# Wood pellets replacing coal.



## Snowfan (Nov 6, 2011)

I just got done reading a magazine article about some electrical power generating plants converting from burning pulverized coal to burning wood pellets. I started thinking about it and came up with several questions.
I like the idea of the cleaner burning fuel and the projected increase in jobs. Maybe some of you can offer some input and educate me.
The short article didn't state the quality of the wood pellets these plants burn or how much less or more pellets are required to generate the same MWh. Might this negatively effect the price the average Joe will pay for pellets for heating their homes? Different size or shape or moisture content?
What are your thoughts?


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## werb2008 (Feb 5, 2015)

pellet stoves around here in Pa are usually used to help offset the heating system in the home,while some do heat the whole house with them coal and wood is still king around these neck of the woods, average price around my area 235 ton for pellets and 200 for coal.pellets burn much cleaner but also requires power for the blower.what kind of impact will this have for the average customer ,probably nothing they will get cheaper power not the customers.I don't know if its the same kind of pellets used in homes.


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## cherrick (Feb 6, 2015)

Pellet stoves are fairly common technology. Use Google searches to expand you knowledge. Tractor Supply sells the bags of pellets in many places. In the cold, cold north lots of folks are going pellet. 

Just remember you need electricity for the auger motor and the thermostat and the igniter.


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## Skandi (Oct 21, 2014)

Pellets are really common here, them and pressed blocks, both are often made with sawdust, so THAT is expensive if you want it for bedding. I know that in the UK and here they grow willow for electrical generation, but I don't know if it is peleted beforehand, I guess so. A good use for waterlogged land imo, been watching the fields with it here, seems to take 3 years between harvests, so goes pretty young.

Energy in pelets around 4.8 MWh/tonne (~7450 BTU/lb).
Energy in coal middling (not sure on this one, was much harder to find) 6.6-8.1MWh/tonne


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## wy_white_wolf (Oct 14, 2004)

Snowfan said:


> ...Might this negatively effect the price the average Joe will pay for pellets for heating their homes? Different size or shape or moisture content?
> What are your thoughts?


It very well could. I work a coal fired power plant. We did have a company pitch the idea to us. While we could have used a large variety of pellets the plants that would have supplied us also made pellets for home heating. So they would be competing for the same feedstock to make the pellets.

Our smallest unit burns 7 to 8 ton of coal an hour. Tonnage would have been about the same for wood pellets. My BIL only uses about 2 ton to heat his house all winter. That a big difference in what the market.

WWW


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## Harry Chickpea (Dec 19, 2008)

Not sure what advantage would be gained in power generation with the extra step of pelletizing wood. The McNeil plant in Burlington VT burns wood chips at a rate of up to 76 tons per hour of uncured wood waste to generate 50 megawatts.


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## where I want to (Oct 28, 2008)

Because stripping land of wood to replace coal, which is fairly unlimited, is not a solution. It can augment, but not replace. Take too much wood and floods and pollution increase as forests both slow water flow and clean water that passes through them.
Here "biomass" generation for utility use has deprived me of bedding, mulch, etc as it has been diverted to these places to be burnt rather that refresh the soil. 
Then, because we are at the Pacific ocean, chips are a steady stream being sent to China.
It is simply not anything other than a minor help to a few locations. I shudder at the damage that occur if it gains too much market share. Sweden is into it big time but the amount of regulation needed to keep it sustainable is incredible and then they are only trying to maintain a basically coniferous forest that had millennia of human activity already.


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## Darren (May 10, 2002)

I w


Harry Chickpea said:


> Not sure what advantage would be gained in power generation with the extra step of pelletizing wood. The McNeil plant in Burlington VT burns wood chips at a rate of up to 76 tons per hour of uncured wood waste to generate 50 megawatts.


That's interesting. fifty megawatts isn't a big power plant. If the rate scales, a 1,000 megawatt base load plant would burn 1,520 tons per hour or 36,480 tons per day.. You'd be looking at some serious forest depletion unless that was supplied by coppicing willow. I wonder how many acres that would take to grow.


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## wy_white_wolf (Oct 14, 2004)

Harry Chickpea said:


> Not sure what advantage would be gained in power generation with the extra step of pelletizing wood. The McNeil plant in Burlington VT burns wood chips at a rate of up to 76 tons per hour of uncured wood waste to generate 50 megawatts.


I think you may have that number wrong. Our smallest units produce 100MW and only burn 7 to 8 ton of coal per hour. Wood is about the same % of carbon so the weight burned is the same but the volume is about double.

All our units together are rated at 780MW and we burn about a train load (~130 cars) a day at full load.

WWW


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## Harry Chickpea (Dec 19, 2008)

You can look at the Burlington Electric site. That is what they quote. I suspect that there is a tremendous efficiency hit from the wood being wet and not pre-dried. They apparently tried a gasification technique using water and hot sand but had problems.


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## Snowfan (Nov 6, 2011)

If I understand things, the pellets are basically a by-product of other industries. So, maybe, the scrap and sawdust would simply be diverted from being a waste product to being sold to a pellet producer. I can't imagine actually harvesting trees solely for the purpose of producing fuel pellets. I imagine, like any commodity, the laws of supply and demand will prevail. Still, as an old fart, I would buy a wood pellet stove, furnace or outside boiler.


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## beenaround (Mar 2, 2015)

Snowfan said:


> I just got done reading a magazine article about some electrical power generating plants converting from burning pulverized coal to burning wood pellets. I started thinking about it and came up with several questions.
> I like the idea of the cleaner burning fuel and the projected increase in jobs. Maybe some of you can offer some input and educate me.
> The short article didn't state the quality of the wood pellets these plants burn or how much less or more pellets are required to generate the same MWh. Might this negatively effect the price the average Joe will pay for pellets for heating their homes? Different size or shape or moisture content?
> What are your thoughts?


A plant has been planned for Lima Ohio for some time, over 10 years. The gist of it is 2 plants would be built, one to produce the energy and one to produce the pellets. The interesting thing is the pellets would be made out of land fill garbage. 

The burning would be a processes called gasification. I was interested in this bit of news way back when because I'd just bought a wood burning boiler that also used gasification. Works very well. 

The plant/s are still on hold.


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## beenaround (Mar 2, 2015)

Snowfan said:


> If I understand things, the pellets are basically a by-product of other industries. So, maybe, the scrap and sawdust would simply be diverted from being a waste product to being sold to a pellet producer. I can't imagine actually harvesting trees solely for the purpose of producing fuel pellets. I imagine, like any commodity, the laws of supply and demand will prevail. Still, as an old fart, I would buy a wood pellet stove, furnace or outside boiler.


How about one that could burn them all. Alternate Heating Systems out of Pa builds that boiler. I've used one for at least 10 years and no, I'm in no way affiliated with the company although they could throw me some parts now and then for the effort. 

This boiler can be set up to burn mulch which people who produce it can't find enough places to dump it. I never have, requires a feed system like the pellets and mine is just setup for wood.


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## where I want to (Oct 28, 2008)

beenaround said:


> A plant has been planned for Lima Ohio for some time, over 10 years. The gist of it is 2 plants would be built, one to produce the energy and one to produce the pellets. The interesting thing is the pellets would be made out of land fill garbage.
> 
> The burning would be a processes called gasification. I was interested in this bit of news way back when because I'd just bought a wood burning boiler that also used gasification. Works very well.
> 
> The plant/s are still on hold.


Can they really make pellets out of land fill that do not have bits of plastic and other chemicals in them?


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## Robb40 (Oct 3, 2013)

I used to heat with a wood pellet and corn burning stove. When I bought the thing, corn was less then three dollars a bushel. Then, they start making corn ethanol and the price skyrocketed up to eight dollars a bushel. I burned wood pellets for a time until they went up in price. I heat with an outdoor, forced air wood burner now. 

What the power plants intend to burn is biomass. It isn't just wood pellets. It can be made of dry grasses, corn stalks, straw and even waste paper products. They are even considering burning the solid waste left from sewage treatment plants that would otherwise go to a landfill. The wood pellets can be made up of waste wood products from factories as well as trash wood from tree trimming. 

The pellets that are used to generate power are quite a bit larger than what you would use in your pellet stove at home. But, they are produced in a similar manner by compressing biomass at high pressure. The biomass pellets have to have a uniformly low moisture content. By burning biomass in pellet form, the can produce a high heat without as much pollution. The burning process is tightly controlled and produces little ash (which, by the way, can be used to make fertilizer). Some power plants mix biomass with coal to help reduce the amount of pollution generated. But, all power plants have some kind of scrubber to clean up the emissions. So, biomass pellets are a fairly clean fuel. 

The jury is still out as to whether or not biomass is cost effective to burn on it's own. It does require a considerable amount of energy to harvest and process it. For the most part, power companies that invest in biomass are doing so for the carbon credits they get for using a renewable fuel. They can either use the credits to offset the pollution from their older coal burning plants or sell the credits to companies that need them to offset their pollution to meet EPA standards. A new power plant may create a few new permanent jobs. They are mostly automated.


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## beenaround (Mar 2, 2015)

where I want to said:


> Can they really make pellets out of land fill that do not have bits of plastic and other chemicals in them?


Probably not, the garbage would be ground fine, made into a slurry with some liquid and then made into pellets.

Gasification is a process of extracting the gas out of a product, burning it and what's left is coal which it then burns. It really burns just about everything up before it ever gets to the chimney. 

I empty my ash pan about once a week and I burn 24/7. My pan is about the same size as an 8"x 9" cake pan. There is a build up of ash inside the ceramic chambers, but untill it gets fairly filled (once a month) the fire just keeps burning it up as it passes through. The fire in the system reach's 2000, by the time it gets to the chimney, it never gets over 300. It burns just about everything up.


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## Snowfan (Nov 6, 2011)

Robb40, I too have lots of discussion about the pros and cons of biomass as a fuel source. I think it's just too early for an uneducated old fart like me to really weigh the differences. I'm not sure about the ethanol thing either, and I work at an ethanol plant.


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