Biomass energy potential in Thailand

Shin-ya Yokoyamaa, Tomoko Ogia, Anan Nalampoonb

aNational Institute for Resources and Environment, 16-3, Onogawa, Tsukuba, Ibaraki, 305-8569, JapanbRoyal Forest Department, 61 Phaholyothin Road, Chatuchak, Bangkok, 10900, Thailand

Received 5 May 1998; accepted 30 August 1999

Abstract

Estimation of biomass energy potential including biomass residue and forestry biomass in Thailand was carried

out taking into account the amount of biomass residue which has already been used and the possibility of biomassenergy plantation in accordance with the National Plan of the Thai Government. According to this estimation, 65PJ can be derived from agricultural and forestry waste and 770 PJ can be generated if half of the area allocated for

cultivation of plantation forests could be used for biomass energy plantations. Today, biomass energy is 810 PJ,which is 30% of the total primary energy. 7 2000 Elsevier Science Ltd. All rights reserved.

Keywords: Biomass; Biomass energy; Forestry residue; Agricultural residue; Thailand

1. Introduction

Biomass energy has been attracting attentionfrom the viewpoint of carbon dioxide mitigationby replacing fossil type fuel. If biomass is grownin a sustainable manner, its production and usecreates no net accumulation of carbon dioxide inthe atmosphere, because the carbon dioxidereleased during combustion is o�set by the car-bon dioxide biochemically ®xed by photosyn-thesis. Along with this context, IPCC report [1],for example, focuses on the biomass energy plan-tation to mitigate carbon dioxide in the atmos-phere. According to the BI (Biomass-Intensive)Variant of LESS (Low-Emissions Supply System)

scenario [2] of IPCC report, biomass plays a

major role (especially as a feedstock for methanol

and H2 production and power generation),

accounting for 72 EJ (Exa joule=1018 J) or 15%

of primary energy in 2025 (47% of biomass for

power generation) and rising to 325 EJ or 46%

of primary energy by 2100 (29% of biomass for

power generation) in the BI Variant.

If the productivity (50 t�haÿ1�yÿ1) [3] and heat-

ing value (20 GJ/ton) of fast growing Eucalyptus

are applied to the above-mentioned scenario,

720,000 km2 is required in 2025 and 3.25 million

km2 in 2100, respectively. Since the productivity

of biomass (50 t�haÿ1) is almost double the aver-

age commercial yield of Eucalyptus, the nearly

Biomass and Bioenergy 18 (2000) 405±410

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doubled land area is required if an average com-mercial yield is applied. It is understood by thisestimation that a wide area has to be used forenergy plantation to produce primary energyfrom biomass.

However, to the contrary, the forests are beingdestroyed in these tropical and subtropicalregions; according to the FAO Report [4], about100,000 to 150,000 km2 are converted annuallyto non-forest land. This is mainly due to shiftingagriculture in South-east Asian countries, pastu-rage in Latin America, and gathering wood forfuel in Africa. In addition to these problems withdeforestation, a large area is being converted toindustrial and residential areas due to industrial-ization and urbanization in most developingcountries. Consequently, it is important to surveyhow much biomass is available, and at the sametime, how much land is also available in spite ofthe increasing deforestation.

With respect to the biomass residue, it hasbeen reported that a considerable amount of bio-mass residue has a great potential to be substi-tuted for fossil fuels. Hall and co-workers [5]reported that 111 EJ per year, about one-third ofthe total primary energy commercially used in1985 in the world, is generated from forestry andagricultural residue. However, not all residuegenerated can be used for energy as they havepointed out.

The most signi®cant potential sources of bio-mass for energy are forestry and agricultural resi-due at present and in the future from forestrybiomass from managed energy plantations. Inthis paper, estimates of the available amount ofbiomass residue were made by examining theagricultural and forestry residue data as well asagricultural products in Thailand. Furthermore,an estimation of the available biomass energy byplantation was made by assuming that the landfor reforestation is fully or partly used for energyplantation in accordance with the National Socialand Economic Plans of the Thai Government [6].

2. Energy potential of biomass residue in Thailand

According to the Thailand Energy Situation

1994 published by the Department of EnergyDevelopment and Promotion, Thailand's totalprimary energy supply in 1994 amounted toabout 2700 PJ (65.82 Mtoe; million tons oilequivalent, 10,000 kcal/l equivalent in oil), anincrease of 11% over the previous year, of which58.4% came from indigenous sources and 41.6%from imported sources as shown in Table 1.

The total production of renewable energy orbiomass energy in 1994 was 810 PJ (19.4 Mtoe),an increase of 9.3% over the previous year,accounted for 51.6% of the total indigenousenergy production. It is noteworthy that hydro-power, geothermal, solar, and wind energies areexcluded from renewable energy in the data. Asseen in Table 1, biomass energy including fuelwood, rice husk, and bagasse were a major con-tribution to the primary energy supply, makingup more than half as regards the indigenousenergy source. The total energy of biomass was810 PJ (19.348 Mtoe). Table 2 shows the detailsfor biomass energy: fuel wood was dominant(83.7%), followed by bagasse (13.8%) and ricehusk (2.5%). Fuel wood includes both woodused directly and as a raw material for the pro-duction of charcoal.

The energy content of biomass residue wasestimated from the data of crop-to-residue ratio,moisture content, and heating value of residue ofselected agricultural products. Table 3 shows theenergy content of the biomass residue. The pro-duction of rice was 18.447 Mt in 1994. Rice huskand rice straw were generated from paddy. Bhat-tacharya et al. [7] reported that the rice-to-huskratio was 0.267 and rice-to-straw ratio was 1.695on an air-dried basis. The heating values of thesetwo types of residue were assumed to be 16.3 GJ/t on a dry basis, being the same value as reportedby Hall et al. [8]. The energy content of rice huskand rice straw was 70.3 and 445 PJ, respectively.For sugar cane, the production in 1994 was37.569 Mt. The sugar cane-to-bagasse ratio wasassumed to be 0.29 on the basis of a 5-year studyby the National Energy Administration [6]. Themoisture content of bagasse was taken to be49% [9] and the heating value was 17.33 GJ/t [7].The energy content is thus estimated to be 96.3PJ. Similar procedures were taken for corn cob

S. Yokoyama et al. / Biomass and Bioenergy 18 (2000) 405±410406

and cassava stalk to calculate their energy con-tent [7,8]. Although biomass residue other thanthose listed in Table 2 has to be taken into con-sideration, the coconut shell and husk, palmfrond, old fruit trees, cotton stalk, cassava stalk,groundnut shell were neglected since their pro-duction is relatively small.

Table 4 shows the biomass energy consump-tion of industrial sectors in Thailand. From thistable, it can be seen that biomass energy plays animportant role in industry together with fossilfuel. Particularly biomass is utilized by the foodand beverage industries. Since the ®nal consump-tion of biomass energy in industrial sectors was162.7 PJ (3.891 Mtoe) in Table 4 and the totalbiomass energy was 480 PJ (11.477 Mtoe) asgiven in Table 2, we can see one-third of the bio-mass energy is consumed in industrial sectorsand two-thirds in the domestic sector.

By comparing Table 2 with Table 3, we cansee bagasse is completely utilized as an energysource, while rice straw seems to have a greaterpotential. However, rice straw is already used asan industrial raw material for ®bers in pulp pro-duction. It is also extensively used as animalfeed, compost, and soil conditioner on agricul-

tural land. Rice husk is also utilized as ®ller inthe brick-manufacturing industry and as beddingmaterial for animals. Corn cobs are used aswood charcoal additives and animal feed.

For sawdust, only a small portion is usedas dumping material for land®ll in sawdustmounds in the charcoal making. Taking thisinto consideration, there is not a great poten-tial for these agricultural wastes as energysources, but all of the types of residue are notfully utilized. It is reasonable to assume that10% of total residue is e�ectively used asenergy or an extra 65 PJ can be produced.

If we enhance the improvement of e�ciency ofenergy conversion for ®nal use, biomass can beutilized more e�ciently. Overend [10] reportedthat the most of bioenergy used in cooking deli-vers only 5±8% of its heat to the cooking potand improved cook stoves could move this e�-ciency into the 20% region. He also stated thatan industrial ¯uidized bed in a combined heatand power mode can attain a net e�ciency ashigh as 75%. In Thailand one-third of biofuel isused in the industry sector, while two-thirds areemployed in the domestic sector. If e�ciency ofenergy conversion in domestic use can be raised

Table 1

Energy balance in Thailand (1994)a

Fossil energy A A

Total biomass Domestic (B) Import (C) A+B A+B+C

Total primary energy supply 810 (19,378) 761 (18,197) 1181 (28,244) 0.52 0.3

Total ®nal consumption 480 (11,477) 1853 (44,335) ± 0.26

a Reference: Thailand Energy Situation 1994 [unit: PJ(M toe)].

Table 2

Biomass energy in Thailand (1994)a

Fuel wood Charcoal Rice husk Bagasse Total biomass energy

Total primary energy supply PJ(k toe) 16,221 (678) 7 (0.3) 483 (20.2) 2667 (111.5) 19,378 (810)

Total ®nal consumption PJ(k toe) 3,902 (163) 4,458 (186.3) 450 (18.5) 2,667 (111.5) 11,477 (480)

a Reference: Thailand Energy Situation 1994 [unit: PJ(k toe)].

S. Yokoyama et al. / Biomass and Bioenergy 18 (2000) 405±410 407

from 8 to 20% by introducing improved cookingstoves and cooking utensils such as the ¯at pan,an additional 64.5 PJ can be generated (810 PJ�2/3� 0.12=64.5 PJ).

3. Energy potential of biomass plantation

The forest area of Thailand is presently133,521 km2. The yearly change of the forestarea of Thailand can be seen in Table 5. Forestarea decreased drastically after 1973 when thepopulation increased steadily at an annual rate ofone million people. Deforestation is mainly dueto the transformation of forest land into agricul-tural area producing cash crops and the shiftingculture by hilltribe people. As compared to thistrend of deforestation, the Thai Government hasset forth a national forest policy as given inTable 6. Due to the rapid deterioration of the en-vironment incorporated with the increasingawareness of the Thai Government and its peopleregarding the greenhouse e�ect and global warm-ing, the 7th NSDEP (National Social and Econ-omic Development Plans 1992±1996) emphasizednature conservation and environmental protec-tion more than the previous plans. The pro-portion between conservation and productionforests has been reversed over past plans [6], i.e.,5/8, of the whole reserved forested land will beallocated for conservation purposes whereas pro-duction areas will share only 3/8 of the remainingreserved forested land of about 77,000 km2.

The Thai Government is encouraging the pri-

vate sector including the local farmers to grow

more trees. The Royal Forest Department distri-

butes millions of tree seedlings to the people free

of charge each year expecting that they will be

another source of timber or fuel wood in the

near future. The tree species are various; eucalyp-

tus, pine trees, teak, rose wood depending on the

local situation.

According to this plan, it is expected that 15%

of the country area (77,000 km2) plus private

farm lands and idle areas are the maximum po-

tential for energy plantations. We assume half of

this area (38,500 km2) can be used for biomass

energy plantation because the production forest

has to be used for pulp and paper as well as tim-

ber production. When we assume the appropriate

value for productivity and heating value of

wood, we can estimate the energy potential from

biomass plantation each year. The average pro-

ductivity of fast-growing trees such as Eucalyptus

or hybrid poplar is assumed to be 10 dry

t�haÿ1�yÿ1 and the heating value of wood is

assumed to be 20 GJ/dry ton. For the pro-

ductivity of biomass, this value is regarded as

valid on average in Thailand because much

higher productivity of wood has been reported

elsewhere [11]. We calculated from multiplication

of the area, productivity, and heating value that

770 PJ can be produced each year equivalent to

50% of total domestic energy in 1998. There is a

trend that domestic energy is shifting from bio-

mass residue to natural gas and kerosene with

Table 3

Energy of biomass residue

Production

(kton)

Residue Residue coe�cient Production

(kton)

Moisture content Dry weight

(kton)

Energy content

(PJ)

Rice 18,447 Rice husk 0.267 4925 0.124 4314 70.3

Rice straw 1.695 31,268 0.127 27,297 445

Sugar cane 37,569 Bagasse 0.29 10,895 0.490 5556 96.3

Corn 3800 Corn cob 0.273 1037 0.0753 959 17.0

Cassava 19,091 Cassava stalk 0.088 1380 0.30 1176 20.8

Wood 1548 Saw dust 0.1 155 0.20 124 2.0

Total 80,455 ± ± 49,960 ± 39,426 649.4

S. Yokoyama et al. / Biomass and Bioenergy 18 (2000) 405±410408

increasing incomes and changes in lifestyle inThailand. Thus biomass residue collected in alarge scale will be e�ciently used for power gen-eration in future.

Acknowledgements

The authors are grateful for Professor S. C.Bhattacharya of Energy Program, Asian Instituteof Technology for his valuable discussions on theagricultural residue in Thailand.T

able

4

Energyconsumptionin

industrialsectors

inThailand(1994)a

Coalandlignite

Petroleum

Naturalgas

Electricity

Biomass

Total

Foodandbeverage

4.3

(103)

25.8

(618)

±(±)

16.3

(389)

149.2

(3569)

195.6

(4679)

Textile

1.9

(46)

24.0

(573)

1.2

(29)

19.6

(470)

±(±)

46.7

(1118)

Loggingandfurniture

±(±)

1.6

(39)

±(±)

2.2

(53)

0.5

(11)

4.3

(103)

Pulp

andpaper

19.1

(457)

6.0

(145)

±(±)

3.9

(94)

±(±)

29.1

(696)

Chem

istry

5.8

(139)

12.2

(291)

9.1

(219)

17.0

(407)

6.1

(147)

50.3

(1203)

Non-m

etal

96.0

(2296)

35.4

(848)

12.9

(309)

15.8

(377)

6.9

(164)

166.9

(3994)

Metal

1.8

(42)

12.5

(298)

±(±)

9.3

(222)

±(±)

23.4

(562)

Metalprocessing

±(±)

4.7

(112)

1.1

(26)

15.3

(365)

±(±)

21.0

(503)

Others

0.9

(23)

39.7

(949)

±(±)

3.6

(87)

±(±)

44.2

(1059)

Total

129.8

(3106)

161.9

(3873)

24.3

(583)

103.0

(2464)

162.7

(3891)

581.7

(13,917)

aunit:PJ(ktoe).

Table 5

Change of forest area in Thailand

Year Forest area (km2) % of country are

1960 277,082 54.0

1973 222,281 43.3

1976 198,422 38.7

1978 175,224 34.1

1983 154,028 30.0

1985 150,856 29.4

1988 143,826 28.0

1990 141,110 27.5

1993 133,521 26.0

Table 6

Reservation of forest land in the NSEDPa

Forest area (%)

NSEDP Period Planned (%) Existing

I 1962±1966 50 52

II 1967±1971 50 48

III 1972±1976 50 42

IV 1977±1981 50 34

V 1982±1986 40 30

VI 1987±1991 40 28

VII 1992±1996 40 28

a NSEDP (National social and Economic Development

Plans).

S. Yokoyama et al. / Biomass and Bioenergy 18 (2000) 405±410 409

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