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Hog farm adds wind to renewable energy collection

The partners who teamed up to give the world the first microturbine powered on biogas produced from hog waste have joined forces again to show how agriculture businesses can use renewable energy to cut the bottom line.

The Colorado Office of Energy Management and Conservation and Colorado Pork, LLC, have installed a 65-kW wind turbine to complement the Lamar, Colo., hog farm’s combined heat and power system. TriState Generation and Transmission and Southeastern Colorado Power Association are once again contributing technical assistance and collecting data.

Project partners learn from turbine

“We would like to get other farms in similar situations interested in using these technologies,” said OEMC Senior Deputy Director Ed Lewis. “To do that, you have to show people how the systems work, how well they are going to work and what they are going to cost.”

The turbine will give Colorado Pork the chance to see how an intermittent power source combines with the steady generation of its CHP system. The farm now gets about 24 kW from the biogas-powered Capstone microturbine. Although that is less than the wind turbine’s 65-kW rating, “Wind only generates about one third of the time,” noted Lewis. “It’s good to have the wind backed up by a device that is always producing.”

SECPA, the farm’s utility, and its power wholesaler TriState will be learning more about how small wind projects affect the grid. The interconnected turbine will help the power providers identify and address issues from contract provisions to safety equipment and procedures.

TriState Senior Engineer Mike McCoy observed that the demonstration process is very important for moving any renewable technology forward. “With the anaerobic digester project, we discovered 999 ways not to run a CHP system,” he recalled. “We haven’t done that much small wind in Colorado, so we need to go through that process,” he added.

Resources, cost makes small wind feasible

The gap in experience is not for lack of resources. Southeastern Colorado’s average wind speed of more than 13 miles per hour supports Colorado Green, the state’s largest wind farm. Nearby, the town of Lamar has installed 6 MW of wind power.

OEMC and Colorado Pork collected data from a wind anemometer on the farm for one year and compared it to data from Lamar’s large anemometer. OEMC loans anemometers to sites that are considering small wind power development.

Lewis hopes that the latest phase of the Colorado Pork project will encourage the region’s agricultural community to take a greater interest in renewable energy. “The cost of an anaerobic digester system can be daunting to a smaller operation,” he explained, “especially since the systems tend to work better on new or add-on lagoons. Wind turbines are relatively inexpensive by comparison, and easier to install.”

Using a refurbished Vestas E15 wind turbine from Energy Maintenance Service, the total installed cost of the unit is $85,000, including all electrical connections. With no credit for peak reduction, the wind turbine will generate about $11,000 worth of electricity per year for an estimated payback of eight to 10 years.

Demonstrations build education resources

OEMC funded this project, and plans to highlight it in educational workshops throughout the agricultural community. A video presentation explaining small wind power and the installation of this turbine is also in the works. The resources on Colorado Pork’s CHP system will be updated to include information on the wind turbine, too.

There will soon be more data to add from another addition to the CHP system, a Stirling engine with a nameplate capacity of 55 kW. Like the microturbine, the external combustion Stirling engine will run on biogas. Combined with the Capstone unit and the wind turbine, the Stirling will move the hog farm closer to generating its entire 100- to 196-kW load.

The new engine also presents another renewable energy opportunity for cutting operating costs. “Since heat drives the pistons, a concentrated solar array could heat water to run the Stirling,” Lewis conjectured.

For the partners in the Great Colorado Pork Renewable Energy Experiment, it’s another day, another demonstration.