It's different because you can still change your password thus restricting access again, and also everyone else's passwords to the same system are still effective. You have a problem if everything shares the same password and it can't be changed- that is security by obscurity. Or if you have a system where everyone's password is their birthday, and then it leaks that this is your obscurity system.
If a password is used directly to grant access to you system, then yes, that is security by obscurity and is bad security. In a more sufficient security system, you might use a password as a shared secret to authenticate someone's identity, and use that identity to grant access. This is a completely different security architecture, and is better. It's different because authentication and authorization are treated as separate issues.
Certainly obscurity can add to security, but you really want a security system that is sufficient without it.
This is completely different from grid-connected solar.
Most likely this will not be deployed until the utility implements real-time pricing (or at least hourly pricing, rather than the monthly pricing we have now), where electricity prices vary during the day based on the exact system conditions. They will have to pay you at the price when they draw power from your battery (or more likely, you will just use the power in your house, and pay that much less), and you will pay a lower rate to charge at night (or whenever it is cheapest if the electricity supply changes drastically). This is a net savings for you, even if there is a small loss of electricity in the process. In this case, the utility wouldn't even have to ask- your charging system would probably do it automatically just to save you money through arbitrage in the electricity market.
If there is no instantaneous pricing, they will have to pay you a fee just for being available, plus pay you back for whatever power they draw. This fee would exceed any loss. In this case, the utility would have to control your battery because you would have no incentive to discharge otherwise. This is similar to load-shedding agreements utilities have now with large customers.
How do you maintain availability of power for the car owner?
Yes, sure, you might be able to harness some from, say, a haulage company at the end of the day when they shut up shop but in general you can't just steal charge from people's electric cars (because the first new-father in the middle of the night that can't drive his wife to hospital is going to create a ton of bad press for you).
There are two obvious ways you can maintain availability of power for the car owner.
1) Let the owner say the next time they need to have a full or partial charge- when they leave for work, when they finish work, when they get back from vacation in 2 weeks, etc. You want to do this anyway so the system can decide the best time to charge the battery. And a "don't discharge" option would be very simple if you expect emergency trips. Most people don't.
2) Make sure they have enough power to get to the nearest battery swapping station if they happen to need to drive somewhere right after the battery is discharged.
Nope. Either they will be paying you far more than your net loss in charge for the availability, or they will be paying you at far higher retail prices when they buy the power from you than when you are charging the battery. Either way, you're going to make money on it. And the utility will save money by keeping less reserves available, and avoiding use of more expensive generators.
That makes sense for dividends, which are the shareholders' portion of the corporation's profits, but not for capital gains. The corporation did not pay a tax on the increase of its share price, and property owners did not already pay a tax on the increase in their property value prior to selling that property and paying capital gains tax.
If a sole proprietor is making over $1M in profit per year, and not re-investing it into growing the business, then that business can afford to pay a higher tax rate on the amount of profits over $1M.
If a partnership or multi-member LLC is making more than $1M per year in profit, then those profits are divided between the partners/members before the tax rate is applied, so we're talking about profits over $N million where N is the number of partners/members (assuming equal ownership).
If they used some of that profit to hire employees, then that would be a business expense and they wouldn't pay the taxes on it. So this really isn't a burden on small businesses.
However, as heat can be converted to other forms of energy, there are ways to dissipate and/or use the surplus heat. Also, higher efficiency methods of converting heat into electricity or other useful forms of energy will delay the saturation point. So, he's correct in theory, and his details are probably not an accurate prediction.
Nope, pretty much anything reasonable you do with energy turns into heat, and eventually gets radiated to space at an equilibrium temperature, which rises according to the heat flux. He already assumed 100% conversion efficiency (which is not possibly thermodynamically), but when you use that electricity to do something, you get heat as a byproduct. Some waste energy is light that can be radiated to space directly, but if you can use light with 100% efficiency for other purposes, you'd do that and it would eventually become heat at the surface.
So we're stuck without exponential growth in energy use, or making that energy use take place somewhere outside of the Earth (which is probably what will happen), or finding some way to dissipate unusable energy (currently waste heat from conversion AND from end-use) to space much faster than longwave radiation, or finding ways to increase value without exponential increases in energy use.
boy... you are going to sprain something reaching so hard.
Not reaching at all. Just trying to illustrate that the low gas light and tank full nozzle switch are not accurate measurement devices. My main point, though, is that the fuels being compared are not sufficient to isolate the effect of ethanol on mileage.
a) My car said "full". My gallons in were roughly the same (about 12.25 gallons) as every other time they low gasoline light came in.
I have never had refills that consistent. I guess I don't always refill exactly when the light comes on. Of course, I don't drive often these days, and haven't for 10 years. I find that level of consistency, refilling to +/- 0.05 gallons quite surprising. Anyway, you never specified that you recorded the fill amount at the E0 pump, only the next refill after. Actually, you never specified whether you took the measurement before or after using a given fuel. Unless you did both and calculated the exact mileage for both adjacent tanks (rather than just some random E10 tank), it's hard to say. The error in "around" 12.25 and "around" 265 or 300 miles can be significant. 261 miles / 12.4 gallons is 21 mpg, 270 miles / 12.1 gallons is 22.5 mpg, and 295 miles / 12.5 gallons is 23.6 mpg. It is even more so if around 265 miles means between 250 and 275, and around 12.25 gallons means between 12 and 12.5.
Not 35 miles difference. You get to the point in mileage where your mileage light "always" comes on and you notice it's not coming on...
IT'S NOT A 35 MILE DIFFERENCE. There is less energy density in ethanol than gas. It's like a 20 mile difference. That's about 7%. Your methods are not nearly good enough to measure a 7% change. Not even close. Especially in 3 trials.
Or using your expectation of up to a 10% reduction, it's a 5 mile difference, which is hardly significant. 10% less than 300 miles is 270 miles.
Yes, my expectation from Keith Knoll's report is that I'd lose 3.5% mileage per tank using 10% ethanol. Reality is not matching that expectation. Hell, my worst case expectation would be that I would lose 10% with ethanol but my observed loss is over 10%. Having ethanol in the tank provides worse gas mileage for my honda element than the mystery substance I'm going to presume was 100% gasoline (since super and premium do not raise my mileage).
100% gasoline doesn't really mean something specific. It just means it's some mix of liquid hydrocarbons with some limits of how much of certain ones are in it. It is only different from other "non-100%" gasoline in that it presumably wouldn't contain additives beyond what comes out of the refining process. However, they might just mean ethanol-free, and who knows what it would contain. Or maybe the E10 has other components such that it is not 90% regular gasoline. Maybe it has less alkenes because ethanol makes them evaporate; alkenes have higher energy content than the rest of the fuel. Who knows. Since they don't advertise the chemical makeup of the fuels, it is impossible to know unless you mix and chemically test the fuels yourself.
You can only expect the 3.5% reduction if the E10 mix is actually 90% the-same-gasoline-as-E0 and 10% ethanol. All we know is that it is at most 10% ethanol, and 90% other stuff. Hell, it could be 85% gasoline, and 5% stuff to keep the ethanol mixed. And that 3.5% is specific to the fuels they were using; the actual amount depends on the energy density of the particular batch of gasoline, and could be higher or lower.
You should not expect super or premium to raise your mileage, unless your car requires them. It generally just means higher octane, which means less energy than regular. They generally contain more additives (like ethanol or MTBE) to raise the octane rating, and those additives are probably not actually octane.
And I calculated the mileage at fillup after each those 300 mile tanks. I knew exactly how far I had driven-- and i knew exactly how many gallons I had just put in the car.
But you still didn't know the relationship between the fill level that time and the previous time. All you know is that the pump clicked off, but they were different pumps. Maybe the shutoff mechanism is higher on the nozzle on the E0 pumps, and you actually had an extra gallon or so those times.
The mileage was about 24.5 mpg for a mixture of city and highway driving for each 300 mile tank. That's close to the theoretical top of the mileage range for pure highway driving.
I have not calculated after fillup for every 265 mile tank but the ones I did come in just below 22 mpg.
So, one would expect that if you mix 10% ethanol with the fuel in the 300-mile tank, if all else is equal, you'd get about 23.5 mpg. So your mileage is 1.5 mpg lower than expectation, only a 6% difference, which is in the range of the effect of getting a car wash.
It's really an 8% difference because of the lower energy density of E10, and 3 is a small number of times to repeat, especially with how inaccurate your measure of fuel consumed per refill is. You could easily overestimate by a gallon range 3 times out of 3 (either randomly, or maybe because shell pumps happen to shut off later). Someone else might underestimate by a gallon 3 times, assume their fuel economy is the same, and not get involved in discussions about it.
But again, even if you did this 1000 times on your car, it would not be sufficient to draw any conclusions about the effect of ethanol as an additive on fuel economy, because you have not eliminated possible systemic bias in measurements, have not used a range of vehicles, and have not controlled for other possible differences in the fuels, or alternatively have not directly measured their energy density.
They found a decrease in fuel economy of 3.68+/-0.44% at 95% confidence for E10, which is consistent with the ~3.5% decrease in energy density for the fuel.
Adjusting for fuels is relevant. If you get a less than 5% mileage drop using E10, this is to be expected, because there is less energy in the fuel. It's not because your car is using it poorly.
If they are mixing crappier gas with the ethanol because the mix allows them to meet the minimum octane rating, then this could easily explain a lower than expected mileage. If you are using 91 octane E10, your car might not even run on the gas the ethanol is mixed with. OTOH, if if the "100% gas" really is additive free, they might be mixing in isooctane, which would explain a higher than expected mileage. This is different than high-octane fuels, which don't actually contain extra octane.
Ethanol, as an additive, is something that most cars will benefit from, relative to the gas it is mixed with. It increases the octane rating and reduces direct emissions of pollutants. Currently, it replaces additives like MTBE (which in turn are what eventually replaced lead). I'm not sure if ethanol is better environmentally than MTBE, but I'm fairly sure it's better than lead additives. Isooctane might give you better mileage, but it also might increase carbon monoxide emissions relative to other additives.
I agree that there are downsides to using ethanol as an additive; the data just doesn't show that it reduces fuel economy itself.
I also agree that ethanol, as an alternative fuel given America's supply and technology is dumb. And there is certainly some political pressure to use more of it as an additive as a way to promote more use as an alternative fuel, and to subsidize the corn industry.
And arguing against several of those points is the very consistent swap between 265 and 300 miles per tank.
A tank is a very imprecise measure of fuel. Did you at least record exactly how many gallons each refill (rather than estimating from the tank size), and make sure the fuel gauge was in an identical spot, while stopped on flat ground, before each refill? Otherwise, perhaps you have a regular commute with 30-mile intervals, and just refilled when it was sort of near empty.
If you filled the tank 1/2 gallon higher with E0 (due to a difference in the nozzle), and went 1/2 gallon lower on the E0 (due to commute patterns and/or effects on the fuel gauge), that would explain the difference.
Regardless, even if your results were consistent enough to give statistically significant differences in miles per gallon (after taking into account energy density), that only shows that it was unlikely to be from differences in things like temperature, tire inflation, driving pattern, etc.
So I again refer you back to experimental results using fuels controlled to make sure they are in fact comparable. And again, the difference with your experience could be specific to your car, or a measurement bias, or a difference between the fuels aside from the ethanol content.
Since posting this, I'm also reading that some refiners have been caught occasionally goosing the fuel slightly above 10% ethanol to increase their profits too.
That doesn't surprise me.
Still- no damage to my car reported at my regular tuneups so it could not be too high.
Absence of damage in one engine is not sufficient to estimate the amount of ethanol. But they would probably get in very serious trouble if they went way over consistently.
You would have to run a fair few numbers to know for sure(once you get into total energy cost of manufacture, and similar considerations, things get kind of hairy...); but vehicle electrification might actually reduce pollution, even if fossil fuels are still being used to generate the power.
It definitely will, unless the electricity generation is 100% coal.
The main difference for manufacture, etc is the battery. Here's a paper on that:
It basically says that the share of energy and other environmental costs for battery manufacture is small compared to the savings from using European electricity instead of an ICE. For example, the life cycle greenhouse gas emissions are more than 30% lower. If you substitute Australia's energy mix (basically the most coal-heavy around), you still get 6% lower life-cycle emissions from the electric vehicle.
I have a few concerns about the poll. The biggest one is that the percentages only add up to 75%.
I think people who thought their mileage decreased would be much more likely to answer that poll.
And I think it is unlikely that those who answered the poll know how to measure such things properly. Some might even be comparing their observed mileage to the what was advertised on the sticker.
Some of the comments make it clear that they are comparing mileage years ago with E0 to now with E10, when their car is older. And at least one comment shows that they are using an octane boosters which I believe is not supposed to be done with E10.
So I think it's really hard to draw any conclusions from it.
That's right, assuming that it's actually 10% ethanol rather than "up to" 10% ethanol, and that the other 90% is the same stuff as the 100% gasoline.
It is possible that, for whatever reason, your car did worse with a switch to E10, or better after switching to E0. Could be just your car, and not the model. Or maybe the ethanol dissolved some junk from your fuel system. It is also possible that something else was different about the test. I'm guessing none of the measurements were very precise. It's even possible that pump nozzles were different lengths, or that the different density makes your fuel gauge read empty earlier.
But it's really likely that there are other differences between the two types of gas besides the 10% ethanol.
It may be anecdotal, but he isn't alone. There are an alarming amount of these anecdotes. Anecdotally, I've been able to repeat results like these with three different vehicles I've owned (they weren't flex-fuel vehicles, though--like most vehicles).
The plural of anecdote is not data.
It is also likely that few if any of these anecdotes involved comparable fuels and adjustments for the reduced energy density of the E10 fuel.
They found a decrease in fuel economy of 3.68+/-0.44% at 95% confidence for E10, which is consistent with the ~3.5% decrease in energy density for the fuel.
I would argue that their tests on 16 vehicles are much more reliable than comparing unknown amounts (only counted the number of miles to get near empty) of unknown fuels (one of which might have about 10% ethanol), in unknown driving conditions using one vehicle, even if it is just one study without peer review.
Now, there is certainly evidence that the manufacture of ethanol consumes as much or more fossil fuel than the energy content of the ethanol. But that's the cost (along with the resulting additional emissions) we should be comparing to the tailpipe emissions reductions from Ethanol blends.
There are a couple of problems with the above analysis. First, the calculations involving random event probabilities are wrong. For example, the probability of getting heads exactly once when you flip a coin twice is 50%, not 100%. Second, lists of possible wait times are averaged without weighting them by their probabilities. For example, the average of 10 minutes 90% of the time, and 4 minutes 10% of the time is 9.4 minutes, not 7 minutes.
A light time of say 1 sale / minute, then your time is 1 minute since you can see what cashier is open.
If 3 customers arrive over the course of a couple of minutes, there is a 25% chance of an issue with one of them, an 8% chance of an issue with 2 of them, and an issue with all 3 is extremely rare. In any of those cases, the smoothly flowing lines will start to back up until the issues are resolved.
A medium time of when you have say 4 ppl in a queue, which is 12 sales/minute. That means that there is 50% chance of hitting a line that is going to have an issue. The reason is that the queue is NOT dependent on which line you choose by the DEPTH of the queue. You have limited capabilities to decide just by looking at others if they will have issues. In addition, the time will take between 4-20 minutes to get to the cashier, with an average of over 10.
No, if issues are randomly distributed, you have a 59% chance of no problems in your line (0.875^4), a 28% chance of 1 problem (0.41 * 0.875^3), a 10% chance of 2 problems, a 3% chance of 3 problems, and a 0.4% chance of 4 problems. Since these cases each take 4, 8, 12, 16, and 20 minutes, respectively, the average wait is 6.3 minutes. If you simplify and say that on average there are 0.5 problems, you still get 4 minutes plus 50% of a 4 minute delay, which is 6 minutes.
Finally, when the queue hits 8, then it is 100% certain that you will have a slow down of some type. In addition, the time will take between 13 to 40 minutes to get to the cashier with an average of close to 20.
At length 8, you have a 34% chance of no problems, and a 66% chance of at least one problem. It will take 8-40 minutes, and the average is 13.8 minutes, not 20 minutes. In the simple case, you have on average one 4 minute issue, plus 8 minutes of normal wait, for a 12 minute typical wait.
Assume that it is the medium load, which is 12 sales. There will be 1.5 issues during that time, but at least 1 cashier will run full out. As such, the time will be between 5-10 minutes, with an average of about 6. In addition, you will be moving through the line QUICKLY.
Yes, on average 1.5 issues divided across 3 cashiers is 0.5 delays per cashier, which gives the same 6 minutes as the 3 separate lines.
With the heavy load, that is a total of 24 sales. That means that there will be 3 issues. That means that you have a time of between 8-12 minutes, with an average of 10 minutes.
No, your average is around 12 minutes just like the separate lines, but you are more likely to have a wait closer to 12 minutes, and less likely to have an 8 minute wait, or a 40 minute wait. Even though there are on average 3 issues, sometimes there are more, and sometimes there are less.
So yes, a single line makes you have wait time closer to the average more often, and reduces the likelihood of a very long or very short wait. But it does not reduce the average, nor change the best or worst case. You can't magically make the cashiers process more purchases per minute with a different line ordering.
But the point is, when one line is moving faster, more new customers get in that line. And therefore, you, as an individual customer, are more likely to have a shorter wait. Yet on average, you have an average wait.
Take the 8-person lines. About 34% of the time, one of them processes 8 people in 8 minutes (and 8 new people get in that line). 26% of the time, there
More people go through the fast line, so you are more likely to be in a fast line than a slow one. You are also more likely to wait longer the times you are in the slow one. And on average, you will wait an average amount of time. Of course if there are many lines chances are there is at least one faster one.
Other than side effects, a single feeder line won't change the average waiting time. But it will make the first people to get in line get to the register first, which matches one way of looking at fairness, and also it optimizes the maximum wait time.
Let's try a simple example. Line A moves at 1 minute/customer, B moves at 2 minutes/customer, and C moves at 3 minutes/customer, then you have a 55% chance of being in line A, the fastest one. This is because in 6 minutes, 11 total customers make it through the line, and 6 of them were in line A. 1/3 of the lines are the fast line, and 1/3 of the people at the register at a given moment went through the fast line, but 55% of people go through the fast one.
And you're in the fastest line exactly 1/3 of the time (clock time, not purchases) if the lines are the same length, or more than 1/3 of the time if people are smart and accurately estimate the total wait time in each. And on average, you wait an average amount of time.
But the fast line processes more people per minute. So you spend a disproportionate number of waits in the fast line, and a disproportionate amount of time each visit to the slow line.
And on average, you spend the same amount of time in each line. And on average, you spend an average amount of time in line.
However, if people are smart and predict which line is moving faster (in a case where the delays are predictable, like a line of people with packed carts and a wad of coupons in their hand), that line will be longer and the others shorter. Then you are still in the fast line more often, but the wait time in each line would typically be more equal, and thus you also spend much more time in fast lines.
So any way you look at it, you are more likely to be in a the fastest line than the slowest (i.e. better than 1 in N chance, where N is the total number of lines). You're just more likely to remember being in the slow one.
But one single feeder line is more fair, even if it isn't more efficient.
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Assuming no subsidies anywhere along the production/sales/installation process making the solar panels feel artificially cheap.
And what about the subsidies that make conventional electricity feel artificially cheap?
Nor counting losses converting power to storage and back again to match energy demand that doesn't coincide with peak production.
Solar production tends to match up pretty well with peak demand. Better than, say, regular power plants.
...or just use the usual tactic, ratchet up the subsidies a little more to further hide the underlying inefficiencies.
You're right, it's only fair to subsidize energy from fossil fuel sources. You know, real energy.
It's different because you can still change your password thus restricting access again, and also everyone else's passwords to the same system are still effective. You have a problem if everything shares the same password and it can't be changed- that is security by obscurity. Or if you have a system where everyone's password is their birthday, and then it leaks that this is your obscurity system.
If a password is used directly to grant access to you system, then yes, that is security by obscurity and is bad security. In a more sufficient security system, you might use a password as a shared secret to authenticate someone's identity, and use that identity to grant access. This is a completely different security architecture, and is better. It's different because authentication and authorization are treated as separate issues.
Certainly obscurity can add to security, but you really want a security system that is sufficient without it.
This is completely different from grid-connected solar.
Most likely this will not be deployed until the utility implements real-time pricing (or at least hourly pricing, rather than the monthly pricing we have now), where electricity prices vary during the day based on the exact system conditions. They will have to pay you at the price when they draw power from your battery (or more likely, you will just use the power in your house, and pay that much less), and you will pay a lower rate to charge at night (or whenever it is cheapest if the electricity supply changes drastically). This is a net savings for you, even if there is a small loss of electricity in the process. In this case, the utility wouldn't even have to ask- your charging system would probably do it automatically just to save you money through arbitrage in the electricity market.
If there is no instantaneous pricing, they will have to pay you a fee just for being available, plus pay you back for whatever power they draw. This fee would exceed any loss. In this case, the utility would have to control your battery because you would have no incentive to discharge otherwise. This is similar to load-shedding agreements utilities have now with large customers.
How do you maintain availability of power for the car owner?
Yes, sure, you might be able to harness some from, say, a haulage company at the end of the day when they shut up shop but in general you can't just steal charge from people's electric cars (because the first new-father in the middle of the night that can't drive his wife to hospital is going to create a ton of bad press for you).
There are two obvious ways you can maintain availability of power for the car owner.
1) Let the owner say the next time they need to have a full or partial charge- when they leave for work, when they finish work, when they get back from vacation in 2 weeks, etc. You want to do this anyway so the system can decide the best time to charge the battery. And a "don't discharge" option would be very simple if you expect emergency trips. Most people don't.
2) Make sure they have enough power to get to the nearest battery swapping station if they happen to need to drive somewhere right after the battery is discharged.
Nope. Either they will be paying you far more than your net loss in charge for the availability, or they will be paying you at far higher retail prices when they buy the power from you than when you are charging the battery. Either way, you're going to make money on it. And the utility will save money by keeping less reserves available, and avoiding use of more expensive generators.
That makes sense for dividends, which are the shareholders' portion of the corporation's profits, but not for capital gains. The corporation did not pay a tax on the increase of its share price, and property owners did not already pay a tax on the increase in their property value prior to selling that property and paying capital gains tax.
If a sole proprietor is making over $1M in profit per year, and not re-investing it into growing the business, then that business can afford to pay a higher tax rate on the amount of profits over $1M.
If a partnership or multi-member LLC is making more than $1M per year in profit, then those profits are divided between the partners/members before the tax rate is applied, so we're talking about profits over $N million where N is the number of partners/members (assuming equal ownership).
If they used some of that profit to hire employees, then that would be a business expense and they wouldn't pay the taxes on it. So this really isn't a burden on small businesses.
However, as heat can be converted to other forms of energy, there are ways to dissipate and/or use the surplus heat. Also, higher efficiency methods of converting heat into electricity or other useful forms of energy will delay the saturation point. So, he's correct in theory, and his details are probably not an accurate prediction.
Nope, pretty much anything reasonable you do with energy turns into heat, and eventually gets radiated to space at an equilibrium temperature, which rises according to the heat flux. He already assumed 100% conversion efficiency (which is not possibly thermodynamically), but when you use that electricity to do something, you get heat as a byproduct. Some waste energy is light that can be radiated to space directly, but if you can use light with 100% efficiency for other purposes, you'd do that and it would eventually become heat at the surface.
So we're stuck without exponential growth in energy use, or making that energy use take place somewhere outside of the Earth (which is probably what will happen), or finding some way to dissipate unusable energy (currently waste heat from conversion AND from end-use) to space much faster than longwave radiation, or finding ways to increase value without exponential increases in energy use.
boy... you are going to sprain something reaching so hard.
Not reaching at all. Just trying to illustrate that the low gas light and tank full nozzle switch are not accurate measurement devices. My main point, though, is that the fuels being compared are not sufficient to isolate the effect of ethanol on mileage.
a) My car said "full". My gallons in were roughly the same (about 12.25 gallons) as every other time they low gasoline light came in.
I have never had refills that consistent. I guess I don't always refill exactly when the light comes on. Of course, I don't drive often these days, and haven't for 10 years. I find that level of consistency, refilling to +/- 0.05 gallons quite surprising. Anyway, you never specified that you recorded the fill amount at the E0 pump, only the next refill after. Actually, you never specified whether you took the measurement before or after using a given fuel. Unless you did both and calculated the exact mileage for both adjacent tanks (rather than just some random E10 tank), it's hard to say. The error in "around" 12.25 and "around" 265 or 300 miles can be significant. 261 miles / 12.4 gallons is 21 mpg, 270 miles / 12.1 gallons is 22.5 mpg, and 295 miles / 12.5 gallons is 23.6 mpg. It is even more so if around 265 miles means between 250 and 275, and around 12.25 gallons means between 12 and 12.5.
Not 35 miles difference. You get to the point in mileage where your mileage light "always" comes on and you notice it's not coming on...
IT'S NOT A 35 MILE DIFFERENCE. There is less energy density in ethanol than gas. It's like a 20 mile difference. That's about 7%. Your methods are not nearly good enough to measure a 7% change. Not even close. Especially in 3 trials.
Or using your expectation of up to a 10% reduction, it's a 5 mile difference, which is hardly significant. 10% less than 300 miles is 270 miles.
Yes, my expectation from Keith Knoll's report is that I'd lose 3.5% mileage per tank using 10% ethanol. Reality is not matching that expectation. Hell, my worst case expectation would be that I would lose 10% with ethanol but my observed loss is over 10%. Having ethanol in the tank provides worse gas mileage for my honda element than the mystery substance I'm going to presume was 100% gasoline (since super and premium do not raise my mileage).
100% gasoline doesn't really mean something specific. It just means it's some mix of liquid hydrocarbons with some limits of how much of certain ones are in it. It is only different from other "non-100%" gasoline in that it presumably wouldn't contain additives beyond what comes out of the refining process. However, they might just mean ethanol-free, and who knows what it would contain. Or maybe the E10 has other components such that it is not 90% regular gasoline. Maybe it has less alkenes because ethanol makes them evaporate; alkenes have higher energy content than the rest of the fuel. Who knows. Since they don't advertise the chemical makeup of the fuels, it is impossible to know unless you mix and chemically test the fuels yourself.
You can only expect the 3.5% reduction if the E10 mix is actually 90% the-same-gasoline-as-E0 and 10% ethanol. All we know is that it is at most 10% ethanol, and 90% other stuff. Hell, it could be 85% gasoline, and 5% stuff to keep the ethanol mixed. And that 3.5% is specific to the fuels they were using; the actual amount depends on the energy density of the particular batch of gasoline, and could be higher or lower.
You should not expect super or premium to raise your mileage, unless your car requires them. It generally just means higher octane, which means less energy than regular. They generally contain more additives (like ethanol or MTBE) to raise the octane rating, and those additives are probably not actually octane.
And I calculated the mileage at fillup after each those 300 mile tanks. I knew exactly how far I had driven-- and i knew exactly how many gallons I had just put in the car.
But you still didn't know the relationship between the fill level that time and the previous time. All you know is that the pump clicked off, but they were different pumps. Maybe the shutoff mechanism is higher on the nozzle on the E0 pumps, and you actually had an extra gallon or so those times.
The mileage was about 24.5 mpg for a mixture of city and highway driving for each 300 mile tank. That's close to the theoretical top of the mileage range for pure highway driving.
I have not calculated after fillup for every 265 mile tank but the ones I did come in just below 22 mpg.
So, one would expect that if you mix 10% ethanol with the fuel in the 300-mile tank, if all else is equal, you'd get about 23.5 mpg. So your mileage is 1.5 mpg lower than expectation, only a 6% difference, which is in the range of the effect of getting a car wash.
It's really an 8% difference because of the lower energy density of E10, and 3 is a small number of times to repeat, especially with how inaccurate your measure of fuel consumed per refill is. You could easily overestimate by a gallon range 3 times out of 3 (either randomly, or maybe because shell pumps happen to shut off later). Someone else might underestimate by a gallon 3 times, assume their fuel economy is the same, and not get involved in discussions about it.
But again, even if you did this 1000 times on your car, it would not be sufficient to draw any conclusions about the effect of ethanol as an additive on fuel economy, because you have not eliminated possible systemic bias in measurements, have not used a range of vehicles, and have not controlled for other possible differences in the fuels, or alternatively have not directly measured their energy density.
I pointed out earlier in this thread that this has been studied by NREL.
http://feerc.ornl.gov/pdfs/pub_int_blends_rpt1_updated.pdf [ornl.gov]
They found a decrease in fuel economy of 3.68+/-0.44% at 95% confidence for E10, which is consistent with the ~3.5% decrease in energy density for the fuel.
Adjusting for fuels is relevant. If you get a less than 5% mileage drop using E10, this is to be expected, because there is less energy in the fuel. It's not because your car is using it poorly.
If they are mixing crappier gas with the ethanol because the mix allows them to meet the minimum octane rating, then this could easily explain a lower than expected mileage. If you are using 91 octane E10, your car might not even run on the gas the ethanol is mixed with. OTOH, if if the "100% gas" really is additive free, they might be mixing in isooctane, which would explain a higher than expected mileage. This is different than high-octane fuels, which don't actually contain extra octane.
Ethanol, as an additive, is something that most cars will benefit from, relative to the gas it is mixed with. It increases the octane rating and reduces direct emissions of pollutants. Currently, it replaces additives like MTBE (which in turn are what eventually replaced lead). I'm not sure if ethanol is better environmentally than MTBE, but I'm fairly sure it's better than lead additives. Isooctane might give you better mileage, but it also might increase carbon monoxide emissions relative to other additives.
I agree that there are downsides to using ethanol as an additive; the data just doesn't show that it reduces fuel economy itself.
I also agree that ethanol, as an alternative fuel given America's supply and technology is dumb. And there is certainly some political pressure to use more of it as an additive as a way to promote more use as an alternative fuel, and to subsidize the corn industry.
And arguing against several of those points is the very consistent swap between 265 and 300 miles per tank.
A tank is a very imprecise measure of fuel. Did you at least record exactly how many gallons each refill (rather than estimating from the tank size), and make sure the fuel gauge was in an identical spot, while stopped on flat ground, before each refill? Otherwise, perhaps you have a regular commute with 30-mile intervals, and just refilled when it was sort of near empty.
If you filled the tank 1/2 gallon higher with E0 (due to a difference in the nozzle), and went 1/2 gallon lower on the E0 (due to commute patterns and/or effects on the fuel gauge), that would explain the difference.
Regardless, even if your results were consistent enough to give statistically significant differences in miles per gallon (after taking into account energy density), that only shows that it was unlikely to be from differences in things like temperature, tire inflation, driving pattern, etc.
So I again refer you back to experimental results using fuels controlled to make sure they are in fact comparable. And again, the difference with your experience could be specific to your car, or a measurement bias, or a difference between the fuels aside from the ethanol content.
Since posting this, I'm also reading that some refiners have been caught occasionally goosing the fuel slightly above 10% ethanol to increase their profits too.
That doesn't surprise me.
Still- no damage to my car reported at my regular tuneups so it could not be too high.
Absence of damage in one engine is not sufficient to estimate the amount of ethanol. But they would probably get in very serious trouble if they went way over consistently.
You would have to run a fair few numbers to know for sure(once you get into total energy cost of manufacture, and similar considerations, things get kind of hairy...); but vehicle electrification might actually reduce pollution, even if fossil fuels are still being used to generate the power.
It definitely will, unless the electricity generation is 100% coal.
The main difference for manufacture, etc is the battery. Here's a paper on that:
http://dx.doi.org/10.1021/es1029156
It basically says that the share of energy and other environmental costs for battery manufacture is small compared to the savings from using European electricity instead of an ICE. For example, the life cycle greenhouse gas emissions are more than 30% lower. If you substitute Australia's energy mix (basically the most coal-heavy around), you still get 6% lower life-cycle emissions from the electric vehicle.
I have a few concerns about the poll. The biggest one is that the percentages only add up to 75%.
I think people who thought their mileage decreased would be much more likely to answer that poll.
And I think it is unlikely that those who answered the poll know how to measure such things properly. Some might even be comparing their observed mileage to the what was advertised on the sticker.
Some of the comments make it clear that they are comparing mileage years ago with E0 to now with E10, when their car is older. And at least one comment shows that they are using an octane boosters which I believe is not supposed to be done with E10.
So I think it's really hard to draw any conclusions from it.
That's right, assuming that it's actually 10% ethanol rather than "up to" 10% ethanol, and that the other 90% is the same stuff as the 100% gasoline.
It is possible that, for whatever reason, your car did worse with a switch to E10, or better after switching to E0. Could be just your car, and not the model. Or maybe the ethanol dissolved some junk from your fuel system. It is also possible that something else was different about the test. I'm guessing none of the measurements were very precise. It's even possible that pump nozzles were different lengths, or that the different density makes your fuel gauge read empty earlier.
But it's really likely that there are other differences between the two types of gas besides the 10% ethanol.
It may be anecdotal, but he isn't alone. There are an alarming amount of these anecdotes. Anecdotally, I've been able to repeat results like these with three different vehicles I've owned (they weren't flex-fuel vehicles, though--like most vehicles).
The plural of anecdote is not data.
It is also likely that few if any of these anecdotes involved comparable fuels and adjustments for the reduced energy density of the E10 fuel.
You mean someone who can get comparable mixes and run controlled tests... Like NREL?
http://feerc.ornl.gov/pdfs/pub_int_blends_rpt1_updated.pdf
They found a decrease in fuel economy of 3.68+/-0.44% at 95% confidence for E10, which is consistent with the ~3.5% decrease in energy density for the fuel.
I would argue that their tests on 16 vehicles are much more reliable than comparing unknown amounts (only counted the number of miles to get near empty) of unknown fuels (one of which might have about 10% ethanol), in unknown driving conditions using one vehicle, even if it is just one study without peer review.
Now, there is certainly evidence that the manufacture of ethanol consumes as much or more fossil fuel than the energy content of the ethanol. But that's the cost (along with the resulting additional emissions) we should be comparing to the tailpipe emissions reductions from Ethanol blends.
They are serious... And don't call me Shirley.
There are a couple of problems with the above analysis. First, the calculations involving random event probabilities are wrong. For example, the probability of getting heads exactly once when you flip a coin twice is 50%, not 100%. Second, lists of possible wait times are averaged without weighting them by their probabilities. For example, the average of 10 minutes 90% of the time, and 4 minutes 10% of the time is 9.4 minutes, not 7 minutes.
A light time of say 1 sale / minute, then your time is 1 minute since you can see what cashier is open.
If 3 customers arrive over the course of a couple of minutes, there is a 25% chance of an issue with one of them, an 8% chance of an issue with 2 of them, and an issue with all 3 is extremely rare. In any of those cases, the smoothly flowing lines will start to back up until the issues are resolved.
A medium time of when you have say 4 ppl in a queue, which is 12 sales/minute. That means that there is 50% chance of hitting a line that is going to have an issue. The reason is that the queue is NOT dependent on which line you choose by the DEPTH of the queue. You have limited capabilities to decide just by looking at others if they will have issues. In addition, the time will take between 4-20 minutes to get to the cashier, with an average of over 10.
No, if issues are randomly distributed, you have a 59% chance of no problems in your line (0.875^4), a 28% chance of 1 problem (0.41 * 0.875^3), a 10% chance of 2 problems, a 3% chance of 3 problems, and a 0.4% chance of 4 problems. Since these cases each take 4, 8, 12, 16, and 20 minutes, respectively, the average wait is 6.3 minutes. If you simplify and say that on average there are 0.5 problems, you still get 4 minutes plus 50% of a 4 minute delay, which is 6 minutes.
Finally, when the queue hits 8, then it is 100% certain that you will have a slow down of some type. In addition, the time will take between
13 to 40 minutes to get to the cashier with an average of close to 20.
At length 8, you have a 34% chance of no problems, and a 66% chance of at least one problem. It will take 8-40 minutes, and the average is 13.8 minutes, not 20 minutes. In the simple case, you have on average one 4 minute issue, plus 8 minutes of normal wait, for a 12 minute typical wait.
Assume that it is the medium load, which is 12 sales. There will be 1.5 issues during that time, but at least 1 cashier will run full out.
As such, the time will be between 5-10 minutes, with an average of about 6. In addition, you will be moving through the line QUICKLY.
Yes, on average 1.5 issues divided across 3 cashiers is 0.5 delays per cashier, which gives the same 6 minutes as the 3 separate lines.
With the heavy load, that is a total of 24 sales. That means that there will be 3 issues.
That means that you have a time of between 8-12 minutes, with an average of 10 minutes.
No, your average is around 12 minutes just like the separate lines, but you are more likely to have a wait closer to 12 minutes, and less likely to have an 8 minute wait, or a 40 minute wait. Even though there are on average 3 issues, sometimes there are more, and sometimes there are less.
So yes, a single line makes you have wait time closer to the average more often, and reduces the likelihood of a very long or very short wait. But it does not reduce the average, nor change the best or worst case. You can't magically make the cashiers process more purchases per minute with a different line ordering.
But the point is, when one line is moving faster, more new customers get in that line. And therefore, you, as an individual customer, are more likely to have a shorter wait. Yet on average, you have an average wait.
Take the 8-person lines. About 34% of the time, one of them processes 8 people in 8 minutes (and 8 new people get in that line). 26% of the time, there
More people go through the fast line, so you are more likely to be in a fast line than a slow one. You are also more likely to wait longer the times you are in the slow one. And on average, you will wait an average amount of time. Of course if there are many lines chances are there is at least one faster one.
Other than side effects, a single feeder line won't change the average waiting time. But it will make the first people to get in line get to the register first, which matches one way of looking at fairness, and also it optimizes the maximum wait time.
Let's try a simple example. Line A moves at 1 minute/customer, B moves at 2 minutes/customer, and C moves at 3 minutes/customer, then you have a 55% chance of being in line A, the fastest one. This is because in 6 minutes, 11 total customers make it through the line, and 6 of them were in line A. 1/3 of the lines are the fast line, and 1/3 of the people at the register at a given moment went through the fast line, but 55% of people go through the fast one.
And you're in the fastest line exactly 1/3 of the time (clock time, not purchases) if the lines are the same length, or more than 1/3 of the time if people are smart and accurately estimate the total wait time in each. And on average, you wait an average amount of time.
But the fast line processes more people per minute. So you spend a disproportionate number of waits in the fast line, and a disproportionate amount of time each visit to the slow line.
And on average, you spend the same amount of time in each line. And on average, you spend an average amount of time in line.
However, if people are smart and predict which line is moving faster (in a case where the delays are predictable, like a line of people with packed carts and a wad of coupons in their hand), that line will be longer and the others shorter. Then you are still in the fast line more often, but the wait time in each line would typically be more equal, and thus you also spend much more time in fast lines.
So any way you look at it, you are more likely to be in a the fastest line than the slowest (i.e. better than 1 in N chance, where N is the total number of lines). You're just more likely to remember being in the slow one.
But one single feeder line is more fair, even if it isn't more efficient.