Renewable Thinking

Pigs and Renewable Energy?
by Alex Osteen -- March 4th, 2013

Next time you eat barbecue in the state of North Carolina, you’ll be supporting renewable energy. Bet you didn’t know.

North Carolina is the number two hog producer in the nation after Iowa. If you think about agriculture in NC, you’d probably think of tobacco or Christmas trees. In my hometown, some people grow cabbage. But our soil is mainly poor-quality, infused with reddish clay, so there’s not a lot of corn or soybeans like in the Midwest. For whatever historical reasons, we have lots of pigs instead. Maybe it’s that we like our pork products so much. Maybe somebody a hundred years ago decided to get into the hog business on a whim and the idea caught on. Your guess is as good as mine. But as it stands now, there are almost as many pigs in the state as people, at 8.9 million hogs in 2012. Most of the hog farms in the state are in the eastern counties.

From an environmental health perspective, hog farms can be problematic. The swine waste that is created at a concentrated animal feeding operation is substantial and farmers have to figure out what exactly to do with it. Commonly, this waste is collected in a large pool or lagoon downhill of the barns. Once the lagoon fills up, farmers will spray it onto a nearby field as low-grade fertilizer for cattle feed or grass. Until recently, the state didn’t have many regulations on the books for the treatment of these lagoons and contaminants leaked into ground water as well as into the air. A serious consequence of this is methane leaks, which pose a serious greenhouse gas emissions problem.

Wouldn’t it be great to be able to do something positive with all this ugly, smelly pig byproduct? That’s the idea behind NC General Statute Section 62-133.8. The 2007 state law mandates that a total of 12.5% of electricity generated in North Carolina come from renewable sources. They call it a Renewable Energy and Efficiency Portfolio Standard (REPS, for short). It is meant to promote diversity in generation and begin the process of weaning us off of fossil fuels. In this law, however, there is a cutaway for 0.2% of swine waste generation by 2018.

So, the idea is to line then cover the swine lagoons with a rubber-like material that will capture the methane that the swine waste produces.  These are called anaerobic digesters. The methane is then piped to a collection hub where it is cleaned then fed into a combustion turbine. There, it is burned to create electricity. A pilot project led by Duke University’s carbon neutral initiative within the Sustainability Office is actually working on how to go about doing this in practicality.

It’s an interesting solution that tackles two problems at once.


  1. Leah
    Mar 4, 2013

    Thanks for covering this topic, but it looks like you could stand to learn some more. First, we do know why NC has such a large hog population. North Carolina politician Wendell Murphy was able to pass significant legislation to allow this growth – and he profited from it as well. Read the Pulitzer-Prize winning News & Observer series “Boss Hog” for more information. In addition, while it would be wonderful to get more of the type of projects developed by the Duke Carbon Offsets Initiative, they are considered too expensive to be placed on most of NC’s 2,000 hog farms, and the electric utilities are having trouble meeting the renewable energy set-aside. The N&O wrote a great article on that topic as well.

    As you say, this is an interesting solution to the hog waste problem, and we should continue to work to get these systems placed on hog lagoons. However, we are still a far cry from making environmentally-friendly pork. A plant-based diet is still the best choice for the planet.

    • Ken
      Mar 4, 2013

      The question at hand isn’t why we have a large population. That’s a red herring.

      The utilities are not having issue meeting the RPS. Duke bought enough RECs more than a year ago to be in compliance through 2018 at least. So that is not accurate.

      Eating local is best.

    • Alex Osteen
      Alex Osteen
      Mar 5, 2013


      Thanks so much for sharing your insight and thoughts on the issue! I’m glad that my post struck a chord. Thanks also for talking about the history of hogs in NC. I certainly wasn’t aware of those details, as I mentioned, and am interested to read the N&O articles you cited.

      Another point you raised is interesting: Indeed we wouldn’t have the problem with swine waste if people only ate plants; however I don’t view this as a probable outcome in the near future.

      As for costs of the digesters and pipeline with this REPS requirement, utilities will be (are being) forced to make that capital investment which could increase the rates they charge. However, a study should be done to determine how much of a change we would expect it to induce.

      As for the farmers, they end up winning in all this because they aren’t the ones paying for the system and often, to the contrary, earn lease payments from it. Plus, the problem of what to do with the hog waste gets addressed.

      Please keep sharing in the future, I love getting feedback!

  2. Hi there! Would you mind if I share your blog with my twitter group?

    There’s a lot of folks that I think would really appreciate your content. Please let me know. Thanks

  3. Alex Osteen
    Alex Osteen
    Mar 5, 2013

    Sure, you can share my blog. Thanks for asking.

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