Pig power.

• Author: Wood, Suzanne
• Position: CASH CROP

Hog waste gives farmers headaches. Fortunately, technology that turns it into electricity and income is bringing relief.

Corporate livestock producers face one big problem: disposing of their animals' waste. It's especially true for those raising hogs, whose size and dietary preferences create large amounts of noxious manure. Thankfully, technology offers a solution.

Hog farmers have long known that adding select microorganisms to animal waste can convert it to biogas. That can fuel electricity generation or be refined into natural gas. These efforts were small-scale until about 10 years ago, when a sweeping state energy bill required publicly owned utilities to convert a portion of their portfolio to renewable energy. Bladenboro farmer William Storms and Raleigh-based AgPower Partnership LLC are turning waste from nearly 30,000 pigs into about 7,900 megawatts of electricity for Raleigh-based North Carolina Electric Membership Corp. each year. When the $5 million project went online in 2013, it was the state's largest swine waste-to-energy project.

Boulder, Colo.-based Carbon Cycle Energy LLC is developing the country's largest anaerobic digester in Warsaw. It will treat hog, agricultural and food waste, producing 290,000 megawatts of electricity each year. That's four times what all existing swine waste-to-energy projects in North Carolina produce. The biogas derived from the giant digester will be upgraded on-site and injected into the natural-gas supply. The company broke ground on the $100 million project in December 2016, and production is expected to begin this fall.

North Carolina offers plenty of opportunities for these projects. It has more than 2,100 permitted hog farms. According to the U.S. Department of Agriculture, in 2015, North Carolina's $2.2 billion in hog sales was second in the U.S. Duplin and Sampson were the top two hog-producing counties in the state that year and the top two in the country in 2012.

North Carolina has the most swine waste-to-energy projects in the country. The latest is between Wilmington-based biogas specialist Optima KV LLC and Charlotte-based Duke Energy Corp., the country's largest utility. The project will use captured methane to generate electricity at two power stations. Gas from anaerobic digesters on farms will be piped to a centralized location where it will be purified and injected into the natural-gas system that feeds the plants. "Our on-farm digesters will integrate with and support the...