So much potential energy is going to waste.
If manure digesters could overcome the hurdles that now face them, thousands of U.S. dairy producers could reap tremendous opportunity, AgSTAR’s Chris Voell said last week during an educational seminar, “Opportunities to Advance Manure Digesters in the U.S.” at World Dairy Expo in Madison, Wis.
With more waste-to-methane gas systems, there would be more renewable energy available to power dairies, other businesses and homes. Methane emissions would be cut, air quality improved, odor cut. Dairies could benefit financially from selling their power. And those digesters could be running 24/7 – unlike wind and solar power sources.
But until current energy policies change, the spread of digesters is likely to move slowly, said Voell, AgSTAR’s national program manager.
There are 126 digesters operating on dairies in the U.S. today. But another 2,500 dairies – all 500 or more cows -- are candidates for digesters.
“We have the technology and the interest” to expand the use of manure digesters, Voell said, but until current energy policy opens doors for them, “investors aren’t coming into this field in a big way.”
Among livestock operations, dairies dominate digester technology. Fifty percent of today’s dairy digesters are concentrated in four states: Wisconsin (with 25), New York (with 22), Pennsylvania and California (each with 15). The No. 1 benefit of dairy manure digesters is the dried solids used for cow bedding.
Renewable energy is already in big demand in several states. The nation’s digester landscape, however, is “a patchwork from state to state and from energy company to energy company,” Voell said. “Policies are all over the board.”
AgSTAR has successfully encouraged more development and adoption of anaerobic digestion technology. It’s an outreach program designed to reduce methane emissions from livestock waste management operations by promoting the use of biogas recovery systems. But AgSTAR can’t do it alone.
Policy is changing in some states to be more digester-friendly, says Allison Hogge, another AgSTAR program manager. Vermont, for example, recently enacted a feed-in tariff that guarantees producers certain rates for renewable energy. That amount is reportedly 18 cents per kilowatt hour. With such support, digester development is picking up steam in Vermont, which already operates eight manure operators, making it the No. 5 state in the number of operating manure digester systems.
Wisconsin, which is home to the most manure digesters with 25 in operation, has also worked to smooth the process, particularly with an easier interconnection to the energy grid.
Policy is tightening in California, however. The state has 14 dairy (and one heifer) manure digesters in operation. Voell says California has the opportunity for 900 digesters at dairies with 500 or more cows. But most of the state’s dairies are located in the Central Valley, which has some of the worst air quality in the nation. State regulators oppose any new sources of nitrogen oxide (NOx) emissions in the valley. As a result, regulatory hurdles and concerns over the NOx emissions from digesters’ energy-creating equipment are stalling more development there.
But hope exists for digester expansion nationwide. For starters, says Hogge, agencies like USDA and the Environmental Protection Agency, are starting to recognize the digester obstacles. That should help.
And the government has provided some assistance. The Food, Conservation and Energy Act of 2008 provided more money for digesters. AgSTAR lists several digester funding opportunities on its website. According to Hogge, some of the government funding sources most likely to support anaerobic digester projects include:
Moreover, the digester industry just this year formed the American Biogas Council to promote digester technology and benefits and to help legislators in Washington, D.C., understand what digesters offer.
More is needed. Federal and state subsidies could boost digester development, Voell said. Fossil fuels and ethanol have benefitted from government help. “Producing energy from biogas is difficult,” he said. “It needs a level playing field.”
And more overall players would float all boats. “If we want to transform the industry,” said Voell, “we need more companies and supporting operators to make it successful for those who want to put digesters in place.”