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The Power of Poop

October 10, 2008

Renewable energy is all about taking things that are free and plentiful (and renewable, obviously) and turning them into energy. Wind and sunlight clearly fit the bill as does geothermal heat, but what about poop? It’s free, we certainly have sh*tloads (sorry) of the stuff and, well, it’s definitely renewable. Plus, powering up with poop reduces the amount of poop nastifying our environment.

Seriously? Seriously.

The most recent large-scale poop-power operation—the world’s largest biomass power plant run exclusively on chicken manure—opened in the Netherlands in September. The plant will produce over 270 million kWh of electricity and power 90,000 households using what may be the country’s most abundant resource: chickensh*t.

You see, the Netherlands had a chicken poop problem. (FYI: the Dutch word for chicken is kip.) Dutch chickens produce 1.2 million tons of poop annually. That’s a lot more than the little country could handle so they did what anyone with a chicken poop surplus would do—they sent it (800,000 tons of surplus chicken manure) abroad, at vast expense.

Now that the biomass power plant is in place, at least one-third of the country’s chicken poop will avoid deportation. The plant will burn about 440,000 tons of chicken crap to generate power, and then sell the leftover ashes as fertilizer.

The plant’s creator claims that this new system is carbon neutral because it removes chicken waste from the fields. When poop is left out in the open it emits greenhouse gases like methane and CO2. So by sequestering poop in the power plant, they are preventing potential emissions. But is it really a mean green renewable energy machine? Hmmm…while removing chicken turd from the fields certainly reduces ground and water pollution (and minimizes methane emissions), burning sh*t isn’t exactly clean. Burning anything creates air pollution and emits at least a little CO2. 

Alas, why burn poop when you can digest it? (Yep, still serious.) That’s how dairy farmers around the world are harnessing the power of poop to generate gas. Farmers send cow manure into an anaerobic digester—a large tank that most farmers describe as a super-efficient overgrown cow stomach—where anaerobic bacteria go to town on the “manure slurry,” creating a biogas rich in methane. The gas is used to power a natural gas engine, which in turn powers a generator that produces electricity. After 15 to 20 days in the digester, the leftover manure is dry. It’s composted and used to fertilize the grains that are fed to the cows. The cows eat and poop and the process begins again. 

Cows are a little more, ahem, “productive” than chickens. A single cow generates 120 to 150 pounds of poop per day and that, when converted to biogas, produces about the same amount of energy as a pound of coal. That sounds a lot more impressive when you add up all that gas. Last year, Hillcrest Saylor Dairy Farm’s 600 cows produced 1.2 million kWh or electricity, enough to power the farm and a few nearby homes.

Cows and chickens aren’t the only power poopers on this planet. One company has come up with a way to use septage (rhymes with dressage) to make landfill gas capture faster. They’re mixing this rather classy-sounding substance—it’s actually the stuff that comes out of septic tanks—with ground up garbage. The resulting stew of grossness is loaded with bacteria and organic matter, a recipe for super-fast decomposition, which is also a recipe for speedy methane production. Just as in a digester, that methane can be used to produce power. As an added bonus, the accelerated garbage decomp frees up landfill space and extends a landfill’s life.

The moral of the story: never underestimate the power of poop—or pee for that matter.

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6 Comments leave one →
  1. Michel permalink
    November 8, 2008 7:05 pm

    Methane digesters for the creation of biogas are the new wave of alternative energy production. Although they have been around for a while they are more economically feasible to do now.

  2. daveharcourt permalink
    January 27, 2009 9:28 am

    I’m afraid you are not correct, the Dutch facility is based on burning the chicken waste and not fermenting it. Its a biomass not a biogas plant!

    see http://www.digivu.co.za/2008/09/biomass-the-oldest-renewable-biofuel-developments/

  3. makaimauka permalink
    January 27, 2009 3:31 pm

    Thanks for the comment daveharcourt. We double-checked our post and it does refer to the Dutch facility as a biomass power plant that burns chicken poop. But thanks for raising the issue of how biogas and biomass plants are different! Hope you enjoy future posts on Mauka to Makai!

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