Converting Agricultural Residues and Manure into Bioenergy
- Green Movement
- Mar 22, 2021
- 3 min read
For transportation and power, sustainable, renewable energy supplies are an essential part of the response to the climate, fiscal, environmental, and security problems that our fossil fuel usage has generated. Bioenergy—the use of biomass, such as plant materials and compost, to generate green fuels for transportation and electricity—can offer a low-carbon, long-term alternative to fossil fuels while encouraging cities to take advantage of local resources. The use of crop residues and manure to generate bioenergy provides a major incentive for local and regional economies, with the ability to access opportunities throughout the world. Biomass is considered a green energy source because it is generated in at least the same amount as it is consumed, with no net deforestation or food production competition. The gas produced by the decomposition is predominantly a mixture of methane and carbon dioxide.
Two Sources of Sustainable Agricultural Biomass
1. Residues from Cropping Bread, wheat, and rice crops include not only the grains we consume or feed to animals, but also stalks, husks, cobs, and other biomass that is unfit for direct human consumption.
These materials have traditionally been used as animal bedding, burnt, or dumped on farms. Recent technological advancements, on the other hand, now enable farmers to convert agricultural residues into biomass-based fuels like ethanol or use them to generate electricity. Farmers' ability to sustainably extract crop residues ranges from field to field, and even within a field, depending on soil quality, land slope, management methods, and regional environment.
2. Waste from Livestock
Livestock raised in very large confined animal feeding operations (CAFOs) contain almost unmanageable amounts of manure, which can be used for bioenergy but often routinely pollutes water sources in many areas of the world. Farmers can use anaerobic digesters to convert manure into biogas while reaping economic and environmental benefits on the smaller end of the livestock production scale. They can use the biogas on the farm to provide heat and electricity, or they can purify it and sell it as clean natural gas for use elsewhere. At this scale, using anaerobic digesters to remove biogas from manure will improve water quality, reduce manure methane emissions, and allow farmers to return nutrients to their soils.
Vietnam potential for bioenergy
Vietnam, as an agricultural area, has a lot of biomass energy potential. Agricultural wastes are most plentiful in the Mekong Delta region, which accounts for roughly half of the country's total, and the Red River Delta, which accounts for 15%. Rice husk from paddy milling stations, bagasse from sugar mills, coffee husk from coffee processing plants in the Central Highlands, and wood chips from wood processing industries are all significant biomass options. Vietnam has set an aim of providing a total biomass power capacity of 500 MW by 2020, with a goal of 2,000 MW by 2030.
Biogas has a 10 billion m3/year capacity and can be obtained from landfills, animal excrement, agricultural wastes, municipal wastewater, and other sources. The country's biogas capacity is high due to the country's livestock population of over 30 million animals, mainly pigs, goats, and water buffalo. While most livestock dung is now used to feed fish and fertilize fields and crops, biogas processing has the ability to have a higher-value use.
Landfills, animal excrement, crop wastes, municipal drainage, and other forms of biogas have a capacity of approximately 10 billion m3/year. Due to the country's high livestock population, which consists primarily of pigs, goats, and water buffalo, the country's biogas capacity is considerable. While the majority of livestock dung is currently used to feed fish and fertilize fields and gardens, biogas processing has the ability to have a higher-value use.
Hoang Tu Anh
References
Anonymous (2021). "The quest for renewable and sustainable energy". Retrieved from https://mg.co.za/special-reports/2021-03-26-the-quest-for-renewable-and-sustainable-energy/
Pranjar Mehar (2021). "A methodology to better incorporate organic waste for enhanced energy conversion". Retrieved from https://www.techexplorist.com/methodology-better-incorporate-organic-waste-enhanced-energy-conversion/37314/
Union of concerned scientists (2014). "Turning Agricultural Residues and Manure into Bioenergy". Retrieved from https://www.canr.msu.edu/uploads/files/Agricultural-Residue-Ranking.pdf
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