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posted by CoolHand on Tuesday November 15 2016, @08:27PM   Printer-friendly
from the if-a-tree-falls-in-the-forest-can-i-join-the-mile-high-club dept.

Washington state-based Alaska Airlines today made history flying the first commercial flight using the world's first renewable, alternative jet fuel made from forest residuals, the limbs and branches that remain after the harvesting of managed forests.

The fuel used a 20 percent blend of sustainable aviation biofuel.

While 20% doesn't seem like much (it's still 80% aviation fuel), if the airline were able to replace 20 percent of its entire fuel supply at Sea-Tac Airport (from which it took off), it would reduce greenhouse gas emissions by about 142,000 metric tons of CO2. This is equivalent to taking approximately 30,000 passenger vehicles off the road for one year.


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  • (Score: 2) by Reziac on Wednesday November 16 2016, @06:09AM

    by Reziac (2489) on Wednesday November 16 2016, @06:09AM (#427392) Homepage

    My experience is that 10% ethanol in gasoline reduces fuel economy by around 10% under normal conditions, but by as much as ~40% when towing a heavy load (probably because the truck's power is reduced, especially on hills, by some sort of square of the mass factor).

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  • (Score: 3, Informative) by Kromagv0 on Wednesday November 16 2016, @03:55PM

    by Kromagv0 (1825) on Wednesday November 16 2016, @03:55PM (#427560) Homepage

    My experience says otherwise and I do keep track of fuel economy closely using the on board computer and pumped gallons with miles driven. Having access to both non-oxy and the standard E-10 fuel, both 91 octane, as well as having vehicle I tow with frequently. So in my car without towing on the highway on E-10 I will get about 33-35 mpg when going to and from my lake property. If instead I fill up with non-oxy I will get 35-37mpg. When I am towing on a tank of E-10 when going to and from my lake property I get 27-28 mpg when running non-oxy on the same trip I will get 28-29 mpg. This however is in a vehicle with a more performance engine than most and in both cases the E-10 and non-oxy fuel are both 91 octane so it isn't like I am seeing benefits from a higher octane fuel in not having to run rich to prevent pre-ignition. I find that the 2 greatest factors that affect my mileage is how hard I flog the vehicle, I tend to view cloverleafs and freeway ramps as my own personal race tracks, and what the weather is.
     
    If you are seeing a dramatic drop, more than the 3-4% expected, in fuel economy when going between non-oxy fuel and standard E-10 it would seem that there is something wrong with your engine. For example in your case it sounds like the truck is suffering from some pre-ignition problems so that when you are running regular 87 octane E-10 fuel it is running rich to prevent pinging. This is only made worse when you have additional load when towing. Things get better when you are running non-oxy fuel as it is likely a higher octane likely 91 or maybe even 93. I would suggest getting an induction cleaning done on the engine and maybe look into using fuel with a higher amount detergents (find a station that has "Top Tier" fuels [toptiergas.com]) in it as well as possibly look into using some of the fuel system cleaners like the Chevron Techron [walmart.com] or Berryman B-12 products [fleetfarm.com] for a bit to see if you can get some of those carbon deposits cleaned out that likely are causing you some problems.

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    T-Shirts and bumper stickers [zazzle.com] to offend someone
    • (Score: 2) by Reziac on Wednesday November 16 2016, @04:35PM

      by Reziac (2489) on Wednesday November 16 2016, @04:35PM (#427588) Homepage

      With the '78 F100 (302V8) when it was new I kept good track, and the drop was indeed about 10%, and it ran hot. Less difference after the engine was rebuilt, but it also got less fussy about its fuel.

      With the '91 F350 (460 V8) it was rebuilt shortly before I bought it. Best case it gets about 14mpg which is pretty damn good for that engine and a 6000 pound truck that will do 0-60 in 7 seconds (durn thing thinks it's a race car). When I'm towing it's usually a 10,000+ pound load (my horse trailer is 4000 pounds empty) and an unfortunate amount of hills. When I was moving cross-country I quickly learned to hit Cenex gas (no EtOH) when I could, cuz I'd climb hills better and go a lot further on it. Made about the same difference as using midgrade vs regular.

      No fancy new onboard computers in my household. :)

      --
      And there is no Alkibiades to come back and save us from ourselves.
      • (Score: 2) by Kromagv0 on Wednesday November 16 2016, @08:43PM

        by Kromagv0 (1825) on Wednesday November 16 2016, @08:43PM (#427761) Homepage

        The '91 probably does have a knock sensor that will richen the mix if it detects knocks. The fact that you mention that using midgrade vs. regular makes about the same difference as that between non-oxy vs E-10 would also indicate that you may have some pre-ignition problems that are "solved" by having a richer mix with 87 octane E-10. Furthermore you mention on the '78 that the difference was less pronounced and it was a lot less fussy after a rebuild which would indicate that it may have been suffering from a similar fate as the rebuild would have cleaned out the carbon buildup. Also in 78 they wouldn't have been adding ethanol but likely methyl tert-butyl ether [wikipedia.org] instead as an octane booster and oxygenating agent. To me both of these describe symptoms of hot spots from carbon buildup either in the combustion chamber or on the valves so using some of the backyard petrochemist cleaners and then sticking with a high detergency fuel going forward may solve the problem. The fact that things are worse towing also makes sense with this explanation as well given that there there is a large consistent load in that case which will always make pinging worse if it is happening.
         
        Personally I have never been a big fan of having oxygenated fuels for general use as you have vehicles designed sub-optimally for them. Instead I would love to see E-100 fuel for sale as a pump fuel and then have a vehicle designed to run on E-100. You can make some big power, at the expense of lots of fuel consumption, from ethanol since you can burn so much more of it for a given charge of air. Add in that it has a really high latent heat and really high octane rating you have a great fuel for high boost or high compression engines to further increase the power output. Flex fuel vehicles suck because they are a compromise as they are designed to run on anything from 87 octane E-10 to 115 octane E-85 which means they make a lot of compromises along the way. I have a project car that I am converting over to a no compromise E-85 vehicle (don't even think of trying to run it on 87 octane E-10 as it likely wouldn't start) because no one has done a supercharged alcohol burning A-series engine [wikipedia.org] with a 12:1 compression ratio and 9lbs of boost. I want to see if I can get that motor (bored to a standard 60 over or 1380cc) to put out 200-250hp because in that light of a car that is a lot of power.

        --
        T-Shirts and bumper stickers [zazzle.com] to offend someone
        • (Score: 2) by Reziac on Wednesday November 16 2016, @09:33PM

          by Reziac (2489) on Wednesday November 16 2016, @09:33PM (#427783) Homepage

          I got the '78 brand new. First encountered ethanol mix (at least that's how it was labeled) I believe in 1979, and was immediately unhappy with it (ran hot, reduced economy, sharply reduced power). Truck would have had maybe 6,000 miles on it, mostly highway use. Unlikely to be carbon buildup at that point. Before it got rebuilt it was so twitchy about water in the gas that I could tell within half a block. Never a problem in MT but by the time I'd been in CA six months, I'd blacklisted about half the gas stations around. (Funny how those were all the ones that got dug up during an EPA crusade against leaking tanks.) Had also noted better fuel economy on Texaco, and markedly better on Chevron, but after a certain point not worth the price differential. Once EtOH was ubiquitous, well, it ran enough hotter that a dead thermostat was a necessary component (and greatly improved power on hills). I did use a lot of midgrade in it, and premium when towing. Never used any additive other than occasionally Heet or STP in winter. It always passed CA's now-ridiculous emissions standards, usually in the lower third of the range. (Protip: go somewhere that cleans the sensor between customers. Makes a huge difference.)

          The '91 was rebuilt end-to-end not long before I got it, and runs like a new truck. It does sometimes have its own ideas, like if the engine is below-zero cold, it flat won't run any faster than it decrees proper and ignores the throttle, like it or not, until it warms up. The '78 was cold-blooded too; seems to be a Ford thing.

          Only person I've talked to with a flex vehicle said it was going to be traded in soon as possible, cuz the thing has no torque and is useless if you get stuck in snow or ice, which here in MT is inevitable.

          --
          And there is no Alkibiades to come back and save us from ourselves.
  • (Score: 2) by Arik on Wednesday November 16 2016, @03:59PM

    by Arik (4543) on Wednesday November 16 2016, @03:59PM (#427564) Journal
    My experience is that your experience is exceptionally poor. When I've kept records and done the math myself, it's ranged from ~4-8%. It's certainly not impossible that some engines cope with it more poorly than the ones I have tried though.

    --
    If laughter is the best medicine, who are the best doctors?
    • (Score: 2) by Reziac on Wednesday November 16 2016, @04:25PM

      by Reziac (2489) on Wednesday November 16 2016, @04:25PM (#427580) Homepage

      I kept good track with the F100 (302 V8). And it was indeed about 10%. It was fairly fussy about its fuel, tho -- I could tell immediately if there was water in the gas. Less so after it was rebuilt.

      --
      And there is no Alkibiades to come back and save us from ourselves.
      • (Score: 2) by Arik on Wednesday November 16 2016, @05:48PM

        by Arik (4543) on Wednesday November 16 2016, @05:48PM (#427641) Journal
        I suspect that's (a|the) factor producing variance from the manufacturers tests. Alcohol tends to suck up humidity. Pure alcohol that's never left the lab might give you what their tests show, but then in reality by the time you burn it there's some water in it.
        --
        If laughter is the best medicine, who are the best doctors?
        • (Score: 2) by Reziac on Wednesday November 16 2016, @08:19PM

          by Reziac (2489) on Wednesday November 16 2016, @08:19PM (#427747) Homepage

          Could be. In desert life nighttime condensation can be a problem, and I expect the EtOH sucks it right up.

          --
          And there is no Alkibiades to come back and save us from ourselves.