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Author Topic: Biomass  (Read 383 times)

rboyd

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Biomass
« on: April 19, 2017, 05:26:07 PM »
There is an increasing reliance by some countries on highly controversial sources of biomass; wood chips from US forests in the UK, and corn ethanol and palm oil for liquid fuels. Some propose that such biomass is at least as bad as using fossil fuels, others say it is a low carbon fuel, so good to have a thread where we can have a discussion on this. Some background reading:

WOOD PELLETS

Good background article on wood pellets:
http://e360.yale.edu/features/wood_pellets_green_energy_or_new_source_of_co2_emissions

Most wood energy schemes a disaster for climate change
http://www.bbc.com/news/science-environment-39053678

related Chatham House Paper
https://reader.chathamhouse.org/woody-biomass-power-and-heat-impacts-global-climate?_ga=1.100125086.1068450642.1492613978#

note - the above paper also pretty much destroys the assumptions used to support the case for BECCS

GROWING LIQUID FUEL

Corn Ethanol a net conributor to climate change?
http://www.climatecentral.org/news/ethanol-backfiring-for-climate-change-20760

https://link.springer.com/article/10.1007/s10584-016-1764-4

Sugarcane Ethanol, in the Brazilian environment, reduces emissions vs gasoline
https://biotechnologyforbiofuels.biomedcentral.com/articles/10.1186/s13068-017-0722-3

Increasing EU use of palm oil driving deforestation and peatland destruction
https://www.theguardian.com/environment/2016/jun/01/leaked-figures-show-spike-in-palm-oil-use-for-biodiesel-in-europe

« Last Edit: April 19, 2017, 06:55:25 PM by rboyd »

DrTskoul

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Re: Biomass
« Reply #1 on: April 19, 2017, 06:20:06 PM »
Thanks...  ::)
“You can know the name of a bird in all the languages of the world, but when you're finished, you'll know absolutely nothing whatever about the bird... So let's look at the bird and see what it's doing -- that's what counts.”
― Richard P. Feynman

TerryM

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Re: Biomass
« Reply #2 on: April 19, 2017, 07:43:57 PM »
Wood sounds like a poor substitution, but that's far from any area of expertise I might possess. The only comment I'd like to make is that burning wood for heating is illegal in Las Vegas due to the inversion layer there and the gasses emitted.


Terry

Bob Wallace

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Re: Biomass
« Reply #3 on: April 19, 2017, 09:08:26 PM »
Wood is not a low carbon fuel.  It's a fuel that contains carbon that was already in the above-surface carbon cycle as opposed to fossil fuels whose carbon is stored well below the surface.

Some of the carbon in plants is temporarily out out the atmosphere as the plant takes in CO2 and emits the oxygen.  The carbon is stored both above and below the surface.  The amount below the surface (at least some inches below the surface) is taken out of the above surface carbon cycle.  The amount above will stay in the plant while it is alive and then will return to the atmosphere when the plant decomposes or burns.

If the carbon is taken in by a redwood tree it may stay in that tree for 2,000 years or more.  If an annual grass or herb the above ground carbon may be back in the atmosphere in a few months.  Or very quickly if eaten by an animal and converted to methane.

We don't have the luxury of using only perfect solutions.  Sometimes we are forced into picking the lesser of the evils or the better of the sort-of-goods. 

IMHO burning biomass is far superior to burning coal.  And until we can build out a renewable energy system, including adequate storage, we are going to burn something.  The general public demands that the grid operates 24/365, not just when the Sun shines or wind blows.

How we produce our biomass is important.  Wood waste is available and the cost of burying it in landfills is not acceptable in most cases.  It would be best if the nutrients went back on the forest floor to feed the next generation but that will not happen.  And put back on the forest floor it would give up it's carbon to the atmosphere in a year or so.  If we burn it to produce electricity rather than coal or natural gas then we are ahead in terms of greenhouse gas.

Growing biomass plantations is an option.  We've long grown pulpwood on plantations.  Plant quick growing trees, harvest them, plant a new generation.  There are some perennial grasses which can produce large amounts of biomass on marginal land.  Switchgrass, an American native, requires modest amounts of fertilizer and water the first year while it is established.  After that it grows on its own, can be harvested one or two times a year, and fixes significant amounts of carbon in its extensive root system.

The problematic biomass, IMO, is where forests are cut and not replanted.  Sometimes the real goal is not to produce biomass but to make the land available for cattle or farming.

gerontocrat

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Re: Biomass
« Reply #4 on: April 20, 2017, 07:53:11 PM »
Biomass is a tricky subject as it is a catchall for so many different things. In Denmark unwanted wheat stalks are, or were, a major source of fuel for elecricity generation. The major source of biomass fuel is palm oil - but from plantations replacing natural rainforest - and goodbye biodiversity. In  Brazil, vast areas of new sugar plantations were developed for ethanol, although originally it was existing plantations with sugar nobody wanted to buy. All Plantations are mono-culture, and immediately reduce diversity and destroy habitat.

Until proven otherwise biomass as a source of fuel is not good. The major cause of the mass extinction  currently underway is destruction and degradation of habitat ( though climate change is increasingly an additional stress). Biomass is part of the problem.

CO2 is not the whole story of man's destruction of his home.


Bob Wallace

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Re: Biomass
« Reply #5 on: April 20, 2017, 08:58:58 PM »
Until proven otherwise biomass as a source of fuel is not good.

Rapeseed/canola, a variety of mustard, can be grown between crops of annual wheat.  It requires no fertilizer, using what was left behind by the wheat, nor irrigation.  It helps stabilize the soil decreasing wind and water erosion.  It also helps keep excess fertilizer out of waterways.

Switchgrass and other native perennials can be grown on marginal land which is no longer usable for food or fiber.  Burned out cotton fields, for example. Once established they need no fertilizer or irrigation.  They fix significant amounts of carbon below the surface with their extensive root systems.  Over time they improve the soil and return it to usefulness for agriculture.  Their tops can be harvested once or twice a year for ethanoyl. 

Once established some varieties of poplar and eucalyptus trees can be harvested (5 to 8 years) and then new growth will appear from the stumps.  This new growth will reach harvest size in about four years.  If the plantation is harvested at a rate of something like 25% per year animal/insect biodiversity can be maintained.   

sidd

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Re: Biomass
« Reply #6 on: April 20, 2017, 11:32:15 PM »
Re: canola

I have and do raise canola. You do need fertilizer, unless you have seriously overfertilized on the previous crop. Irrigation depends on how far west you are, the 100W longitude is still a good cutoff. You can sorta intercrop by, for example, broadcasting seed into standing crop before harvest, but you have to get it in well before the first frost, so it can grow enough to survive under winter snow. Does not particularly help soil stabilization compared to other winter grasses, roots aint very deep, something like turnips are better. Canola is 40% oil by weight, but you do well to extract about 35% with a press, for more you need to go to something like xylene solvent, which i will not do. The meal can be fed to livestock, but not in excess, they get diarrhea. Canola oil makes pretty biodiesel especially if you use it fresh, but i send it thru the food service industry, collect 85% of it back as used oil for biodiesel.

Re: switchgrass

I looked at miscanthus several times, but the cellulosic ethanol process is still not up to snuff, and i dont want to go through a gasification stage. I'd rather put the land in pasture and run livestock on it.

Re: coppicing

this is promising, but needs the gasification stage also, before fuel can be made.

sidd
« Last Edit: April 20, 2017, 11:52:46 PM by sidd »

DrTskoul

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Re: Biomass
« Reply #7 on: May 05, 2017, 02:16:02 PM »
From : "LCA of pellet burning technologies" by Thomas Willem de Haan

Pellets as a heating fuel in domestic appliances can be considered as a low carbon fuel, relative to the alternative fossil fuels. The emissions of a pellet heating system can be as low as 6,04 g CO2/MJ whereas its least polluting fossil counterpart emits 62,8 g CO2/MJ. If the pellets are being transported overseas, the CO2 emission would amount to 27,7 g CO2/MJ. This is still less than half the figure for the lowest fossil heating fuel but the most optimal use of pellets is for application on a local scale. The most influential parameters are the management of the forest the used wood is taken from and the transportation of the pellets. All the calculations are based on the premise that the harvested wood is regrown. As long as the wood is being harvested in a sustainable way, the low net CO2 emission as determined in this paper can be achieved. It should be emphasized, however, that sustainable harvesting is absolutely necessary to maintain the delicate balance.  Another conclusion to be drawn from this study is that the transportation of sawdust pellets over long distances has considerable impacts. Nevertheless, even transatlantic transported pellets have a lower net CO2 emission than heating with fossil fuels.
“You can know the name of a bird in all the languages of the world, but when you're finished, you'll know absolutely nothing whatever about the bird... So let's look at the bird and see what it's doing -- that's what counts.”
― Richard P. Feynman

rboyd

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Re: Biomass
« Reply #8 on: May 06, 2017, 07:02:14 PM »
From : "LCA of pellet burning technologies" by Thomas Willem de Haan

Pellets as a heating fuel in domestic appliances can be considered as a low carbon fuel, relative to the alternative fossil fuels. The emissions of a pellet heating system can be as low as 6,04 g CO2/MJ whereas its least polluting fossil counterpart emits 62,8 g CO2/MJ. If the pellets are being transported overseas, the CO2 emission would amount to 27,7 g CO2/MJ. This is still less than half the figure for the lowest fossil heating fuel but the most optimal use of pellets is for application on a local scale. The most influential parameters are the management of the forest the used wood is taken from and the transportation of the pellets. All the calculations are based on the premise that the harvested wood is regrown. As long as the wood is being harvested in a sustainable way, the low net CO2 emission as determined in this paper can be achieved. It should be emphasized, however, that sustainable harvesting is absolutely necessary to maintain the delicate balance.  Another conclusion to be drawn from this study is that the transportation of sawdust pellets over long distances has considerable impacts. Nevertheless, even transatlantic transported pellets have a lower net CO2 emission than heating with fossil fuels.

The big issue is the two sentences "It should be emphasized, however, that sustainable harvesting is absolutely necessary to maintain the delicate balance. It should be emphasized, however, that sustainable harvesting is absolutely necessary to maintain the delicate balance". In our deregulated and profit-driven world excatly the opposite will tend to happen / is happening.