Converting animal poop to power makes sense, but today it is too expensive. The good news is it reduces greenhouse gas emissions and curtails odors from farms.
Biomass is an important part of our nation’s effort to generate electricity from renewable sources. In Washington, where electric rates are low, it is difficult to make an economic argument using biomass to solely produce power.
Our state’s forest products companies have burned wood wastes for decades as part of the manufacturing process. It is called co-generation. Pressurized steam is run through power turbines and then used to make paper, lumber and plywood. In fact, during the last recession, our mills kept afloat by selling their electricity.
In recent years, our state’s farmers started investing in biomass plants to turn animal dung into electrical energy. The process is complex. Here is how it works.
Digesters are oxygen-free tanks in which microorganisms break down manure and capture methane that otherwise would be released into the atmosphere as a greenhouse gas.
The biogas from digesters is mostly composed of methane and can be burned to produce electricity or cleaned and pressurized for transport in natural-gas pipelines. Fertilizers are byproducts which farmers can use or sell.
By diverting waste from open-air lagoons, digesters limit the potential for spills that can pollute waterways and air contamination.
That process is expensive. To offset those higher expenses, state and federal officials have provided grants and guaranteed loans.
Farm Power in Skagit County received $500,000 grants from the state and federal governments and $2.1 million from the U.S. Department of Agriculture to build a plant that generates enough electricity for 500 homes. Puget Sound Energy uses Farm Power as a way to achieve the state’s requirement that 15 percent of its electricity must come from renewable sources (other than hydropower) by 2020. But in recent years, costs have slowed further development.
In 2011, University of Vermont professor Dr. Qingbin Wang pegged the initial investment at $2 million per farm for equipment and added that grants and subsidies from government agencies were necessary. Wang estimated that converting manure from the 95 million animals in the U. S. would produce renewable energy equal to 8 billion gallons of gasoline — approximately 1 percent of the nation’s total energy consumption.
President Obama is encouraging U.S. farmers to build manure digesters and pipe the methane gas to electric generators. According to the White House, agriculture accounts for 36 percent of America’s methane emissions.
In 2014, the president issued a “biogas opportunities road map” with a goal of producing enough power for 1 million homes by 2025. Last year, 70,000 homes got their electricity from farm generators.
The Wall Street Journal reported last month that construction of new farm digesters has slowed sharply over the past two years. Some big meatpackers that have supported development of digesters have become more cautious.
WSJ reported that Perdue Farms Inc., among the largest U.S. chicken processors, has pledged to contribute poultry waste to a planned Maryland biogas project, but the company has rejected several other manure-to-energy proposals. “With today’s fossil-fuel prices, many such projects “can’t stand on their own,” said Mike Phillips, director of special projects for Perdue AgriBusiness.
In Wisconsin, some dairy farmers are not only scrapping plans for new manure-to-power plants but are shutting down existing ones. Higher-than-expected maintenance costs also makes those systems less economical.
Just as the costs to generate electricity from wind turbines and solar power have come down, hopefully, manure biogas power plants will be less expensive to build and operate in the years ahead. The environmental benefits alone make it worth pursuing.
Don Brunell, retired as president of the Association of Washington Business, is a business analyst, writer, and columnist. He lives in Vancouver and can be contacted atTheBrunells@msn.com
