standing up, which significantly lowers the train weight per person.

    Now, Denmark is admittedly a bit of a developing country when it comes to trains. Obviously a pure electrified system running on hydro power would do a lot better. DSB's long distance trains use 0.12kWh per person km. A Tesla uses about 0.35kWh per km, which comes to 0.09kWh per person km with 4 people.

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  75. What first world hell hole do you live in by presidenteloco · · Score: 1

    where they don't build grocery stores within walking distance.

    That is soooo.... 1950s/60s/70s.

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  76. Wait, what?? by presidenteloco · · Score: 1

    Members of congress have a library? Don't they know libraries are full of liberals? "There's only one book worth reading!" I was pretty sure they stayed far away from libraries, and radical interwebs and such.

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  77. Re:Masstransit is more energy efficient than perso by Anonymous Coward · · Score: 0

    Any combustion engine running at surface conditions can do maybe 20 - 30% efficiency tops.

    Better than that. There are internal combustion engines which reach 50% at sea level. The Wartsila-Sulzer RTA96-C 108,920 hp marine diesel exceeds 50%. Heck, even the TDI diesel engine in my 1999 Golf tops out at very close to 40%. The LM-2500+ gas turbine, a derivative of the CF6 which powers some 747s, adapted for shaft output, is over 39%.

    I'm suspicious of those figures. Are they taken in a July heatwave which is not far (+20*) from typical weather, or closer to Harsh German Winter (-100* delta)? Because that latter is pretty close to 30,000' temps.

  78. This is 'merica: why *british* thermal units by Anonymous Coward · · Score: 0

    Do we not have good 'murican energy units? Why must we use a unit developed by our former colonizing overlords. Nor do we want that "continental" "european" Systeme International stuff.
    At least Watts were named after a Scotsman, and they may soon be independent once again.
    Joule? Named after a 19th century English beermaker.

    kilotons of TNT seems to be a wholly US developed unit.

  79. Re: Most electric cars are powered by burning coal by jeff4747 · · Score: 1

    Nope. You forgot about the transmission. The diesel is most efficient in a narrow RPM range. When it's connected to a generator, it can remain in that RPM range. When it's attached to a transmission that is attached to the wheels, it can't. The worst is low-speed acceleration, where electric motors do quite well.

    Since you're so new to the subject, you could start here: http://science.howstuffworks.c...

  80. upper atmosphere versus lower by Anonymous Coward · · Score: 0

    IIRC pumping greenhouse gases directly into the higher atmosphere makes a big difference.

  81. Re:Most electric cars are powered by burning coal by jeff4747 · · Score: 1

    When you're talking about trains or earthmovers, there is no battery. It's generated as-needed.

    When you're talking about all-electric cars, the battery hurts range. Whether or not that's a problem depends on your driving patterns. If you're a typical commute-to-work-and-a-few-errands urban/suburban driver, the range is likely well beyond what you would consume in a day. If you are not that kind of driver then the range may be a factor.

  82. Study didn't look at everything by Shirley+Marquez · · Score: 1

    The study only looked at the fuel consumption of the two modes of travel. Unsurprisingly, a packed plane did well compared to a car with one person in it. The ground travel can do better in a number of ways: a more fuel-efficient car, putting more people in the car, instead studying multi-passenger vehicles like buses and trains.

    The current study also fails to look at another important issue: the high impact of air travel on the ozone layer. Because it takes place at high altitudes (and thus releases pollutants into the upper atmosphere), studies have shown that flying causes a lot of damage to the ozone - much more than the same level of polluting activity at ground level.

  83. Too bad... by MoarSauce123 · · Score: 1

    ....that there is no plane going from by car port to my workplace.

  84. Re:Masstransit is more energy efficient than perso by radl33t · · Score: 1

    thanks for the follow up