Crop residues: how much biomass energy is out there?
Recent news about a Vietnamese company that will be using fat catfish waste to turn it into biodiesel fuel, or about Brazil's coffee farmers who will be using 25% of their entire harvest as a feedstock for biofuels (because 25% of the beans are low quality and considered to be "waste"), focuses attention on the messy streams of waste-biomass that are out there and that can be used as a source of energy.
Such waste-streams can be converted into many different types of biofuels, based on a variety of conversion processes, resulting either in biogas, biohydrogen, liquid biofuels (first generation or second generation biofuels such as cellulosic ethanol), or solid biofuels (densified into easily transportable bio-pellets and briquettes) to be used in biomass co-firing or combustion systems.
But just how much biomass waste are we talking about? And how much energy does it contain? There are many different categories from countless industries. The most obvious category is that of agro-forestry residues, but there's also household waste, residues from cattle and dairy farming, and from a whole range of industrial processes (from paper production to abbatoir waste and wood products manufacturing). It is very difficult to assess the actual amount of biomass that literally goes to waste from all these processes on this planet.
But several attempts have been made, and we highlight just one of those. The FAO produced a meta-study about residues from commonly cultivated crops (excluding forestry), based on 12 pre-existing studies. And these are the results:
These are the waste streams from only one category of residues, as they exist on this planet today, anno 2006. In total they contain between a minimum 25 and maximum 176 exajoules of energy. Consider that the entire world currently consumes roughly 440 exajoules of energy (from all sources: coal, natural gas, oil, nuclear and renewables), and one understands that biomass holds great potential. Moreover, new bioconversion technologies, such as the enzymatic conversion of ligno-cellulose into sugars that can be fermented into ethanol, promise to become the most cost-effective technology for the production of liquid biofuels from these biomass residues.
biomass :: biodiesel :: ethanol :: biogas :: bioenergy :: biofuels :: energy :: sustainability :: Africa ::
It must be said that the above numbers do not reflect the local consumption (for fibre, fodder and fertilizer) of those residues. This consumption currently ranges between 10 and 30%, depending on the crop and the location. Moreover, some of the crops require a fraction of the biomass to be returned to the field, to maintain fertility, whereas other residue streams can be used without that requirement.
More information:
:: FAO: Agricultural and Forest Residues - Generation, Utilization and Availability [*.pdf]
:: IEA Bioenergy Task 40: A quickscan of global bio-energy potentials to 2050
:: IEA Bioenergy Task 40: International bioenergy transport costs and energy balance
:: Joanneum Research(Austria): Next steps in co-firing biomass including transportation [*.pdf], considers international biomass residue trade.
:: University of Utrecht, Dpt. of Chemistry: Biotrade: International trade in renewable energy from biomass
:: K Ericsson, LJ Nilsson - Biomass and Bioenergy, 2004: International Biofuel Trade - A Study of Swedish Imports
:: FAO: Biomass Briquetting - International Workshop - RWEDP Report No.23, 1996
:: Bio-pellets, bio-briquettes: An International Forum Connecting People with Hands-On Solutions to World Poverty: Briquetting: An Answer to Desertification, Health Problems, Unemployment and Reforestation in Developing Communities [*.pdf]
Such waste-streams can be converted into many different types of biofuels, based on a variety of conversion processes, resulting either in biogas, biohydrogen, liquid biofuels (first generation or second generation biofuels such as cellulosic ethanol), or solid biofuels (densified into easily transportable bio-pellets and briquettes) to be used in biomass co-firing or combustion systems.
But just how much biomass waste are we talking about? And how much energy does it contain? There are many different categories from countless industries. The most obvious category is that of agro-forestry residues, but there's also household waste, residues from cattle and dairy farming, and from a whole range of industrial processes (from paper production to abbatoir waste and wood products manufacturing). It is very difficult to assess the actual amount of biomass that literally goes to waste from all these processes on this planet.
But several attempts have been made, and we highlight just one of those. The FAO produced a meta-study about residues from commonly cultivated crops (excluding forestry), based on 12 pre-existing studies. And these are the results:
RPR = residue-to-product ratio (for each ton of produce, the RPR indicates the amount of residue that becomes available)
LVH = lower heating value - ranges differ considerably; higher heating value was not included
Production = millions of metric tons, calculated by multiplying the production of an agricultural product (e.g. rice) by its RPR
Potential = production times LVH
LVH = lower heating value - ranges differ considerably; higher heating value was not included
Production = millions of metric tons, calculated by multiplying the production of an agricultural product (e.g. rice) by its RPR
Potential = production times LVH
These are the waste streams from only one category of residues, as they exist on this planet today, anno 2006. In total they contain between a minimum 25 and maximum 176 exajoules of energy. Consider that the entire world currently consumes roughly 440 exajoules of energy (from all sources: coal, natural gas, oil, nuclear and renewables), and one understands that biomass holds great potential. Moreover, new bioconversion technologies, such as the enzymatic conversion of ligno-cellulose into sugars that can be fermented into ethanol, promise to become the most cost-effective technology for the production of liquid biofuels from these biomass residues.
biomass :: biodiesel :: ethanol :: biogas :: bioenergy :: biofuels :: energy :: sustainability :: Africa ::
It must be said that the above numbers do not reflect the local consumption (for fibre, fodder and fertilizer) of those residues. This consumption currently ranges between 10 and 30%, depending on the crop and the location. Moreover, some of the crops require a fraction of the biomass to be returned to the field, to maintain fertility, whereas other residue streams can be used without that requirement.
More information:
:: FAO: Agricultural and Forest Residues - Generation, Utilization and Availability [*.pdf]
:: IEA Bioenergy Task 40: A quickscan of global bio-energy potentials to 2050
:: IEA Bioenergy Task 40: International bioenergy transport costs and energy balance
:: Joanneum Research(Austria): Next steps in co-firing biomass including transportation [*.pdf], considers international biomass residue trade.
:: University of Utrecht, Dpt. of Chemistry: Biotrade: International trade in renewable energy from biomass
:: K Ericsson, LJ Nilsson - Biomass and Bioenergy, 2004: International Biofuel Trade - A Study of Swedish Imports
:: FAO: Biomass Briquetting - International Workshop - RWEDP Report No.23, 1996
:: Bio-pellets, bio-briquettes: An International Forum Connecting People with Hands-On Solutions to World Poverty: Briquetting: An Answer to Desertification, Health Problems, Unemployment and Reforestation in Developing Communities [*.pdf]
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