Duke Hog Waste-to-Energy Conversion System Attracts Google Investment
September 12, 2011 | Andrew Burger
Large-scale, aka industrial, hog farming is a big business in North Carolina. It’s also a large-scale source of water and air pollution, including the emission of significant amounts of greenhouse gases (GHGs), including methane, which by weight is 21x more potent a greenhouse gas than CO2.
We also know refined, or purified, methane as the natural gas found in reservoirs deep underground that is used to heat homes and generate electricity across the US. So why not capture methane from farms and use it as source of power and heat.
That’s just what Duke University and Duke Energy — both named after their founder, James Buchanan Duke, have been doing at a 9,000-head hog finishing farm northwest of Yadkinville, NC, where they’ve been using a $1.2 million prototype system designed to serve as a model for hog farmers aiming to better manage waste, reduce GHGs and find a clean, renewable means of generating cheap electric power, according to a Duke Today report.
An “open source” design built mostly with off-the-shelf technology so that others could freely reproduce it relatively easily and affordably, the hog waste-to-energy system has been up and running for almost three years at Lloyd Ray Farms, where it’s been generating enough electricity to power 35 homes. It also thwarts the release into the atmosphere of nearly 5,000 metric tons of CO2 per year, the equivalent of taking 900 cars off the road.
The electricity from the system is generated in a gas turbine using methane produced in an anaerobic digester and captured in an aerobic basin. Gas from incomplete combustion is flared, which converts the more potent methane into CO2.
The pilot plant’s success has attracted the interest of Google, which has agreed to share operational and maintenance costs for the first ten years of operation with Duke Energy and Duke University.
In addition to producing electricity, the hog waste-to-energy plant produces revenue by selling carbon offset credits, a share of which Google will receive for a term of five years. It also creates renewable energy credits for Duke Energy.
Google has announced its support of the project in a blog post and YouTube video.