Picture of Make Biodiesel!
Instructable #2 in my series on biodiesel.

This is my tutorial for using my appleseed processor to make biodiesel. This tutorial will get you through the process of making biodiesel, but not the necessary washing process. I will do my next instructable on dry-washing biodiesel.

Biodiesel is a great way to go green, and cut your carbon footprint quite substantially, not to mention it's cheaper than diesel. Biodiesel will run in a diesel engine, I don't recommend trying it in a gas engine.
The process for making biodiesel uses an oil, a catalyst, and an alcohol. In this case: Waste vegi oil (WVO), NaOH (lye), and methanol.

Please read up on this before you start, and please understand the chemical dangers involved in this process.
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Step 1: Safety

Picture of Safety
First off, some disclaimers and safety info.

NaOH (or KOH, depending on your catalyst of choice) is extremely caustic and will cause extreme irritation if it comes into contact with your skin, eyes, or any other part of you. Methanol is a harmful alcohol. It will cause blindness or death if ingested; one way it's absorbed into your body is through your skin, so simply handling the stuff with bare hand is bad for you. Lastly, Methoxide, the substance produced when you mix your catalyst with the methanol, is an extremely toxic nerve agent. It can do some serious bodily damage.


I use a chemical resistant p100 respirator when I do this process, as well as eye protection. I use some heavy-duty chemical-proof gloves from Northern Tool. Long sleeves are recommended.
stib7 years ago
If you're making biofuel from waste products good on you, but if you think that biofuel is the 'green' solution to everyones transport needs I have to rain on the parade a bit. Biofuel sounds like a good idea until you start thinking about the consequences of it a little.

Like the way it's pushing up the price of foodaround the world, and the fact that producing food crops uses about 2.3 times more fossil fuelenergy to grow than the energy they provide.

Looks like I can swap destroying the climate with my car for causing global famine with my car. Makes you wonder what would it take to get people to ride bikes instead.
odiekokee stib1 month ago

Overpopulation is going to destroy man-kind far before climate change. Thank the good folks who are against contraception and work so hard for disease control for that.

servant74 stib6 years ago
yep, but riding bikes on a 50 mile one way commute in Houston TX or LA kind of sucks. ... such is life for those outside the sweet spot areas where walking, bicycling, or even train commuting is an option.
lol, perhaps your problem was taking a job that required communing 100 miles a day.
If he's making it from WASTE oil, than tell me again how that will drive up food prices? It was going to be thrown away anyways; hence the term "waste".
drinkmorecoffee (author)  stib7 years ago
One word: Algae. Biofuels from food crops- bad idea, biofuels from non-food sources- the way of the future.
Well, biofuels from non food crops sounds good, until farmers who were growing food crops realise there's more money in growing fuel crops and give up growing food. It's not rocket surgery, it's market economics 101. If everyone switches to biofuels we can kiss the last of the world's rainforests goodbye. Biofuels from algae does sound promising, but then there will be impacts on marine environments. It just takes a lot of area to power the private car fleet with plant based sources. But you know I use biofuel for most of my transport needs: I eat food and ride a bike.
drinkmorecoffee (author)  stib7 years ago
Yes, but algae can be grown in the middle of nowhere. The fact that soil conditions matter a lot less with algae means it doesn't have to take up food crop land, or rainforest areas. There's still plenty of ground to cover, but algae is very promising.
actually, soil conditions don't matter at all to algae, because it grows in the WATER, thats right, not the middle of nowhere, the middle of the OCEAN, its actually a promising idea, I've heard of it before. About the farmers switching to it, most like there land, not the ocean, I'm sure that a new job niche will only do good things for the economy (now, I've tried to make this neutral enough so that I don't spark a huge debate, but, in advance, sorry if i offend anyone)
drinkmorecoffee (author)  smithy8137 years ago
Well, the most promising way to grow it right now is in tanks, above ground. No harvesting required. This could be done in the middle of nowhere, somewhere where the soil is no good for growing food-crops.
remember we can always go down or up so we could have tanks stacked on top of eachother 10 stories down and 10 stories up, that would reduse the surface area of the tanks on land by 95%
I like the one where they use overgrown plastic baggies hung row after row, with the algae solution pumped into the top and it slowly winds its way to the bottom. Still has big tanks to drain it into, but it does allow for circulation and central harvesting / maintenance / feeding. Some bloke in El Paso TX seems to have come up with it, but they are still working on which is the most profitable strain of algae for them. personally I have seen plenty of swimming pools and ponds that could use to have some cleaning done ... at least there the algae could be used rather than just thrown / flushed away if algae harvesting was easy to do.
OI VEY! soylyent green!
nicoroc stib3 years ago
dident you read the comment above? bio fuel is being grown with alge that feeds on sewage waste and has 50% its weight in useable oil, that dose nothing to food prices and it cleans waste water naturaly, oh and after they extract the oil from the alge the left over "green powder" is considered a "super food" that is sold in health food stores so its making food also.
drinkmorecoffee (author)  nicoroc3 years ago
Fascinating. What are your sources for that?
theres tons of info on bio alge, just ask google, lol, out here in california they're doing some tests out in desert areas and i think austrailia too
drinkmorecoffee (author)  nicoroc3 years ago
There sure is a lot of info out there. But you should still provide sources when making claims like that.
as far as fuels go, people need to reinvent the automobile. most people, say new fuels (most are bogus) but we all need to turn to something simple and completely eco-friendly. A great tech piece would actually be a tesla turbine to power vehicles, their powerful, energy efficient, structurally superb, and with todays metallurgy they have slim chances to fail.
You're thinking too small. Its society that needs to change not the car. Energy should be distributed locally rather than through a national grid system. Cities should be high density with district heating and cooling. With integrated public transport cars wouldn't be needed other than for recreation.
look in the world for civilizations to grow they need some form of an economic platform, most turned to a form of capitalism (since theoretically it works). Now not just with capitalism, any form of economic growth system needs an infinite plan of resources and time. Why this has to do with fuel sources like gasoline, the modern civilizations have been accelerated by the growth of a commodity. If you look at the word commodity, it implies the function of running out. Onto what i was wanting to really say, the problem with a national grid and a local grid is you are still using a polluting resource that is the problem. Also Without an national grid, there is no form of transportation between city's. Now with a local grid, these would be so hectic to run, most areas don't have fuel sources, there would be little to no imports and exports, areas that were once inhabited could not (nevada) due to resources, and if you had a large central city where people of the surrounding area lived there this city would be so large to not even travel without some form of a motor vehicle.
bingo1912 stib4 years ago
Yup, what he said,,,,,
Pkranger88 stib7 years ago
So you've made complaint. What's your solution, all wise and knowing?
T2Pogi stib7 years ago
There are many sources of veggie oil and tapping into these sources will no greatly impact the food situation. There is jatropa seeds, coconut oil (many countries in asia have a surplus capacity of this oil due to the scare re "unhealthy" oils), and of course, there is the waste oil for small consumers like us. now if you are talking about ethanol from corn, you may be right. that route is apparently not the way to go.
JimU8 months ago

For how long do I need to keep the oil heated?

JimU8 months ago took me a minute to figure out how you got six for your 50 X 6 = 300. You've got to follow the PEMDAS order of operations. The 4 + 2 should have been in (parentheses) to equal 6. The answer should have been 202 the way you had it set up. And how did you get the 4? Is that a constant no matter if it's 50 liters or 500 or 5000 liters? I'm new at this, but I have the knowledge of math and chemistry to make it happen. Thanks.

JKans1 year ago
I know I'm reviving an old thread but I would really enjoy another write up on the washing process or at least the OP's opinion on the best place to find this information. I am very interested.
akinich1 year ago
hi I would like to know if I can use ethanol instead of methanol
Interesting. Is there any other way to make this, using less toxic chemicals?
WWC2 years ago
This is what i used for my waist oil collection and processor for making Bio-Diesel.
Two 55 gal hot water heaters for processing. I diaphragm pump for collection. A dedicated collection truck.
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Sun Gear3 years ago
very well done. i have been doing reseearch into biodiesel and subsicuentally i ahve stumbled upon algae biodiesel. The process is the same from what i ahve found but instead ot methanol you use ethanol. This site is loaded with information for algae biodiesel, you can even use the algae to make ethanol too!
theturn3 years ago
Don't forget to adjust for purity of your catalyst :
In many cases its dificult to get 100 % pure catalyst (NaOH or KOH)
Divide your base (4 grams in above example) by purity.
If NaOH is used and its 90% pure divide 4 by 0.9 = 4.44 and add this to your titration result using above example (4.44 + 2) = 6.44 x 50 = 322g needed.
Failing to do this, you could leave free fatty acids (FFA) in your processor / finished biodiesel because you didn't account for purity and add enough catalyst.
The point of titrating is to find out exactly how much "extra" catalyst we need to deal with the FFA's over the basic formula for virgin veg oil.
Hope this helps.
Qcks3 years ago
Glycerin can be used to distil out a higher proof methanol product.

The less water you have in the Methoxide product, the higher quality the biodiesel you'll produce.

If you can get ahold of sodium peroxide that'd have even less water in the methoxide product.
Does biodiesel run as good as regular diesel or is there any noticeable differences like gas mileage, the way your engine sounds, your exhaust smell......?
It runs better than regular fuel IMO.

Bio diesel acts as a lubricant as well as a fuel for your engine. Depending where you get your waste oil from is what it will smell like for example if the majority of your oil stars out as cooking oil ( like from chip trucks) then your exhaust will smell like french fries. :P
jmiranda23 years ago
Two new technologies make ultra-pure biodiesel (that does not gel at 45F) from farm and municipal waste treatment plant effluent possible to make for $2/gal. production cost. Technology #1 Hydroponic algae farming - see and This is a patented process. An adjunct technology from an Israeli firm, Patz (see sold under the name Patz-OZy, provides both the front-end treatment of the effluent (eliminating the need for a biodigester) and also the back-end separation of the cellulosic material from the runny liquid effluent. Technology #2 is patented, took 18 yrs. to develop/patent and is still in a professor's lab at Syracuse University. The method is called "supercritical transesterfication". Some benefits of this technology: minutes instead of hours, 96% efficient conversion, virtually all unwanted glycol byproducts eliminated. scalable (allows on-site processing) at 1/2 the price. Google Dr. Lawrence Tavlarides / Dr. George Anitescu (George has since moved on to NIST in Colorado.)

How To Guy6 years ago
How is biodiesel worse for the environment? Diesel is a fossil fuel. Biodiesel isn't. Besides, I wish all exhaust smelled like greasy french fries.
The main reason they are saying that bio diesel is bad for the environment is not true. what is bad is raising crops and using the oil for fuel instead of human consumption. When this happens the price if food goes up and less land is used for the production of food.. As our population grows so does the amount of land we use to live on, decreasing the amount of farmland. Couple that with the fact that more and more small farmers are leaving the farms.
Hug a farmer. they are a dying breed
the fact that its a fossil fuel doesn't make it worse for the environment, only certain fossil fuels are worse for the environment, the good thing about biodiesel is that it can be made out of waste products and wont run fossil fuels
psi30004 years ago
WARNING!!! You imply that your p100 respirator will protect from Methoxide, when in fact IT WILL NOT!! NO RESPIRATOR WILL. Only fresh air supply will. Just a heads up. The best thing to do is mix the Methoxide and make the bio diesel outside with the wind blowing in the right direction. I wish there was a respirator that could help as this is the only thing holding me up from making my own bio diesel. I have everything to my my processor even and I stopped when I found this out.
hi tufrat look on the journey to forever web site it gives covertion tables for both koh and naoh.Its agood site for allthings earh friendly. regards
dsandds20036 years ago
is the Methanol the same as they use for the E-85 cars?What is kinda ironic is when they were first building tractors they came with a 3-way valve. These old tractors used gasoline,kerosene and diesel. Now we use entirely different engines. As a matter of fact before gasoline was popular most engines ran on moonshine....Think about it????
drinkmorecoffee (author)  dsandds20036 years ago
E-85 is Ethanol. Different stuff. .... And do not, whatever you do, buy an E-85 vehicle. Any car with a gas engine can run E-85. Car manufacturers slap an E-85 sticker on a car and charge a butt-load of money for it.
 Not completely true.  While about any gasoline engine CAN run on E85, not all will do it correctly.  For example, I've run my 93 Dodge Shadow 3L on E85 for a few months, until I noticed a white coating on my spark plugs when I pulled them out.  The ECU doesn't know to add additional fuel, and the engine runs lean, all the time.  This burns the pistons/spark plugs/cylinders and can eventually damage your engine.  If you're not sure your vehicle can account for ethanol, I suggest running about 60% gasoline 40% E85.  This won't run lean enough to do damage and will usually result in more power and fuel economy than straight gasoline or straight E85.
TufRat5 years ago
 What is the method if you are using KOH instead of NaOH, particularly the mass/ volume KOH used instead of NaOH?
dpacjones6 years ago
If you heat the oil first, 180F is ideal, minimum 140F, and a maximum of 210F, you can evaporate alot of the water and the oil filters alot better. Keep the lid off, and wrap the barrel with insulation to help keep it warm and speed up the process. Also if you do have water in the oil you can heat it, let it settle overnight in a barrel/ bucket with a drain on the bottom, then in the morning the water should be seperated on the bottom of the barrel, open the bottom valve and drain off the water and other particles that have gathered on the bottom. the longer you let it settled the better. good luck!
Derin6 years ago
I read in the paper that fast food places use Magnesol to re-use burnt oil.It fixes the color,fixes the smell but does not remove the carcinogenic stuff.
Skor4596 years ago
Step 1) Piss in jar Step 2) Put in car Step 3) ??? Step 4) Profit
lol. the fuel gnomes tell you that one?
They tell me to burn things.
excuse me, why put a jar of pee in your gastank?
If it looks like biodiesel, it must be biodiesel.
pickford786 years ago
Bio Diesel is worse for the environment. don't use it!
drinkmorecoffee (author)  pickford786 years ago
Do explain, please.
The vegetable oil is made of more carbon. try burning your mixture and then burn diesel. use the same ammount and see how much carbon comes off.
Also, many farmers are cutting down massive amounts of trees and others greenhouse reducing plants to make crops for biodiesel. With less trees there is higher amounts of greenhouse gasses going into the atmosphere. Personally I think biodiesel is a step in the right direction.
drinkmorecoffee (author)  pickford786 years ago
You're absolutely right, but the diesel just came out of the ground. Where did carbon in the oil come from? -The plant it's made from. Where did the carbon in the plant come from? -The air. It's not necessarily about how much carbon is going into the atmosphere, it's how much you're leaving there. Biodiesel is miles closer to carbon neutral than diesel, just sayin'.
I think youre correct but it is much cheaper to make biodiesel
good point, i think.
Bubbler6 years ago
At the beginning, you mention the water factor and how to avoid using the sludgy bottom of the tank contents. In an industrial setup, this is handled by storing re-cycled oil in a high narrow tower. After it has been ther for a good few months, gravity takes care of the solids (metal grindings) and water. It all settles to the bottom of the tank. A tap at the bottom of the tank o s turned on to expel the lower contents until the flow turns from a muddy colour, into the black used engine oils. This system could be utilised by storing veggie oils in a PVC down pipe of six metres length or maybe less, in a vertical position.
Derin6 years ago
ok,*drinks more coffee* lol
puffyfluff6 years ago
I think I just convinced my parents to get diesel cars after showing them this. Awesome job!
Pkranger887 years ago
Awesome. I will definitely stay in tune. I've been doing research on this for a while.
One problem we're running into locally is that home processing is becomming so common that commercial recyclers are taking over at restaurants so obtaining quantities of waste oil is extremely difficult. Whereas 2 years ago I could get the oil for free or even cheap, not it costs about $2/gallon. For that price, making my own is really not that much different cost wise than just buying diesel.
I have 33 acres, so now I'm looking into efficiencies of raising certain crops to get my own oil.
Keep up the good work. If you want any collaboration, my email is I'm a research associate for the National Institute for Aviation Research.NIAR
What about Hemp?
Illegal in the US as I recall. It would probably make a good oil for bio-D. The problem of course would be all those folk running along behind your car trying to inhale your exhaust. Visualize a Los Angeles freeway at 5:00PM. 70,000 cars running on Hempolene.192,000 stoners running in and out of traffic seeking the least efficient operating engine. Just bring tears to my eyes.
Not all hemp, but the authorities keep a CLOSE eye on you so I am told. Some varieties are better at production of THC than others. The high producers are not the best for rope/celulose, but trying to explain that to some county mounty in the middle of nowhere doesn't work well. So keep it simple and don't is the best common answer.
THC producing Hemp is illegal to grow while the non-THC Hemp is perfectly fine. The issue comes in that you will likely have random checks and testing on your crops from law enforcement. This destroys the plant, by the way. Hemp does make rope, paper and even clothing. I wasn't looking at using Hemp but rather Soy, sunflowers or switchgrass, etc.
I'm not a grower of any sort of plants, except the weeds that have replaced my lawn.
Pkranger88 What are the characteristics of the plants and oil you hope to produce? How much bio-diesel do you hope to make per month? What quantities will be required to satisfy your needs?
If anyone reading has an interest in commercial hemp production, as opposed to DEA attraction, this site has some good basic information.
Hemp might be a good alternative to fossil fuels, and the smoke and mirrors of wind, solar, and manure.
LOL, I know it's illegal but wondering if it is viable compared to other biomass.
drinkmorecoffee (author)  Pkranger887 years ago
Oh neat. With the way diesel prices are going right now $2 a gallon for oil may still be cheaper pretty quick here. I'm interested to hear what you do on your land if you end up growing anything. I wish we had enough land to grow anything, but sadly all the land we do have is too shady to grow any crops. Thanks for the positive comment! -DMC
nnsg6 years ago
servant74 nnsg6 years ago
It does work. Folks that do it regularly use a 'dual fuel' system, starting and ending using 'petro-desil' and running in between on straight veg-oil. Dear ol' Mr. Diesel initially envisioned being able to run on veg oil or just about anything that burns directly. It works, just not in the higher compression engines we like to run today (but they do burn it more efficiently).
drinkmorecoffee (author)  nnsg6 years ago
Well, yes. It probably did work, but it's not the most efficient way to go. SVO (straight vegetable oil) works best if you do some engine modifications first (heated fuel lines, etc.). I wouldn't recommend just pouring it in.
TWMCNANEY6 years ago
You are really good at making instructables. I hope that you are going to make another one on how to dry the diesel. Im making a proccesor for Biodiesel with the other instructable that you posted.
Squ336 years ago
$2 per gal of veg oil isn't bad. Even comparing it to straight crude right now:

$2 per gal veg oil (an oil barrel= 42 gal)= $84 per barrel VS.

straight crude oil (U.S presently)= $123 per barrel

I went to my local supermarket yesterday and found that I could get 25 lbs of lard for about $35, which is cheap as well.
bio Flossy6 years ago
Hi Drinkmore coffee, thanks for the info, by the way I was just joking about Mac Donalds!! In the UK you need a licence to remove waste oil from any where!! So I'm looking at alternatives, will let you know of any succeses. Thanks again.
bio Flossy6 years ago
Hi Guys, does anyone know what the conversion rate of oil to biodiesel is? I just wondered if I need to ask one or two take-aways or do I need Mac Donalds chain, just for one gallon?
drinkmorecoffee (author)  bio Flossy6 years ago
If I understand the question right, it's one to one. One gallon of oil makes one gallon of biodiesel. I would recommend NOT getting oil from macdonalds or any other fast food place that burns their oil, because it won't react to make biodiesel and it won't burn in your car. Asian restaurants have the best oil, by far, but any place that fries food will do.
Matt D6556 years ago
actually isopropyl alcohol can be found at ur local pharmacy.
drinkmorecoffee (author)  Matt D6556 years ago
It can be, but the stuff you get at the pharmacy is by no means concentrated enough.
alexk66066 years ago
I can't wait for #3 on how to clean the biodiesel! WHen are you going to come out with it?
drinkmorecoffee (author)  alexk66066 years ago
Probably some time in the next week or two, I need some more fuel to wash first! Trouble getting methanol and all that....
bloodniece6 years ago
The Germans during WWII used to run some of their tanks using hemp oil instead of diesel.

Hemp: American History Revisited: The Plant with a Divided History By Robert Deitch
Sunkicked6 years ago
Great Instructable, can't wait to see the third part about washing the fuel. The debate about the merits of biodiesel will go on forever until one of three things happen: 1.) Solar Panels and their batteries get into the 90% efficiency range, thus eliminating the need for any kind of liquid fuel. 2.) As mentioned below we find a way to make fuel from scrap plastic and other forms of garbage (like the Mr. Fusion from Back to the Future II). 3.) A Zombie Apocalypse occurs and there's only a handful of survivors. Then they're going to NEED biofuel as a sustainable way to transport themselves around the Land of the Living Dead.
tercero7 years ago
Being a non certified car kinda guy, but, you probably can't use bio diesel in most of the northern states and Canada...well, at least from October to let's say the middle of April. It would probably sludge in the tank wouldn't it? (This is the part where I'm asking a question because I really don't know. I don't own a diesel and assume bio diesel gel's under a certain temp).
You are right so any biodiesel and veggie oil fuel rig needs to have preheater installed in the vehicle to ensure the viscosity stays low. Making your own biodiesel is just a the tip of the iceberg of knowledge in using non-traditional fuels in combustion engine vehicles.
drinkmorecoffee (author)  tercero7 years ago
Yes, it does gel at a certain point. The key is to blend it with 20-30%regular diesel. That way it doesn't gel.
westly19867 years ago
Im a Driller on an Oil Rig. Bio Diesel's great, but who the heck wants to make there own supply??? - The Rig Pig
drinkmorecoffee (author)  westly19867 years ago
I do.... :P
Derin nature2237 years ago
diesel ruins catalysts and normal and new diesels can run biodiesel
nature223 Derin7 years ago
dude..they make a Diesel specific catalyst,and no they cannot...they run specifically on LOW SULFER DIESEL, you put bio in a post 2007 diesel engine you VOID YOUR me,I read up on this before posting
Web_MST3K7 years ago
I keep waiting for someone to figure out how to make a backyard thermal depolymerization device. The sweet thing about it is that--in theory at least--you could use almost anything containing carbon as feedstock; waste plastic, lawn clippings, kitchen waste, etc. In short, waste becomes fuel instead of rotting away in landfills. One of the byproducts of this process is carbon black, carbon that does not have to go back into the atmosphere.

Putting it another way; thermal depolymerization can be used to make a carbon negative synthetic fossil fuel.
tallpaul1007 years ago
Yes what about hemp? can anybody think of a reason against using hemp oil?
How do you tell the difference between burnt and unburnt oil?
sypher7 years ago
The gov is passing laws that prohibit individuals from obtaining WVO. It is targeting "unknown environmental impact and uncertified emissions". As a history lesson, the first cars were powered by steam boilers which ran steam pistons and batteries that drove electric engines. THEN the discovery of oil, we all know the story from there. Electric motor tech sounds sci-fi, but it works, also our batteries now are amazing. Batteries are expensive and so are the motors, but you buy nice, you cry once, you buy crap, you help out a pointless war, not to mention cry every day at the pump. What you are doing is innovative, but do not stop at bio-diesel, keep exploring. yes I know, rant... rant... rant... XD
mtverbal7 years ago
where do I find those filter bags? And do you throw away the glycerine?
drinkmorecoffee (author)  mtverbal7 years ago
Try ebay for the filter bags. You can compost the glycerin, although you want to get the excess methanol out of it first. You can also make soap from glycerin.
You could also make nitroglycerin with it....
This is awesome. Do you know, are you putting more money into this than you will save by not buying diesel?
just mike7 years ago
does anyone know anything about making oil from algae
best site you will ever find on oil fron algae
oh cool, thanks
LinuxH4x0r7 years ago
Awesome! diesel is still the ultimate fossil fuel. I wish I had a diesel hybrid, that would be awesome
nnygamer7 years ago
If I recall one reason for refining the oil it to remove the glycerin in it. Glycerin is what builds up in the engine when burned. You know when you burn oil in a pan you end up with a sticky substance on it? Refine that out and you can sell it to places like make up companies (if you have quantity/quality and regularity). That's if I remember right.
bumpus7 years ago
i've been trying to get my dad to convert our 1984 Mercedes 300TD to bio diesel for a while now, this might just make him re-consider....
Phoghat7 years ago
I read the 1st part and have a question. Some people tell me that all they do to use the waste oil is to fine filter it. Otto Diesel designed the engine to run on peanut oil. That being said, what is your reply?
drinkmorecoffee (author)  Phoghat7 years ago
Well, you're right. Diesel originally invented his engine to run on oil. Not just peanut oil, but the idea was that oils from local crops could be used wherever in the world the engine was being used. Typically if you want to run your car on waste vegi oil, some engine modifications are needed. A lot of oils (peanut oil especially) tend to gel at rather high temperatures when it gets cold. Biodiesel is less of a problem in cold weather, and can more easily be blended with regular diesel if it's extremely cold. I've also heard (though I need to verify this) that biodiesel will get better mileage than SVO (straight vegetable oil). I'm actually very interested in SVO systems, but at the moment this is what I'm working on. Thanks for the comment! -DMC