Agricultural residues and household energy

Table of Contents
What are agriculture residues? Agricultural residues characteristics Who uses them? Agricultural residues potentiality in developing world Advantages Disadvantages Devices External links and references Contributors

[top] [end]What are agriculture residues?

Agriculture residues directly burnt as fuel in developing world include crop residues, forest litter, and also grass and animal garbage. Crop residues are more widely burnt than animal waste and forest litter.

Crop residues encompasses all agricultural wastes such as straw, stem, stalk, leaves, husk, shell, peel, lint, stones, pulp, stubble, etc. which come from cereals (rice, wheat, maize or corn, sorghum, barley, millet), cotton, groundnut, jute, legumes (tomato, bean, soy) coffee, cacao, olive, tea, fruits (banana, mango, coco, cashew) and palm oil.

Eucalyptus Litter

Crops	Crop wastes	Residues production
Rice	Straw, husk, bran	1.5t of straw and 0.2t of husk from 1t of rice
Wheat	Straw, husk, bran	2t of residues from 1t of wheat seed
Maize	Stalk, leaves	6t of waste from 1t of maize (leaves + stalks 4t)
Sorghum	Straw, bran	2.5t of residues from 1t of sorghum seed
Barley	Straw, bran	1.5t of straw from 1t of barley
Millet	Straw, bran	2t of residue from 1t of millet produced
Cotton	Stalk, lint, hull	0.2t of waste from 1t of cotton seed
Groundnut	Shell, stalk, leaves	25% of shell weight from non husked
Jute	Stem	na
Tomato	Stem	na
Coffee	Pulp, husk	3.6t of waste from 1t of green coffee
Olive		na
Banana		na
Coco	Hull, fibre	0.9t of waste from 1t of coconut
Palm oil	Shell, fibre, fruit bunches	75% waste from weight of fruit bunch
Mango	Peel

Sources: (1) Memento de l’agronome : quatrième edition 1640 pages (2) J lamptey and al – 1990- bioenergy – IDRC/UNU - 210 page (3) CowiConsult – 1984 – Etude d’une utilisation efficace des déchets agricoles comme fuel domestiques au Sénégal 250 pages

Forest litter is mainly constituted of dry fallen leaves. Plantations of those species widely used for reforestation or soil conservation/sand fixation such as Eucalyptus and Casuarina equisetifolia, provide an important biomass litter yearly.

Eucalyptus Litter

Animal garbage is livestock manure. Generally dry animal wastes directly used as fuel are cow and camel dung, and sometimes that of horse and sheep. The quantity of manure produced depends on the amount of fodder eaten, the quality of fodder and the liveweight of the animal. The excrement-yield values vary among the species.

SPECIES	Daily manure yield as % of liveweight	Animal liveweight (Kg)	Animal liveweight (Kg)	Dung yield (Kg/day)	Dung yield (Kg/day)
Cattle	5	135	800	6.8	40.0
Buffalo	5	340	420	17.0	21.0
Pigs	2	30	75	0.6	1.5
Sheep/goats	3	30	100	0.9	3.0
Chickens	4.5	1.5	3	0.1	0.1

Source: (1) Memento de l’agronome : quatrième edition (2) GTZ – 1989 – biogas plants in animal husbandry – 134 pages

Filao Litter

[top] [end]Agricultural residues characteristics

In the developing world, most agricultural residues burnt as fuel are used in their natural state with some pre-treatment like drying, and cutting, and compacting in rare occasions. Crop residues are characterized by its seasonal availability and have characteristics that differ from other solid fuels such as wood, charcoal, char briquette. The main differences are the high content of volatile matter and lower density and burning time.

Agricultural residues	Volatiles (%)	Fixed carbon (%)	Ash (%)	HHV (Kj/kg)	LHV (Kj/kg)	Density (%)
Arhar stalk	83.47	14.76	1.77	15.00	14.85
Bagasse	75.10	16.87	8.03	19.50	19.37	40 - 60
Bamboo dust	75.32	15.59	9.09	16.02	15.87
Cotton stalk	70.89	22.43	6.68	18.26	17.85	10 - 20
Coconut coir	70.30	26.77	2.93	18.20	17.79	7 - 8
Corn cob	80.20	16.20	3.60	15.58	15.23	10 - 20
Dhaincha stalk	80.32	17.01	2.67	19.63	19.43
Groundnut shell	68.12	24.97	6.91	17.20	17.06
Jute stick	75.33	19.00	5.67	19.45	19.01
Mustard shell	70.09	14.48	15.43	17.61	17.47
Pine needle	72.38	26.12	1.50	20.12	19.97
Rice husk	60.64	19.90	19.48	13.38	13.24	9
Sal seed leaves	60.03	20.22	19.75	18.57	18.42
Sal seed husk	62.54	28.06	9.40	20.60	20.13
Coffee husk				16.00		10

Concerning animal waste, the calorific values of cow dung and chicken droppings are respectively 16 – 19 Mj/kg and 14 - 16 Mj/kg. Cow dung calorific value is more important than the one of wood.

Filao Litter

The large potentials of agro-industrial residues like bagasse, groundnut shell, palm oil residues are mainly used to meet the energy need of the factories.

[top] [end]Who uses them?

The rural families in the villages who own agricultural land use their own agricultural residues which varies throughout the year as per the crop planted. They use it as a household fuel for cooking, heating water and for space heating in colder climates.

Agricultural wastes are directly burnt to meet the need of cooking. Crop residues are yet used to light wood and charcoal.

West African potters burn a large amount of agricultural residues in their traditional pottery pit in order to produce their canaris, earthenware jars, ceramic stoves and other pottery.

In the part of the world faced by the scarcity of woodfuel and the cost-effective fuel substitutes, agricultural waste (owing to its high potentiality) may play a major role on sustainable energy. However the traditional use of crop residues and the lack of information on modern technologies such as briquetting, pelleting, and bioconversion, limit the development of large scale use which leads to increase the value of agricultural output.

Agriculture as a biomass supplier is yet affected by soil quality. Agricultural wastes can be used as either fuel or fertilizer. So the bio digestion of agricultural residues leads to provide both energy (biogas) and upgraded fertilizer than raw waste.

[top] [end]Agricultural residues potentiality in developing world

Agricultural wastes potentiality can be estimated by the following formulae:

Formula to estimate agricultural wastes

Where:

means the potentiality of crop residues where “a” represents the crop production; “b” designs the crop residue yield production, and “i” the type of crop. when the calorific value of each type of crop is used the potentiality can be calculated in TOE (ton crude oil equivalent).

Eucalyptus Litter

means the potentiality manure production where “alpha” represents the number of animal head; “b” designs the garbage yield production, and “i” the animal species.

Filao Litter

means the potentiality of crop residues where “S” represents the area of plantation; “R” designs the residue yield production per unit of surface, and “i” the type of crop.

The statistical data about agricultures production are available for any country in the FAO website.

Example: the Senegal crop residues production
Crop productions

CROP	CROP PRODUCTION ( tonnes ) 1999	CROP PRODUCTION ( tonnes ) 2000	CROP PRODUCTION ( tonnes ) 2001	CROP PRODUCTION ( tonnes ) 2002	CROP PRODUCTION ( tonnes ) 2003	CROP PRODUCTION ( tonnes ) annual production
Groundnut	1 014 250	1 061 540	943 837	501 298	900 000	884 185
Sugarcane	889000	850000	890000	890000	890000	881 800
Oil palm	64000	65000	65000	65000	70000	65 800
Cotton	14 649	20 411	34 237	33 913	34 000	27 442
Millet	675000	600221	470105	414687	450000	522 003
Maize	66132	78593	106444	97858	103000	90 405
Sorgho	147444	143750	140297	143892	154000	145 877
Rice	239 786	202 293	243 907	177 756	177 756	208 300
Coco	4 700	4 700	4 700	4 700	4 700	4 700

Crop residues productions

Crop	Residues	Calorific value (KJ/Kg)	Annual crop production (tonnes)	Waste yield (%)	Annual residues production (tonnes)	Energy (TOE)
Groundnut	Shell	17	884185	25.0%	221 046	89.5
Sugarcane	Bagasse	19.37	881800	30.0%	264 540	122.0
Oil palm	Wastes	16	65800	72.5%	47 705	18.2
Cotton	Stem	18.3	27442	20.0%	5 488	2.4
Millet	Wastes	18	522002.6	200.0%	1 044 005	447.4
Maize	Wastes	18	90405.4	600.0%	542 432	232.5
Sorghum	Wastes	18	145876.6	250.0%	364 692	156.3
Rice	Wastes	12	208299.6	170.0%	354 109	101.2
Coco	Wastes	17.9	4700	87.0%	4 089	1.7
TOTAL			2830511.2		2 848 107	1171.2

In Senegal the total of annual crop wastes equals 2 848 107 tonnes or 1171.2 TOE, which represents the amount of imported oil consumed. However the quantity available and exploited is low, under 40%. Bagasse and groundnut shell are widely burnt by industries to meet their energy need in the factories.

[top] [end]Advantages

Agricultural residue is a fuel which is available free of cost to the poor rural families.
It is also a useful way to dispose of the crop residues in the field, instead of burning them in situ.
Agricultural wastes remain safer than LPG which poses some safety concerns in local transport and use;
It is easy to handle and transport;
Low impact on women’s time for harvesting
Agricultural wastes are much easier to light than wood and charcoal.

[top] [end]Disadvantages

It is responsible for extreme cases of air pollution when it is burned in open fires or traditional or Improved stoves.
It is very bulky and has to be carried to the homes.
The seasonal availability of crop residues can be limit for its use.
Its burning time is worse.
Its storage requires more space in house.

[top] [end]Devices

Although the world rice production is important, particularly in developing countries, where it is cropped by family exploitation, its residue is widely used as fuel for cooking. In countries where rice production is important, such as Thailand and the Philippines, improved cooking stoves are made.

Improved cooking stoves used in Thailand : the Meechai, improved rice-husk stove without chimney.

The Meechai

The mayon turbo stove disseminated by REAP Canada

Mayon turbo stove (Photo: REAP Canada)

Mayon turbo stove (Diagram: REAP Canada)

[top] [end]External links and references

http://www.ashdenawards.org/winners/mrhp
http://www.reap-canada.com

[top] [end]Contributors

User:Grant Ballard-Tremeer 1 September 2003
User:Dr Karabi Dutta 11 September 2003
User: Mamadou Fall 12 July 2007

Categories: Fuels| Agricultural residues

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Page created: 01 September 2003; Last edited: 22 August 2007; Version: 7
Knowledge Bank text is available under the terms of the GNU Free Documentation License.

Pagename: AgriculturalResidues @HEDON: KCAA