BMP testingBy-products of the agri-food industry

Oil palm empty fruit bunches — BMP: 2 studies, weighted mean 179 m³ CH₄/t VS

Oil palm empty fruit bunches (EFB) are a fibrous, lignin-rich waste of oil mills; digestion is slow and benefits from pretreatment.

CH₄ ≈ 52 % (estimate)

Published 7 March 2025Updated 29 October 20263 min readFeedstockData Editorial Team

Photo CEphoto, Uwe Aranas / Wikimedia Commons, licence CC BY-SA 3.0, source file; changes: cropping

Weighted mean: 179m³ CH₄/t VS
Range: 169–189m³ CH₄/t VS
Records: 2studies
Publications: 2sources
Temperatures: 40 °C, 55 °Cof the test

Methane in biogas

≈51–54% CH₄

Medium methane content · ≈ 5.2 kWh/m³ of biogas

estimate from the substrate type The collected studies contain no measurement. The interval follows from the approximate composition (carbohydrate-dominated (no protein or fat characteristics)) and the yields of compound groups according to FNR.

How we calculate it and what the zones mean

Rating for biogas plants

not rated — editorial rating for biogas plants

Not rated: no dry matter or volatile solids in the data. We calculate the rating when the dry matter and volatile solids of the material are known.

Editorial rating per the methodology

Add to the co-digestion calculator CSV data

BMP curves from 2 studies

Weighted mean Individual records

Dashed lines are a model curve (first-order kinetics, B(t) = B₀·(1 − e^−kt)); the end point comes from the publication. All curves are model curves.

Cumulative methane production over the test [m³ CH₄/t VS]. The thick line is the weighted mean of all records (179); dots mark the end values given in the publications. Point at the chart to read values; click a legend item to hide or show a record.

Records and sources

Download CSV

Source	BMP m³ CH₄/t VS	Temperature	Sample	Curve
Chanthong et al. (2024) DOI	169	40 °C · mesophilic	raw empty fruit bunch (EFB)	end point (model curve)
Saelor et al. (2024) DOI	189	55 °C · thermophilic	untreated oil palm empty fruit bunches (EFB), thermophilic	end point (model curve)
Weighted mean	179	arithmetic mean 179, SD 14

Process properties

fibrous
slowly degrading
low in nitrogen
carbon-rich
high dry matter
seasonal
editorial classification

Low confidence: the description is based on general characteristics of the substrate group, not on studies of this material. Treat it as a hint to be verified.

Advantages

Methane potential in the Substraty.pl BMP set: weighted mean 179.2 m³ CH₄/t VS (SD 14.4; 2 records, 2 sources).
Empty oil palm fruit bunches (EFB): a dry and durable material with no acidification risk, which does not load the system with VFA (Hendriks and Zeeman 2009).

Drawbacks and risks

The fibrous structure clogs feeding (Poh and Chong 2009: EFB as solid mill waste).

Co-digestion — what to combine it with, what to watch out for

combines well
substrates: high alkalinity (buffer) — e.g. Cattle manure, Pig slurry, Cattle slurry, Duck slurry, Rumen and digestive tract content
Slurry supplies N and alkalinity, balancing the high C/N of the material.^[1][2]
combines well
substrates: protein-rich — e.g. Food waste, Municipal sewage sludge (mixed), Poultry manure, Organic fraction of municipal solid waste, Grass clippings
The high C/N of the material balances protein substrates, limiting the ammonia risk.^[1][3]

Dosing

No source limits on the dose for this substrate.

Introduce gradually, starting with a small dose and monitoring the process (e.g. FOS/TAC, pH, gas composition).

Practical requirements

Shred: shredding increases the surface available for degradation and speeds it up, but does not necessarily raise the final gas yield (FNR 2010, Ch. 3 “Triturado”).
Control floating crust and sediment: when solids are fed directly into the digester, the risk of their formation depends on the substrate (FNR 2010, Ch. 3).

Sources of the process data

The co-digestion calculator will assess a specific mixture containing this substrate.

What it is and where it comes from

Empty fruit bunches (EFB) are the largest stream of solid biomass in palm oil mills. They arise after the fruit has been separated from the bunches, and their quantity is considerable in relation to the mass of fruit processed. They are burned, composted, used as mulch or used to produce solid fuels. There is no palm oil production in Poland, so the material is known mainly from the literature.

Properties relevant to digestion

EFB is a classic lignocellulosic material: it contains a lot of cellulose and hemicellulose and a high share of lignin, and at the same time relatively little soluble sugar and protein. The fibrous structure hinders access by enzymes, so hydrolysis is slow and the yield in a short test limited. The material contains a small amount of residual oil. A high C/N ratio requires the addition of nitrogen, for example from POME or manure. The risk of acidification is small, but clogging of feeding systems because of the fibrous structure is significant.

How to read the spread of results

The dataset contains several records from several sources: raw EFB at 40 °C and EFB without pretreatment under thermophilic conditions at 55 °C. The results are close to one another. Even so, differences in temperature, inoculum, size reduction and test duration may matter, because with lignocellulosic materials ending the test too early underestimates the result. The degree of maturity of the bunches and their moisture content also have an effect.

In biogas plant practice

EFB requires size reduction, and in industrial installations also pretreatment (steam, alkaline, biological), which increases the availability of cellulose. Dosing in a mixture with POME or manure stabilises the process. Competition from other uses, such as fuel or compost, affects profitability. For installations in Poland the material has no practical significance, but it is a good model for other lignocellulosic wastes.

Because of the large quantity of EFB in oil mills, the material is the subject of numerous studies on pretreatment. Results for raw EFB should therefore be treated as a reference point for assessing the extent to which pretreatment raises the yield relative to unprocessed material.

Methodology in brief

BMP is the amount of methane obtained from volatile solids (VS) in a batch test, given in m³ CH₄ per tonne of VS (numerically the same as NmL CH₄/g VS in the publications) and converted to normal conditions (0 °C, 101.325 kPa). The weighted mean gives each publication a total weight of 1, split equally between its results for the substrate — a paper testing twenty varieties does not outweigh a paper with a single sample. In inter-laboratory programmes the unit is the laboratory (total weight 1), and within it the weight of a test grows with the number of bottles (replicates). Results after pretreatment (e.g. thermal, chemical, enzymatic) are shown separately and are not included in the mean.

Solid lines are curves measured in the tests. Where a publication gives only the final result, we draw a first-order kinetic model, B(t) = B₀·(1 − e^−kt): only the end point comes from the publication, and the shape of the curve serves purely as visualisation — do not read the production on a particular day from it. For this substrate k = 0.091 d⁻¹ was assumed (no kinetic data for the group – the median of all available rate constants k (93 values) was used).

The statistics describe the spread of published results — a descriptive compilation, not a meta-analysis or a guarantee of plant yield.

Full methodology and correction policy

Bibliography

All sources of the site: bibliography.