Rubberwood as biomass fuel: why supply is predictable, and what limits it

Rubberwood has an advantage no other biomass feedstock in Thailand has: predictable supply. It comes from the replanting cycle, not a harvest season. It also has constraints that have to be managed honestly.

Why rubberwood differs from other biomass

Most agricultural residues — rice husk, bagasse, palm bunches — arrive with the harvest. Every year has a glut and a shortage.

Rubberwood comes from felling plantations that have finished their tapping life, which happens continuously and can be forecast from the age of the trees. A rubber tree yields economically for roughly 20–25 years, then has to come out.

With 22.6 million rai planted nationally and 13.6 million in the South, the volume from replanting is large enough to support industry.

Which part becomes what

Good logs go to sawmills and furniture, where they fetch far more than fuel.

Branches and offcuts are the main chip feedstock.

Stumps and roots are dense and burn well, but the soil has to come off first.

Sawdust from mills makes good pellet feedstock because it is already fine.

The distinction matters: two suppliers can both say "rubberwood" and mean different parts, with different calorific values and ash levels.

The advantages

More consistent than mixed wood waste, because it is one species at a similar age. Mixed offcuts swing in calorific value depending on what happened to arrive that week.

Close to the user. Most Southern plants are within a few hours of the feedstock.

No competition with food land. It is a by-product of a crop grown for latex, not something planted to burn.

The challenges

Moisture is high and seasonal. Wood felled in the rainy season is noticeably wetter, affecting both calorific value and the tonnage that fits on a truck.

Soil contamination, especially from stumps and roots. Poor screening means high ash and fast equipment wear.

Competition from the timber trade. When furniture prices are good, quality logs go there and less remains as fuel.

Logistics. Biomass is bulky; freight is a large share of delivered cost, and beyond a certain radius it stops working.

What actually decides whether a project works

Not whether there is enough wood. These three:

1. Distance from the feedstock. Every kilometre carries cost.
2. Screening capability. The single biggest lever on ash and equipment life.
3. Batch-to-batch consistency. More useful than an attractive average.

Our plant is in Trang, in the middle of the Southern planting belt, and screens every batch before processing. See delivery coverage or call +66 92 392 2292.