On the Cal-Gon dairy farm in Salem, PGE operates a facility that converts more than 20 tons of cow manure into energy each day.
Manure enters a 28-foot high digester where it releases methane gas, which then fires a generator on the farm, feeding up to 70 kilowatts of renewable electricity directly to PGE customers. Leftover materials are processed through a solids separator into relatively odor-free fibers and liquids that can be used for commercial nursery or farm soil applications.
The project started generating electricity in March 2002.
PGE hopes this system will eventually be cost-competitive with other renewable resources like wind turbines and solar power.
“The PGE biogas program increases the supply of electricity through the effective use of a renewable resource, helping limit our reliance on finite supplies of natural gas,” said Joe Barra, PGE’s director of distributed resources. “At the same time it reduces air pollution and gives an important boost to the dairy industry.”
Livestock manure management has limited the growth of the dairy industry. Biogas facilities give producers more flexibility in manure disposal — lowering odor, and lowering need for commercial fertilizer — potentially increasing herd size. In addition to the small-scale Cal-Gon Farms plant, PGE has investigated the design of biogas systems for dairies with as many as 20,000 head of cattle. With 400 dairy farms in Oregon, the Oregon Dairy Farmers Association and the Oregon Department of Agriculture are optimistic about biogas’s potential to help the industry, the economy and the environment.
Through pilot projects like the ones at Cal-Gon Farms, PGE continues to explore the development of clean, competitive energy technologies for the future that will help transform the electric power industry.
Agricultural benefits
- Improved manure management: Reduces the buildup of manure solids in farm storage lagoons. Recycles fiber for use as bedding or soil enhancements.
- Processes nitrogen to make liquid byproducts like commercial fertilizer, more readily available for crops.
Environmental benefits
- Better air quality. Captures and uses methane gas that would have otherwise entered the atmosphere from manure. Uncontrolled methane is a toxic greenhouse gas, 20 times more harmful to the atmosphere than carbon dioxide.
- Helps control undesirable nutrients in soil and surface water supplies.
- Reduces odor.
Resource benefits
- Lowers demand for natural gas and other finite supplies of fossil fuel.
- Fuel source is 100 percent renewable. Reduces dependence upon finite fossil fuels.