By Dave Miller · off-grid sparky · 22 years wiring solar, batteries and sheds in central QLD

“After blowing three fuses in my shed, I learned wood gas generators need a proper charcoal bed or they're just expensive firewood burners.”

Look, if you're off-grid in Australia and want reliable power without diesel, a wood gas generator is the real deal. No fancy tech, just wood and a bit of sweat. Here's how it actually works.

Gasification Principle: How It Actually Works

Forget burning wood like a campfire. Gasification is about starving the fire of oxygen to turn wood into gas, not smoke. You get two stages:

• Pyrolysis: Wood heats up (300-500°C) and breaks into gas, tar, and charcoal.
• Combustion: The charcoal burns with limited oxygen, creating heat to turn the gas into clean fuel (CO, H₂, CH₄).

Result: You get wood gas (not fire) to run an engine. Simple. Effective. No magic.

Filtering: Don't Skip This (Or Your Engine Dies)

Filtration essentials

Wood gas has tar and particulates. If you skip filtering, your engine will clog in 20 minutes. Here's the non-negotiables:

• Primary filter: A 100-mesh stainless steel screen (cheap, $20-$50 from hardware stores) to catch big chunks.
• Secondary filter: A water scrubber (a bucket with water and a pipe) to cool gas and trap tar. Must be vertical – no sloping.
• Final filter: A 5-micron paper filter (like for car air filters) before the engine. $15-$30.

Engine Connection: How to Plug It In

Wood gas needs a modified engine. Standard petrol engines won't run on it. You need:

• A diesel engine (easier to convert) or a petrol engine with a gas conversion kit (e.g., from Wood Gas Systems Australia).
• Connect the gas line to the engine's air intake (not fuel line). Never use a standard carburettor – it'll flood.
• Use a gas pressure regulator (like a BBQ regulator) to keep gas flow steady. $30-$60.

Start with a small engine (e.g., 5-10kW generator). Don't try a 50kW setup on day one. You'll regret it.

Practical Tips for Aussie Conditions

Wood type & sizing

• Wood type matters: Hardwoods (eucalypt, ironbark) work best. Avoid softwoods (pine) – they gum up the system. Don't use wet wood – it's a tar factory.
• Size right: For a 2kW off-grid setup, you need a 1.5m³ gasifier. Bigger = more wood, more hassle. Keep it small.
• Maintenance: Clean the filter every 2 hours of running. Check for tar buildup weekly. A $50 scraper from Bunnings is your best friend.
• Fire risk: Gas is flammable. Keep it 10m from your house. Use a spark arrestor on the exhaust.

Australian Suppliers & Price Guide

Don't waste money on dodgy imports. Here's what's actually available in Australia:

Real talk: A $200 "wood gas kit" from eBay is a scam. It'll leak gas and cost you more in repairs. Stick to local suppliers.

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.