Where Ethanol Fuel Actually Makes Sense

Growing mass quantities of corn to make ethanol to replace gasoline is stupid. It takes energy to grow the corn, and cornfields have a major environmental impact. It would be far better to replace most of the excess corn fields with pasture. Feeding grass to livestock is more humane and healthy. And pastureland can support a wide variety of native species, both plant and animal.

And don’t even think of engineering super bugs that break down cellulose into sugar so we can use plant fiber to make ethanol. This is Bond Villain technology. Or, to be more precise, a perfect scheme for KAOS.

Plant based ethanol is not going to replace gasoline by itself.

With all this being said, it does make sense to grow a bit of excess corn during good years. A bit. We want surplus food capacity on average so we don’t go hungry when there is a bad crop. Fermenting the excess on good years is sensible. Mandating corn based ethanol every year is dumb.

Also, there are many niche sources of waste sugar and starch that can be fermented into ethanol, as David Blume points out in Alcohol Can be a Gas. The key word is niche: stale doughnuts, defective fruit, cattails grown in nutrient rich wastewater…

These distilleries need to be small scale operations, otherwise they waste too much energy transporting the raw materials to where they are to be fermented. This is not Exxon scale business. This is one reason why creating a small business friendly environment is important part of cleaning up the natural environment.

So, ethanol from biomass can be a useful niche fuel source. Instead of adding ethanol to automotive gasoline, how about some niche fuel uses?

Ethanol for Small Engines

The government has ruined the gasoline can. Modern gas cans dribble out fuel slowly. Filling up a lawn tractor is a great way to get a backache. Spilling fuel is nearly impossible to avoid with the cheaper cans. The modern gasoline can is a poster child for environmental regulation run amok.

But the government over regulated gas cans for a reason: gasoline is dangerous stuff! A leaking gas can in the trunk of a passenger creates a dangerous concentration of explosive vapors. There is an argument for making idiot proof gas cans.

Gasoline is also toxic and slow to biodegrade. When spilled, it sinks quickly into the ground contaminating the upper groundwater. And those idiot proof gas cans are environmentally worse in this regard. (These metal gas cans are somewhat less bad, but they are heavy.)

hauling gasoline by passenger car is dangerous and unpleasant

What if we could do without gas cans entirely?

Replacing automotive gasoline with ethanol is currently impractical, but what about ethanol for small engines: lawn mowers, weed eaters, backup generators, chainsaws, and whatnot? Ethanol is much safer to handle than gasoline. Even at full concentration it has a higher ignition point. And you can put out an ethanol fire with water.

Ethanol has a low toxicity. People drink small quantities for the fun of it. Bacteria quickly eat that which is spilled. Even if the government mandates poisoning ethanol fuel with methanol, the mix would be less toxic than gasoline. Teachers used to hand out methanol coated paper to school children – methanol is an ingredient in mimeograph fluid. And, once again, if spilled methanol biodegrades rapidly. We need not fear contaminating groundwater.

Fuel cost is a much smaller consideration for small engines than it is for automobiles. Safety is worth a price premium, especially for those who have their garages connected to their homes.

The barrier we need to cross is engines that can burn alcohol. There are difficulties with the fuel. Since it is hydrophilic, we need extra efforts to keep water out. And some materials used in small engines corrode when ethanol is present. (Gasoline protects metals, like a very lightweight oil.) However, the technology to safely store ethanol, is well established:

ethanol tanks are old tech

It’s a matter of modifying small engine design to take the properties of alcohol into consideration. And, once again, burning alcohols for fuels is old tech. Indy cars ran on methanol back in the 1970s.

But is the market going to be around long enough to justify the retooling? Liquid fuels for the smallest engines is becoming obsolete. Battery powered string trimmers are adequate as long as you are just doing an hour’s worth at a time. (Or, one can buy extra battery packs…) Battery powered push mowers are available now at a non-astronomical price. We haven’t tried them out yet, so no opinion on whether they will replace liquid fuel powered mowers. Battery powered riding mowers are still rather expensive but are starting to look promising for medium yards. The reduction in noise and vibration might justify the price for some customers. (See appendix below for some numbers.)

The longterm case for liquid powered small engines might get limited to power users: professionals and people with very large yards.

We might want to look into other markets before investing efforts to use niche ethanol.

Other Possible Uses for Alcohol Fuels

Suppose we have more than enough ethanol capacity than we need for lawnmowers and the like? Or suppose electric versions dry up the market? Is there still reason for investing in small scale ethanol production?

Well, batteries aren’t going to replace liquid fuels for standby electric generators for obvious reasons. But that’s a pretty small market. And there are alternatives like propane.

Alcohol can also be used for cooking fuels. Sterno canned heat is basically methanol with a gelling agent. Once again, propane is a competitor.

Another possibility is alcohol for space heaters. Clearly alcohol is preferable to kerosene! It burns cleaner and you can put out an alcohol fire with water.

For survivalists, alcohol is better than propane. You can make your own if civilization breaks down. And for hardcore eco-hippies, sustainably sourced alcohol is better than propane as a matter of principle. These are some pretty small markets.

Boats are a possibility. Gasoline fires are a significant safety hazard for motorboats. An alcohol fire can be put out with water – which is readily available for boaters for obvious reasons. On the other hand, keeping the fuel dry is a challenge for boaters. A big bonus for alcohol fuel is for boating on small lakes – no pollution hazard. Whether this justifies the cost is another matter. Fuel costs for boats are significant.

Finally, we have the possibility of alcohol fueled small tractors. Fuel cost is a significant consideration for farmers, so alcohol will be a hard sell vs. petroleum fuel. But some farmers will be able to make their own fuel. Whether it would pay is an interesting question.

Another interesting question is whether there would be a market for bringing back spark ignition small tractors. Diesels are the norm. For small tractors without cabs, the farmer rides behind the smokestack. Breathing particles from diesel engines is not healthy. Some studies indicate that the smallest particles from diesel engines can travel from the sinuses to the brain, causing senility. This kind of defeats the purpose of getting back to nature…

Marketing and Tinkering Possibilities

Designing small engine equipment from scratch to burn alcohol is not for those with shallow pockets. But how about parts for existing models so that they can retrofitted to run on alcohol? In these days of 3D printing and computer driven machine tools, short runs of retrofit kits might pay. They would definitely make interesting projects for the eco oriented Maker hobbyists.

Retrofitting old tractors is an other interesting project. The fuel systems on old spark ignition tractors can be extremely simple and easy to access. Corrosion issues for the engine proper, is another matter. And are the compression ratios high enough on these old tractors to get reliable ignition with a less explosive fuel? (To get optimal use of alcohol fuels definitely requires upping the compression ratio.)

These are questions for the gear heads in the audience.

Somewhere in the ghosts of defunct tractor manufacturers lie the plans for spark ignition tractors. Maybe there are some old factories that could be reopened. Something to think about for those with real money to invest…

Appendix: Are Liquid Fueled Riding Mowers Obsolete?

A quick look at the Home Depot web site yields 42 inch cut gasoline powered lawn tractors ranging from $1450 to $1900. Engines have power ranging from 17.5 to 20 horsepower. These are just regular riding mowers, not zero turn. The zero turn mowers range from $2400 to $3700, with horse power ratings going up as high as 24.5 for the zero turn mowers.

Switch the search to electrics and we got only one regular lawn tractor for $4000, and several zero turn mowers with prices ranging from $4000 to $4400. The electric mowers are more expensive, but not astronomically so, especially for the zero turns. Lack of noise and fumes make these appealing to the luxury oriented lawn owner.

But let’s look at the power ratings. There aren’t any power ratings listed for the electrics, but there is mention of energy. A high end Ryobi has a 100 amp hour battery pack for a 48 volt system. That means 4.8 kilowatt hours per charge. One horsepower is roughly ¾ of a kilowatt. So the electric mower has 6.4 horsepower hours of energy storage. The ad copy says the mower can run for 2.5 hours easily. That would require running at an average of 2.5 horsepower.

Compare this with the gasoline powered mowers which go up to nearly 25 horsepower for the high end.

We wonder how well this expensive electric mower can handle high grass. 2.5 electric horsepower is more useful than 2.5 gasoline horsepower. Electric motors have great torque at low speeds, reducing stall problems. And with direct drive replacing belts and hydrostatic transmissions, energy transfer is going to be much more efficient.

But efficient enough? Actual testing is in order.

And how well can the electric handle the damp air of a garage with no air conditioning? What about grinding leaves on a cold day?

Alcohol fueled mowers might remain a viable choice.


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