For the past two years I have driven around for free, using scrap wood instead of gasoline. It's a daily challenge, and yet remains the most rewarding choice I've ever made. Wood gasification represents independence to me; only a few folks can thumb their nose at the gas stations and keep driving. Several of us are now doing so, thanks to Wayne Keith over at Drive On Wood, the wood gas community website. One of our catch phrases is "smile with every mile" or SWEM. And it's true! It puts a smile on my face every time. But this daily pleasure comes with a lot of work.
Start Your Wood Gasification Engines!
Every time I take a short trip to the post office, it's about a 5-minute procedure to get rolling. Wood gasifiers are much like wood stoves, in that they need a fire to be lit, and it takes time to warm up. Fortunately they are designed to heat up fast and without needing "kindling" - there is always a layer of charcoal ready to burn.
So when I'm ready to go, I'll put the mail in the truck, and open some valves up. Off comes the lid, and I run fans to create a draft. Lighting the gasifier with a propane torch is fast and easy. And at this point I add a 12-pound bag of wood, close the lid, and let the fans heat up the fire. I watch the output of the wood gas (it has a peculiar odor), and once satisfied I will crank up and head out. By the time I make my round trip of about 10 miles, most of the wood I added will be gone.
Preparing Logs for Wood Gasification Fuel
The wood itself is quite a job. It sounds wonderful to drive around for free, but nobody is handing you wood chunks on a silver platter. Anyone who heats their home with wood knows what I'm talking about. For the most part, you need to find scrap lumber, downed limbs, sawmill waste, etc. Almost none of this wood is exactly the right size. I will eventually build a wood chunker like this one to process sawmill slabs, but currently I use a chop saw and a splitting axe.
Using these, I can process enough wood in one morning to last for a week of driving. But that's not the end of it! Most of this wood is still green, and won't burn in the gasifier as-is.
Drying wood is not hard — but it does require thinking ahead. You can't dry wood very well in the winter, when it's raining, snowing or frozen solid. Smart drivers would cut plenty of extra in the summer and store it away for use in bad weather. You may have guessed that I'm not always among the smart ones ... for this winter season I've gone scrounging for already dry wood, so that I can skip the drying step.
Once the truck is going, it very quickly comes up to temperature. Still, during the first mile you have to take extra care at stoplights, because the gas produced is weak. You don't want to stall the engine right in the street. I much prefer a long straight stretch of road for the first mile, so I can warm the gasifier up fully without stopping. Once warm, there's no problem stopping for any short length of time. The gas is ready and waiting when you set off again.
At the post office, I don't have to do much for the gasifier. Shut the engine off, and close a valve to the intake. As you can see, it blends right in with the other cars in the parking lot. I take care of business inside, and return to a still hot gasifier, making plenty of gas for me to fire up the engine. Once I'm rolling, there is a short lag while the gasifier comes back to full blazing heat. This slight power lag can surprise you at first, but planning ahead will keep you out of trouble. A shot of gasoline can ease the transition, or I can wait for the blowers to heat things up again.
Cost to Fuel a Vehicle with Wood
Soon enough, I'm headed back up the street on 100% wood power, mission accomplished. Total cost of the trip? A couple ounces of gasoline to crank up, and some extra time. Out of pocket cost is practically zero. I'll arrive home on wood gas, and close the valves again. If I need to make another trip, I don't need to relight, just run the fans and it heats back up. After 3-4 hours without oxygen, the insides cool off and the fire goes out. No smoke exits the system, everything is sealed inside.
As you can see, wood gas is quite practical for a short trip around town, and the extra trouble it takes is well worth it. As a rule of thumb I won't start the truck for less than a 5-mile round-trip. At that point a bicycle, electric vehicle or small efficient car is more effective - and maybe I should be combining more trips... or seeing some of the countryside.
But what about a longer distance? Like a 500 mile trip? Stay tuned for Part 2.
If you'd like to learn more about gasification, please visit Drive On Wood.