IJERD – International Journal of Environmental and Rural Development (2013) 4-2

Research article
erd

Assessment of Sustainable Energy Potential of NonPlantation Biomass Resources in Sameakki Meanchey
District in Kampong Chhnang Province, Cambodia
VIBOL SAN*
Faculty of Science, Royal University of Phnom Penh, Phnom Penh, Cambodia
Email : san.vibol@rupp.edu.kh, sanvibol@gmail.com

DALIN LY
Faculty of Agro-Industry, Royal University of Agriculture, Phnom Penh, Cambodia

NEANG IM CHEK
Faculty of Science, Royal University of Phnom Penh, Phnom Penh, Cambodia
Received 15 December 2012

Accepted 10 June 2013(*Corresponding Author)

Abstract Biomass has always been a major source of energy for mankind, and accounts
for about 14% of the world’s total energy supply. Biomass is a clean energy resource,
considered neutral on CO2 emissions, that has a high potential for meeting increasingenergy demands as a substitute for fossil fuels. Biomass energy sources are abundant in
Cambodia. We assess the energy potential of the following non-plantation biomass
resources: (1) agricultural residues, (2) animal manure. The production of agriculturalresidues and animal manure was based on the production of crops obtained from the
National Census 2008 and one study site. This information was categorized into: (i)primary residues (paddy straw, sugarcane tops, maize stalks, empty coconut bunches andfronds, palm oil fronds and male bunches etc.) and, (ii) secondary residues (paddy husks,
bagasse, maize cobs, coconut shells, coconut husks, coir dust, saw dust, palm oil shells,
fiber and empty bunches, etc.), and (iii) animal manure. The estimation of residue
generated can be calculated from the residue to product ratio (RPR). To estimate thepotential for deriving additional energy from a residue, it is important to establish thepresent utilization pattern of the residue. The results of energy potential analysis indicatethat agricultural residues could have produced 212.11 GJ in 2010. The total annual
potential of biogas from animal manure in 2006, 2007 and 2008 was 1357.96 thousand m3,
1432.89 thousand m3 and 1452.66 thousand m3, respectively, and the corresponding
energy potential was 29.87 GJ, 31.52 GJ and 31.96 GJ, respectively. If this energy
potential can be developed in order to meet the demand for energy, it can reduce thepressure on natural forests, the impact on human health, especially of women and children,and the amount of greenhouse gas emissions.
Keywords biomass, conservation, energy potential, residues, sustainable energy

INTRODUCTION
Biomass has always been a major source of energy for mankind, and accounts for about 14% of theworld’s total energy supply. The term biomass refers to all organic materials that originate fromliving organisms e.g. wood, agricultural residues, animal manure etc. Biomass sources are therefore
diverse(Bhattacharya et al. 2005). Biomass is a clean energy resource that shows high potential as a
substitute for fossil fuels and to meet the world’s increasing energy demand.
Biomass energy sources are abundant in Cambodia. Fuelwood is the most common source ofenergy for the majority of the population in the Kingdom. Firewood and charcoal are often referred
to as traditional fuels, yet they remain the dominant source of energy for cooking within thedomestic sector, and are used extensively by industry and the service sector. The Statistical
Yearbook 2008 published by the National Institute of Statistics reported that fuelwood was by far© ISERD
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the most commonly used fuel for cooking purposes; 85.0% of Cambodian households in 2007.
Around 98.2 percent of rural households used fuelwood and charcoal.
In Sameakki Meanchey district in Kampong Chhnang province, fuelwood is the main energy
source for cooking, boiling water, preparing animal feed and protecting cattle against insects.
Approximately 96% of the households in the district depend on fuelwood as a primary energy
source for cooking along with other energy types such as charcoal, animal dung, crop residues,
LPG, kerosene, and biogas(San et al. 2012a). Kerosene was the main energy source used by local
people (60.5%) for lighting (San et al. 2012b). Other energy sources used for lighting among the767 households interviewed were rechargeable batteries, 57.9%, and electricity, 5.1%.
Although wood biomass is important for people in Sameakki Meanchey district, nonplantation biomass is an alternative energy source that could reduce pressure on natural forests by
reducing fuelwood dependency for cooking and boiling water and reduce greenhouse gas (GHG)
emissions.
OBJECTIVE
The objective of this study is to assess the sustainable energy potential of the following biomass
resources in Sameakki Meanchey district, Kampong Chhnang province, Cambodia: (i) agriculturalresidues, (ii) animal manure, and (iii) fuelwood saving potential through improved efficiency.
METHODOLOGY
Site description
Sameakki Meanchey District located in the south western Kampong Chhnang Province wasselected as the study area. The district lies in the south of the province and shares a border with
Kandal and Kampong Speu Provinces to the south. The district is subdivided into 9 communes(Khum) and 85 villages (Phum). The total number of households in 2010 was 15,516 households ofwhich the total population was 73,303 people (NCDD, 2010). The average household size was 5.37
(Mode = 5) (San et al. 2012a).
Non-plantation energy potential assessment
This section presents the methodologies used to assess the potential of the different non-plantation
resources considered in this study. These can be categorized into: (i) primary residues (paddy straw,
sugarcane tops, maize stalks, coconut stalks and fronds, palm oil fronds and male bunches etc.) and,(ii) secondary residues (paddy husk, bagasse , maize cobs, coconut shells, coconut husks, coir dust,
saw dust, etc.), (iii) animal manure, and (iv) fuelwood released through efficient improvement. The
production data of each non-plantation biomass resource was obtained from the homepage of the
National Committee of Sub-National Democratic Development (NCDD, 2010).
Primary and secondary residues: The term agricultural residue is used to describe all the organic
materials which are produced as by-products from harvesting and processing of agricultural crops.
Agricultural residues, which are generated in the field at the time of harvest are defined as primaryor field based residues (e.g. rice straw, sugar cane tops), whereas those co-produced during
processing are called secondary or processing based residues (e.g. rice husk, bagasse). The
availability of primary residues for energy applications is usually low since collection is difficult
and they have other uses as fertilizer, animal feed etc. However secondary residues are usuallyavailable in relatively large quantities at the processing site and may be used as captive energy
sources for the same processing plant involving little or no transportation and handling cost. Theenergy potential of various primary and secondary residues was estimated.
Energy potential of the residues: The estimation of residue generated was calculated on the basisof the residue to product ratio (RPR). To estimate the potential of deriving additional energy from aresidue, it is important to establish the present utilization pattern of the residue (Bhattacharya et al.

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1999).
)∑(()

Where ARG is the amount of a residue generated annually (t yr -1), RPR is the residue
production ratio, AH is the annual harvest of the crop or product (t), EPresidue is the total energy
potential of residue (J t-1), SAF is surplus availability factor (dimensionless), EUF is the energy use
factor (dimensionless), and LHVresidue is the lower heating value of residue (J t-1).
Fuel characteristics: Moisture content of residues normally varies widely at different stages of
harvesting and storage. The moisture content of a residue influences its fired heating value andshould be known. A review of RPR values at different moisture content and lower heating values(LHVs) for different residues was carried out by Bhattacharya et al. 1996. The RPR values reportedby them can be used for estimating the energy potential of agricultural residues; however, countryspecific RPR and LHV values should be used wherever possible.
Animal manure: Animal manure is principally composed of organic material, moisture and ash.
Decomposition of animal manure can occur either in an aerobic or anaerobic environment. Underaerobic conditions, CO2 and stabilized organic materials (SOM) are produced. Under anaerobic
conditions, CH4, CO2, and SOM are produced. Since the quantity of animal manure produced
annually can be substantial, the potential for CH4 production and hence energy potential of animal
manure is significant. Energy potential of recoverable animal manure is estimated by Bhattacharya
et al. 1997. A preliminary estimation of energy potential of animal manure was reported by
Bhattacharya et al. 1997. The amount of dry matter from an animal, recoverable fraction of animal
manure, volatile solid fraction, and biogas yield values reported by them, could be used for
estimating the energy potential of animal manure.
Fuelwood released through efficiency improvement: In the household sector, large amounts offuelwood are consumed, normally in inefficient traditional stoves, for cooking and water boiling
purposes. Energy saving through improved cooking stoves is discussed in this paper. A
methodology for estimation of fuelwood released through efficient improvement was reported by
Bhattacharya et al. 1999.
RESULTS AND DISCUSSION
The potential for energy production from crop residues
The main occupation of households in the study is farming. Rice paddy is the main crop in the
study area. The other major crops grown in the study area are corn, peanuts, and cassava. During
the dry season, farmers in the research area could not grow rice because they lacked a water source
for irrigation. Rice production per ha in 2008 ranged from 1ton to 2.5 ton. It is necessary to notethat total production of corn, peanuts and cassava increased in 2007 but declined in the following
year because production demand decreased.
Table 1 Types of crop residues, RPR and calorific value for agricultural residue
Residue
Crop
Rice

Straw,
Rice husks
Corn
Stover, cobs
PeanutStraw, leaves, shell
Cassava
Stalks
Source:(Sajjakulnukit et al. 2005)

Moisture(%)

RPR

Energy use
Factor

8.17
8.83
8.65
---

0.447
0.230
0.250
2.663
0.088

0.000
0.531
0.193
0.007
0.000

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Surplusavailability
factor
0.684
0.469
0.670
0.760
0.407

LHV
(MJ kg-1)(as received)
8.83
12.85
16.63
18.00
16.99

IJERD – International Journal of Environmental and Rural Development (2013) 4-2

The crops grown in the study area produce various types of crop residues. These residues arise
from the harvesting of these crops and their subsequent processing into various products. The data
in Table 1 shows the types of crop residues found at the study site. The estimated energy potential
is performed based on residue product ratio (RPR) and as received caloriﬁc values as shown in
Table 1.
Greater rice production in comparison to other crops in the study area contributed to highavailability of rice residues such as rice husk and rice straw. Rice husk, also called rice hull, is theoutermost layer of the paddy grain. It is separated from brown rice during the first step in the
milling process. The unutilized rice husk mainly causes waste disposal problems and breathingproblems because of its low density but could be an option for biomass energy systems. The use ofrice husk as a solid fuel may be a promising way to avoid these problems and provide considerable
amounts of useful energy (Chungsanguit et al. 2010). Rice straw is another by-product of rice and agreat bio-resource since it is one of the richest materials in terms of its lignocelluloses (Yoswathanaet al. 2010). However, it is important to note that rice straw is also an import fodder for animals in
Cambodia. Table 2 shows the estimated energy potential from agricultural residues in 2008. The
production of agricultural residue is calculated based on the production of crops obtained from the
National Committee for Democratic Development in 2010. Total of estimated energy potentialfrom crop residues is approximately 212.11 GJ in 2008.
Table 2 Energy potential of agricultural residues in 2008
Product
Rice
Corn
PeanutCassava

Residue
Straw,
Rice husks
Stover, cobs
Straw, leaves, shell
Stalks

Production(tonne)31,53735913
95Residue available for energy(tonne)14,097.00
7,254.00
8.75
2,431.32
8.36
Total

Energy potential
(GJ)
85.14
93.21
0.13
33.57
0.06
212.11The potential for energy production from animal manure
In the study area the most important animals are cattle/buffalo, pigs, chickens and ducks. Other
livestock includes goats, sheep and horses, but the numbers are comparatively small. Livestock
farms produce polluting wastes. Traditionally their disposal has been by direct use as fertilizers orin some instances as landfill. These methods cause severe environmental problems such as odour,contamination of water, methane emission etc. The present study focused only on cattle/buffalo,
pigs, chickens and ducks. Livestock populations over three years were obtained from the National
Committee for Democratic Development 2010 (NCDD 2010).
Table 3 Dry matter, recoverable fraction, and volatile solid of animal waste
Number (head)
Animal

2006

2007

2008

Buffalo/cattle
37,922
40,773Pig
15,31913,900Chicken42,40243,368
Duck
2,462
2,780
*Source: (Sajjakulnukit et al. 2005)

40,96015,19046,282
2,151

Fresh Waste*(kg head-1 d-1)

Recoverable
fraction*

12.40
1.50
0.03
0.03

0.50
0.80
0.80
0.40

Dry mater*
(DM)
(%)
17.77
35.22
33.99
26.82

Volatilesolid*
(%)
13.64
24.84
22.34
17.44

Values for different characteristics of animal manures considered in the present study, such as
dry mater, fraction recoverable as well as physical and chemical properties are given in Table 3.
The heating value of biogas is taken as 22 MJ m-3 (IPCC, 2006). The estimated amount of animal
manure recoverable, the potential of biogas production and the total potential of energy fromanimal manure are presented in Tables 4 and 5. The total annual potential of biogas from animal
manure in 2006, 2007 and 2008 is 1357.96 thousand m3, 1432.89 thousand m3 and 1452.66© ISERD
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thousand m3, respectively, and the corresponding energy potential is 29.87 GJ, 31.52 GJ and 31.96
GJ, respectively.
Table 4 Biogas yield and recoverable DM of animal manure
Number (head)
Animal2006
37,922
15,31942,402
2,462

Buffalo/cattle
Pig
ChickenDuck

2007
40,773
13,90043,3682,780

2008
40,96015,19046,2822,151

2006
30499.53
2953.53
157.82
7.23

Recoverable DM(tonne DM yr-1)
2007
2008
32792.51
32942.91
2680.33
2929.08
161.41
172.268.16
6.32

Biogas yield(m-3 kg-1 VS)
0.286
0.217
0.242
0.310

Table 5 Energy potential from animal manure
AnimalBuffalo/cattle
Pig
ChickenDuck

2006
37,922
15,31942,402
2,462

Number(head)
2007
40,773
13,90043,3682,780

2008
40,96015,19046,282
2,151
Total

Amount of biogas(Tm-3 yr-1)
2006
2007
2008
1189.80
1279.25
1285.12159.23144.48157.89
8.53
8.73
9.31
0.39
0.44
0.34
1357.961432.891452.66

Energy potential
(GJ)
2006
2007
2008
26.18
28.14
28.27
3.50
3.18
3.47
0.19
0.19
0.20
0.01
0.01
0.01
29.87
31.52
31.96

Fuelwood saving through efficiency improvement
The New Lao stove, known as the Cambodian improved stove, is the most frequently used stovetype in the study area (33%), followed by the Three Stone stove (18%), the Siam and Lao
Kompong Chhnang stove (13%), the Traditional Lao stove (10%), the Korng Rey stove (9%), theself-made or clay stove (2%) and the Samaki stove (2%) (San et al. 2012a). The study conductedby San et al. (2012) reports that more than 50% and 35% of households in the study area owns 2stoves or 1 stove, respectively. Some households use two different types of stove in their household.
Therefore, we assumed that households were using the same type of traditional stove in theirhousehold in order to calculate fuelwood saving by switching from inefficient traditional cooking
stoves to improved cooking stoves (Table 6). We also assume that all traditional cooking stoves are
replaced by New Lao Stove, which is a more energy-efficient cooking stove. The average fuelwood
consumption rate per family per year for cooking and boiling drinking water in study area is 1.87
and 1.02 tonne (San et al. 2012a).
Table 6 Biomass saving potential in residential cooking and boiling drinking waterType of stoveThree Stone
Siam
Loa Kampong Chhnang
Traditional Loa

Fuelwood
consumption(tonne family-1 year-1)
2.89
2.89
2.89
2.89

Efficiency (%)
Traditional
Improved
stove
stove
10
25
15
25
16
25
11
25

Saving potential
(t)
(GJ)
0.61
0.40
0.36
0.57

27.74
18.50
16.65
25.89

CONCLUSION
All biomass residues including primary and secondary residues have the potential to provide 244
GJ in 2008. Rice straw and rice husks have higher energy potential compared to other crop residues
because of their ready availability in large quantities. Animal manure, which produces 31.96 GJ in2008, is considered to be the main resource for biogas production. Improving the efficiency ofbiomass use for cooking and boiling drinking water through improved cooking stoves can savehuge amounts of fuelwood per family per year. More than 16 GJ per family per year were saved© ISERD
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when local households in the study area switched from inefficient traditional to energy-efficientcooking stoves.
The results of the study clearly indicate that non-plantation biomass residues provide a
promising potential energy source for local people in the study area. If this potential energy source
can be developed to meet their energy demands, it could reduce; the pressure on natural forest, theimpact on human health, especially women and children, and greenhouse gas emissions.
ACKNOWLEDGEMENTS
The authors would like to express their gratitude to The Economy and Environment Program forSoutheast Asia (EEPSEA) for providing financial support. Part of this study was supported by the
MEXT/JSPS KAKENHI Grant Number 24252002 led by Dr. Nophea Sasaki of the University of
Hyogo. The authors also would like to thank to Mr. David Ford for checking this paper.
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