By Fiona Gallagher· permaculture designer · food, animals and preservation on 12 acres in Tassie
“After wasting three hundred litres of rapeseed on a clogged injector, I learned that filtering vegetable oil to 10 microns is the only way to keep our off-grid generator running in the Tasmanian cold.”
A $150 vegetable oil conversion kit lets you run a diesel generator on waste cooking oil instead of bought fuel. Filtering and heating are non-negotiable, but done right it cuts diesel costs for off-grid Aussies running through cold months.
No, it's not magic. But it'll save you cash on diesel when you're off-grid. Here's how it actually works.
No, it's not magic. But it'll save you cash on diesel when you're off-grid. Here's how it actually works.
Because diesel costs $2.20/L+ in remote areas. Used cooking oil? Free if you're a cafe owner. Or $10-$20 for filtered oil. You'll pay for the system, but the fuel's dirt cheap.
Filtering: Don't Skip This
Raw oil = engine death. You need:
3x 100-micron fuel filters (cheap, $15-$25 each)
1x 25-micron filter (essential, $30-$40)
50L plastic drum (for storage)
Process: Pour oil through the 100-micron filter, then the 25-micron. Let it sit 24hrs. That's it. No fancy lab. If it's cloudy? Throw it out. Don't risk it.
Heating: Non-Negotiable
Vegetable oil thickens below 40°C. Your engine will seize. You need:
Green Fuel Systems (VIC): greenfuelsystems.com.au - $2,500 for full kit + install. Best for 4WDs.
Don't try to do it yourself. You'll ruin your engine. Pay the $2k now, not $10k later.
Practical Tip: Only use oil from commercial kitchens (not home cooking). Restaurant oil is clean. Home oil has food residue = engine clogs. And never mix with diesel. Ever.
Australian Pricing Breakdown
System cost: $2,800 (full conversion)
Annual fuel cost: $500-$800 (vs $3,000+ for diesel)
ROI: 3-4 years. After that, it's free fuel. Simple math.
Final Word
It works. It's reliable. But it's not a magic fix. You need to filter, heat, and get a proper conversion. Skip any "cheap" conversion kit online. They'll kill your engine. Stick with Aussie suppliers. Do the work right, and you'll be off-grid on free fuel for years. No fluff. Just results.
When to Call a Professional
While many off-grid projects are achievable as DIY, certain situations require licensed professionals:
Electrical work beyond basic 12V DC additions — requires a licensed electrician
Structural modifications to buildings or load-bearing elements
Gas line installation or modification
Solar array installations above safe voltage thresholds
Any work that affects the structural integrity of your property
Always check local regulations and obtain necessary permits before commencing work.
The Project Farm video does a side‑by‑side dyno test of straight veg oil against diesel and biodiesel, showing actual MPG and fuel flow numbers, which directly answers the performance questions I get asked most.— Fiona Gallagher
