Livestock Research for Rural Development 23 (10) 2011 Guide for preparation of papers LRRD Newsletter

Citation of this paper

Changing waste into an asset: pig biogas in Lao PDR

Sirixai Phanthavongs, Meryl Pearce and Udoy Saikia

The School of the Environment (Geography), Flinders University, Adelaide SA 5001, Australia.


This paper is based on initial findings of research conducted between 2009 and 2010 on the value of raising pigs as a means of poverty alleviation in Lao PDR. The paper provides a comparison of two groups of households, namely those that raise pigs with biogas digesters installed, and households that raise pigs without biogas digesters. The biogas digesters transform the faecal waste matter from the pigs into energy that is used for small scale domestic cooking.


The results show that households that raise pigs with biogas digesters experienced greater social, economic and environmental benefits than those without biogas digesters. Social benefits included a reduction in the time spent collecting fuel wood for cooking, thus providing more time for other productive activities. Furthermore, using biogas as an alternative to fuel wood and charcoal can reduce the amount of greenhouse gas emissions associated with cooking activities and decomposition of animal waste.

Keywords: Fuel wood collection; household cooking


The Lao People’s Democratic Republic (Lao PDR) is a land-locked and mountainous country in Southeast Asia. The population of the country is 6.3 million (World Bank 2010) - 27% of which live in urban areas, and 73% are in rural areas with an average density of 24 persons per km2 (NSC 2007). Almost 80% of the labour force is involved in agricultural or agricultural-related activities (Burgos et al 2008). Four fifths of the total population is involved in farm related activities, of which 59% are subsistence farmers. The agricultural sector including livestock accounted for 41.3% of the Gross Domestic Product (GDP) in 2007. Keeping livestock in the rural areas is seen by the local population as a valuable way to accumulate assets (Burgos et al 2008). In 2006, of the agricultural sub-sectors contributing to the GDP 58.1% was from crops, 34.9% from livestock and fisheries and the remainder from forestry (NSC 2008). Lao PDR is one of the world’s poorest countries and is classified as a least developed country. In terms of poverty, Lao PDR is ranked 133rd of out 177 countries (UNDP 2007).


In 1992 the country signed the United Nations Framework Convention on Climate Change (UNFCCC) and ratified the Kyoto Protocol in 1995, but is not bound by an emissions target. Based on the guidelines of the Intergovernmental Panel on Climate Change (IPCC), a greenhouse gas (GHG) emission inventory was conducted in Lao PDR in 2000 (Moore and Sengdouangchanh 2007, p. 3). The results of the inventory showed that Lao PDR is a net sequester of carbon dioxide with a net annual carbon dioxide removal of 414.900 gigagramme (Gg). Total methane emissions is 312 Gg per annum, of which 81% derives from the agricultural sector.


Although Lao PDR is not bound by a specified emissions target under the Kyoto Protocol, nonetheless, the government is keen to cooperate in addressing all environmental concerns with the international community (Moore and Sengdouangchanh 2007, p. 3). The government of Lao PDR has set a target to electrify up to 90% of all households by the year 2020. According to the Department of Energy Promotion Development, 60% of 952,386 households had access to electricity in early 2008 (Department of Energy Promotion Development 2010). Despite this, a large percentage of the population still uses fuel wood for household cooking and heating because they find it too expensive to use electricity for cooking. Although current data on the use of fuel wood are not yet available, data obtained in 2003 by the Netherlands Development Organization (SNV) showed that 97% of the rural and 68% of urban population continue to use fuel wood as their main source of energy for cooking (Boers and Ghimire 2003). The high consumption of fuel wood challenges the country’s effort to address global GHG emissions and exposes local communities to a future risk of exhausting the wood supply.


Attempts have been made to identify the social, economic and environmental factors that enable farming communities in particular to modify their traditional practices so that they can protect their sustainable livelihood. New cost effective, efficient and environmentally appropriate technologies have been introduced into the agricultural sector. One such technology introduced into Lao PDR is the collection and use of biogas, generated from animal (cow, buffalo, pig) manure, as fuel energy for household cooking. Based on data collected from 81 households in Nongphouvieng village, Vientiane province, this paper outlines the role of biogas as a source of cooking energy and its potential to support sustainable agricultural development in rural Lao PDR.


The study area of Nongphouvieng village is located approximately 51 km south of the capital Vientiane. The village has 252 households with a population of 1,552 people. The main sources of income of the villagers are raising livestock including cows, water buffalos, pigs and others), rice farming, and making alcohol and charcoal for selling. The village was among the first Lao villages in which biogas digesters were installed. Following a visit by the Lao government delegation to biogas projects in China, there was a request from the Lao government to the Chinese government to set up trial biogas projects in Lao PDR. As a result of this request, in March 2004, 30 biogas digesters (linked to existing pig stalls) were installed in 30 households in Nongphouvieng village at no cost to the householders. Then in mid-2007, a SNV biogas project was introduced to an additional 30 households in the village, but householders were required to provide an upfront payment of 50% of the total cost of the materials used in the construction of the biodigesters. Each family paid about 1,800,000 Kip (211.76 USD) towards the capital and instalment costs of their biodigesters. There are currently 60 households in total in the village that have biodigesters.


Before the methane can be harvested at least 8 to 10 pigs are needed to provide the required faecal load to the digester. An intake hole allows the animal faecal waste to be manually fed into the digester daily and an outlet allows for the release of organic matter after some time. This organic matter can be used as bio-fertilizer for plants. The size of 4 m3 of digester can provide up to 15 kg of gas for cooking each day. The biogas digester, where the gas is stored, is built as an underground dome using concrete. On top of the dome is a gas control valve connected to a gas pipe that leads to a gas stove in the kitchen. At the start of the digester setup around 50 bags of animal waste are fed into the digester and after 5 to7 days it will start to generate the gas. The design has a limitation however in that the distance between the location of digester and the kitchen cannot exceed 30 to 50 m as a distance beyond this will cause the gas pressure to be too low.

Materials and Methods

The research is based on a grounded theoretical framework and draws on qualitative and quantitative data collected from interviews with 40 households with biogas digesters (henceforth referred to as group A) and 41 households that raised pigs without biogas collection (group B). The data collection was conducted during 2009 and early 2010.


A number of procedures were required before the data collection could start. Firstly, the cabinet of the Ministry of Agriculture and Forestry was approached to obtain a permit, this was followed by further communication with local authorities and staff involved in the Biogas Pilot Programme, which is under the Department of Livestock and Fisheries and supported by the Netherlands Development Organization (SNV). After obtaining approval from the ministry, then communication with the district office of the Provincial Agriculture and Forestry Office occurred. The agricultural district office appointed an officer to introduce the researcher to a village head to inform the village about the research project and to ask for their involvement in the project. The village head then assigned one person to follow the researcher as a local facilitator as well as to ensure that the research was carried out in the right manner. All these procedures took over a month before data collection could commence.


Consent was obtained from all the participants volunteering in the research. Data were obtained through verbally-guided questionnaires and focus groups. The data were translated into English. SPSS was used for the quantitative data analysis.

Results and Discussion

Fuel Wood and Charcoal Use


The measurement of the amount of fuel wood used was based on how local people collect the wood, that is, by cartload, where one full cartload of fuel wood is equivalent to around 1m3 of fuel wood.  The amount in cubic metres was then converted into kg based on the formula of Walker (Walker 2009). According to Walker (2009) 1 m3 of dry wood is equivalent to a weight of 240 kg and wet wood weighs around 540 kg. Based on these figures, the amounts of fuel wood (in m3) used by local farmers in Nongphouvieng village were converted into kg. Charcoal was measured by bag, where each bag has a capacity of 15 kg. Table 1 provides a summary of the quantities of fuel wood and charcoal used by households (HH) in groups A (households with biogas digesters) and B (households without biogas digesters) in the study and the time spent on cooking-related activities by both groups. Participants in group A were asked to provide information on their fuel wood and charcoal use prior to the installation of the digesters and to compare it with their current practices (Table 1).


Results show that in group A the amount of fuel wood used dropped by 69.30% when the biogas became available. Since the installation of the biogas system, annually group A used around 74.90% less fuel wood compared to group B. The amount of charcoal used within group A households also decreased (by 47.31%) since the installation of the digesters. Group A currently uses 35.36% less charcoal than group B. The reason that group A continues to use charcoal is that local people cannot use a biogas stove for grilling. Nevertheless, on average group A households save up to 416,775 Kip (49.03 USD) each year as a result of the reduction in consumption of fuel wood and charcoal. After biogas installation about 37.50% of households in group A continued to collect fuel wood. Some of the households collect fuel wood for domestic cooking and also for commercial purposes such as making alcohol and charcoal for selling.

Table 1. Impact of biogas installation on household (HH) energy consumption patterns

Energy consumption patterns

Group A: HH before installation of biogas (Situation 1)

Group A: HH after installation of biogas (Situation 2)

Group B: HH without installation of biogas (Situation 3)

Percentage reduction between situation

1 and 2

Percentage change between situations

2 and 3

Fuelwood consumption in kg/year






Charcoal consumption in kg/year






Fuelwood (in kg) per HH per year






Charcoal consumption (in kg) per HH per year






Money spent on fuelwood and charcoal per HH per year (USD)

620,550 Kip

(73.00 USD)

203,775 Kip

(23.97 USD)

447,756 Kip

(52.67 USD)



Number of times wood is collected per HH per year






Social and Environmental Benefits to the Local Community


The households with biogas collection expressed greater financial and time-saving benefits, and environmental benefits such as a reduction in the odours from pig waste since the digesters were installed compared to group B households. As a result of not having to spend time collecting fuel wood and preparing fires twice daily for cooking respondents commented ‘I can turn the biogas stove on to cook anytime I want now’; and ‘I don’t need to sit in front the fire and take care of it anymore’. There were also social benefits detailed by the biogas users. In particular the women said that they were much happier using biogas: ‘my face and hands are not black anymore as I am not using charcoal now’; other participants added ‘now my husband gets up to cook rice in the morning because he likes cooking with the biogas stove’. Environmental benefits were also identified with local people emphasising ‘now our village has become cleaner and there are less bad smells of pig dung’; and ‘there are less flies in the village than before having biogas.’


Economic Benefits to the Local Community


Raising pigs is highly desirable for local people as a means of accumulating assets and also for accessing a fast turn-around in cash gains. A cost-benefit analysis was carried out based on the data from Nongphouvieng village; a summary of the results is given in Table 2.

Table 2. The cost of raising pigs


Unit cost


Total Cost

Purchase 1 piglet

450,000 Kip


450,000 Kip (52.94 USD)

Piglet food 1 bag

17,000 Kip

1 bag

17,000 Kip (2.00 USD)

Pig food (for a pig weighing 15 to 30 kg)

95,000 Kip

3 bags

285,000 Kip (33.53 USD)

Pig food (weighing in excess of 30 kg)

90,000 Kip

2 bags

180,000 Kip (21.18 USD)

Transport of pig food

4,000 Kip

6 bags

24,000 Kip (2.82 USD)

Transport of pig to market

15,000 Kip

1 pig

15,000 Kip (1.76 USD)

Customs fee and animal mobilization authorization fee

14,000 Kip

1 pig

14,000 Kip (1.65 USD)

Vaccination fee

2,000 Kip

1 pig

2,000 Kip (0.23 USD)

Total cost



1,140,000 Kip

(134.12 USD)

After housing for 3.5 months, the pigs can be sold at a price of at least 1,462,500 Kip (172.06 USD). The profit made from a pig after deducting all the expenses is 322,500 Kip (37.94 USD). This amount may not seem much per pig, however, when people raise more pigs such as 20 or up to 40 pigs the profit that they can make after a couple of months was calculated to be between 6,450,000 and 12,900,000 Kip (758.82 USD to 1,517.64 USD) and each year they can sell two generations of pig offspring. From a comparative perspective this profit is regarded as a high income as the average salary of a government employee ranges from 500,000 to 800,000 Kip (58.82 to 94.12 USD) per month. Raising pigs is therefore considered a highly profitable business which attracts local people to the activity. Participants in this study commented ‘I’ve raised pigs for nearly 10 years, I got this house because of raising pigs’; and ‘I got my lod tock tock (farming machine) because I kept pigs’ and ‘Because of pigs I can send my children to school’.


There were secondary economic benefits associated with the organic matter removed from the biogas digester, in that it was used as a bio-fertilizer for rice crops. This not only resulted in improved yields but also in financial savings through not having to buy fertiliser.


A problem associated with the lucrative nature of raising pigs is it has lead to an overstocking of pigs. This is a problem in particular for those with biogas digesters (group A), where the recommended design specifications are that no more than 10 pigs should service one digester. The pigs in group A are housed in a concentrated area to facilitate dung transfer to the digester intake, whereas the pigs in group B can roam more freely. Because of overstocking neighbours of some pig owners complained that ‘it was good only the first year, but now we start getting bad smells again’; and ‘it has such a bad smell it even makes me not want to eat’ and ‘I have a headache because of the dung smell’. Overall however, the feedback from the villagers including group B households was that the installation of biogas digesters in the village was very good and many people looked forward to having one. One respondent commented ‘I saw my neighbour have a biogas digester, now their family life has become more convenient. I want to have the same as them and I am waiting for the biogas project to come again’; others said ‘I want to use biogas, but I am not sure what to do’; and ‘I want to install it [a biogas digester], but I don’t have enough money’.


Calculated GHG Emissions


Additional environmental benefits to using the biogas digesters include a reduction in GHG emissions. While these are not of major relevance to the uneducated subsistence farmer, they nonetheless have implications from a broader environmental perspective.


Applying the formula of Ritter (Ritter 2010) to the quantities of fuel wood and charcoal used by the farmers in Nongphouvieng village (Table 1), the GHG emissions associated with fuel wood, charcoal and biodigester use were calculated.  Based on the formula of Ritter (Ritter 2010), burning a 1 kg log of wood emits 1.65 kg of carbon dioxide. Although the amount of charcoal used by farmers in Nongphouvieng village is less than the amount of fuel wood used, charcoal use generated more carbon dioxide emissions than the burning of fuel wood. According to Reumerman and Frederiks (2002) to produce 1kg of charcoal requires 7 to 10 kg of wood (or an average of 8.50 kg), therefore, the amount of carbon dioxide emitted from using or making charcoal is more than double from fuel wood. A comparison of the calculated carbon dioxide emissions from using fuel wood and charcoal of each group is shown in Figure 1.

Figure 1. Calculated carbon dioxide emissions from fuelwood and charcoal use

Before the installation of biogas digesters it is estimated that households in group A generated almost 380.00 tonnes of carbon dioxide annually from wood fuel and charcoal use; these figures dropped to around 180.00 tonnes, which is a 52% reduction. By comparison group B’s emissions were almost 360.00 tonnes that is almost double that of group A after biogas installation. Interestingly, from a comparative perspective the percentage reduction in carbon dioxide emissions before and after digester installation within group A show that the reduction was higher for fuel wood (69% reduction) than charcoal (47% reduction). Similarly a comparison between group A (after digester installation; situation 2) and group B clearly shows that carbon dioxide emissions from households with biogas installation is around 90.00 tonnes less than households without biogas installation.


According to Meynell (Meynell 1978) the average volume of faecal waste (henceforth referred to as dung) produced by a pig each day is 0.24 m3. This amount produces 0.56 to 0.71 m3 of methane each day (Meynell 1978).


There were 488 pigs in group A and 885 pigs in group B (giving 1,373 pigs in total) as shown in Figure 2. Applying the estimates described (Meynell 1978) above to the 1,373 pigs in Nongphouvieng village yields approximately 329.500 m3 of dung per day. Calculations show that each day the pigs produced up to 768.80 m3 of methane. About 273.20 m3  of methane was thus generated from pigs raised in group A before installation of the biogas digesters and another 495.60 m3 from group B. Pigs are generally raised for about 105 days before they are sold for meat and two sets of offspring can be raised each year. This would have resulted in around 57.30 tonnes of methane being produced from group A before biogas installation and 104.00 tonnes from group B. However, after the installation of biogas digesters in group A (situation 2), around 200 m3 which is equivalent to 42.00 tonnes of methane per year was produced. While the calculated change in methane emissions is small (57.30 versus 42.00 tonnes), nonetheless there are reductions in emissions. From an environmental perspective, however, almost 50.00 m3 per day or around 10.00 tonnes of methane is released into the atmosphere each year from pigs in one small village alone. Furthermore, more biogas is produced than can be consumed by individual households, with the excess gas released, unused to the atmosphere, while others in the village (group B pig owners) do not have access to the excess biogas. Design limitations mean that the biogas cannot be used beyond individual households (due to inadequate pressure in the system, as outlined earlier).

Figure 2. Calculated methane production from pigs in Nongphouvieng village



Flinders University and AusAid for funding the research; the Ministry of Agriculture and Forestry of Lao PDR; the Department of Livestock and Fisheries; and the Biogas Pilot Project teams. The head of Mai Park Nguem District, the head of Nongphouvieng village, the village masons and the local facilitator who assisted with organising and conducting interviews; and the interviewees for their participation in the study.


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Received 15 September 2011; Accepted 19 September 2011; Published 10 October 2011

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