The food industry has been discovering the bottom line benefits of recovering biogas from food waste, and farmers are realizing similar returns from manure biogas recovery. Now the U.S. Department of Agriculture just chipped in with the new Biogas Opportunities Roadmap, part of which demonstrates how marrying food waste and manure could turn those two massive disposal streams into a valuable asset for U.S. farmers.
The Roadmap specifically focuses on the role that livestock farmers can play in reducing methane emissions while adding more renewable biogas to the U.S. energy portfolio. Since the Roadmap was prepared with considerable input from the agriculture industry including the Innovation Center for U.S. Dairy, let's take a look at the manure/food waste commingling aspect from the dairy farm perspective.
Tackling agriculture-related methane emissions is one focus of the Environmental Protection Agency's climate change management strategy, but the sticking point is how to convince farmers that investing in a digester system will pay off.
That's where the Roadmap comes in. The figure of $2.9 billion comes from a biogas research report prepared by the Innovation Center last year, which informed part of the Roadmap's strategies. It refers to the market potential for recovering biogas from 9 million tons of manure annually, from 4 million dairy cows.
Rather than focusing exclusively on manure, the Innovation Center looked at the potential for combining manure and food waste in co-digester systems at 2,647 dairy digesters.
The payoff could be significant for individual dairy farms. In addition to producing captured methane that could be used to power farm operations, leftover solids are inert and can be used as fertilizer or soil enhancer without wreaking the environmental havoc posed by land-based methods for disposing of raw manure (namely, storing it in open lagoons or spraying it on fields).
With further drying and processing, the solids could also be recycled for livestock bedding, and there is also some potential for recovering useful plant nutrients.
On dairy farms, digesters can increasingly be part of the solution to manure management challenges and enhance our ability to sustain our farms for the next generation.
It's also worth noting that biogas co-digestion is starting to emerge in municipal wastewater treatment, as illustrated by a New York City pilot program for commingling food waste with its existing wastewater biogas recovery systems.
It calls for the Environmental Protection Agency and the departments of Energy and Agriculture to work with the dairy industry and other stakeholders to overcome obstacles to bigas digester investment.
Tracking biogas digester performance and tweaking digester systems to produce more high-value products, such as nitrogen and phosphorus, are two key parts of the plan.
Also included is the development of new financing arrangements, which we're thinking could include something similar to the power purchase agreements (PPAs).
PPAs have already kickstarted the market for distributed solar energy, and PPA-style financing is already starting to emerge as a means of enabling property owners to invest in energy efficiency improvements without an up-front investment, so biogas digesters could be a logical next step.
Image (cropped): cheeselave
Tina writes frequently for TriplePundit and other websites, with a focus on military, government and corporate sustainability, clean tech research and emerging energy technologies. She is a former Deputy Director of Public Affairs of the New York City Department of Environmental Protection, and author of books and articles on recycling and other conservation themes. She is currently Deputy Director of Public Information for the County of Union, New Jersey. Views expressed here are her own and do not necessarily reflect agency policy.