Editor: Due to the length of this article, only a portion is included in ECHO Asia Notes. The full article, including illustrated steps related to the assembly of 200- liter drum kilns as well as charcoal and wood vinegar production, can be accessed via the web link here.
Until recently, firewood was taken for granted in northern Thailand. With vast forests full of many types of trees, upland households could afford to be choosy concerning the wood they used for cooking.
However, in recent years, more and more communities are facing restricted access to forest products due to the establishment of national parks. In many areas, deforestation caused by agricultural activities, such as the encroachment of large plantations, is also resulting in declining access to firewood.
In upland communities, commercial types of cooking fuel like propane are not readily accessible or affordable. With limited options, communities and development organizations have begun considering alternative fuels.
The Upland Holistic Development Project the Thailand affiliate of Plant with Purpose has been exploring alternative cooking fuels. Biogas and gasifier stoves hold promise, but UHDP staff members have observed that many of their focus communities are not ready to adopt these specific approaches, partially due to the cost of materials and equipment.
Charcoal is the third alternative cooking fuel being evaluated. The potential switch to charcoal is not too drastic, since local families are already very aware of the fuel. Small "bucket" cooking stoves favored by hilltribe families are generally affordable and can accommodate both firewood and charcoal. These stoves average 300 baht (the current exchange is 29 baht Thai to $1.00 US).
The Charcoal Option
But how does the heating value of charcoal stack up against firewood? According to a 1987 article by J.D. Keita, FAO Regional Forestry Officer, the heating value of wood is generally around 3500 Kcal/kg for green wood and 4500 to 4770 Kcal/kg for dry wood. Charcoal, however, has a heating value near 7500 Kcal/kg. Keita states further that, "Although carbonization causes a loss of energy, the charcoal produced gives a higher yield in use than wood. Thus, the thermal energy yield of wood is, on average, 8 percent and can even go as low as 5 percent with the popular three-stone African stove. Charcoal has a thermal energy yield of about 28 percent (Unasylva, No. 157-158)."
Energy from biomass (biological or renewable sources) includes direct wood fuel such as firewood and charcoal and plays an important role throughout the developing world. Almost two-thirds of Asia-Pacific's population is rural, and among them, traditional biomass remains the most important source of energy (Gumartini, p.16). Although projections through 2020 show an overall declining trend for wood fuel consumption in the region, an increasing trend is expected for charcoal. According to Gumartini, the growing use of charcoal is due to increased income and urbanization (p. 19).
Kittichai Sumpansinkor, UHDP technician responsible for field research and development, states that for charcoal to be readily accepted by families in the project's focus area, it must be available, inexpensive, easy to use and of good quality. In Thailand's north, although the consumption of composite charcoal (made from carbonized, compressed wood aggregates) is growing, traditional lump charcoal is still common, produced from the wood of culled litchee (Litchi chinensis) and longan (Dimocarpus longan) trees as well as select forest species.
The cost of good quality lump charcoal currently averages 13 baht per kg. UHDP's C o-Director, Jamlong Pawkham, estimates that the expense breaks down to approximately 4.40 Thai baht for the preparation of each household meal. This cost potentially adds up to 400 baht per month. With monthly household incomes in UHDP's focus area rarely exceeding 4000 baht ($138 US), such expense for cooking fuel exceeds what most families are willing to pay. Sufficient quantities of charcoal are also difficult to transport into remote upland communities.