Cross-posted at WeArePowershift.org
On April 22, 1970, students participated in an massive action declared by Gaylord Nelson, a senator from Wisconsin. Motivated by the recent Santa Barbara oil spill, teach-ins were held at college and university campus across the United States to protest environmental degradation. “Earth Day,” as the event was known, later became a prominent, annual avenue for citizens to discuss important issues affecting both their local communities and the wider world.
A White Paper from the
April 2012
Contact: Mike Tidwell, director, 240-460-5838, mtidwell@chesapeakeclimate.org
The Climate Impact of Poultry Waste Disposal Practices and Manure-to-Energy Power Systems
The volume of manure produced by
OVERVIEW
The intensive poultry production system on
GREENHOUSE GASES (GHGs) AND LITTER
The primary mechanism through which poultry litter influences the climate is through release of the greenhouse gases (GHGs) methane (CH4) and nitrous oxide (N2O), both of which have many times the ability of carbon dioxide (CO2) to trap heat in the atmosphere. Over a 20-year time frame, CH4 is a staggering 72 times more powerful than CO2 at trapping heat, and N2O is 298 times more powerful than CO2 over a 100-year frame.[7] Many sources, including the US EPA, consider decomposing poultry manure to be CO2 neutral, since the process recycles carbon which already existed in the atmosphere before being sequestered into the plant matter in poultry feed.[8]
Nitrogen and nitrous oxide: Poultry manure is nitrogen (N) rich;[9] however the amount of manure N which actually becomes converted to climate-damaging N2O through the nitrogen cycle depends on the way in which it decomposes in/on the soil. Many complex variables shape this process, including the litter’s source (content of poultry feed affects litter’s nutrient content) and when it is applied, crop rotation, tillage and drainage of soil, and climate (temperature and precipitation).[10] One study observes N2O emission rates of between 0.5 and 1.9 percent of the total N[11] applied; [12] however much further research is needed to better understand how manure decomposition on fields influences the climate.
CH4 (Methane): Unlike swine and cattle manure, poultry manure tends to be stored in solid form, in which the anaerobic environment hospitable to CH4 emissions is comparatively rare. [13] [14] [15] One study estimates methane emissions for poultry are less than 0.2 lbs per animal per year. [16]
EXCESS MANURE
Poultry litter can be a feasible and economical substitute for synthetic fertilizers on many farms. If poultry litter which has an alternative, appropriate use as a fertilizer is diverted to power an MTE operation, the unmet nutrient needs of crops will likely be satisfied by synthetic fertilizers. The Haber-Bosch process used in creating synthetic fertilizers relies heavily on natural gas.[17] This implies that MTE is only climate-appropriate if it employs excess manure and does not introduce additional fossil fuels into the system through fertilizer production.
Most sources agree that excess poultry manure is produced on
REDUCING GHGS BY REPLACING FOSSIL FUELS: MANURE TO ENERGY
Poultry production uses intense amounts of (fossil-fuel derived[21]) energy, particularly in providing for the heating and cooling needs of poultry houses. [22] If MTE can meet these needs using waste material it has the potential to generate a positive effect on climate. Some sources estimate that 85-90 percent of the 3-6,000 gallons of propane [23] being used annually by an average grower to heat poultry houses could be met by an onsite MTE operation.[24] As a relatively local fuel source, poultry waste may also eliminate some of the energy consumed in transporting fossil fuels.
METHODS
Poultry manure can be transformed into useful energy byproducts through the application of heat, or through ba
cterial digestion. Combustion, gasification and pyrolysis employ various ratios of heat and oxygen to alter waste material, while bio-digestion (anaerobic digestion) does so through the actions of microbes. Importantly, poultry litter’s chemical and physical composition is generally less consistent than fossil fuels or biofuels like wood. This irregularity, as well as variation in MTE operation sizes, emissions-capture technologies, and byproduct quality, makes it difficult to state definitively which MTE technique is most climate appropriate. [25]
Combustion processes burn litter material using great amounts of both oxygen and heat (3600 F)[26] to produce heat, CO2, H2O, and ash. This ash is generally a valuable fertilizer, high in phosphorous, potassium and other micronutrients.[27] The ash embodies the nutrients in a form that is greatly concentrated in both mass and volume compared to raw litter, making it more feasible to transport.[28]
Combustion technologies can be used to produce space heat for poultry growers, or on a larger scale the fuel can be burned in a boiler to produce steam heat and run a turbine to generate electricity. Since combustion occurs in a high oxygen environment, NOx emissions may be a greater concern with this technique than with others if the appropriate capture technologies discussed in the next section are not used.[29] Combustion may also be the most economically feasible at the small scale.
Gasification is similar to combustion but employs lower temperatures (1100 to 1800F) and lower (or insufficient) amounts of oxygen to burn poultry litter. Gasification produces CO, H2, ash, and a biogas with a heating value equivalent to 10-20 percent that of natural gas (100-200 Btu/cubic foot). The controlled burn and lower amounts of oxygen involved in the process may lower its risk of NOx production.[30]
Pyrolysis is the process through which organic matter is converted into charcoal (a concentrated form of fixed carbon). It employs almost no oxygen and very low temperatures (between 390 and 1100 F) to create a fixed carbon byproduct called bio-char.[31] The char acts to sequester carbon permanently, though its value as a traditional fertilizer appears low. [32]
Pyrolysis can produce a medium-value gas up to half the heating value of natural gas (350 to 550 btu/cubic foot).[33] Other useful energy products include bio-oils which could be refined further to create a bio-diesel. Some studies claim that poultry manure is particularly well suited to pyrolysis because of its relatively low moisture content;[34] however pyrolysis may demand more expensive technology than combustion or gasification. Little to no oxygen involvement in the burn reduces the likelihood of producing NOx gases; furthermore using biochar as carbon-sequestering soil amendment may improve the climate profile of this technique. [35]
Bio-digestion/Anaerobic Digestion uses bacteria to convert manure into methane gas (60-70 percent), carbon dioxide (30-40 percent) and waste water. The methane has 60-80 percent of the energy value of natural gas (600-800 Btu/cubic foot) and can be used for heating, electricity generation, lighting or cooking.[36] [37]
The emissions profile for anaerobic digestion appears to be relatively low; [38] however, unlike the thermal processes which transform manure nutrients into more usable forms, digestion produces a large quantity of nutrient-rich waste water that must be refined further for use in agriculture.[39] Digestion also appears better suited to swine or cattle manures which have higher moisture contents,[40] and its technical requirements may make it less economical for small operations.[41] [42]
CAPTURING AND REDUCING EMISSIONS
The thermal or biological techniques used to transform poultry manure into energy are not without emissions. In order for manure to be considered a potentially renewable and climate-appropriate fuel, producers must make use of the best available technologies for capturing or reducing these emissions.
Two of the most effective techniques for reducing NOx gases are Selective Non-Catalytic Reduction (SNCR) and Selective Catalytic Reduction (SCR). SNCR involves the injection of ammonia or urea into the incineration furnace during combustion to reduce NOx emissions. One report anticipated the efficiency of this capture method to be 25-50 percent; [43]however some concern exists that a modest amount of ammonia may escape during this process (“ammonia slip”[44]). SCR involves an additional control device to manage the injection of ammonia into flue gases and may have a capture efficiency of up to 90 percent. SCR, though more expensive, appears to be the most efficient capture method where technologically feasible.[45]
Other capture technologies to address air-quality concerns include a fabric filter or “bag house” which can control emissions of small particles[46] and “scrubber” techniques to capture 80 to 99 percent of sulfur dioxide and hydrogen chloride.[47] [48]
FURTHER RESEARCH
CCAN’s preliminary literature review is not intended to be an exhaustive, scientific accounting of the issues surrounding poultry manure disposal and climate change. Nevertheless, areas where further data is necessary did present themselves during the course of our research.
We at CCAN feel MTE holds significant potential to be a tool in Maryland’s fight for a renewable and climate-safe energy base. In order to confidently move forward we advise industry leaders to accept the need for caution, utilize the best possible technologies, and continue to pursue a deeper understanding of poultry waste’s climate implications.
NOTES
[1] Landers and Ridlington 2011, p. 2
[2] Lichtenberg, Lynch and Parker 2002, p. 3
[3] Kleinman 2009, p. 5
[4] Landers and Ridlingon 2011, p. 1
[5] Kleinman 2009, p. 5
[6] Ibid
[7] Dunkley 2011, p. 3
[8] Alternative Resources 2001, p. 16
[9] Most of this N is excreted as uric acid – an organic form of N which is inaccessible to plants.
[10] Dr. Josh McGrath, 3/9/2012 (email)
[11] Lori 1999, p. 1 (The typical N content of litter is around 2-4 percent of total weight.)
[12] Kuikman, Oenema and Velthof 2003, p. 221
[13] Desjardins et al 2009, p. 213
[14] Dunkley 2011, p. 3
[15] Zhao 2007, p. 2
[16] Bicudo et al 2003, p. 18
[17] Bartels and Pate 2008, p. 4
[18] Baranyai and Bradley 2008, p. 10
[19] Ibid, p. 7
[20] Lichtenberg, Lynch and Parker 2002, p. 34 table 3
[21] Desjardins et al 2009, p. 219
[22] Dunkley 2011, p. 6
[23] Kristen Hughes 3/1/2012 (email)
[24] Wimberly, Jim. 2008, p. 7
[25] Baranyai and Bradley 2008, p. 16
[26] Ibid, p. 17
[27] Echols and Habetz 2006, p. 4
[28] Costello 2007, p. 12
[29] Baranyai and Bradley 2008, p. 17
[30] Ibid, p. 28
[31] Bassilakis et al 2002, p. 589
[32] Ibid.
[33] Baranyai and Bradley 2008, p. 34
[34] Bassilakis et al 2002, p. 590
[35] Dunkley 2011, p. 6
[36] Cherosky, Li and Mancl 2011, p. 1
[37] Chesapeake Bay Commission et al 2012, p. 12
[38] Dr. K.C Das 2/29/12, (phone conversation)
[39] Darby, et al 2010, p. 11
[40] Ibid
[41] Dr. K.C Das 2/29/12, (phone conversation)
[42] Darby, et al 2010, p. 11
[43] Alternative Resources 2001, p. 7
[44] Ibid
[45] Ibid
[46] Ibid
[47] Echols and Habetz 2006, p. 6
[48] Alternative Resources 2001, p. 7
REFERENCES
ACKNOWLEDGEMENTS
CCAN is also grateful for the expert guidance provided by the following individuals:
I can’t remember ever participating in so many actions on an issue organized by religiously-based groups over such an extended period of time. It is a very hopeful sign that among people of faith, many different faiths, there is a clear stirring into action on this huge moral issue, this threat to human civilization and the ecological systems that have allowed for its development over the last 10,000 years.
-Cross-posted at WeArePowershift.org
-Written by Dakota Thomas, a senior at the University of Virginia’s College at Wise, in Wise County, Virginia
One can’t make it ten feet down the street of Wise without seeing a “Friends of Coal” sticker on a bumper or a sign espousing that “We keep the lights on.” And while coal is the driving force behind our economy today, people of the area’s minds are captivated by it as though the coal industry can do no wrong. But the coal industry is above all else a business. They make a profit by developing new, cheaper (read: less human dependent and more robotic) technology, or by securing legislative outcomes that favor them rather than good policy.
Commemmorating the 2nd Anniverary of the Deepwater Horizon explosion and prolonged, enormous oil leak, residents of Virginia Beach demonstrated this past Friday.
Led by Oceana Virginia, the action included a mock oil spill, a fisherman whose livelihood was suddenly threatened, a sickened oil-covered dolphin, and a greedy oil tycoon profiting while people and wildlife suffer. Rarely do we see such a clear contrast between the risks of dirty energy for many and the wealth it brings a few.
Now is a critical time to note the dangers of offshore oil development. Offshore seismic testing threatens Virginia’s coast. Offshore seismic studies for oil and gas clearly signify a first step toward drilling. We know that would only prolong our dependence on fossil fuels and cause more climate pollution, so please take action to oppose seismic testing. If you are able to attend the hearing in Norfolk this Tuesday, we are counting on you to tell the federal government that we cannot allow seismic testing for oil and gas. To stop global warming, slow sea level rise, and protect our coast, we need to develop renewable energy now.
On Saturday, I helped lead Richmond’s 99% Spring Training Workshop. Among the many incredible lessons from the event, my greatest takeaway came via a pre-recorded video on the history of non-violent civil disobedience. Watching the history of America’s greatest social movements unfold reminded me of the incredible power of non-violent civil disobedience, when done correctly. Ironically, the weekend before, I was moved beyond words by Chris Hayes’ monologue on the same topic during his weekly cable television show.
Throughout the week, my mind has traveled through time in remembrance of the most courageous and effective strategies of social change. From women’s suffrage to the civil rights movement, non-violent civil disobedience has been used effectively to effect positive change in our society. However, the most memorable image of all, and a moment in courage I will always remember, belongs to “Tank Man”.
Despite the threat of earthquakes and flammable drinking water and contaminated rivers, the Maryland General Assembly this week failed to pass a bill protecting Marylanders from the worst dangers of hydraulic “fracking” for natural gas. Our lawmakers failed to pass a simple bill that would have funded basic safety studies before any such drilling would be allowed in our state. How did this failure happen? The answer is simple: the American Petroleum Institute happened.
Annapolis, 4/6/12
By James McGarry
With time running out in the Maryland General Assembly, a group of minority business and civic leaders from across the state gathered Friday in Annapolis to urge immediate passage of the Offshore Wind Energy Act (SB 237) in the Senate Finance Committee. Leaders highlighted the health and environmental benefits of the bill, as well as the fact that tens of millions of dollars in minority business funds will be lost if the Senate Finance Committee fails to act.
In attendance representing Maryland businesses were Lance Lucas, President of the Greater Baltimore Black Chamber of Commerce, Vernon Wade, President/CEO of Wade Enterprises, Inc. and chair of the Prince George’s County Chamber of Commerce, and Shawn Young of the Prince George’s Electrical Association. In addition to the thousands of jobs that would be created over the next five years and the more than $100 million in economic opportunities for minority businesses, the speakers emphasized the environmental and health benefits that would result from the bill, citing that African American children are disproportionately affected by asthma.
“If Maryland doesn’t act now, this opportunity could pass us by,” said Wade, before adding that, “we can consider this a game changer.”
The bill must clear the Senate Finance Committee to reach the Senate floor for a vote by Monday, April 9, before the end of the legislative session. It cleared the House of Delegates on March 30 by a margin of 88-47. Supporters are currently working hard to secure a sixth vote in the eleven member panel. Committee Chairman Thomas “Mac” Middleton said the panel will not vote until after the bill has firm majority support within the committee.
Ben Chou posted this great piece earlier today on the NRDC’s Switchboard blog – follow the link below to head on over and check out the full article.
Preparing for Climate Change: A Tale of Two States, Maryland and Virginia
Although separated by only the Potomac River, the District of Columbia, and parts of West Virginia, the states of Maryland and Virginia could not be farther apart when it comes to preparing for climate change. According to a new NRDC report released today, Ready or Not, Maryland is among the states doing the most to prepare for climate change while Virginia is among 29 states that are far behind in their planning efforts. [Click here to read the rest.]
In the first-ever demonstration of its kind in Annapolis, about 400 Marylanders joined hands Monday to form a “circle of support” around the State House in a hopeful call for final passage of the Maryland Offshore Wind Energy Act (HB 441/ SB 237).