Turning Grass into Gasoline: Green Fuel Revolution

[Music] the world runs on fuel and we get a reminder of that every time there's some disruption in our supply with the caused by geopolitical embargoes natural disaster pandemics or hackers we regularly get a reminder of how dependent we are on fuel in this video we are exploring some theoretical sources of potentially producing this crucial commodity if you absolutely had no other way to just buy it using something most people already have in surplus grass my name is andy from the youtube channel how to make everything so curiosity stream challenged me to try and produce

my own fuel from scratch so today i'm going to try and take grass for my lawn and see if i can convert it into a fuel that i can use to power my lawnmower [Music] there are an estimated 40 to 50 million acres in the united states alone dedicated to growing grass for purely cosmetic purposes this makes grass the single largest irrigated agricultural crop in america maintaining watering and fertilizing lawns has a pretty negative environmental impact all while producing no real crop so what if we could actually put to use this arguably wasted cropland and

drive enough fuel to potentially power our own lawn mower making fuel from plants is not a new idea and most people are likely aware of ethanol produced from crops like corn in the u.s 95 of ethanol is produced from corn and 25 of corn cropland is used for the production of ethanol however corn-based ethanol is not exactly cost-effective or efficient and likely only exists with the help of government subsidies this is in part because the ethanol is limited to being derived just from the starch of an ear of corn in contrast to corn based ethanol

cellulothic ethanol is seen as the real future for cost-efficiently deriving ethanol from plants in contrast to using just a starch from corn that otherwise could be eaten by humans or livestock sodium lothic ethanol is derived as the name implies from cellulose which is inedible to humans cellulose composes the majority of plants including the rest of the corn plant but also in much faster and more effectively growing grasses the challenge then is turning the cellulose into a sugar that can then be fermented into alcohol cellulose like starch is a chain of sugar molecules there are two

main ways to break them down to just the sugars one way is based on specially designed enzymes similar to the ones that we found in animals that can digest cellulose the second way is with the use of an acid called acid hydrolysis i'm going to attempt the second way since i have easy access to an acid like sulfuric acid by just buying drain cleaner from the local hardware store i'm going to try and limit myself to just the type of equipment available to your average consumer which is going to make things a bit harder without

industrial scale equipment for grinding and reacting everything things might get a little messy i need to improvise a bit on my equipment and it's probably going to take a bit of trial and error this process is not easy even under ideal laboratory settings bringing you a shot and see what i can do so let's move my lawn and get started [Music] of all the grass that i mowed this past week and i've been laying it slowly dry out in the sun and now i'm going to try and pulverize it using this mulcher to make it

into a fine powder the finer we can get it the more surface area we have to react and extract cellulose from so let's give it a shot and see if we can get some nice fine powder of grass it ended up being a little bit more difficult than i expected the mulcher was not as effective as i wanted in actually pulverizing the grass into the fine powder that was really hoping for and i tried a few other ways like a blender or a grinder and none of them were really that effective and were a lot

more laborious and slow which for the volume we're trying to work with is not ideal so i got all the grass mulched up as best as i could so next up sulfuric acid a couple gallons of drain cleaner they're mostly pure sulfuric acid we're going to react it in a process called acid hydrolysis and that is basically the chemical reaction where you react the cellulose in the grass with an acid to break down the cellulose chain into smaller molecules that are sugars and that these sugars will be able to ferment and a lot of times

they use high pressure and high heat which is not going to be too achievable with the setup i have but i did manage to find one paper that was fairly promising that talks about using a diluted sulfuric acid solution of about two percent [Music] it took a lot more line than i expected but it was able to neutralize our solution to something that is balanced at 7ph i'll be ready to start the next phase of fermenting so to test it first i took a brix refractometer here and took a reading of the solution here which

would give an idea of the sugar content we were able to extract and that should work out to roughly 83 grams per liter with the volume of the solution we have that should work out to roughly 20 pounds of sugar if the math is correct so when that ferments actually get about half a gram of ethanol for every gram of sugar so theoretically we should be able to yield roughly 10 pounds of ethanol which works out to about a gallon and a half will we actually get that probably not there's some potential that the sugars

that were broken down from the cellulose are not ones that are fully fermentable that's kind of the challenge people run into with this but hopefully we should get a good yield from this so the next step is to add the yeast and leave it to ferment [Music] so while we leave that to ferment just a quick reminder if you want smart fun content like this video in the future go ahead and subscribe to curiositystream's youtube channel since they're the ones helping me do all these challenges even after the addition of three different electric heaters to

the actual barrel itself my little diy moonshining distiller it's still not getting quite hot enough so i'm going to try and put it into a smaller container and heat that should be a little bit easier so i'm going to siphon out using a brewer siphon suck out all the juice from inside here fill up this container heat this up with the barrel heater and should hopefully get a better result because it'll be easier to heat with a smaller volume and then we can start distilling out and see if we get any alcohol in this first

batch [Music] basically everything below the boiling point of water collected that and got a very small sample kind of disappointing for the huge supply that i tried to ferment much less than the couple gallons i was hoping to get based on my initial measurement of the sugar with the brexometer there's potential there's some other things in there that gave me a false reading on the brexometer so we got different results from what i wanted i was able to yield a very small amount likely just a few tablespoons for this 30 gallons of fermentation that i

attempted i think this is kind of what the the big challenge with doing this process for producing ethanol is that you get all these kind of side chemicals that inhibit fermentation so you have to do a whole extra step to try and remove that most likely it was these inhibitors that prevented fermentation to happen there's also some other potential issues that might have happened with not being able to grind the grass up fine enough and not really being able to seal the barrel well enough while it fermented could have allowed secondary fermentations to happen and

really decrease the yield to solve with the difficulty of getting it to the extra small particle size i'm gonna bite the bullet and upgrade to an even more expensive blender go from the 30 blender to the 300 blender and see how much improvement that can make and lastly i'm gonna do this in some smaller batches so i can control it and i can seal things up a little bit better both for when i'm reacting with acid and then also the fermenting and create a much stronger seal and won't have to worry about oxygen or other

contaminants getting in and disrupting our results [Music] so i'm gonna try three different batches and see which of those work and which one will actually give me usable results so first up one of the versions i'm gonna do is exactly what i did before with the acid hydrolysis but then before i ferment it i'm gonna run it through a type of filter through some sawdust that's soaked with both sulfuric acid and lye that should hopefully remove a lot of these inhibitors the second way i'm going to do is apparently by just using a higher concentration

of acid you get a lower result of these inhibitors so i'm going to try that as well and then the third way is kind of a multi-stage process of doing it one form of acid hydrolysis at first wash everything away sugars that aren't as fermentable and other byproducts pulverize the product even further and then a last step of acid hydrolysis then after that you hopefully get just the glucose that we're after [Music] all the grass ferments i brought my mower over to someone mechanically inclined to convert it from running on gasoline to be able to

run on ethanol [Music] so what we just did was take apart most of the mower by removing anything that had to do with fuel which gasoline for normal gas mower because of the difference between alcohol and gasoline we can't actually use the same fuel mixing system without an adjustable carburetor without being able to adjust the main jet on the carburetor we can adjust the fueled air ratio which needs to be moved up about 20 percent to run on alcohol so what we've done here is we've replaced the entire fuel mixing system with one of our

own where we have a vapor bubbler carburetor that actually draws air in through these pipes and bubbles our alcohol and that mixes in to make gas vapor which flows up through the tube into this ball valve which acts as our new throttle and down into the intake of the mower where it's put into the cylinder and ignited now back to the three test patches and to do some two-step distillation to extract just the ethanol [Music] so after extracting the ethanol from the three smaller batches i was able to achieve a higher result from all three

however still not a huge amount further research revealed to me that a higher acid concentration was the best bet for a higher yield but in the end it's still likely going to be a pretty low yield without laboratory precision so let's boost our acid concentration and do another large batch and see what we can get so basically went through the same process took some 30 pounds of grass ground it up to a fine powder mixed it with acid one change i did was just a higher percentage of acid from what i read the higher your

acid the more yield you're going to get kind of increases our cost by having to buy more drain cleaner but by increasing that i was able to get a higher yield so after the acid hydrolysis neutralized it pitched it with the yeast this time with a stronger yeast a little bit of a booster got that fermenting [Music] and then distilled it out and got a much more significant yield [Music] and then one last step i did this time to further concentrate it and remove more of the water that's mixed in with it was a device

called molecular sieves so these little pellets have little pores in them just big enough to let in and absorb water molecules but too small to absorb any ethanol which is a larger molecule so that makes it possible to further concentrate the ethanol into a relatively pure got a final yield here decent supply i think it should be enough to potentially mow at least part of my lawn so we're gonna fill up the now adapted mower now converted to run on ethanol thanks to adrie and see if we can get to start then wilson lawn [Music]

[Music] so i was able to succeed i was able to take the ethanol produced and run the mower and actually mow some lawn it seemed a little bit rough on the engine and ended up dying right at the end i'm not sure if it just ran low on alcohol for it to actually power it or if too much water vapor actually formed in the engine and that caused it to die overall i'd probably not recommend running a lawnmower on ethanol as it does produce water vapor that is left in the final solution and can be

a little rough on your machine it did work and we have achieved the main goal of this project [Music] so let's break down the cost first the one-time upfront costs a few things i was able to procure for free such as the barrels and a few miscellaneous things but things like the blender the mulcher the distillation kit and paying the mechanics to convert my mower all came in into just under a grand for all of that up front but that's just the one-time fee once you're set up the ongoing cost of running each batch is

a little bit more manageable so a few things are pretty cheap the yeast is under 10 a bag of lime to neutralize it is around 12 but by far the biggest expense especially since i had to change my recipe to a higher acid solution is the sulfuric acid at 14 gallons per batch that comes in at 350 dollars for a final yield that's under a quarter gallon and then of course there's the hours of labor having to put into this to actually produce it by far the largest time consuming expense was mulching and grinding everything

up into a fine powder that ended up taking a pretty long amount of time and overall it took roughly 14 hours of hands-on labor to produce each batch so at today's local minimum wage rate that would be an extra 175 dollars per each batch so that comes out to a total of 525 dollars per each batch with a final yield that was less than a quarter gallon that means that using my method this comes out to over three thousand dollars per gallon putting that at a mere one thousand times as expensive as the current price

of gas at a little over three dollars a gallon but trying to do this cheaply or efficiently was never the real goal of the video it was just to see if it was possible if you had no other option to buy gasoline or other fuels and at the end of the day i did end up succeeding at achieving it very high sticker price but it is achievable so this really touches on an emerging topic of a lot of research of cellulosic ethanol which holds great potential for future sources of ethanol because cellulose is such a

easily procured and growing source of sugar but it's really highlights the challenges that are faced in doing so the acid and other steps involved are very cost prohibitive trying to find a more efficient cost effective way to do it is the main challenge right now so hopefully some more efficient ways can be figured out this can be the future source of some of our fuel so it's been a fun experiment to try and see what exactly you can make fuel from next up for curiosity stream i'm going to try and recreate another commodity that's been

a little bit challenging to get lumber and see if i can produce it using alternative methods so stay tuned for that if you like this video go to curiositystream.com to sign up and start streaming today also while you're here subscribe to their channel on youtube for tons more like this video in the future