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Clean Power north carolina hog manure biogas

Published on June 28th, 2014 | by Tina Casey

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30,000 North Carolina Hogs Churn Out Renewable Manure Biogas, And That’s Just For Starters

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June 28th, 2014 by
 
We suck at math, so maybe you guys can figure this out. If 30,000 hogs create enough manure biogas to run a 600-kilowatt generator, how much electricity can 10 million hogs produce?

We’re only asking because the new 600-kW Storms Hog Farm manure biogas-to-electricity plant in North Carolina has just officially passed its proof-of-concept stage, leaving the field wide open to build even bigger hog manure biogas plants in the state. With a hog population of 10 million the last time we checked, that could add up to quite a bit of biogas, possibly contributing to a sustainable fuel cell market in the region, including fuel cells for electric vehicles.

north carolina hog manure biogas

Hog (cropped) by Jeremy van Bedijk.

Biggest Hog Manure Biogas Plant In North Carolina

The Storms Hog Farm facility was developed by AgPower Partners LLC. For those of you familiar with the topic there are a few other hog manure-to-biogas ventures up and running in North Carolina, but according to APP Storms Farm is the largest fully operational one in the state.

The Storms facility actually started up last fall, but it held a ribbon-cutting this past Friday to put the official seal on its operation at proof-of-concept level, marking 90 days of sustained operation at peak or nearly peak capacity.

At that rate, the facility sends enough electricity into the grid to offset the consumption of 300 average homes.

The heart of the operation is the proprietary Two-Stage Mixed Plug FlowTM anaerobic digester from a company called DVO, Inc.

For those of you who are new to the topic, manure biogas is emitted from the tiny microorganisms that digest (aka decompose) the organic matter in manure. Anaerobic refers to bacteria that live in oxygen-free environments, hence the anaerobic digester.

The difference between allowing manure to decompose in lagoons or open fields versus enclosing the operation in a digester is striking.

According to DVO, the digesters reduce emissions of methane-rich biogas by about 90 percent compared to disposal on land or in fields.

Once the microorganisms have done their work, the remaining solids can be used as soil enhancer without the baggage that raw manure has. Unlike raw manure the digested solids are nearly free of pathogens (“almost undetectable” according to APP), and there is “virtually no odor.”

DVO’s proprietary process also involves removing extra phosphorus and ammonia nitrogen, which helps to make the case for using the digested solids as a fertilizer while reducing the risk of nutrient overload in local waterways.

Hog Manure Biogas Is Not As Easy As It Sounds

We’ve spilled quite a bit of enthusiastic ink over livestock manure biogas, but although the technology is available, getting it to the point of commercial viability can be a challenge.

In 2008, for example, hog giant Smithfield sold off a hog manure biogas facility in Utah that failed to perform as expected. Apparently the farm’s high-efficiency hog raising strategies, including diet, breeding, and water use, resulted in a decrease in the nutrient content of the manure.

Since less nutrients translate into less biogas, there goes the profitability of your biogas facility.

The breeding angle in particular could pose some interesting challenges for the future. Our sister site PlanetSave, for example, has reported on a new “enviropig,” bred specifically to generate manure that is safer for land application. However, a move in that direction doesn’t necessarily translate into manure that is more efficient for biogas generation.

Plenty O’ Reasons For Manure Biogas

On the other hand, direct profitability is just one driver for making manure-to-energy operations a standard feature of the livestock operation of the future.

Another important motivator is the avoidance of fines for unsound manure disposal practices, as Smithfield found out the hard way back in 2010 (for the record, the hog farms involved in that action were owned by Premium Standard Farms, which Smithfield absorbed in 2007).

The electricity produced by biogas can be used onsite or sold to the grid, helping to reduce utility costs, and the opportunity for renewable energy credits can also help to offset the cost of the operation.

For the Storms Hog Farm biogas facility, that’s what makes the operation viable.

The project got off the ground in 2010 with a grant from the North Carolina Department of Energy, as part of a much broader program to tackle the state’s exploding hog waste disposal problem.

 

Here’s how it works out for Storms Hog Farm, according to APP’s press materials:

North Carolina Electric Membership Corporation purchases all of the electricity under a long-term contract. This revenue, combined with tipping fees for processing the off-site agricultural waste, the sale of the carbon credits andRenewable Energy Certificates, and the sale of other valuable byproducts, support the sustained operation and maintenance of the facility.

As for that fuel cell connection, check out the toilet of the future invented by CalTech students for the Bill and Melinda Gates Foundation “Reinvent the Toilet” challenge last year, which converts human manure to biogas for fuel cells.

Just sayin’.

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About the Author

Tina Casey specializes in military and corporate sustainability, advanced technology, emerging materials, biofuels, and water and wastewater issues. Tina’s articles are reposted frequently on Reuters, Scientific American, and many other sites. Views expressed are her own. Follow her on Twitter @TinaMCasey and Google+.



  • Mike Nestor

    Disappointed to see a discussion justifying the continuing exploitation of sentient beings on Cleantechnica. No discussion of the moral implications – just doing numbers and stats to see if this is viable. No discussion of the contribution of animal agriculture to deforestation, water and soil degradation and total ghg contribution to global climate change at all? Sloppy at best, deliberately misleading at worst.

    • Jan Veselý

      The devil is in details. Animal agriculture can be devastating but it also can be used for GHG sequestration, soil and water recovery, mainly in hot and dry climates. Google Allan Savory.

      And biogas can be produced from virtually every biomass, every organic waste. Manure “just” significantly rises the methane yield (organic nitrogene, some cool microorganisms).

  • Kyle Edwards

    Who runs Barter town? Master Blaster!

  • Bob_Wallace

    “virtually no odor.”

    That, alone, is enough reason to turn pig poo into power.

    Pigs out stink any other animal I’ve ever been around. Not so bad if you raise them ‘free range’ where their poop is spread out, but in feed lot conditions or spread on fields in heavy amounts the smell is deafening.

    • Matt

      You ever been in an industrial chicken house? I raised both and worked in both. Also once you run that cow/chicken/pig droppings thru a digester you not only get gas but a great soil enricher that yes does not smell bad at all. And much easier to run that at a city people dropping plant, since we mix all kinds of other shit into that stream.

      • Bob_Wallace

        I grew up on a farm. My uncle had a commercial egg farm. We spread wood shavings on the floor before we brought in a new round of hens and tossed down more shavings as needed. When the hens were “aged out” we’d fork out the accumulations. When one broke through the crust the ammonia would knock one back a few steps.

        But nothing was as intense as cleaning out the hog pen.

        I’ve no experience with a digester. I do have experience driving the tractor with the manure spreader attached. When the wind was blowing I’d wear a rain slicker and they’d hose dpwn the tractor and me when we got back to the barn.

        That was my second least favorite jobs. Not as bad as being the person who worked inside the silo and spread/tramped down the silage as it was blown in the top. In a heavy rain of sticky corn and cane chop and a swarm of yellow jackets. Constantly on alert for the sound of a rock or mangled rabbit coming up the chute.

  • Crispybernt

    I get 2 megawatts…

    • Bob_Wallace

      10 million / 30k = 333

      333 * 600 kW (0.6 MW) =~ 200 MW. (Which one of us is right? These big numbers mess me up sometimes.)

      What we next need is the CF number. “(M)arking 90 days of sustained operation at peak or nearly peak capacity” suggests it might be high.

      • Jan Veselý

        Our EU experience says – about 8000 hours/year. The process is continuous and it works perfectly as a baseload. But it is a gas burning in an combustion engine, so it can be also built as a peaker plant. You just need bigger engine and gas tank.

        • Bob_Wallace

          Long term, the use is more likely as dispatchable generation rather than “always on”.

      • Crispybernt

        You are correct, my error…

        20 WPP ((watts per pig)

        60030=20 Watts per pig

        Ave house = 1,000 watts=50 PPH. (Pigs per house)

        10,000,000/50=200,000 houses=.2 GW=200 megawatts=.2 ave nuclear reactors…

        Or so…

        • Bob_Wallace

          I’ve got to find a way to use that metric in the future – WpP….

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