The Loyd Ray Farms Swine Waste-to-Energy Offsets Project
Duke University and Duke Energy have partnered to pilot an innovative system for managing hog waste that will reduce greenhouse gas emissions, generate renewable energy, and substantially eliminate a host of pollutants and issues associated with the waste from swine farms, including odors, ammonia, nutrients and pathogens. This system is located at Loyd Ray Farms, an 8,600-head swine finishing facility in Yadkin County, NC. It is intended to serve as a model for other hog farms seeking to manage waste and develop on-farm renewable power.
The project involves the capture of methane generated by the hog waste which is captured and collected under a plastic cover over the anaerobic digester. The gas collected under the digester cover is used to power a 65-kW microturbine, the electricity from which is used to support the operation of the innovative waste management system. From the digester, the liquid waste flows to an aeration basin which treats the water for ammonia and remaining pollutants so that it can be re-used for irrigation and barn-flushing. Any electricity not needed to power the innovative system is kept on the farm to support normal farm operations.
The project creates carbon offsets through the destruction of the methane, which will be shared by Duke University and Google. It also produces renewable energy credits (RECs) which Duke Energy counts towards its NC Renewable Energy and Energy Efficiency Portfolio Standard (REPS) requirements for the generation of electricity from swine waste.
In addition to capturing and destroying methane, the project meets the state’s stringent environmental performance standards required for all farms that receive funding through the Lagoon Conversion Program and which are required for new and expanding farms. These standards include the substantial reduction of odors, ammonia emissions, nitrogen, phosphorus and heavy metals, and the prevention of discharge of waste into surface and groundwater.
Read more about the project. See below for a diagram of the system. View more detailed plans of the system here and here, designed by Cavanaugh and Associates. These plans were designed specifically for the Loyd Ray Farms project; any application to other projects may require additional design and engineering.
Diagram of the Innovative System at Loyd Ray Farms. Credit: Marc Deshusses, Duke University.
View the following video about the collaboration between Duke University and Google, Inc.: