Anyone Figured Out How to Use Grass Clippings as a Biomass Fuel??

[R&D Guy]

I live on a 1/3rd acre lot that is mostly grass, and every year from about May to the end of Septemeber I just about fill a 96 gallon yard waste container. I know I'm not alone in that fact either, and how easy would it be to get grass clippings from the neighbors. Has anyone figured out how to make a biomass stove that can burn grass clippings? I'm sure I could heat my home for a good 3 months with what I cut each summer.

Obviously there are a bunch of big issues - likely the biggest I think would be drying the grass out. I'd think that you'd also have to put it in some sort of pellet form, but like I wondered; maybe someone's already thought of all that.

 

[karl]

Drying it should be easy. It will dry in a day or two in the sun. You would just need to way to spread it out. The problem is 96 gallons really isn't that much. One gallon equals .133680556 cubic feet. So 96 gallons is just under 13 cubic feet. I'm guessing you could heat your house for a day or two on it, not three months.

 

[myzamboni]

with a 1/3rd acre, he's filling that 96 gallon container with every mow.

 

[mkmh]

I live on a 1/3rd acre lot that is mostly grass, and every year from about May to the end of Septemeber I just about fill a 96 gallon yard waste container. I know I'm not alone in that fact either, and how easy would it be to get grass clippings from the neighbors. Has anyone figured out how to make a biomass stove that can burn grass clippings? I'm sure I could heat my home for a good 3 months with what I cut each summer.

Obviously there are a bunch of big issues - likely the biggest I think would be drying the grass out. I'd think that you'd also have to put it in some sort of pellet form, but like I wondered; maybe someone's already thought of all that.

Some folks have been working on this...
http://www.reap-canada.com/bio_and_climate_3_2.htm

Of course some important considerations are:
Type of Grass
Pellet Stove Type

So far the grass pellets have been found to produce a lot of ash (as you'd expect) so they won't burn well in most stoves. They point out in the article that Bixby stoves do pretty well in tests, as do some Harman stoves.

As far as a consumer device/process for pelletizing our own grass clippings I think we are a long ways off. No dount it could be done, but i'm not sure it would ever be cost effective.

 

[mkmh]

Drying it should be easy. It will dry in a day or two in the sun. You would just need to way to spread it out. The problem is 96 gallons really isn't that much. One gallon equals .133680556 cubic feet. So 96 gallons is just under 13 cubic feet. I'm guessing you could heat your house for a day or two on it, not three months.

Agreed. I typically toss my clippings in the composter and it is amazing how fast they break down. Putting grass in pellet form for burning would involve getting rid of all the moisture content. I could see a 96 Gallon container of grass adding up to 2 or 3 40 LB bags of grass pellets.
Having said that, I think there is still some potential to start blending grass in with wood pellet mixtures (on a large scale). This would likely result in a standard (or lower) grade pellet...but I would think this type of blend could result in a lower cost per ton.

 

[R&D Guy]

with a 1/3rd acre, he's filling that 96 gallon container with every mow.

Yes sorry I meant to add that I just about fill it every week.

 

[R&D Guy]

Thanks for the link mkmh! The wheels are turning now.

Anyone have a good link that shows how pellets are made?

 

[begreen]

Drying it should be easy. It will dry in a day or two in the sun. You would just need to way to spread it out. The problem is 96 gallons really isn't that much. One gallon equals .133680556 cubic feet. So 96 gallons is just under 13 cubic feet. I'm guessing you could heat your house for a day or two on it, not three months.

Agreed. I typically toss my clippings in the composter and it is amazing how fast they break down. Putting grass in pellet form for burning would involve getting rid of all the moisture content. I could see a 96 Gallon container of grass adding up to 2 or 3 40 LB bags of grass pellets.
Having said that, I think there is still some potential to start blending grass in with wood pellet mixtures (on a large scale). This would likely result in a standard (or lower) grade pellet...but I would think this type of blend could result in a lower cost per ton.

A bit off topic, but how are you composting your clippings mkmh?

 

[TMonter]

Clippings are mostly water. When you dry then I'm betting you find they don't weigh all that much.

 

[mkmh]

Drying it should be easy. It will dry in a day or two in the sun. You would just need to way to spread it out. The problem is 96 gallons really isn't that much. One gallon equals .133680556 cubic feet. So 96 gallons is just under 13 cubic feet. I'm guessing you could heat your house for a day or two on it, not three months.

Agreed. I typically toss my clippings in the composter and it is amazing how fast they break down. Putting grass in pellet form for burning would involve getting rid of all the moisture content. I could see a 96 Gallon container of grass adding up to 2 or 3 40 LB bags of grass pellets.
Having said that, I think there is still some potential to start blending grass in with wood pellet mixtures (on a large scale). This would likely result in a standard (or lower) grade pellet...but I would think this type of blend could result in a lower cost per ton.

A bit off topic, but how are you composting your clippings mkmh?

Nothing fancy..I just chuck them in one of those black garden composters mixed in with our (non-meat) food waste, leaves and other stuff. I notice that every time I put grass in the temperature shoots right up and stuff breaks down pretty quickly. Generally I try to let my mulching mower take care of everything..but when I get behind on mowing I find that it is easier to bag and compost.

 

[mkmh]

Thanks for the link mkmh! The wheels are turning now.

Anyone have a good link that shows how pellets are made?

Sure. The New England Pellets site has a decent breakdown. No trade secrets are revealed, but you get the idea ;-)
(broken link removed to http://www.pelletheat.com/pellets/process_1.php#photo)

 

[karl]

The grass has alot of nitrogen in it and casues it to heat up and break down. Try to train your dog to pee in it and the stuff will break down really quickly )

 

[wg_bent]

I think we should burn the other kind of "Grass" Really give the BI folks something to complain about. That or they'd get really mellow! The Peace and Love Neighborhood. :lol:

 

[karl]

Maybe we could put the amount of smoke we generate into perspective for the BI people that way. So when they start complaining about my new Summit. I'll tell them it puts out less than two joints an hour worth of smoke. Seriously though, I would like to know how many grams an hour a cigarette puts out. So I could give people the comparision. Is it realistic so say a 3.5 gram an hour stove burnt all day equals a couple packs of cigarretes.

 

[BrotherBart]

Maybe we could put the amount of smoke we generate into perspective for the BI people that way. So when they start complaining about my new Summit. I'll tell them it puts out less than two joints an hour worth of smoke. Seriously though, I would like to know how many grams an hour a cigarette puts out. So I could give people the comparision. Is it realistic so say a 3.5 gram an hour stove burnt all day equals a couple packs of cigarretes.

One source says that a cigarette puts out .4 grams per hour or .8 per pack. Of course the source is BI.

http://burningissues.org/comp-emmis-part-sources.htm

 

[karl]

The problem with their numbers is that it can't be .4 per cigarette or is per 30 cigarettes? There chart is confusing. And only .8 per pack. There are 20 cigarettes in a pack. How can 30 cigarettes put out half the smoke as 20? Maybe it's a typo and then meant 8 grams per pack. Still, I would like to find the numbers on a website other than theirs.

 

[begreen]

A cigarette only burns for 5-6 minutes. or say .04gms. x 20 = .8gms/hr.