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NC Farm Turns Pig Manure to Electricity

by 5m Editor
28 October 2011, at 9:56am

NORTH CAROLINA, US - Loyd Ray Farms has joined a handful of the state's pig farms in using manure in a digester to provide the farm's electricity.

The old saw about using every part of a pig but the squeal now includes its droppings, which are producing electricity on a Yadkin County farm, reports News Observer.

Duke University is a partner with Duke Energy and Google in testing a system that captures methane, a potent greenhouse gas, from manure. The gas fuels a small power plant that makes enough energy to run the waste-processing system and part of the farm itself.

Loyd Ray Farms joins a handful of North Carolina hog farms that have become energy innovators. They are prompted by state laws aimed at boosting renewable energy and phasing out open waste pits that can taint water and release harmful ammonia into the air.

"I was kind of curious myself how it was going to do," said farm owner Loyd Bryant, who has more than 8,600 hogs. There will be a few more records to keep but it's not going to be no big thing. And it might bring my power bill down."

The powerful troika collaborating on the project will also benefit. The university and Google, which owns a data centre in Lenoir, score credits to offset their carbon emissions. Duke Energy gets help in meeting a state mandate that, starting in 2012, utilities make electricity from swine waste.

The university and the utility also hope for insights in how to make such innovations more affordable – the Loyd Ray project cost $1.2 million – and fit them into a slowly expanding menu of energy choices.

"This is a learning opportunity for us to get it on the ground, refine it and understand the benefits and the costs," said Tatjana Vujic, director of Duke University's Carbon Offsets Initiative. With the experience already gained, using off-the-shelf parts, Duke researchers believe they could build a similar system now for much less.

Beginning next year, North Carolina utilities have to get 0.07 per cent of their electricity from hog waste. The figure rises to 0.20 per cent by 2018. State law includes a similar requirement for poultry waste.

The renewable energy credits that Duke Energy will reap from the Yadkin County farm will only partly meet its obligation in 2012, company spokesman Jason Walls said.

Open house today

After three years of work, the new project is up and running. Dignitaries will attend an open house today. They will find a newly equipped swine farm that, although it opened in 1998, is now able to meet the state standards for odour, ammonia, nutrients, pathogens and metals that would be demanded of a new farm.

According to News Observer, Bryant, like most hog farmers, previously sprayed effluent from an open waste lagoon onto fields of grass and millet. The new system will let him return the spray area to growing corn and other crops.

Grants from the federal Natural Resources Conservation Service and North Carolina's lagoon-conversion program paid $500,000 toward the project. Duke Energy and Duke University picked up construction and operating costs for 10 years. Google bought in last month, agreeing to help pay the university's costs for five years in return for a share of carbon offsets.

The project builds on research into lagoon alternatives that began in 2000, after large waste spills focused attention on the lagoons' environmental costs.

North Carolina remains a leading hog-producing state, with more than 2,100 farms raising 9.4 million hogs a year.

Loyd Ray's is the first system using an anaerobic digester, which decomposes waste, to be permitted by the N.C. Division of Water Quality as an innovative animal-waste management system.

It's expected to capture methane – a greenhouse gas 21 times more potent than carbon dioxide – that is the equivalent of nearly 5,000 metric tons of carbon dioxide a year. A 65-kilowatt micro-turbine fuelled by the gas produces enough electricity to power 35 homes for a year.

Mike Williams, director of N.C. State University's Animal and Waste Management Center, said he knows of only four other NC hog farms that use anaerobic digesters to produce energy. All four are in Eastern North Carolina.

The problem is that harvesting energy from pig poop is too expensive for most hog farmers to shoulder alone, reports News Observer. Utilities will not pay enough for the electricity to make them economically viable, he said. Loyd Ray's energy never leaves the farm.

"We need to put more of these things on the ground ... to make them more efficient and affordable," he added.