2.1. Current Practices and Production of First Generation Biofuel
The production of biofuels in Thailand increased more than ten-fold within five years from 2005 to 2010, and the share of its production in the Asia Pacific region increased considerably from around 6% in 2005 to 19% in 2010 [
9] (
Figure 1). Ethanol is produced in Thailand mainly by the fermentation of molasses, a by-product of sugar manufacturing and cassava (also known as tapioca); while biodiesel is manufactured by transesterification of vegetable oil, mainly palm oil [
10]. Ethanol blended with gasoline (petrol), is called gasohol.
Figure 1.
Biofuel production in Thailand in the Asia Pacific [
9].
Figure 1.
Biofuel production in Thailand in the Asia Pacific [
9].
Sugarcane and cassava are the base crops for ethanol production, while palm oil and jatropha are used for biodiesel production. Sugarcane can be directly used to produce ethanol, whereas molasses, a by-product during sugar production, is fermented by yeast to produce ethanol [
11]. Molasses-based ethanol dominates ethanol production in Thailand, amounting to 1.17 million liters/day in 2011, up 54.5% from the 2010 average production of 0.76 million liters/day. This accounts for 80% of the country’s total ethanol production [
12]. Cassava-based ethanol production was 0.28 million liters/day in 2011, down 12.8% from the average 0.33 million liters/day in 2010, due to record high cassava prices [
13].
The biodiesel production was favored by increases in the harvested palm crop area by 33,600 hectares in 2008, 48,700 ha in 2009 and an estimated 45,000 ha in 2010, compared to the annual target of 80,000 ha [
12]. In spite of fluctuating Crude Palm Oil (CPO) yield, it is estimated that the CPO production should be enough to meet demand for use in biodiesel production [
14]. The government is also promoting jatropha production by encouraging small farmers to grow it on small tracts of land without affecting their primary cash crops [
3].
Figure 2 shows the quantities of various feedstocks for biofuel production in Thailand during 2006–2011.
Figure 2.
Feedstock use for ethanol and biodiesel production in Thailand [
14].
Figure 2.
Feedstock use for ethanol and biodiesel production in Thailand [
14].
The prioritization of sugarcane, cassava, oil palm and jatropha as feedstock is primarily based on their production potential, which is dependent on soil characteristics, climate, water availability, the farming system and farm management. Apart from the biophysical conditions, other socio-economic and environmental parameters, such as competing uses of biofuel crops, the threat to food security, economic risks to producers and small farmers, and the impact on land use and climate change are also considered (
Table 2). Among the four basic feedstocks of biofuels, oil palm appears to have negative impacts on food security, farm practice issues, land use and marginalization of small farmers.
2.1.1. Ethanol Production
Although ethanol and biodiesel were promoted at the same time in Thailand, ethanol had penetrated the market successfully before biodiesel, because of its feedstock supply readiness [
15]. The Thai government set the National Ethanol Program and Gasohol Strategic plan on December 6, 2003 with an ethanol production target of 1.0 million liter/day by the end of 2006 and of 3.0 million liters/day by the end of 2011. At the same time, the government also made provisions for excise tax incentives, investment promotion incentives to manufactures of ethanol and promotion for ethanol [
16].
Table 2.
Qualitative basis for prioritizing biofuel crops in Thailand [
3]
Table 2.
Qualitative basis for prioritizing biofuel crops in Thailand [3]
Feedstock | Social Risks | Economic Viability | Environmental Impact |
---|
Uses as Food, Feed and Fuel | Threat to Food Security | Risks to Primary Producers | Marginalization of Small Farmers | Changes to Existing Farming Practices | Land use Change and Potential for Conflicts | Favorable Impact on Climate Change |
---|
Sugarcane | Competing | Little | Yes | No | No | No | No |
Cassava | Competing | Little | No | No | No | No | No |
Oil Palm | Competing | Considerable | Yes | Possible | Yes | Yes | Yes |
Jatropha | Competing | Little | Yes | No | No | Yes | Yes |
Ethanol production further increased in line with an upward trend in domestic gasohol consumption following its relatively cheaper price compared to regular gasoline. Unlike biodiesel, the government did not regulate compulsory use or sale of gasohol to substitute regular gasoline. Instead, gasohol prices remained 10%–15% below regular gasoline prices due to the excise tax, plus a price subsidy for E20 and E85 (a mixture of 85% ethanol and 15% premium gasoline) gasohol derived from the State Oil Fund and increasing the number of gasoline stations that could accommodate E20 gasohol [
17].
Although ethanol production steadily increased over the years, it fell short of achieving the target production of 3.0 million liters/day in 2011. The actual production was only around 1.42 million liters/day (
Figure 3). The consumers have substituted both gasoline and gasohol for the highly-subsidized liquefied petroleum gas (LPG) and natural gas vehicles (NGVs) [
13]. However, ethanol consumption is likely to continue its growth, due to an increase in the number of E20 vehicles and E20 gasohol stations and the government’s tax incentives for eco-car manufacturers, and as the price subsidy for E20 and the phase out of gasoline 91 from the market bear fruition.
2.1.2. Biodiesel Production
Thailand began a campaign to promote biodiesel production and consumption in 2005, but the initial production of biodiesel was insignificant until February 1, 2008, when the government adopted a policy requiring replacing all regular diesel with B2 biodiesel (a mixture of diesel with 2% biodiesel) [
12]. Due to compulsory use of B100 (pure biodiesel) for B2 biodiesel production and increased B5 biodiesel demand, B100 production increased in 2009 and 2010.
Figure 3.
Ethanol and biodiesel production in Thailand and 15 year Alternative Energy Development Plan (AEDP) target [
8,
14].
Figure 3.
Ethanol and biodiesel production in Thailand and 15 year Alternative Energy Development Plan (AEDP) target [
8,
14].
Although, it is mandatory to regular diesel with biodiesel, the production has fallen short of the targeted production of 3 million liters/day in 2011 (
Figure 3), as the actual production in 2011 was only around 1.72 million liters/day, mainly due to under-targeted planting of palm oil trees and unpredictable weather patterns [
14]. However, biodiesel production is expected to grow significantly, due to the mandatory B5 rule (a mixture of diesel with 5% biodiesel) that came into force in January 2012 and growing diesel consumption.
The production trend for ethanol and biodiesel in Thailand has been increasing over the years. The number of registered biofuel plants (
Table 3) has increased and so has their production efficiency. However, it is not clear whether the current trend is likely to meet the government’s long-term target. Both ethanol and biodiesel production fell short of achieving their targeted production in 2011, and future compliance to the target not only depends on climatic conditions for crop yield, but also to a greater extent on the government’s incentives, which affect the price difference, blending rates and consumption preference. According to Preechajarn and Prasertsri [
14]:
Although the production of ethanol is likely to increase with the operation of new ethanol plants, the consumption level of ethanol depends on whether the government is able to completely suspend all Octane 91 regular sales as planned.
Five out of the total six refineries are not ready to shift from Octane 91 regular gasoline production to gasohol production by October 2012 and have been negotiating with the government to delay the plan until 2014 or else the government will have to subsidize the additional costs of imported petroleum products for gasohol production during their production restructuring process.
In the case of biodiesel, although the number of biodiesel plants has remained constant since 2010, increased production of biodiesel is likely due to the compulsory mandate of B5 that came into force in January 2012.
However, the productivity of fresh fruit bunches of crude palm oil is estimated to drop in 2012 as a result of dry conditions and a natural reduction in productivity a year after palm plantations reaped record yields in 2011.
2.2. Estimated Potential and Production of Second Generation Biofuel from Agricultural Residues
Thailand with its agriculture-based economy employs agricultural wastes and by-products for the generation of biofuels using commercially viable technologies. According to the Department of Alternate Energy Development and Efficiency (DEDE), the potential of electricity generation through biomass resources in Thailand is 4,400 MW and that for ethanol and biodiesel are estimated at 6–10 million liters/day and 4–5 million liters/day, respectively [
18]. Although the study by DEDE does not specify which particular agricultural residues and by-products are utilized to estimate the potential, other studies indicate that bagasse (a by-product of sugar production) and rice husk (the remains from rice milling), with a total energy content between 560–620 PJ, are the major biomass used for energy production in Thailand [
19,
20]. We have estimated that by using 20% of available agricultural residues alone, there exists the potential to produce between 3.1–8.6 million liters/day of ethanol and 2.1–5.7 million liters/day of biomass to Fischer-Tropsch (F-T) diesel (
Table 4). These values were derived by assuming a 365 day/year operation for biofuel (bioethanol and biomass to F-T diesel) production amounts in
Table 4
Table 3.
Number of registered biofuel plants in Thailand since 2006 [
14].
Table 3.
Number of registered biofuel plants in Thailand since 2006 [14].
Year | No. of approved/registered ethanol plants | No. of approved/registered biodiesel plants |
---|
No. of bio-refineries | Combined production capacity (million liters/day) | Capacity in use (%) | No. of bio-refineries | Combined production capacity (million liters/day) | Capacity in use (%) |
---|
2006 | 5 | 0.78 | 48 | 3 | 0.6 | 1 |
2007 | 7 | 0.96 | 54 | 5 | 1.3 | 14 |
2008 | 11 | 1.6 | 58 | 9 | 2.3 | 53 |
2009 | 11 | 1.7 | 65 | 14 | 5.4 | 31 |
2010 | 19 | 2.9 | 40 | 13 | 5.4 | 34 |
2011 | 19 | 2.9 | 50 | 13 | 5.4 | 32 |
2012 | 21 | 3.7 | 51 | 13 | 5.4 | 44 |
Bioenergy from agricultural residues is acknowledged as possessing favorable sustainability benefits, notably greenhouse gas emissions (direct and indirect), net energy balances, water consumption and usage, food security and biodiversity [
21,
22,
23,
24]. Sustainable extraction rates of agricultural residues are influenced by edaphic factors (
i.e., soil type, soil fertility), land slope, tillage, cutting height, crop yield, weather and wind patterns [
25,
26,
27]. For example, findings from a Canadian study show that the sustainable extraction rate of agricultural residues could range from 44% to 64% [
28]. The actual amount of residues that could be sustainably extracted in Thailand would require further analysis to be determined by edapho-climatic studies. However, for this study, we assume a more conservative extraction rate of 20% for bioenergy applications, requiring balance for maintaining soil health and function and other utilizations in some sectors, such as animal fodder,
etc.In this study, we estimated the potential availability of sustainably-derived agricultural residues based on the information [
29] to contribute to transportation fuels in Thailand from the following major crops—maize (
Zea mays), rice (
Oryza sativa), sorghum (
Sorghum bicolor), sugarcane (
Saccharum officinarum), wheat (
Triticum aestivum), cocoa (
Theobroma cacao), coconut (
Cocos nucifera) and coffee (
Coffea arabica) (
Table 4). Herein, we have quantified the technical potential for biofuel production via biochemical ethanol (enzymatic hydrolysis and fermentation) conversion, as well as diesel production (thermochemical syngas to Fischer-Tropsch diesel) (
Table 4)
Our analysis shows that approximately 10.4 × 106 (10.4 million) bone-dry tonnes per year of agricultural residues to be potentially available for biofuel production (based on a 20% residue extraction rate).
Using the conversion factors [
30], our estimation indicates that the potential for ethanol production per year from agricultural residues is in the range of 1.14–3.12 billion liters. This would be sufficient to offset 25.1%–68.5% of Thailand’s (year 2011) national consumption of gasoline as transportation fuel (
Table 4,
Table 5). Alternatively, 0.8–2.1 billion liters per year diesel (biomass to F-T diesel) could be technically produced from agricultural residues to displace 5.7%–15.1% of its transportation diesel utilization in the year 2011 (
Table 4,
Table 5). Our estimated values are comparable to and consistent with a potential of 6–10 million liters/day of ethanol and 4–5 million liters/day of biodiesel calculated by the Department of Alternative Energy Development and Efficiency (DEDE) [
18]. However, the likely growth and development of the cellulosic ethanol sector based on agricultural residue feedstock could result in increased competition over resources from other utilization, such as for animal fodder and cooking fuel. Previous work [
31] recommends that targeted policies would be required to help achieve sustained access to available cheap feedstock, thereby ensuring long-term sustainably of the biofuel industry.
The government of Thailand is also promoting research and pilot projects for the development of second generation biofuels, generated from non-food feedstock, such as ligno cellulosic biomass from agricultural residues and waste. According to the Energy Policy and Planning Office and the Department of Alternate Energy Development and Efficiency, the total amount of crop and wood residues in Thailand in the year 2002–2003 was about 47.8 Mt, which would have been enough to replace 130% of the then gasoline consumption and 17% of Thailand’s crude oil imports through biofuel production [
32]. A facility using a molasses-based ethanol plant has opened a second production line using second-generation biofuels in the form of cane bagasse as a pilot project with the production of 10,000 liters/day bioethanol, which will be increased to its full capacity of 120,000 liters/day once fully developed [
14].
However, full commercialization of second generation biofuels will be years away without significant additional government support. Unprofitable large-scale production due to relatively high production costs, the need for technological breakthroughs to make the processes more cost-and energy-efficient and additional development of a whole new infrastructure for harvesting, transporting, storing and refining biomass are some of the challenges for second generation biofuel production in Thailand [
33]. The development and monitoring of large-scale demonstration projects and more investment in research, development, demonstration and deployment is needed to move forward to second generation biofuel production and to ensure it can be undertaken sustainably [
33].
Table 4.
Estimated technical potential of second generation biofuel production from agricultural residues in Thailand (Source: Authors).
Table 4.
Estimated technical potential of second generation biofuel production from agricultural residues in Thailand (Source: Authors).
Agricultural Residuesa | Production (tonnes/year) | Residue Type | Residue to Product Ratio (RPR)b | Moisture Content (%)c | Residue (wet tonnes/year) | Residue (dry tonnes/year) | Residue, 20% Sustainable Extraction (dry tonnes/year) | dBiochemical Ethanol (million liters/year) | eBiomass to Fischer-Tropsch Diesel (million liters/year) |
---|
Low | High | Low | High |
---|
Maize | 4.45 × 106 | Stalk | 1.5 | 15 | 6.68 × 106 | 5.68 × 106 | 1.14 × 106 | 125 | 341 | 85.2 | 227 |
Rice | 3.16 × 107 | Straw | 1.5 | 15 | 4.74 × 107 | 4.03 × 107 | 8.06 × 106 | 886 | 2,420 | 604 | 1610 |
Sorghum | 5.40 × 104 | Stalk | 2.62 | 15 | 1.42 × 105 | 1.20 × 105 | 2.41 × 104 | 2.65 | 7.22 | 1.8 | 4.81 |
Sugarcane | 6.88 × 107 | Bagasse | 0.3 | 75 | 2.06 × 107 | 5.16 × 106 | 1.03 × 106 | 114 | 310 | 77.4 | 206 |
Wheat | 1.10 × 103 | Straw | 1.2 | 15 | 1.32 × 103 | 1.12 × 103 | 2.24 × 102 | 0.0247 | 0.0673 | 0.0168 | 0.0449 |
Cocoa | 7.63 × 102 | Pods, Husk | 1 | 15 | 7.63 × 102 | 6.49 × 102 | 1.30 × 102 | 0.0143 | 0.0389 | 0.0097 | 0.0259 |
Coconut | 1.30 × 106 | Shell | 0.6 | 10 | 7.79 × 105 | 7.01 × 105 | 1.40 × 105 | 15.4 | 42.1 | 10.5 | 28 |
Coffee | 4.90 × 104 | Husk | 2.1 | 15 | 1.03 × 105 | 8.74 × 104 | 1.75 × 104 | 1.92 | 5.24 | 1.13 | 3.5 |
Total | | | | | | | 1.04 ×107 | 1,140 | 3,120 | 781 | 2,080 |
Table 5.
Estimated biofuel potential in relation to Thailand’s transportation fuel consumption. F-T, Fischer-Tropsch (Source: authors).
Table 5.
Estimated biofuel potential in relation to Thailand’s transportation fuel consumption. F-T, Fischer-Tropsch (Source: authors).
| Potential feedstock sustainably extracted (dry million tonnes/year)a | Estimated bioethanol production (billion liters/year) | Percentage of national (year 2011) gasoline consumption it could potentially displace | Estimated biomass to F-T diesel production (billion liters/year) | Percentage of national (year 2011) diesel consumption it could potentially displace |
---|
Agricultural residues (year 2010 data)a | 10.4 | 1.14–3.12 | 25.1%–68.5%b | 0.8–2.1 | 5.7%–15.1%c |