Palm Kernel Shell (PKS) — oil palm shell for heat plants and industry
If you manage fuel procurement at a municipal heat plant or at an industrial site with a fluidised-bed boiler, the last three seasons have made one thing clear: your biomass portfolio has to be diversified. A1-grade wood chips can cost twice as much at the peak as they do at the bottom, industrial pellet out of the Baltic is exposed to the EUR/USD rate, and domestic cereal straws come with their own seasonal windows. Palm Kernel Shell (PKS) — the shell of the oil palm nut — has been a fixture in this puzzle for several years now, even if it is still not as obvious a choice as wood chips.
We are writing this from a practitioner's perspective. BGT imports PKS from Indonesia and West Africa (Ghana, Nigeria, Côte d'Ivoire), handles containers through Gdynia and Gdańsk, and delivers material by rail and road to professional power generation sites. We hold the KZR certificate — without it, a conversation with the fuel department at any larger heat plant is a non-starter. This post is hard technical data, indicative prices and logistics — not a leaflet.
Below you will find a parameter summary, a comparison with wood, the boiler requirements every process engineer asks about, and a FAQ section covering the questions we field most often from new clients.
What PKS actually is
Palm Kernel Shell is the hard, woody shell surrounding the kernel of the oil palm fruit (Elaeis guineensis). Once palm oil is extracted and the kernel is recovered at the mill, the shell fraction is what remains — from the oil palm sector's point of view it is a by-product, but from the energy sector's point of view it is a high-energy, homogeneous solid fuel with low moisture.
The material arrives at port in its raw form: it is neither pelletised nor briquetted. It looks like coarsely broken, dark-brown to black fragments of nut shell, with a typical grain size of 5–25 mm. This matters — PKS requires no drying or additional processing before being burnt in a fluidised-bed boiler, which sets it apart from fresh forest chips.
Where the material comes from
- Indonesia — the world's largest palm oil producer, mainly Sumatra and Kalimantan. Year-round availability, the widest choice of suppliers, with typical loading ports being Belawan, Dumai or Balikpapan.
- Malaysia — comparable in quality to Indonesian material, but export volumes of PKS are smaller and heavily contested by local power plants.
- West Africa (Ghana, Nigeria, Côte d'Ivoire) — an increasingly important origin for Europe. Shorter sea transit than from South-East Asia, and a growing number of certified mills.
BGT deliberately blends origins to shield clients from local disruptions — monsoon season, shipping embargoes, port stoppages.
Technical parameters — what to expect
Without a parameter table no serious fuel offer stands up, so hand this straight to your operations department:
| Parameter | Typical value | Method |
|---|---|---|
| Calorific value (LHV, ar) | 18–21 MJ/kg | PN-EN ISO 18125 |
| Total moisture (ar) | ≤ 15% | PN-EN ISO 18134 |
| Ash (db) | 3–5% | PN-EN ISO 18122 |
| Volatile matter (db) | 65–72% | PN-EN ISO 18123 |
| Elemental carbon (db) | 48–52% | PN-EN ISO 16948 |
| Sulphur (db) | < 0.1% | PN-EN ISO 16994 |
| Chlorine (db) | 0.1–0.3% | PN-EN ISO 16994 |
| Bulk density | 550–650 kg/m³ | PN-EN ISO 17828 |
| Particle size | 5–25 mm | — |
A few points deserve emphasis:
- Calorific value — PKS is noticeably "stronger" energetically than wood chips (typically 8–12 MJ/kg as received) and comparable to industrial pellet (16–18 MJ/kg). This reflects its low moisture content and high lignin share.
- Ash — 3–5% is more than in A1 wood (< 1%), but far less than in cereal straw (5–10%). In practice this means more frequent de-ashing, but no revolution.
- Chlorine and potassium — this is the flashpoint (literally). PKS contains more chlorine than forest chips, which during high-temperature co-firing can accelerate chloride-induced corrosion of superheaters. We come back to this in the boiler section.
- Bulk density 550–650 kg/m³ — significantly higher than wood chips (200–300 kg/m³). In practice a 40ft container holds 22–26 t of PKS rather than the 14–16 t of chips. The logistics start to make sense.
KZR certification — a hard prerequisite
For professional power generation in Poland, KZR INiG (or the equivalent ISCC EU) is the condition for including the fuel in the RES balance and for selling green energy. Without the certificate, the material is simply useless to a heat plant trading in green certificates.
In practice this means three documentation layers:
- Plantation/mill certification — RSPO or an equivalent sustainable production scheme.
- KZR/ISCC chain-of-custody certificate — from the mill through the trader to the end user, with mass balance preserved.
- Batch conformity declaration — for every delivery, stating parameters, mass, country of origin and the chain reference number.
BGT supplies the full documentation set with every batch. If someone in a sales conversation waves KZR aside, they are not a partner for your heat plant.
Logistics: container, port, rail
The standard scheme we work with:
Stage 1: sea transport
- Loading at the mill's port (e.g. Belawan, Tema, Lagos), 20ft or 40ft container, big-bag FIBC or in bulk with a liner bag.
- Transit to Gdynia or Gdańsk — typically 35–45 days from South-East Asia, 20–28 days from West Africa.
- Packaging standard: 1 t big bag with PE liner, or bulk loading in a container with a liner bag. No pallets, no unnecessary tare weight.
Stage 2: port handling
Customs clearance, phytosanitary inspection (PKS falls under plant-product regulations), sampling to confirm parameters, reweighing.
Stage 3: inland transport
- Truck — makes sense for deliveries below 500 t/month and for clients within a 300–400 km radius of the port.
- Rail — for volumes from several hundred tonnes per month on a weekly cycle. Self-discharging wagons of the Eas or Uacns type in sets of 15–25 wagons, running directly onto the plant's rail siding. This is the standard solution for professional power generation — 1,000+ t per trainload.
The client receives a CIF Gdynia/Gdańsk offer (if they organise collection from port themselves) or DAP plant-siding (if they want a single "door-to-door" price).
Boiler application — for the process engineer
PKS performs differently depending on the boiler type. A short overview:
CFB/BFB fluidised-bed boilers
The natural application. PKS is uniform in particle size, with a calorific value close to high-energy lignite, and works excellently as a co-fired fuel. Shares of 10–30% by weight in fluidised-bed boilers are routine. Above 30% you need to keep an eye on the bed's chloride balance.
Medium-power grate boilers
PKS can be fed onto a grate, but because of the fine particle size and low moisture, combustion can "run away" — it must be blended with wetter biomass (e.g. wood chips) in a 20–40% PKS ratio.
Pulverised-fuel boilers (large professional power)
Requires milling to a fraction < 3 mm and feeding together with coal. This is already an advanced scenario, requiring burner trials.
Chlorine, potassium and corrosion — the critical point
This is where most first PKS trials come unstuck. Chlorine content in the range 0.1–0.3% at shares > 25% in boilers with steam superheat temperatures > 500°C can, after a season, reveal accelerated corrosion of the superheater tubes. Ways to handle this:
- Keep the PKS share in the mix at 10–25% — a safe zone for most fluidised-bed boilers.
- Sorbent additives (ammonium sulphate, kaolin) to neutralise chlorine in the flue gas.
- Ash composition monitoring — annual testing of ash melting temperature as the mix changes.
If you are starting from zero with PKS, we recommend a trial with a 100–200 t batch, monitoring operation across one season, and only then making decisions on target volumes.
Prices and volumes — indicative
PKS prices move with the palm oil season and with ocean freight. Indicative levels for deliveries into Poland over the last 12 months:
| Delivery basis | Price range (EUR/t) | Note |
|---|---|---|
| FOB loading port (Asia) | 90–130 | depending on month and quality |
| CIF Gdynia/Gdańsk | 140–180 | including sea freight and insurance |
| DAP plant siding (central PL) | 170–210 | including rail transport |
Converted to an energy basis (EUR/GJ), PKS at 140–180 EUR/t CIF works out to 7–10 EUR/GJ, which makes it cheaper than industrial pellet (10–13 EUR/GJ) in most seasons and competitive with A1 chips at price peaks.
Contract volumes: we typically talk from 500 t upwards (one consolidated container load) up to tens of thousands of tonnes per year under framework contracts.
PKS vs wood chips vs industrial pellet — when to use which
A short decision cheat-sheet:
| Criterion | A1 chips | Ind. pellet | PKS |
|---|---|---|---|
| Calorific value ar | 8–12 MJ/kg | 16–18 MJ/kg | 18–21 MJ/kg |
| Ash | < 1% | < 1.5% | 3–5% |
| Moisture | 30–45% | ≤ 10% | ≤ 15% |
| Bulk density | 200–300 kg/m³ | 600–700 kg/m³ | 550–650 kg/m³ |
| Indicative price (EUR/GJ) | 6–12 | 10–13 | 7–10 |
| Chloride corrosion risk | low | low | medium |
| Availability in PL | high, but seasonal | high | full via imports |
Our practical recommendation: PKS as 15–25% of the mix in a fluidised-bed boiler stabilises the fuel price and decouples you from the swings of the wood market, without technological risk. This is the most common model we work in with clients.
Orders: seasonality and contract types
The palm oil market has two production peaks per year — in practice this means PKS is available all year round, but the best FOB prices sit in the months of peak mill production (March–May and September–November).
Contract forms we recommend:
- Annual framework contract with a defined volume and pricing formula (e.g. indexation to FOB Malaysia + freight) — for volumes from 3,000 t/year upwards.
- Quarterly spot contracts at fixed prices — for clients trialling the fuel or running a flexible mix.
- Call-off contract with buffer storage at port — for seasonal heat plants that want the fuel on hand from October.
FAQ — the questions we hear most often
Can PKS be co-fired in a boiler designed for hard coal? Yes, after burner trials and assuming a PKS share of up to around 15–20% by mass. Above that threshold you need to realistically assess the chloride balance and the potential impact on the superheater.
Does PKS need a special warehouse? No. A standard enclosed warehouse or a silo of the kind used for pellet is entirely sufficient. With moisture up to 15% and a low fines share, the self-ignition risk is significantly lower than with fresh wood chips.
How long does the first delivery take? From contract signing to the plant siding, imports from Indonesia typically take 8–12 weeks, and imports from West Africa 5–8 weeks. Subsequent deliveries on a rolling-forecast cycle are much faster.
What is the difference between PKS and sunflower husk or olive pit? All three are agro biomass, but PKS has a higher calorific value (18–21 vs 16–18 MJ/kg) and higher bulk density. Sunflower husk is lighter and more often pelletised; olive pit has similar parameters but limited volume availability.
Do we get a sample before contracting? As standard, yes — a 25 kg bag or a 1 t big-bag for analysis at the client's laboratory. For contract clients we also organise reference visits to heat plants already burning PKS.
Summary and recommendations
If you are looking for a fuel that:
- Stabilises the biomass portfolio and decouples it from wood prices,
- Delivers repeatable batch-to-batch parameters,
- Is logistically scalable (container → rail → siding),
- Meets the KZR requirements for professional power generation,
then PKS is one of the most sensible choices in the 2026/2027 portfolio. Not as the sole fuel, but as a 15–25% share of the mix in a fluidised-bed boiler — with a cost advantage of around 15–25% per energy unit versus industrial pellet, and markedly better repeatability than domestic agro.
Practical steps to get started:
- Take a 25 kg sample and test the parameters in your own laboratory.
- Order the first trial container (around 25 t) and run an operating trial for 1–2 weeks.
- Verify the impact on ash and the ash melting temperature — the decision on an annual contract should only be taken after the trial season.
- Contract on an annual cycle with an indexation clause to limit price risk.
If you would like to talk through a specific boiler specification, volume and schedule — the BGT Sales Team will prepare an offer with the full KZR documentation package and CIF/DAP logistics variants within 48 hours.
