Wood: The Ultimate “Drop-in” Fuel
David Bransby, Professor of Energy Crops and Bioenergy, Auburn University
We hear a lot about “drop-in” fuels these days. While this term typically means an infrastructure-compatible liquid transportation fuel, Wayne Keith has come up with his own version of a “drop-in” fuel: wood, or any other biomass you can deliver in small chunks, that can literally be dropped into the down draft gasifier that powers his pickup. While a retrofit to the vehicle is necessary, Wayne considers this minor and does not worry about other infrastructure-compatibility issues, because he has more wood on his small farm than he knows what to do with.
I met Wayne in 2005. He owns a small beef cattle operation at Springville, Alabama, about 30 minutes up I-59 from Birmingham. During our first meeting Wayne told me that he used a rather large, very old Ford pickup to do a lot of his farm work, including transporting farm equipment, hay and cattle, and spreading fertilizer on his pastures. The problem was gas mileage: it was about 8 mpg.
So, way back when gas rose above $2.00/gal Wayne decided to do something about it. He knew that the Germans had figured out how to run their military vehicles with small wood gasifiers when they ran out of gas supplies in World War II. Since he had some experience with building wood burning stoves and working on cars, and had a small custom sawing operation which generated endless “slabs”, or off-cuts, that could be used as fuel, Wayne decided that this was going to be his first line of attack.
Fast forward: in 2011 Wayne officially broke the world wood gas speed record on the Bonneville Salt Flats in Utah, independently recorded at 71 mph, with the previous record having been set at 46 mph. And during the six years prior to this achievement, he gave me a sound lesson in Alabama country ingenuity.
The Technology
Back to our first meeting: I had heard that Wayne was running his pickup on wood, so this is what I had come to see him about on his farm. In our initial discussion he told me that following graduation from high school he came to Auburn University to play football and study, but after a year he decided that this was not for him. He subsequently pursued numerous other interests, including farming, construction, and training security dogs and their trainers for law enforcement agencies.
I told Wayne that I knew about vehicles powered with biomass gasifiers, but understood that their power was limited to the point that they could reach a maximum speed of only 45 mph. I could tell that this comment frustrated him, because he immediately invited me to hop into the passenger’s seat and come for a spin. When the speedometer passed 80 mph on a windy country road I told Wayne that he had convinced me that my information was incorrect, and that I would prefer it if he slowed down since the truck did not have seatbelts.
From there it has been a fascinating journey. First, I was curious about what other fuel besides wood, this gasifier could use. Wayne assured me that he had mixed many different feedstocks with wood, including garbage and junk mail. We proceeded to test pelletized broiler litter, corn cobs and switchgrass cubes. All worked fine.
Without giving any of Wayne’s secrets away (and he has several), the technology essentially involves a down draft gasifier. Synthesis gas is then run through cooling and filtering systems and directly on to the carburetor. Depending on engine size, wood consumption is a little above or below one dry pound per mile, and the range is about 80 miles per gasifier-full of wood. Moisture content of wood should preferably be below 20%.
Coast-to-Coast on Wood
In 2008 Wayne registered to participate in a race for alternatively powered vehicles from Berkeley, CA, to Las Vegas, NV. At my request, he agreed to ride from Charleston, SC, to Berkeley, CA, and back on wood, to promote consciousness of bioenergy. Our plan was to get Wayne and his wood fired pickup onto national TV, but that did not materialize due to competition for media attention from a presidential election and a global economic crisis.
Regardless, Wayne drove 7,300 miles on wood in his “biotruck” during a 3-week trip. We learned a lot along the way, and the trip attracted the attention of numerous local TV stations, as well as the New York Times.
Limited information on small gasifiers suggests that they do not work well at high altitude. However, Wayne again refuted this perception because we climbed over a 10,000-ft mountain pass in Yosemite National Park with no noticeable decline in performance of the biotruck.
The Race
Rules for the race included restriction to use of only an alternative fuel (no fossil fuels except for one gallon of gasoline at the start of the race) and no fuel purchases – fuel had to be scavenged along the way. Also, if participants were prosecuted for speeding during the race, they would be penalized or disqualified. The plan was to have a 3-day phased competition, with two overnight stops between Berkeley and Las Vegas.
Following the start, the biotruck slipped right round the corner and Wayne proceeded to cut up some discarded boards with his table saw powered from a gas electric generator which was fueled with syngas from the gasifier on the biotruck, instead of gasoline. In no time he had prepared enough fuel for the first leg of the race, and off he went.
He was in the lead to start with, but then the gasifier started to clog up repeatedly – something it had never done before. Eventually we discovered that the boards that were being used for fuel were redwood, and redwood does not burn very well. So lack of local knowledge cost the biotruck dearly on Days 1 and 2.
Determined to make up the lost time, Wayne took off fast with different wood as a fuel on Day 3, but was penalized by the race organizers for speeding at 80 mph through Death Valley, where the speed limit is 45 mph. We believe this was a violation of the rules by the organizers, because they had specified penalization only if participants were prosecuted for speeding, presumably by a law enforcement officer, and this did not happen. We concluded that the organizers were frustrated by the biotruck arriving at checkpoints before they did, to monitor the race in their gas powered vehicles.
Wayne came into Las Vegas first, but ended up second overall. However, he was awarded the prizes for the most innovative technology and the lowest carbon footprint. The car that received the first place award had a diesel engine that was run on new cooking oil obtained from stores by bartering race tee shirts for this fuel.
Since the first ever diesel engine was actually designed to run on vegetable oil, we really did not see much that was “alternative” about that option. Furthermore, allowing use of brand new cooking oil from stores, and not even insisting on used cooking oil, seemed like bending the race rules to us, which again emphasized incompatibilities between Alabama and California.
Efficiency and Emissions
Obvious questions that come to mind for curious folks are how the efficiency of the biotruck compares when run on wood compared to running on gasoline, and what the emissions look like. Of course, the first question in this regard is how you measure mileage of wood as a fuel.
Wayne talks about miles per pound of wood, but that is not comparable to miles per gallon of gasoline. We concluded that miles per million btu would be the best basis for comparison. Several engineer friends said it was doubtful that the biotruck could achieve more than 50% of the efficiency of gasoline on this basis.
So we got Wayne to drive his biotruck for 40 miles at exactly 55 mph on a 2-mile test track at Auburn University, first on gasoline, then on wood. The result? When driving with gasoline as the fuel, performance was 20.95 mpg, or 168.6 miles per million btu, while for wood it was 231.6 miles per million btu, or equivalent to 28.78 mpg: an improvement of 37%! And tailpipe emission tests show that the biotruck meets the emission standards required by California, which are the most stringent in the nation.
World speed record
Wayne has now retrofitted several pickups to run on wood, showing an initial preference for Dodge Dakotas, and he has traveled well over 100,000 miles on wood in these vehicles. Each retrofit has resulted in improvements. In September 2011 he officially broke the world wood gas speed record on the Bonneville Salt Flats in Utah, increasing it from 46 mph to 71 mph. Since then he has undertaken yet another retrofit, but this time on a Dodge Ram 2500.
Without question, wood is the ultimate drop-in fuel for Wayne, and I strongly suspect he now has his eye on 100 mph for his next shot at the world wood gas speed record.
http://www.driveonwood.com/press/wayne-keith-sets-woodgas-speed-record
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By Bryan Henry
MONTGOMERY, AL (WSFA) - Going green in a really green Dodge pick-up truck. The man behind the color is Wayne Keith, an Alabama cattleman, trucking along with his bio-truck.
"The actual gasifier was used in World War Two," said Keith.
Wayne Keith has modified an old creation, a 'gasifier' to produce hydrogen and carbon monoxide to power his pick up. Keith says he's used switch-grass and even chicken litter for fuel. Today, it's wood. It's a complicated process.
"You put it in there [the gasifier] and you burn it and it breaks down and that sends hydrogen which comes through the rails on either side of the truck. That's the cooling system, and then it goes back through the filter and to the engine," said Alabama Department of Agriculture Commissioner Ron Sparks.
Keith's modified gasifier has since caught the attention of those promoting renewable energy. In fact, several companies along with Commissioner Sparks will sponsor a coast-to-coast trip for Keith and Auburn University professor Dr. David Bransby. The goal? Make people aware and prove a point on the open road.
"Most people think you have to have liquid to run a vehicle but you don't," said Keith.
From a practical point of view:
"I don't think folks are ready to start hauling wood and gasifiers in the back of their vehicles but the point is the technology is there," Sparks said.
And by the way, what kind of gas mileage does Wayne Keith get?
"On this particular truck I know I can get 5,000 miles per chord of wood," said Keith who claims his truck can go 80 miles an hour on the wood fuel.
Put it another way? One long but cheap trip ahead for Wayne Keith and Dr. Bransby.
Bransby and Keith will leave from Charleston, South Carolina, on September 29th. Once they arrive in Berkeley, California, Keith will participate in a road race to Las Vegas with other drivers who will use similar bio-mass fuel. Keith and Bransby are expected to be back in Alabama by October 17.
Commissioner Sparks estimates we're about 5 years away from using some form of bio-mass fuel on a regular basis.
http://www.wsfa.com/Global/story.asp?S=8787260
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Wayne Keith, and his third generation Bio-Truck powered by wood or other biomass in a down draft gasifier mounted behind the cab. The wood in the gasifier is subject to partial combustion (known as gasification) resulting in production of a mixture of gases (mainly hydrogen and carbon monoxide) known as synthesis gas, or syngas. The syngas is cooled and condensed by running it through a radiator (black rails mounted around the payload), cleaned by passing it through a filter, then directed to the engine through the carburetor to power the vehicle in place of gasoline.
History: In 2003, when the price of gasoline reached $2.00 per gallon, Wayne decided it was too expensive to continue running his 1984 Ford truck on gasoline. He used the truck daily for transportation, and to haul hay, cattle and equipment. The engine in this pickup is 460 cubic inches, and mileage on gasoline is only 8-9 miles per gallon. By 2005 Wayne had designed and constructed his first generation pickup-mounted gasifier to power the Ford on wood instead of gasoline. However, this equipment was not very user-friendly, and heavy on wood. So in 2007, Wayne designed, constructed and installed an improved second generation gasifier on a smaller truck. Finally, in 2008 he developed a further improved third generation gasifier on a third pickup. This most recent version is much more user friendly, and will be the lead vehicle for the Coast-to-Coast and Back tour (September 28 to October 16) and the one that will participate in the Berkeley to Las Vegas race (October 11-13). Wayne has traveled about 20,000 miles on wood in each of his first two trucks, for a total of 40,000 miles, and has not traveled anywhere on petroleum fuels for over two years. This indicates that the wood powered biotrucks are truly work vehicles, and definitely not toys.
Tour models: The third generation gasifier is mounted on a 1991 Dodge Dakota V8 pickup, which will lead the tour and participate in the race. The second generation gasifier is on a 1987 Dodge Dakota pickup that has a V6 engine. This vehicle will be a backup for both the tour and the race. It was necessary to use older model trucks because the technology is difficult to install on more recent models which mostly have advanced fuel injection systems.
Technology/Equipment: The technology that enables solid material like wood to be used as a fuel for the Bio-Truck is known as gasification, which is essentially partial combustion. Complete combustion is what occurs in an open fire which has an abundant supply of air, and therefore, oxygen. When a fire like this burns, the carbon and hydrogen contained in the material being burned get oxidized (oxygen from the air is added to them), to form mostly carbon dioxide (CO2) and water vapor (H2O). These gases are released into the air, and the inert material, known as ash, remains on the ground in solid form. If combustible material like wood or grass is placed in an enclosed vessel (known as a gasifier) into which passage of air (and therefore, oxygen) can be restricted, it can be ignited but restricted to only partial combustion/oxidation. The result is that instead of water vapor, hydrogen is released, and instead of carbon dioxide, carbon monoxide is released. This mixture of gases is known as synthesis gas, or syngas: mainly a mixture of carbon monoxide and hydrogen, but it also contains small amounts of carbon dioxide and methane. A down draft gasifier is located behind the cab of the Bio-Truck. The temperature in the gasifier is between 2,000 and 3,000 degrees F. The syngas flows out of the bottom of the gasifier into a gas radiator (the black “rails” mounted around the payload) to cool it down and condense it. From there the gas is run through a filter to clean it, and then directly through the carburetor to the engine. The energy content of the gas is about 200 btu/cubic foot, compared to 1,000 btu/cubic foot for natural gas.
Speed and Mileage: The race V8 Dodge Dakota travels about 1 mile per pound of wood, and can reach over 80 miles per hour on level road when traveling on wood only. The V6 pickup gets about 1.5 miles per pound of wood, and can do about 65 miles per hour.
Emissions: Because all plants, including trees, obtain their carbon from CO2 in the air, when plant material is burned the carbon is simply returned to the atmosphere where it came from. Therefore, the BioTruck is carbon-neutral because it is just releasing carbon into the atmosphere where it came from. In contrast, use of gasoline or diesel made from oil involves taking carbon from below the ground (oil wells) where it is harmless, and adding it to the pool of greenhouse gases in the atmosphere, thus increasing the risk of global climate change. For this reason it is imperative that we reduce the use of fossil fuels as soon as possible. When stationary, there may be a small amount of smoke emitted from the gasifier, but there are no visible emissions when the trucks are in motion. Tailpipe emissions have not yet been measured, but this will be done before the tour.
Owner/Inventor/Designer/Fabricator: Mr. Wayne Keith, Springville, AL, Phone: (205) 410-6829 Email: waynekeith01@alltel.net. Wayne runs a small cattle ranch in St. Clair County, Alabama.
The “Dakota Twins” – the V8 Dodge Dakota BioTruck that will drive from coast to coast on solid biomass (like wood and switchgrass) as fuel instead of gasoline, together with the V6 backup twin.
http://www.ag.auburn.edu/agrn/bio-truck/info.html
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Wood Gas Wizard
April/May 2012
http://www.motherearthnews.com/green-transportation/wood-gas-zm0z12amzroc.aspx
By Richard Freudenberger
There’s a wood gasification sensation in Alabama, where Wayne Keith hasn’t used more than a few gallons of gasoline since 2004, thus saving about $40,000.
PHOTO: RICHARD FREUDENBERGER
Back in 2004, Wayne Keith drew a line in the sand at $1.50. That’s the price at which the Alabama native would no longer buy a gallon of gasoline. Keith, who makes his living raising cows, growing hay and milling timber in a small town about 30 miles northeast of Birmingham, wasn’t bluffing. He knew he had an alternative fuel in his backyard: the hundreds of pounds of scrap wood he generates every time he runs his sawmill.
Since 2004, Keith has powered his trucks with wood. Sound strange? Trust me, this is no pipe dream. Many years ago, when I managed the MOTHER EARTH NEWS research facilities in North Carolina, we built wood-powered vehicles for the same reasons Keith does today. But Keith has taken wood gasification well beyond what I could’ve imagined. This unassuming, down-to-earth farmer is an energy and transportation pioneer, with more than 250,000 miles of wood gas driving under his belt and about $40,000 saved by using wood chunks instead of gasoline.
“My Dodge Dakota truck gets about 5,200 miles per cord,” Keith says in his easygoing Southern drawl. (A cord is a common measurement for wood, meaning a wood stack 4 feet deep by 4 feet high by 8 feet long.) “I paid for my farm in the early 1990s by selling wood at $27 per cord. Today a cord costs about $50 [wholesale] in this area. I burn scrap wood from my sawmill, but if I had to buy wood, I could still travel for less than a penny a mile.”
For comparison, if gasoline costs $3.50 a gallon, your vehicle would have to achieve nearly 350 miles per gallon for its driving cost to be a penny per mile.
4 Reasons for Wood Gas
The idea of powering vehicles with wood or other biomass energy is nothing new. Trucks, cars, motorcycles, boats, tractors and even airplanes have been adapted to burn wood. By the end of World War II, when there were critical shortages of petroleum, there were more than 1 million wood gas civilian vehicles operating in Asia and Europe.
After the energy crisis of the late 1970s, MOTHER EARTH NEWS revisited wood gas as a homegrown fuel option. We had heard from several readers who’d built their own wood gasifiers. Eventually, we had all of these running on wood gas: a Chevy pickup, a sawmill, and a 12.5-kilowatt electric generator for remote power. But why would anyone want to use wood for motor fuel?
1. Abundant Biomass. Wood is biomass that, well, literally grows on trees. In many areas, there are more wood resources than you can shake a stick at. And you don’t need firewood splits to do this — small branches, construction tailings and other wood scraps make the best fuel.
2. Wood Is Carbon-Neutral. Unlike coal or petroleum, which become environmental problems when they are extracted, refined and burned, a tree absorbs carbon dioxide from the air as it grows. When a tree dies, whether it is burned or left to rot, the carbon dioxide is released back into the atmosphere.
3. Biochar to Enrich Your Garden. When wood is consumed for motor fuel, it creates a byproduct known as biochar. This carbon-rich char can be used as a soil amendment to decrease acidity and reduce nutrient leaching while improving tilth and productivity. (Read more about biochar for gardening in Make Biochar — This Ancient Technique Will Improve Your Soil. — MOTHER EARTH NEWS)
4. Energy Independence. Perhaps the best benefit of wood gas is that wood is a renewable, homegrown fuel. If you have moderate metalworking skills and access to a sawmill, using a wood gasifier can be a major step forward in sustainable, self-reliant living. Wood gasification isn’t for everyone, but it certainly is within reach for many MOTHER EARTH NEWS readers.
Wayne’s Wood Gas World
When I visited Keith on his 100-acre spread, it quickly became clear to me that he enjoys tinkering and has no qualms about getting his hands dirty. Coming up the drive, I spotted the log home he built from his sawmill stock, two homemade wind turbines in the pasture, and several trucks with subtle signs of modifications.
Keith took me to an ’84 Ford truck to show how he had developed his earliest wood gasification designs. Its 460-cubic-inch V8 engine is a behemoth by any measure. Keith says that a large engine is an advantage in a wood gas conversion because wood gas is weaker than gasoline. More specifically, a pound of wood has fewer Btu than a pound of gasoline. (Btu, a standard unit of energy, stands for “British thermal unit,” the amount of heat needed to increase the temperature of 1 pound of water 1 degree Fahrenheit.) The Ford came with a carburetor; Keith says modern trucks with multi-port fuel-injected engines convert better to wood gas.
As we got in the wood gasification truck, I expected him to ignite the wood in the gasifier — the main tank that holds the wood chunks and converts them to gas — but he turned the key and away we went. I assumed he was starting on gasoline to warm up and we’d light the tank soon. But a few moments later, he moved a lever beneath the dash, and without any hesitation from the truck, we were driving on 100 percent wood gas.
I was surprised. First, I had no idea the wood gasifier was even lit. From my past experiences with wood gas, I expected a faint smell of burnt wood lingering around the vehicle. Not here. Second, I’d never felt such a smooth transition from gasoline to wood gas, even with a well-stoked fire in the burner. When Keith told me he hauls 15,000 pounds of large, round hay bales with this truck, I was floored. If an “alternative” fuel can pull a 7-plus ton load, why do we even need petroleum?
As we cruised along the county roads, Keith talked about his motivations for powering the majority of his transportation and farm operation with wood gas.
“From what I’ve read, we are spending $2 billion a day to go after petroleum,” he says. “At that rate, some of these other countries are going to own us. But I’ve got plenty of biomass from my sawmill. As far as I’m concerned, the buck stops here.”
Keith started reading about wood gas during the late 1970s. Decades later, he turned to hands-on trial and error, which proved to be his path to success. These days, Keith almost exclusively uses scrap wood to fuel his trucks.
Keith’s “wood chunker” (fabricated from the differential and a brake drum of an old International truck; see it in action in the Wayne Keith Wood Chunker video), cuts on an ascending bevel so that every revolution of the drum slices off a roughly 2-inch chunk. Keith and his wife, Lisa, lay out the chunks on tarps so they will dry in the sun. After the chunks are dry, Keith stores them in old feed sacks, several of which are easy to keep in a truck bed. The chunker is powered by a thrifty two-cylinder diesel engine. One hour of work can cut and spread up to 2,000 pounds of wood chunks suitable for driving (after drying).
Tests conducted on Keith’s 1993 Dodge Dakota by David Bransby — a professor of energy crops in the Department of Agronomy at Auburn University and Keith’s partner on a coast-to-coast wood gas tour — showed that it takes 16 pounds of dried wood to take the wood gasification truck as far as 1 gallon of gasoline would (21 miles in conservative driving). So one hour of work with Wayne’s chunker produces the equivalent energy value of 125 gallons of gasoline (a value of $437.50 if gasoline costs $3.50 a gallon) that Wayne can use to travel 2,625 miles.
What about environmental costs? I asked Keith whether anyone has challenged the impact of his vehicles.
“I have never cut a live tree to heat my house or run the trucks ... fact is, the gasifiers prefer small limbs and rough chunks from the sawmill,” he says. “And using that in my trucks does not change the natural, carbon-neutral cycle of wood.”
As for tailpipe emissions, one informal test found that the Dakota would meet California’s emissions standards — traditionally the toughest in the nation. More specifically, Bransby contrasts the energy source for Keith’s truck with the main sources of utility energy in their area.
“Wayne’s truck is 67 percent cleaner than an electric vehicle charged on the Alabama grid, because 67 percent of the electricity in Alabama comes from fossil fuels,” Bransby says. “Specifically, 59 percent coal and 8 percent natural gas.”
Wood Gasification 101
Just like gasoline or diesel, wood is a carbon-based fuel. But because wood is solid, it must be converted into a gas before it can power an engine, much like gasoline or diesel must be atomized before they can be ignited. Traditional burning isn’t sufficient — the wood must be heated in a high-temperature, oxygen-starved environment in order to chemically convert and produce the ideal mix of combustible gases in a process called pyrolysis.
When that conversion happens, wood gas is more effective than gasoline. Wood has less Btu “punch” than gasoline to start with, but gasoline loses some of its Btu punch in the conversion to a mist. In Bransby’s 2010 tests, the Dakota achieved 21 mpg on gasoline and 29 “mpg” on wood gas.
Like any typical wood gasification system, Keith’s setup has three basic components: a gasifier, a radiator and a filter.
The wood gasifier consists of upper and lower chambers in the form of drums connected in the middle by a heavy spacer. The upper drum is a lidded hopper where the wood chunks are held. There is an internal air inlet manifold that introduces oxygen a few inches from a restriction, which causes a high temperature (about 2,700 degrees) to be created in a small environment. This is where the gasification takes place.
The hot gases go from the gasifier to a heat exchanger, where the gaseous fuel is cooled with fresh air. The incoming air piped to the gasifier’s inlet never comes in contact with the exiting fuel gases.
Next, the gases go to a radiator, or cooler, which Keith has skillfully camouflaged as a bed rack. There are two inlets and two outlets, so each side of the rack has cooling capacity. Here, the gas temperatures drop below the dew point, and the condensation drains into small tanks.
The third component, the filter, is simply a clamped-lid barrel filled with hay. This removes most of the particulate matter contamination in the wood gas.
After being cooled and filtered, the wood gas is pulled through two branches of PVC piping to the engine compartment. Homemade “slingshot” filters separate any remaining moisture and particulate matter from the incoming gas stream.
The cooled, clean wood gas is directed to fittings Keith has installed in the engine’s air cleaner housing. Two inlets are dedicated to fuel gas and two to fresh air, which is drawn in through separate canister filters. Each of the four inlets includes a butterfly valve that Keith adjusts manually with controls on the dash.
The World’s Fastest Wood Gasification Truck
Impressive as the old Ford was, I was eager to see Keith’s seventh wood gas truck conversion, the ’93 Dakota. Just days before I arrived, Wayne and his son Tally had returned from the Bonneville Salt Flats in Utah, where MOTHER EARTH NEWS sponsored Keith in the famous World of Speed time trials. Not only was Keith’s Dodge Dakota the only wood-powered vehicle there, he was the only competitor to actually drive (not trailer) the vehicle to the event — a distance of about 2,000 miles. (See photos of the Dakota and more in this article's Image Gallery.)
“We made 73.09 mph in the measured mile,” Keith says. “I beat out 12 other vehicles that were running [in other categories] on gasoline, and beat the team with the prior wood gas record of 47.7 mph.”
(Read 73 MPH On Wood Gas Sets New Record to learn more. But 73 mph isn’t the Dakota’s top speed. MOTHER EARTH NEWS Managing Editor John Rockhold took a ride that had to slow down at 84 mph; read about it and watch it happen in I Went 84 MPH in a Wood Gas Truck; see the third video from the top. — MOTHER EARTH NEWS)
In preparation to start the Dakota, Keith flipped the switches on a pair of small in-line bilge blowers and opened the gasifier lid to reveal remnants of cold char in the tank, which he ignited with a propane torch.
“With a poker rod I make a little void that goes down to the center of the hearth,” Keith says. “I’ve got those blower switches fixed to where I can either blow or suck the air through to get the wood going.”
After pouring a sack (about 12.5 pounds) of dried wood chunks into the chamber, he sealed the lid and started the truck on gasoline. We drove about a quarter of a mile on gasoline, then he switched over to wood gas with the touch of a lever.
“On this truck, I’ve got a sensor and gauge that monitor the exhaust gas, telling me if it’s too rich, too lean or just right,” Keith says. “I’ve also got vacuum and temperature gauges — sort of like a doctor’s stethoscope and blood pressure monitor — that let me keep an eye on what’s going on. Since wood gas is slow-burning, it helps to advance the timing a bit. The older Ford does that with a cable, but the newer models are smart enough to automatically adjust to the fuel.”
On a straight stretch of road, we cruised at 75 mph. Other than monitoring the gauges, Keith did not spend much time making adjustments. Aside from the occasional flick of extra levers and the barrels in the truck bed, you wouldn’t know this truck runs on wood instead of gasoline.
As far as how the wood gas system performs throughout the year, Keith says the vehicle performs slightly better on crisp days, when humidity is lower.
“The gasifier works fine in hot weather,” he says. “It increases in power a bit the colder it gets. In very cold weather there could be issues with the condensation freezing, so you’d have to design for that.”
As far as driving range, Keith sized the Dakota’s wood gasifier to allow 50 to 75 miles on one fill. Some of his earlier gasifiers were sized to allow 100 miles or more, but that required more conspicuous tanks.
Wood Gas Revolution?
Clearly there is untapped potential in wood gasification for transportation, but whether it can ever be more than a fringe movement remains to be seen. Making it work isn’t easy. Even Wayne Keith — arguably the best advocate for wood gas — says that 75 percent of success comes down to operator knowledge and experience; the system itself accounts for the remaining 25 percent.
Despite all the money that Keith has saved via wood gas, it’s the self-reliance that is the most satisfying benefit.
“The big plus for me — beyond the clean driving and financial benefits — is being dependent on no one but myself for fuel.”
Wayne Keith’s Wood Gasification Conversion Tips
Choose a truck with ample room under the hood, as well as around the engine and chassis.
Electronic fuel-injected engines have streamlined air intakes, which convert better than carbureted engines.
Multi-port fuel injection is preferable over throttle-body injection. Generally, trucks built after the mid-1980s use fuel injection.
Large-displacement engines have more power and give better results on wood gas.
High compression improves performance with wood gas: It burns slowly and has great antiknock qualities. Wood gas supports a compression ratio of up to 16:1.
It is possible to convert diesel engines to use wood gas, if given the correct compression ratio. But the injector pump has to furnish the ignition with at least 5 percent diesel.
Ignition timing should be advanced because of the slower-burning gas. Modern engines with electronic ignition will automatically advance the timing.
It takes about 200 to 300 hours to convert a truck to wood gas. Keith’s record-setting Dodge Dakota took 250 hours of work.
The cost of materials to convert is about $500. Many components can be found free.
Tools needed: basic mechanic’s tools, a sheet metal nibbler, a metal-cutting reciprocal saw, a power hacksaw, a drill press, a cutting torch, small wire-feed welder, a solid workbench, and a sturdy vise.
The gasifier should be built to match the size of the engine and its airflow volume.
The size of the wood chunks affects engine performance. Smaller chunks react faster and give better performance, but the fuel is consumed faster.
Hardwood has greater energy density, and thus delivers more range per fill, than softwood.
Ongoing maintenance: flushing the cooler and draining the condensation traps every 2,000 miles. Ash residue should be removed every 1,200 miles and the filter medium changed once a year.
Moisture content of the wood chunks should be less than 25 percent.
Wayne Keith’s Wood Gas Wonders
About 250,000 miles driven, almost exclusively on wood gas, since 2004.
About $40,000 saved by not buying gasoline.
Nine trucks converted to wood gas since 2004.
Regularly hauls loads of 15,000 pounds in farm work.
Completed the 2009 Bio-Truck Coast-to-Coast and Back tour, which ran from Alabama to Charleston, S.C., to Berkeley, Calif., and back to Alabama.
Completed the 2009 Escape from Berkeley road rally, which ran from Berkeley, Calif., to Las Vegas. Finished second to Jack McCornack’s MAX car (visit 100-mpg Car: MAX to learn more), partly because of a flat tire on the wood chip trailer.
Set new speed record for wood gas (73 mph) in the 2011 World of Speed event at Utah’s Salt Flats. Read 73 MPH On Wood Gas Sets New Record to learn more.
Wood Gas Resources
MOTHER EARTH NEWS Wood Gas Adventures blog
Learn more about gasification and see videos of various vehicles in action, including Wayne Keith's.
Drive On Wood!
Wayne Keith’s website. Keith is working on a book with detailed plans for his system.
Yahoo! Groups: Wood Gas
The Wood Gas community group on Yahoo! has numerous wood gas veterans among its members, including moderator Mike LaRosa.
VIDEO URL: http://youtu.be/JlNACAEa3vo
VIDEO URL: http://youtu.be/0duRTRC3Sxc
VIDEO URL: http://youtu.be/8yvmh-lKhI0
So... How much wood could a wood-truck chuck if a wood-truck could chuck wood? Let's find out.
Quoting Wayne Keith:
"Most people want to know, how much wood does it burn? In controlled studies we did at Auburn University, my Dodge Dakota got about 1.25 miles per pound of dry wood. It turns out that the truck is 37% more efficient on woodgas than gasoline, so it works out to 16 lbs per gallon equivalent."
"Sometimes people jokingly ask how many miles I get per log. When I tell them that my truck goes 5,200 miles per cord they stop laughing. Firewood in most rural areas sells for around $150 per cord. So if I were to buy wood, I could travel for less than a nickle per mile. However I have never had to buy firewood or cut a live tree to feed my trucks. I get all the scrap wood I can use from my homemade sawmill. Wood gas is a great fit for me since I have scrap wood laying right in my way."
(Read more about Wayne's wood gas trucks in this feature article: Wood Gas Wizard! - MOTHER EARTH NEWS)
You're probably thinking, that's OK for one farmer in Alabama. But what if we all switched to wood power? Deforestation would quickly ruin the countryside, right? Think again. While it's true that we can't power our massive trucking industry with biomass, it's possible that we could provide more than enough wood for passenger vehicles in this country, even with conservative forest management. Here's some figuring we did to determine if this is feasible:
Around 199 million drivers on the road (passenger vehicles only).
The average driver goes about 13,500 miles per year.
Average fuel economy is 20 mpg (16 lbs/gal = 0.8 lbs/mile on wood) - need about 10,800 lbs per driver (2.16 cords).
Total wood requirements = 199 million x 10,800 pounds = 2.1 trillion pounds or 430 million cords.
One acre of woodland can produce about 1 cord of wood annually (very conservative) - need 430 million acres.
The national forest is currently estimated at 747 million acres. The contiguous US is 1.89 billion acres.
The farmland devoted to corn for ethanol is estimated at 33 million acres (13.2 billion gallons/400 gal per acre).
This farmland could produce wood for nearly 23 million drivers, assuming 1.5 cords/acre (managed for max yields).
Same farmland currently serves about 16 million drivers on ethanol, not counting energy inputs and soil depletion.
Current "readily available" logging waste is about 49 million tons per year. This can fuel about 9 million drivers.
Of course, all this is theoretical - wood gasification requires skilled, hands-on operation. It's not turn the key and go. The general public will never accept the mess and hassle of burning wood, either in their homes or their cars. So DIYers, relax and enjoy the bountiful resource we have in this country. Build a gasifier and take advantage of wood energy! No one else wants it - help yourself to all the scrap wood you can get. Your money stays in your pocket, and the environment will thank you for it.
Check out Wayne's website, Drive On Wood! for details about his trucks and further information on wood gasification.
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