Used for millennia to enrich farmer’s fields, cow manure may be poised to become a centrepiece of the green energy revolution, thanks in part to research under way at the University of Waterloo.
Traditional biogas production requires stripping away carbon dioxide from the raw gas produced when manure or other organic matter is put through an anaerobic digester system, in order to isolate pure methane. But now, a team led by UW chemical engineer David Simakov is working on a refining process that uses hydrogen to chemically converts the CO2 into methane.
“This conversion doubles the production rate of the older separation techniques, producing so much renewable natural gas that the volume could be stored and eventually used as a natural battery,” Bloomberg Business News reports. In turn, “the new method results in lower carbon dioxide emissions.”
A potential stumbling block is that “producing the hydrogen needed for the chemical reaction takes a lot of electricity and constitutes the most expensive input in the whole process,” Simakov told Bloomberg. But American Biogas Council Executive Director Patrick Serfass said wind- and solar-generated electricity can be used to power the hydrogen conversion through a process called methanation.
An elegant “natural battery,” methanation solves the problem of storing non-dispatchable forms of energy, acting to “bridge the variability of wind and solar with the reliability of energy from biogas systems,” Serfass said.
“Simakov’s research is still three to five years from producing renewable natural gas economically,” writes Bloomberg, “but the eventual payoff is promising.” According to the Biogas Council, the United States alone has enough raw biogas potential to reduce greenhouse gas emissions equivalent to the tailpipe emissions from 15.4 million vehicles per year.
Simakov also sees his process being used to drive up biogas production from another significant source of GHG emissions: the world’s landfills.
Cow manure would do a much better service left on the field to enrich the soil. Regenerated soil would soak up more carbon and help reduce that in our atmosphere. Those who want methane only have to visit those areas of permafrost and collect it, since more and more of it is escaping as the permafrost melt.
After generating biogas from manure in an anaerobic digester, the liquid residue is used as a (high quality) fertilizer while solid residues are used for animal bedding. Multiple purpose usage (biogas, fertilizer, and bedding) as opposed to spreading manure on field (single purpose usage as fertilizer). Also, spreading manure on fields results in uncontrolled release of methane to the atmosphere!!! Methane is a much more dangerous GHG than carbon dioxide. Collecting methane from the permafrost is impractical of course.