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What We Know About Ethanol & Ethanol Additives Ten Years On
We’re now more than ten years out from the nationwide switchover from non-ethanol gasoline to ethanol-blend gasoline fuels. So we’ve had a decade to see what ethanol does and what it doesn’t. At first, there were serious concerns all the across the spectrum. Some of these fears that the industry had about ethanol have not come to pass, but many have not, or have not been as serious as first anticipated.
Now that the smoke of the past decade has cleared, here’s the best current knowledge about ethanol gasoline – the good, the bad and the ugly.
Ethanol Is Added to Gasoline to Make it More Environmentally Friendly and to Raise Octane
The primary reason ethanol is added to gasoline is to reduce the pollutants produced when burned in an engine. Ever since the Clean Air Act was passed several decades ago, Federal law has mandated that certain things called oxygenates be added to gasoline to help urban air pollution. An oxygenate is something that adds more oxygen to the gasoline so that the gasoline makes fewer pollutants when it is used.
As you’ll see below, ethanol is also added to gasoline because it fills an additional role of adding to the gasoline’s octane value. This helps the gasoline burn correctly, with minimal problems, in today’s engines.
Everyone Blames the EPA for Ethanol, but it’s not Their Fault
The EPA gets a lot of blame from the general public for whatever they dislike about ethanol. But truth be told, it’s not the EPA’s fault. They just do what Congress tells them. And in this case, it is Congress that passed the rules requiring ethanol to be in our gasoline.
Four pieces of legislation were the biggest influencers in the rise of ethanol. President Carter, during his push to reduce the country’s dependence on oil imports, spearheaded the 1980 Synthetic Fuels Act – one of the initial efforts to get people to think differently about the fuels they use. Unfortunately, its momentum was thwarted when the price of oil plummeted in the 1980s, and alternative fuels kind of dropped off the radar – gasoline and diesel were too cheap for people to seriously consider using other things.
Three other pieces of legislation followed that brought us to our current place. The 1988 Alternative Fuels Act required government agencies to purchase vehicles that run on alternative fuels while providing financial incentives for automakers to develop more kinds of vehicles to run on these fuels. This was a big step of faith at the time because ethanol and biodiesel weren’t yet widespread in availability.
The 1990 Clean Air Act gave the EPA authority to push for mandates (like requiring the use of alternative fuels) to make air quality better. One of the actions the Clean Air Act triggered was creating a demand for “boutique” gasoline that has special ingredients added to them to make them better for the environment. See where we’re going with this?
A couple of years later, the 1992 Energy Policy Act defined a long-term goal that by 2010, alternative fuels made from non-petroleum sources would have penetrated 30% of the fuel market. This set the table for the 2005 Energy Policy Act and the Renewable Fuels Standard, or RFS. The RFS is the legislation that defines how much renewable fuel the country would have to use in a given year. This means the ethanol requirement comes from the requirements of the Renewable Fuels Standard which comes from Congress. The EPA didn’t create it, but they have the task of helping to implement it.
Ethanol Didn’t Just Show up in the 1990s. And it Wasn’t the First Thing They Tried
If you didn’t know your history, you might be under the false impression that we only started using ethanol in, say, the 1990s or 2000s. In truth, ethanol as a vehicle fuel has been around for almost as long as there have been cars. The old Model T from Ford was built to run on either gasoline or ethanol. You could consider that (and its similar contemporaries) to be the first “flex-fuel” vehicle.
The laws mentioned earlier require the addition of oxygenates to gasoline to make it cleaner-burning. But ethanol wasn’t the first one they tried.
If you’re over the age of 45-50, you may remember the MTBE that was in widespread use in gasoline in the 1990s. MTBE was the first oxygenate adopted on a large scale. It reduced gasoline emissions and it raised gasoline octane value. At its peak in 1999, 200,000 barrels (8.4 million gallons) per day of MTBE were being produced, all being added to gasoline at a 10% treat ratio.
Unfortunately, scientists began to find evidence that MTBE easily contaminated groundwater. This led to its widespread withdrawal from the market. The search for an oxygenate replacement led the industry to the choice of ethanol to displace MTBE.
It’s Hard Find Non-Ethanol Gasoline (But Easier Than It Was A Few Years Ago)
As consumers became dissatisfied with their experiences with ethanol-blended gasoline, they began to look for alternatives. This typically meant trying to find non-ethanol gasoline. They found that, as we got further and further on from 2006 and 2007, the number of places to get non-ethanol gasoline got smaller and smaller. By 2010, the number of these stations in North America was less than 5,000. In some states, you may have had to travel several hundred miles to find a gas station that has any of its fuel pumps selling non-ethanol gasoline.
Today, the trend of decreasing availability of non-ethanol gasoline has seen somewhat of a reversal. As people found it difficult to find ethanol-free gasoline, they let it be known that they would be willing to pay more to get it. The market responded to this, and many large retailers like Wawa began offering E0 (ethanol-free gas or “pure gas”) at their stations for a substantial markup, often over 40 cents per gallon more. As of the end of 2017, there are around 12,500 outlets across North America that offer ethanol-free gasoline in at least one of their grades. That may seem like a lot, but consider that there are more than 180,000 retail gasoline outlets in North America. Thus, the chances of any one place you come across selling E0 gasoline is going to be less than 10%. But it’s more than it used to be, especially in 2022.
The Fears About E15 Infiltrating the Nation Have Been Largely Unfounded
After E10 became entrenched across the country, the next logical step to anticipate was a possible jump to 15% ethanol or E15 fuel. This pleased the Corn Lobby and advocates for renewable fuels, both of whom have profited from the renewable fuels trend. But ten years on, this anticipated move hasn’t come to pass to the extent initially feared.
Why is that? The biggest reasons have been pushback from consumers and certain types of businesses, along with inherent (but unexpected) limitations that came out of the Renewable Fuels Standard legislation itself. Let’s explain.
A lot of people have been very vocal about not liking 10% ethanol in their gasoline. They didn’t like what they thought it did (more on that later). They also viewed it as an obtrusive government action interfering in their lives.
At the same time, industry groups like small equipment manufacturers (i.e. Briggs & Stratton) and the Engine Manufacturers Association voiced real and loud concerns about the potential effects that E15 would have on small equipment. Both of these groups have played a role in slowing the anticipated spread of 15% ethanol across the country. As of March 2017, E15 was only available in 28 states across the country.
There’s also yet another significant factor at play, and it has to do with the RFS legislation itself. The Renewable Fuels Standard that we mentioned earlier defines, by law, that in a given upcoming year, the nation must use at least x amount of renewable fuels - ethanol and biodiesel, by and large. In 2016, the RFS requirement was 18.11 billion gallons. That went up to 19.28 billion gallons in 2017 and is scheduled to level off at 19.24 billion for 2018.
Now consider that the amount of ethanol that the country uses is determined by two factors – the amount of ethanol in the gasoline (i.e. 10% or 85%) and the amount of gasoline used by the country. If the amount of ethanol in the majority of gas across the country went up from 10% to 15%, that would cause a big jump in the total amount of renewable fuels used. In turn, that has to be balanced by the other side of the equation – the total amount of gas used by drivers. And this is determined by the number of vehicles out there and how much mileage they get.
As expected, the number of cars on the road increases regularly with each passing year. But what was not expected is that cars and trucks are more efficient today than ever before. Blame the government’s CAFÉ standards that force automakers to make more efficient vehicles. These standards have had the unanticipated consequence of drivers simply using less fuel than expected because their cars get better gas mileage.
So Congress is having to balance possibly raising the nation's ethanol average from 10% to 15% with the need to stay within the requirements of the Renewable Fuels Standard. That’s a big reason why E15 hasn’t become as widespread as people first feared – there’s been no requirement for it to be used.
Ethanol Has its Benefits
Lower Emissions
To be sure, ethanol imparts some advantageous qualities when blended into gasoline. First and foremost are reduced emissions. These may not be so important to the average consumer (unless they are concerned about going green), but this is the advantage the EPA likes when it considers its mandate to protect the environment.
Ethanol blended into gasoline at a 10% to 85% ratio results in a fuel that produces lower levels of harmful urban air pollutants than pure gasoline. This brings positive effects on smog and pollution levels in urban areas that may have traditionally struggled with this problem. These benefits are on the order of 30% lower levels of greenhouse gas and harmful exhaust emissions produced. The higher the ethanol percentage, the greater the reduction.
Higher Octane
Oxygenates like ethanol and MTBE already were in use as octane improvers before the 1992 Clean Air Act (after the time when they phased out tetra-ethyl lead). Pure ethanol has an octane rating of 113, while E10 blends have the octane rating listed at the pump, which is usually the same as regular or premium gasoline. Unfortunately for the consumer, it is likely because, despite the ethanol additive having a high octane rating, the fuel blender uses a lower octane base gasoline to end up with the same octane rating in the E10 blend as they had before. So the consumer doesn’t get an added octane benefit in an E10, despite the ethanol fraction having a higher octane rating.
you get Lower Mileage on Ethanol Than Regular Gasoline Because Ethanol Has Less Energy in it (Although the Mileage Drop Can Be Overstated)
The reason people around the country complained so much about the mileage they were getting with ethanol gasoline is that ethanol contains less energy than pure gasoline does. Energy value in petroleum fuels is a function of the number of carbon bonds in the molecule. Gasoline molecules are much longer, with more carbon bonds, than the smaller ethanol molecules, so you have less energy potential in that blended fuel. This will cause a mileage drop or fuel usage increase in any kind of equipment that uses this fuel.
How much of a drop depends on the concentration of ethanol in that fuel. E10 users can typically expect a 3 to 5% drop in fuel mileage just from the fuel alone. E15 users would expect a larger drop and E85 users would see upwards of a 22-25% drop in mileage (which is consistent with the 25% lower energy level of the E85 fuel).
Ethanol Attracts Water From the air, Which Is bad News on Many Levels
When exposed to air, ethanol will pull moisture out of that air and into whatever fuel it's blended with. Ethanol has such a strong attraction to water that chemical producers cannot even sell 100% pure ethanol – it is always 99.8% or less because there will always be at least a tiny bit of water.
As this water accumulates in a fuel or storage tank, it sinks to the bottom of the tank because water is heavier than fuel. It then contributes to a whole host of fuel problems and issues.
It Doesn’t Take Much Water to Cause Phase Separation, Which Makes gas Borderline Unusable
Phase Separation means the ethanol "phase‟ separates from the gasoline "phase‟, transforming the fuel from a homogenous mix of petroleum distillate and alcohol to a fuel with two layers of two different compounds. At this point the ethanol and water will sink below the gasoline phase, producing an ethanol-water phase layer. The typical ethanol-water layer at the bottom of a storage or fuel tank contains around 50% alcohol and 50% water.
We say the fuel is borderline unusable because, when ethanol separates from gasoline, it causes a loss of 2-4 octane points in the fuel mixture. As it separates, it drags down the octane value of the gasoline. An 87-octane fuel that separates can have its octane rating drop to 83-84, which is unsatisfactory for most vehicles and will cause performance issues.
This phase separation process happens over some time such that a lot of storage tanks will have partially separated fuel in them. And as we said earlier, it doesn’t take a lot of water to initiate this process. The general rule of thumb is that you can expect phase separation to start once the gasoline absorbs more than 0.5% in water - only about a couple teaspoons of water per gallon of fuel. This effectively means that any ethanol fuel left long enough will separate and degrade.
Not only will water absorption initiate phase separation in the fuel, it is also one of the impurities that will accelerate oxidation reactions in any petroleum-based fuel. This holds whether it is gasoline, diesel, biodiesel, or ethanol blends. Oxidation reactions are responsible for fuel stratification and the fallout of heavy ends from the fuel mixture. These heavy ends can build up in the bottom of a fuel storage tank, and when they are injected as fuel, they will leave deposits in all parts of the combustion system – combustion chamber, valves, and fuel injectors. At best, you get a higher emissions level running through the catalytic convertor, along with rough running and poor engine performance, while at worst you get lower mileage.
Ethanol Is Damaging to Rubber, Plastic, and Even Some Metals (but Mainly in Small Equipment)
Ethanol damages many kinds of polymer materials found in fuel systems and engines today. Over time, ethanol will soften and dissolve polymer compounds like rubber and plastic. This happens gradually and gets worse the longer the fuel sits in contact with these materials (as it does when you leave fuel sitting inside a lawn mower).
As this happens, the dissolved materials will then be carried out by the ethanol fuel into other parts of the fuel system and engine, and leave performance-robbing deposits in those areas, not to mention the damage to those essential parts that may render the equipment unusable.
Sometimes, in discussions of this kind of problem, you may see ethanol fuel being referred to as being “corrosive” to rubber and plastic. That’s a misnomer – corrosion is a process that happens with metals, not polymers. The ethanol fuel softens and damages those parts. But it is certainly corrosive to metal parts in the fuel system such as small engine carburetors. This process is a good reason why boat owners and small equipment owners are advised not to leave ethanol fuel sitting in the gas tanks and fuel lines of these important and expensive pieces of equipment when they are stored for the off-season.
And if you’re on the business side and you have to manage stored diesel and gasoline fuels, you may recognize that we haven’t even mentioned the microbe-induced corrosion damage that ethanol fuels contribute to in storage tanks. This is a huge problem for stored fuels that we touch on in more detail elsewhere.
Having said all of this, it’s important to acknowledge that the initial fears about this kind of damage happening to vehicles hasn’t materialized (no pun intended). Cars and trucks made in the last 30 years or so have no worries about fuel system damage from ethanol. It’s the small engines and small equipment where the ethanol damage is a real concern.
Two-Cycle and Small Engines Are What Ethanol Gives Fits
Ethanol destroys 2-cycle engines by interfering with the lubrication that the fuel oil mixture provides. Remember that 2-cycle engines use oil mixed into the fuel to provide their essential lubrication. The oil in the fuel bonds to metal parts to keep the engine running. Ethanol fuel attracts water, and that water can prevent the oil in the 2-cycle fuel from bonding to the metal surfaces. This causes catastrophic engine damage and gives a lot of business to small engine repair shops everywhere.
Putting Too Much Ethanol in Your Car Can Fool Your Car’s Computer
No doubt you’ve heard of the “flex-fuel” vehicles. These are vehicles that have had engine modifications to enable them to run on either gasoline or a high concentration of ethanol like E85. These vehicles have no problem running on any concentration of ethanol in their gasoline, from 0 to 10 to 15 to up to 85%.
They can do this because they have special fuel sensors to properly read the ethanol-fuel mixture and special fuel injection modifications to ensure the fuel-air mixture supplied isn’t too rich or lean.
The rest of the vehicle population (excluding classic cars) have all been programmed to be able to run normally on 10% ethanol fuel. But what happens if you fill up at a gas station where the fuel pump says “up to 10% ethanol” but which has 15% or 18% ethanol or higher? We ask the question because that happens a lot more often than you might think – gas stations with actual percentages of ethanol in their gasoline that are higher than labeled.
When this kind of fuel gets burned in a non-flex-fuel engine, the fuel-air mixture starts skewing away from what it needs to be, and the computer senses the result. Remember, the computer is assuming that it’s injecting 10% ethanol or less, and it can’t detect differences and change what it's doing if the actual amount of ethanol is higher than that. Part of this discrepancy comes from the altered density of the fuel (i.e. 15% or 18% ethanol weighs a different amount than 10% ethanol) and part of it is due to higher levels of oxygen (because of higher levels of ethanol) hitting the oxygen sensor. When the O2 level of the exhaust is higher than expected (because the computer is expecting oxygen levels commensurate to that of 10% ethanol, not 15 or 20%), it fools the computer into thinking that the fuel-air mixture is too lean, with not enough fuel in the mix. Essentially, a false positive reading has been created in this scenario.
What does the computer do to fix this false positive problem? It injects more fuel than it needs to, because it’s been fooled by what it is seeing. And that means the driver’s mileage and performance go down even more than expected.
No Fuel Additive Can Remove Ethanol From Gasoline
In the ten years that people have been dealing with ethanol-gasoline, they’ve been exposed to lots of fuel additives coming along, claiming to do weird and wild things with the ethanol in their fuel. Most of them have been proven to be as worthless as their claims are. A few more outlandish claims come along center on fuel additives being able to get rid of the ethanol in the fuel and reverse phase separation.
Some fuel additives claim that by adding them to ethanol-blend gasoline, they make the ethanol disappear. A neat parlor trick, to be sure, but in the end, complete nonsense. Ethanol alcohol is a part of the gasoline once it’s added; there’s nothing you could add to effectively make that part disappear. There’s no chemical reaction going on in the fuel once you add the additive. The ethanol in the gasoline isn’t going anywhere.
And regarding phase separation, some industrial additives claim to reverse and “fix” phase-separated fuel. If it was possible to do that, that would be a huge bonus for people storing ethanol gasoline. But it sounds too good to be true because it is. These “fuel repair” additives have fine print that tells you they only fix partially separated fuel – a long way away from what they imply in their marketing print. And even with partially-separated fuel, they only claim to be able to fix separated fuel that’s just started the process. In other words, they don’t do very much at all.
What time has shown us in the last ten years is that the only thing that you can do to prevent damage or problems from the ethanol fuels available at your local gas station is to use a fuel additive to treat the problems and symptoms that ethanol causes in your engine, fuel system and fuel storage tanks. There’s nothing you can add to ethanol fuel to make the ethanol go away, nor is there any cost-effective way to repair phase-separated ethanol gasoline. These are cases where an ounce of prevention is worth more than a pound of cure.
