Renewable Energy Source Right Under Our Noses
Tony Pallone | March 08, 2018
Could this wheelbarrow hold the key to reducing global warming? Source: Efraimstochter/CC0 Creative Commons.
Combatting global warming is no easy task; solutions can be complex, costly and politically difficult to implement. But one source of renewable energy that could help reduce greenhouse gas emissions is (literally) right under our noses: farm manure.
Researchers at the University of Waterloo, in Ontario, Canada, are developing technology to produce renewable natural gas from manure and add it to the existing energy supply. The work could not only serve to replace a portion of fossil-fuel natural gas, but also eliminate the harmful gases that are released by naturally decomposing manure when it is used as a farm field fertilizer.
An actual 2,000-head dairy farm in Ontario that collects manure and converts it into biogas in anaerobic digesters was used as the basis for the researchers’ computer model. Some of that biogas is already being burned in generators in order to produce electricity, which yields about 30 to 40 percent of the manure’s energy potential. But the researchers have noted the potential for a significant upgrade to the system that would come from converting that biogas not into electricity, but into renewable natural gas.
The technique, called methanation, involves mixing the gas with hydrogen before running it through a catalytic converter. Inside the converter, a chemical reaction produces methane from the carbon dioxide contained in the gas. Although it requires electricity to operate, the researchers say, that power could be generated on-site by renewable wind or solar systems, or taken from the electrical grid at times of low demand. The net result: renewable natural gas that yields almost all of manure's energy potential and also efficiently stores electricity, with only a fraction of the greenhouse gas impact of manure used as fertilizer.
The study showed that a $5-million investment in a methanation system at the Ontario farm would have about a five-year payback period, once government price subsidies for renewable natural gas are factored in.
The research was recently published in the International Journal of Energy Research.
Composted manure is a relatively non polluting slow release fertilizer. Has the university calculated the environmental consequences of removing this fertilizer from the equation and replacing it with polluting chemical fertilizers which can potentially percolate through the soil quickly and disrupt water and soil ecology?