by Scott Mathieson & Leslie Gardner

Like most of you dedicated fellow growers out there, we find a great many things to inspire us at our farm. In our case, it’s 30 acres of vibrant organic veggies, a site adjacent to a seasonal wetland with wildlife habitat, a beautiful region in a supportive community north of San Francisco, a favorable climate with an extended growing season, and a thriving CSA that may hit the 400-member mark this coming season. But perhaps the major focus of inspiration for us these days is our commitment to alternative energy sources. We have a solar array and a wind turbine set up on the property, and most of the farm vehicles are now running on straight vegetable oil (and/or biodiesel).
Biodiesel is a great choice as a substitute for “petrol diesel” because it requires no engine modification. As you know from recent articles here in Growing for Market, biodiesel is vegetable oil from which the heavy compounds have been extracted, using a reactant such as lye and methyl alcohol to separate the glycerites, which results in a fuel whose viscosity is similar to diesel. There are a couple of considerations with biodiesel: 1) the compounds used in biodiesel manufacture are toxic and harmful to the environment, and 2) since biodiesel has solvent properties, grunge built up from petrol diesel will clog your fuel filter in the immediate period following the start of use, and rubber hoses and seals in the engine will deteriorate over time. If you’re making your own biodiesel, you’re handling strong, highly flammable materials. So if you have the right conditions – that is, if you are willing to take on the mechanics and you have a ready source of oil — it makes sense to consider using straight vegetable oil (SVO).
To run your diesel engine on SVO, the oil needs to be heated to a temperature that brings the viscosity down to that of petrol diesel. There are two systems being used by the biofuels community: single-tank and two-tank. In the two-tank system, you install a second tank that holds and heats the oil. You start the engine on petrol-diesel or biodiesel in your original tank, and switch over to SVO when it has warmed. The single-tank system involves changing your engine’s injector nozzles and glow plugs. The oil is heated electrically during the initial period when it isn’t being heated by the engine.
The big advantage of the one-tank system is that you start and run on one fuel, whereas the two-tank system requires switching between the two tanks at the beginning and end of travel. If you haven’t done this correctly upon occasion, you might be looking at some clogged lines and a long session with a blowdryer on a cold morning. But the single tank requires oil of higher quality, flow-wise, unless you want to use petrol diesel or kerosene as a thinning agent. (In both systems you can still use petrol diesel when oil isn’t available.)
Clearly, this whole concept gets more challenging in cold weather climates, but it sure is nice to be using a fuel that is significantly lower in emissions and is carbon neutral (remember, you are releasing current carbon, not prehistoric carbon). And the exhaust smells like French fries, which never fails to give you the munchies!
At Laguna Farm we’ve converted to SVO two tractors, a Toyota pickup truck for farm deliveries, a 1977 Mercedes for family use, and a 15 kilowatt generator that runs irrigation pumps and our 30’ x 18’ strawbale-insulated cooler. We use biodiesel as a start-up fuel for the generator and one of the tractors, for those first and last few minutes of running time.
Locally, we’ve formed the Biofuels Research Cooperative, with a depot site at the farm. Members pay dues and contribute time at work parties and planning meetings for a portion of the oil, which is contracted from a local, high-quality oil producer and bottler. Last year the flow was around 36,000 gallons of mixed oils — the waste product of flushing between oil types in their bottling process. It is uncooked, so it flows evenly at our coldest temperatures (generally mild here in California). The depot was developed to receive 2,000 gallons of oil at a time, which is transported in a veggie-fueled truck and transferred into tanks that are protected with a secondary containment concrete barrier. Before being pumped into the tanks, the oil is first settled by gravity and then filtered to a one-micron level. Members fill their personal tanks and fuel containers by gravity feed from the tanks.
The cost of the conversions varies with the system and your mechanical skills. Kits are available. It is definitely not for the card-swiping quick-fill folks, but more for those who like the idea of being independent of the petroleum industry and running a nontoxic, renewable fuel that is often a waste product ending up in the landfill, or worse, the streams. A lot of the used oil from restaurants is hauled away, at a cost of up to 80 cents a gallon, and incorporated into livestock feed. Collecting from local sources of high quality oil (oil producers or restaurants that change their oil often) can be an interesting experience. It will deliver interesting conversations, looks of surprise, and hopefully fuel for your tank and your soul.
For more info, you can check out www.journeytoforever.org/biofuel, www.greasecar.com, www.elsbett.com.

Scott and Leslie have been running Laguna Farm’s CSA in Sebastopol, CA for over a decade, Scott for 16 years. Laguna Farm www.lagunafarm.com, 707-823-0823, 1764 Cooper Rd., Sebastopol, CA 95472) Scott is past President of the local chapter of CCOF, now proudly uncertified and “beyond” organic. Leslie teaches the growing plant medicine classes and manages the garden at the California School of Herbal Studies.