Can I burn wood to produce electricity?

[RedneckPete]

Outdoor wood boilers are becoming more common for heating buildings and water. I have access to enormous amounts of free wood and construction waste. I often pay to get rid of it.

I have no need for heat, but would love to produce electricity with this wood. Does any such unit exist? If not, why not? Off grid living almost always means living close to wood, surely a unit such as this could be useful.

I plan to build what is essentially a concrete incinerator about 10x10x10 feet out of a pile of coreslabs I have around, but would love to do something useful with the heat that will otherwise go up the chimney.

Any ideas from alternative power experts would be appreciated.

Pete

[almostthere]

Why aren't you selling it? We pay $10/truckload for end pieces and leftovers from a mill.

[seedspreader]

Originally Posted by RedneckPete

Outdoor wood boilers are becoming more common for heating buildings and water. I have access to enormous amounts of free wood and construction waste. I often pay to get rid of it.

I have no need for heat, but would love to produce electricity with this wood. Does any such unit exist? If not, why not? Off grid living almost always means living close to wood, surely a unit such as this could be useful.

I plan to build what is essentially a concrete incinerator about 10x10x10 feet out of a pile of coreslabs I have around, but would love to do something useful with the heat that will otherwise go up the chimney.

Any ideas from alternative power experts would be appreciated.

Pete

I have sat down and tried to figure out a way to do this also. Obviously when producing electricity with wood/fire you need to create steam to turn turbines (at least this is the simplest way I can figure out) so your biggest issue will be watersupply (I THINK I might have a recirculating system that might work) and fuel. I will be keeping an eye on this thread, because I am curious of the same thing.

Of course you will have to have a batter bank etc. to store it I would assume.

[hunter63]

Check out this article:
http://www.motherearthnews.com/Alter...stead_Utility_

"Corse you could fire a steam boiler/engin to turn a gen/set.

[moopups]

High heat and concrete are not an ideal situtation, the concrete is subject to cracking by the constant temperature changes. The Alternative Energy forum may have someone familiar with something this forum may not have heard about.

A sterling engine may be feasable for this purpose.

[rambler]

Selling as firewood might be more $$$ wise.

Surprised you don't need the heat, with your location.

Now, off of my soapbox & to your question:

Would a smoke-run gas engine work out? I think the efficiency of the whole operation would be pretty low, much lower than a Sterling engine for example, but might be an easier to home-putter togerther a woodsmoke engine.

Basically you burn the wood - very poorly - and run the smoke (wood gas) through a slightly modifided gasoline engine. Mother Earth News has done articles on these, as well as many others. Use the engine to run the generator. Use the water jacket of the engine to heat a building - if you need the heat.

I'll guess inefficient, and not sure about dependability, but workable.

--->Paul

[Shadow]

The problem with gasoline engines is their short live span. Even a Auto engine usually begins to give problems at least for me at 100,000 miles, figure 50 miles per hour and that is 2,000 hours. If you are good at maintance make it last 200,000 and you have 4,000 hours of use. Now with a small engine its not going to be that long.
Now try running it on wood smoke and the life really goes down.
Back to the steam idea price a boiler, high pressure type and a turbine to turn in the steam and you can buy electricity for many life times even with free fuel.
Sorry been down this road and there is no answer down it.

[Obser]

Almost all electricity is produced by heat, usually by buring coal, oil or natural gas, sometimes by using fission reactions. A key element in each case is some means of converting heat energy into rotary motion. This is typically done with a steam-driven turbine. Therein lies the problem for small applications.Almost all electricity is produced by heat, usually by burning coal, oil or natural gas, sometimes by using fission reactions. (Exceptions are hydroelectric which uses the energy of falling water to power a turbine and diesel-powered generators which are relatively inefficient). A key element in each case is some means of converting heat energy into rotary motion. This is typically done with a steam-driven turbine (regardless of the fuel source).

Therein lies the problem for small applications. Steam at high enough temperature and pressure to be useful is difficult to produce and control. Some type of heating vessel or boiler is needed that is strong enough to contain the desired (high) pressure. Temperature must be maintained and controlled. The steam output must be directed to where it is needed.

Assuming all those requirements are met, one still needs a turbine and a generator and a lot of labor to keep the system running and an adequate source of water and probably a license from the state. Whew! I wouldn’t be surprised if the “payback period” was 200 years.

A steam engine might offer some advantages, but there aren’t many of them available for purchase in the size range a small generating system would require (and if they were available they wouldn’t be cheap). Also, steam engines are known to be a wee bit dangerous if not well managed.

Sterling engines could offer a possible route – if they became available and affordable in appropriate size/power range. They are at least considered to be less dangerous than steam engines.

Perhaps it would be most cost effective to get rid of the excess wood in some convenient and economical way. I have known of several operations that sold scrap wood at “giveaway” prices, or simply gave it away, to be used as firewood. At one place I regularly got pickup loads of discarded building lumber that was hauled away from construction sites. I could load (overload) a pickup truck for a $10 “donation” – and got many loads of useable lumber (and plenty of firewood).

[wy_white_wolf]

Good post Obser. I was having a hard time putting it into words. My best suggestion would be to sell th wood and invest the money in solar, wind and/or hydro if you want to generate electricity.

[rambler]

Originally Posted by Shadow

The problem with gasoline engines is their short live span. Even a Auto engine usually begins to give problems at least for me at 100,000 miles, figure 50 miles per hour and that is 2,000 hours. If you are good at maintance make it last 200,000 and you have 4,000 hours of use. Now with a small engine its not going to be that long.
Now try running it on wood smoke and the life really goes down.
Back to the steam idea price a boiler, high pressure type and a turbine to turn in the steam and you can buy electricity for many life times even with free fuel.
Sorry been down this road and there is no answer down it.

Your point is well taken, & I agree.

On the other hand, can pick up common engines for $500-1000, and in a stable, non-moving, dirt free, contant output situation they do last longer than 'average' vehicle, dirty start/stop use. I'd say you could double or triple your hours, even on a rebuilt used engine. Typically a stationary engine will run 3x as long as a tractor engine - same model engine - for example.

But still not many hours, and as you say the wood smoke is gonna be harder on it, so back to low hours....

Just exploring the possibilities. Would be fun to play with if one had the time. My uncle build a wood gas burner with a friend of his way, way back - Model T might have still been a common car on the roads back then.... He had said it worked, was a pain to make it go with the setup time & fussy, but worked ok.

I see the link to TMEN here is describing this too, I didn't realize that when I posted.

--->Paul

[comfortablynumb]

go to a steam engine show....

a simple steam engine with a long belt hooked to a dynamo.

bada bing, electricity.

[bgak47]

Sure you can! All you need is a steam engine that is capable of burning wood & is attached to a generator. Why would you want to? Sell your wood & use the money for some kind of more modern system.

[seedspreader]

Originally Posted by bgak47

Sure you can! All you need is a steam engine that is capable of burning wood & is attached to a generator. Why would you want to? Sell your wood & use the money for some kind of more modern system.

If it's construction scrap, it might be unsellable (is that a word??), and could be more $$$ sense to burn it even making unefficient electricity.

[bgak47]

Same answer...get a steam engine & a generator... then spend all of your time stoking the boiler & cutting the wood for it.

[MaryNY]

The process is called wood-gasification. TMEN ran (at least) one of its trucks on it. (I rode in that truck once upon a time, though it wasn't running on wood-gas at the time - drat it! It was dual fuel.) I think if you search "wood-gasification" on the TMEN website you will find the articles they had on it. They used to have some plans I think. Maybe you could contact them and ask about it. The folks from TMEN always said that the truck was okay, but the way to really use the wood efficiently was to use the wood-gas system to generate electricity and then run the truck on the electricity. Maybe they had plans for a wood-gas generator, too. Good luck.

And Rambler - your uncle probably has a wealth of first-hand knowledge on the subject. Lucky you!!

MaryNY

[RedneckPete]

Thanks everyone for the ideas.

The wood I have is garbage, with no value whatsoever. It is a combination of old landscape materials, decks fences and shrubs as well as demolition waste. Most of this material has been crushed with an excavator, and I have been burning it as waste. Please don’t start preaching about burning pressure treated wood and shingles and that sort of thing. I am careful to separate out that material during demolition and again during the burn as much as possible.

I’ve chewed over the idea of boilers and steam and turbines, but can’t think of any way to do it at a reasonable cost. I also chewed over the idea of using a wood smoke engine, but this would require a two chambered burn box, one with an air fed fire, used to produce heat to “cook” the rest of the wood to produce smoke and charcoal. It seems to me that regulating the smoke produced to a constant amount to feed an engine would be a nightmare on a small scale.

I don’t know what I was hoping for, but I like the idea of a steam engine. Will do more looking into this. As it is now, I have to feed the fire anyway. This job is done with an excavator fitted with a grapple, not a time consuming or labor intensive task.

I don’t need heat because I already heat 100% with wood. I use the good logs to produce my own firewood. Below are two pictures, one of my “good” woodpile I use to heat my house and another of the “garbage” wood I need to get rid of.

Pete

[MaryNY]

Check this out -- it may have some info to help you.

http://www.green-trust.org/woodgas.htm

MaryNY

[WisJim]

A steam engine powering a generator would make sense if you also used the waste heat to heat your home, shop, business, etc., and also your hot water and anything else you needed heat for. It would require attention from someone almost constantly, but could produce a substantial amount of power and lots of heat. Would make the most sense for a small community. For the money involved, solar and/or wind, depending on the location and exact site, could be better choices for electrical generation.

[FreightTrain]

Originally Posted by RedneckPete

Thanks everyone for the ideas.

The wood I have is garbage, with no value whatsoever. It is a combination of old landscape materials, decks fences and shrubs as well as demolition waste. Most of this material has been crushed with an excavator, and I have been burning it as waste. Please don’t start preaching about burning pressure treated wood and shingles and that sort of thing. I am careful to separate out that material during demolition and again during the burn as much as possible.

I’ve chewed over the idea of boilers and steam and turbines, but can’t think of any way to do it at a reasonable cost. I also chewed over the idea of using a wood smoke engine, but this would require a two chambered burn box, one with an air fed fire, used to produce heat to “cook” the rest of the wood to produce smoke and charcoal. It seems to me that regulating the smoke produced to a constant amount to feed an engine would be a nightmare on a small scale.

I don’t know what I was hoping for, but I like the idea of a steam engine. Will do more looking into this. As it is now, I have to feed the fire anyway. This job is done with an excavator fitted with a grapple, not a time consuming or labor intensive task.

I don’t need heat because I already heat 100% with wood. I use the good logs to produce my own firewood. Below are two pictures, one of my “good” woodpile I use to heat my house and another of the “garbage” wood I need to get rid of.

Pete

if i wanted to do it w steam i might consider a marine steam engine with a vertical boiler to turn a gen/dynamo.

http://www.users.bigpond.net.au/cowiepeters/


most of the attention is in adding water almost "constantly" to keep the crown sheet covered at all times(top of firebox metal) or it will warp from the heat... which is very bad.

having a custom live steam boiler built will cost thousands!
you might be able to snatch a nice marine engine off ebay for 500-1500 or even use a steam eng from a vintage stanley steamer and rig that to turn a gen... ive seen these sell for a few hundred. steam engines are amazingly strong for their size...( think adam ant) so should be able to turn a good sized gen.

most hazards can be avoided by simply hydro testing the boiler a min once a year,,, modern boilers should be taken to at least double the operating pressure while observing the flue tubes for compression (flattening) and the rolled ends for leaks... i test my 1" scale steam engine to 150% of operating pressure or to 150 psi.

there are two types of steam... plain and live, plain steam is safe... like steam drifting up from you boiling veggies
live steam (steam under pressure) is very dangerous, the dangers in "live steam" is the expansion of it when it hits the cool low pressure atmosphere.... it expands at something like 1500 feet per second.... from a 100 psi boiler. if anything goes wrong, pull the ash pan and pull the pin to drop the fire.. all boilers should have a way to do this

[rambler]

The stirling engine will have less govt regulation, less yearly expense than trying to get a small steam engine certified & operational on a small scale. You will end up getting into epa emmissions as well, with the smokestack. Very much regulation in power plants, only getting worse.

There is no easy way to do this, feeding a power plant takes a lot of time & effort. You need to match fuel in to power out, and blips & varriation from the varied fuel will take some monitoring.

Might want to look into what you have available for fuel really, & how much of this raw btu can be turned into useable power - what the possible electrical value you have.

Then see if it is worth fooling with.

Difference if you want to play with a wood gassifier deal as a hobby, or you actually want to set up a boiler for dependable, full time electrical production.

Sterling is probably the middle ground.

Don't think the $$$ will be there, energy density is too low; govt regulation is too high; on anything above a hobby unit made from scrap parts.

--->Paul