Consumer reports found that E15 causes a drop in fuel economy that's more than 15% [1], meaning you're burning ethanol with your gas for no apparent gain and to the detriment of the environment in the form of increased emissions.
Ironically, on top of it all you're actually increasing your dependence on fossil fuels since since e15 requires more fossil fuel to get you the same distance as e0.
Can someone explain the argument for ethanol-based fuels?
Can someone explain the argument for ethanol-based fuels?
I can't explain everything, but I do know that in winter ethanol percentages in regular gasoline are increased, as I understand to increase vapor pressure which prevents a host of problems.
I'm not sure where you're getting the fuel economy drop from that link - it deals with E10 vs E85, where there's about a 30% drop (significant, but far less than the change in gasoline volume).
I'm curious to see how things change when you use an engine designed specifically for E85. I'm told ethanol behaves a lot like high-octane gasoline, which means an engine built for ethanol could have greatly increase compression, which can improve economy. Alternatively, you can run much higher boost, which I believe can directly improve efficiency, or can simply be combined with a very small engine.
Ethanol separates from gasoline in about a month. If the gas sat at the gas station for a few weeks before you bought it, it can separate before you use it up.
Ethanol will eventually damage the rubber and other components of your non-ethanol-safe fuel system. These components can be replaced with ethanol safe ones.
Small engines in lawn mowers, snow blowers, chainsaws, etc. seem to be more susceptible to damage from gasoline with ethanol in it.
In some places, the high octane gasoline does not have ethanol in it but some cars do not run as well on high octane gas because the gasoline does not ignite at the most efficient time for the engine. Where I live, high octane gasoline has no ethanol, and mid grade gasoline has half as much ethanol as regular grade does. Apparently our mid-grade is a 50/50 mix of regular and high-grade. I don't know if that makes sense, but that is what I've been told by 4-5 different people.
My car does not get as good mileage out of E10 gasoline. I experimented with using high octane gasoline and found that, even though high octane costs more, the extra miles per gallon I got was worth the extra cost. This will likely not be the case in cars that do not run well on high octane gasoline.
In my area, we do have a few gas stations that sell ethanol-free gasoline.
> In some places, the high octane gasoline does not have ethanol in it but some cars do not run as well on high octane gas because the gasoline does not ignite at the most efficient time for the engine.
I don't believe this is the case. Gasoline engines with higher compression need the higher octane fuel because it won't ignite at the temperature and pressure in the cylinder prior to the spark plug firing. Once the plug fires, the temperature and pressure are right for gasoline of any octane level within reason to combust.
There's no downside to running high-octane racing gasoline through a low-compression engine like the Atkinson-cycle engine in the Prius, but no benefit either. Other engines, like the 5.0 V8 in the Mustang GT, have different performance ratings for different grades of fuel. Still other engines, like the 2.0T I4 in the Volkswagen GTI, require high octane fuels for the extra compression they run.
If the engine has adaptive ignition (retards spark in response to
pinging/detonation) then using lower octane fuel in a
higher-compression engine may not result in engine damage - just
less power.
OTOH, using higher octane than the manual / engine specs call for is
just a waste of money for no extra power - but is not damaging to
the engine.
One of the less-noticed issues with ethanol as a fuel is that it
contains/provides ~33% less energy than gasoline[1] - so saving n%
per gallon at the pump may cost you n% in mileage down the road.
[1] http://www.eia.gov/tools/faqs/faq.cfm?id=27&t=4
More stops for gas might benefit fuel vendors by providing them more
opportunities to sell you higher-profit impulse or convenience
purchases over the counter.
> Apparently our mid-grade is a 50/50 mix of regular and high-grade. I don't know if that makes sense, but that is what I've been told by 4-5 different people.
Yes, typically gas stations only have two tanks of gasoline: low-grade and high-grade. When you select mid-grade it's blended at the pump.
What do you drive? Typically the only cars that get really poor fuel economy with "Regular" are cars that specifically call for "Premium". When you fill them with "Regular", the computer essentially puts the engine in emergency limp-home-mode to prevent catastrophic damage, which reduces power and efficiency.
I drive a 1996 Honda Accord EX. It gets better mileage on Regular than Premium, but better mileage on Premium than E10 Regular, even after factoring in the price difference.
Are there any engineers here with actual firsthand knowledge? Or are we just going through the usual repetitions of viral online propaganda?
The "energy to mass ratio" is a straw man. It's a wholly meaningless and propagandist-type figure that people like to repeat. What we really ought to do is load cars with plutonium so their energy to mass ratio is just absolutely stellar, right? I've been running E85 in my 2006 Subaru -- a setup I designed specifically to work at compression and intake temperatures only ethanol is capable of dealing with. If my car ran gasoline in these conditions it would quickly explode.
If the problem with ethanol is economics, let's discuss that. When people mince economics and engineering this way it reminds me of christian scientists or something mincing god and empirical facts. It's just offensive.
I've been running E85 in my 2006 Subaru -- a setup I designed specifically to work at compression and intake temperatures only ethanol is capable of dealing with. If my car ran gasoline in these conditions it would quickly explode.
And this tidbit of knowledge is useful to the rest of us how?
There's nothing wrong with ethanol as a fuel per se. It has the potential to be a great sustainable fuel made from farm waste and other sources. Unfortunately, the bulk of it now is being made from subsidized corn. This pits all of us who would champion ethanol as a sustainable fuel against it since the current state of the industry is based on very bad policy.
There's nothing wrong with ethanol as a fuel per se.
== This is a completely uneducated comment.
Ethanol has poor energy to mass ratio and is unstable and/or reactive chemically with things that aren't stainless-steel, which make up certain "mission-critical" sub-systems of petrol-designed-combustion engines. Its notorious clogging/eating EFI systems/sub-systems that are not "hardened" or and/or specially maintained. The only really "good use" of ethonal is in applications that have terrible environmental side-effects. For example, e85 is very useful if you want to make a cheap substiture for high-octane fuel in performance applications. But notice in California, "octane" ratings are limited to prevent "high-performance" applications for fuel because as a general rule they are "environmentally unsound". But e85 has terrible gas mileage (1/3 less than e10), which even in everday use means more haulage or more mass==more road wrear, more stops to refuel, etc==more environmental damage.
I could go on, but will spare you the rant =D
TLDR: Petrol is a better store of energy/mass a nd depreciates a motor at a slower rate.
[edit: To answer the GP question, the easiest way to get reliable fuel without ethanol is to buy "race gas" with octane ratings > 100+ at something like 2x the price of normal octane fuel ~87.]
This comment is just 400% wrong. And to make the claim that the OP was uneducated just misleads everyone here on HN. I'm someone who has run E85 blends in my 2006 turbo Subaru for the last 4 years. I can personally attest to E85's increased stability and cooling power from my time personally playing and tuning on a chassis dynamometer and gathering real world data. I would prefer E100 if they could sell that at the pumps too: it simply reduces the chance of pre-ignition or dual flame-front events from the petroleum blend.
I think as scientists and engineers it's extremely important we separate the empirical facts from the political propaganda.
Flagged? Seems to me it's pretty tough to get around the mpg arguments. Likewise, the wear on engines is well known in the marine environment -- which is not all that different from driving on PNW roads in the winter. Most of our cars ran fine on E0, and I'm not at all sure what you're concerned about in terms of pre-ignition or dual flame-front events (my car, like most, was designed to run on 87 octane).
How do you know it's wrong? The argument is that ethanol degrades an engine more quickly than gasoline; presumably testing this would require studying a whole fleet of engines for a long span of time--probably longer than 4 years.
> I think as scientists and engineers it's extremely important we separate the empirical facts from the political propaganda.
Right but a single anecdote about your own car doesn't move the conversation forward. It sounds like you may know more on this subject than most, give us some details and sources.
Where I live, a few of the "76" stations advertise very loudly that they don't add ethanol to their fuel. They don't seem to be much more expensive than the E10 stations either.
You're probably burning tax dollars as well if you're burning pure gasoline. And corn used to ethanol is usually feed corn - it was never going to directly be eaten by a human anyways. The degree of indirectness from actual food is at the level where you should also be aware of any activity that promotes farmers doing anything but grow and sell human food.
Using E0 hasn't been cheap for America. The low pump prices paid have made for a car market where small and efficient is less popular than elsewhere on earth, and the prices paid for middle eastern stability (which hasn't been very successful) has been footed by huge (mainly US) military expenditure.
One of the things worse than burning petroleum in cars is burning corn ethanol in cars. It has essentially all of the downside, only amplified through energy inefficiency and politics.
If I had any political power, I'd end the ethanol subsidies. That would be the simplest change to save ~$20b or so ($6b in direct costs, higher corn prices, corn subsidies, use of fossil water and other limited resources, less fuel efficiency)
Small and efficient are popular elsewhere because US gas taxes are hugely lower than the rest of the world (other than producer countries that have huge subsidies, like Saudi and Venezuela). US taxes average 49c a gallon vs UK $4 https://en.wikipedia.org/wiki/Fuel_tax and thats what makes the difference.
Yes. And much of the rest of the world perceives (rightly or wrongly) that the Middle East is that mess that it is in part because of the US need to maintain their low prices by guaranteeing supply through military aid and maintenance of some terrible governments.
Unfortunately, making ethanol out of corn still uses a lot of oil: farm equipment for harvesting corn is powered by diesel fuel and fertilizer is made of petroleum-based chemicals.
I don't understand this argument. Burning E10, my car gets at least 10% worse gas mileage than on E0. So how exactly is any fossil fuel being conserved?
I'm a motorcycle enthusiast, and I remember this getting some attention in the motorcycle industry.
Ducati is involved in a lawsuit because the plastic that they use for the gas tank, some believe that the ethanol that is being mixed in eats away at the material.
The AMA (American Motorcycle Association) has come out against proposed ethanol standards:
>“The AMA supports the use of cleaner-burning fuels, but we are concerned that gasoline containing more than 10 percent ethanol could result in premature engine damage or failure while a motorcycle is being ridden,” Imre Szauter, AMA government affairs manager said last year, “We’re also concerned about any degradation in performance, fuel economy and rideability that may result from the long-term use of blended fuels with greater than 10 percent ethanol.”
One thing not mentioned so far is the use of high pressure fuel pumps for common-rail injection petrol engines. This used to be something you only found on diesels. The lubricity of diesel fuel is a factor in the design and longevity of the high pressure (~1000s PSI) pump.
Some models (eg. E90 BMW 335i) suffered from early high pressure fuel pump (HPFP) failures in the US. It would be interesting to find out if there's any hard data on this (I imagine it'll be closely guarded by the manufacturers) but I'd suspect ethanol in the fuel as a factor - ethanol is even less of a lubricant than petrol and the HPFP may well suffer additional friction as a result.
While this is n executive decision, the EPA is still subject to legislative influence by those that hold the power of the purse.
There are currently 18 members of the U.S. Senate Committee on the Environment and Public Works.
Ethanol has a lower density than gasoline. So, although it has a similar mass-specific energy content, the volume-specific energy content is lower. Ethanol has a greater resistance to ignition than gasoline. But, since consumers buy gasoline in grades based on the octane rating (usually (RON+MON)/2), you don't see any octane benefit in your tank and do get reduced energy content.
It's a scientific fact based upon the free energy content of the same amount of gasoline versus the same amount of ethanol. Ethanol just doesn't have as much energy as regular gasoline. If you've observed the opposite effect, you're experiencing some kind of confirmation anecdote. I can almost promise something else is at work, such as less wind pushing on the nose of your car, different temperature, tire pressure, hills, something.
E85 is really bad, and will cost you 20-25% of your MPG compared to burning the equivalent amount of gasoline.
EDIT: The U.S. government publishes figures more conservative than what I just said, based on the link above me that I just read. They cite NREL/TP-540-43543[1].
It's a scientific fact based upon the free energy content of the same amount of gasoline versus the same amount of ethanol. Ethanol just doesn't have as much energy as regular gasoline.
This by itself is meaningless. Diesel also has less energy than regular gasoline, yet diesel vehicles can generally beat equivalent gasoline vehicles in terms of mpg. There are more factors than simply energy content!
Whoops! Well, anyway, I think my point still- energy content is not the only factor- as diesel can get much more than 12% improved fuel economy. Diesel runs at much higher compression ratios, which is a good part of the increased economy. There's other things too, like the lack of a throttle plate which reduces pumping losses.
If it got cars off the road without replacing them, it would make sense. Unfortunately this isn't the case, because it's now a matter of federal interest to save the auto industry.
Ironically, on top of it all you're actually increasing your dependence on fossil fuels since since e15 requires more fossil fuel to get you the same distance as e0.
Can someone explain the argument for ethanol-based fuels?
1. http://www.consumerreports.org/cro/2011/01/the-great-ethanol...