For achieving reductions in the emission of greenhouse gases that result in global warming, farm manure could be used as a feasible source of renewable energy.
Scientists from the University of Waterloo have been devising a technique for synthesizing renewable natural gas from manure such that it could be added to the prevalent energy supply system for powering industries and heating homes. This process will get rid of harmful gases liberated during natural decomposition of manure while being scattered on farm fields as fertilizer and somewhat substitute fossil natural gas, which significantly contributes to global warming.
“There are multiple ways we can benefit from this single approach,” stated David Simakov, a professor of chemical engineering at Waterloo. “The potential is huge.”
According to Simakov, the technique can be applied to different types of manure, specifically pig and cow manure, and also at landfill sites.
Apart from being put to use in homes and by industries, renewable natural gas can also be used as a substitute for diesel fuel in trucks in the transportation sector, a chief source of greenhouse gas emissions.
In order to investigate the concept, the scientists developed a computer model of a real 2000-head dairy farm in Ontario that gathers manure and transforms it into biogas by using anaerobic digesters. A part of the biogas is hitherto being used to generate electricity by igniting it in generators, thereby minimizing the influence of manure on the environment, and at the same time producing nearly 30%-40% of its energy potential.
Scientists are striving to take those advantages a notable step forward by enhancing (or transforming) biogas from manure into renewable natural gas. This would mandate mixing it with hydrogen, and subsequently passing it through a catalytic converter. Methane would be generated from carbon dioxide in the biogas by means of a chemical reaction in the converter.
Termed methanation, the technique will necessitate electricity to generate hydrogen; however, that power can be produced on-site by renewable solar or wind systems, or derived from the electrical grid when there is low demand. The ultimate outcome will be renewable natural gas that includes nearly all of the energy potential of the manure and also effectively stores electricity; however, it has merely a fraction of the greenhouse gas effect of manure that is used as fertilizer.
“This is how we can make the transition from fossil-based energy to renewable energy using existing infrastructure, which is a tremendous advantage,” stated Simakov, who partners with fellow chemical engineering professor Michael Fowler.
The model investigation demonstrated that an investment of five million dollars in a methanation system at the Ontario farm would, including government cost subsidies for renewable natural gas, have nearly a five-year payback period.
A study related to modeling of a renewable natural gas generation facility at the Ontario farm, on which a post-doctoral researcher and various Waterloo students worked, was reported recently in the International Journal of Energy Research.