PKS are the shell fractions or fragments left after crude palm oil has been extracted from fruit bunches and palm kernel oil has been squeezed from palm nuts. Across the 17,000-island archipelago that’s Indonesia – the world’s foremost palm oil producing nation – and Malaysia, several thousand hillocks of these fibrous shells rise up behind palm oil mills every year.
These unsightly and unhygienic remnants attract swarms of insects that can lay waste to sprawling plantations. They are also potential fire hazards, because of the methane they produce if left to decompose.
In the past, palm oil mills would hire contractors to clear away the PKS – often, they took the cheap and easy way out by just dumping it all in rivers, the sea, or in open fields.
Biomass is a collective term for all plant and animal material that can be burned or digested to produce energy. Examples of biomass include wood, sawdust, straw, poultry litter, and energy crops such as willow and poplar.
In 2011, having recognised the potential of renewable energy – and the opportunity of reducing emissions from coal burning by replacing it with biomass – we started buying PKS in bulk from palm oil mills in Indonesia and Malaysia, and then selling it to power producers across the region.
An August 2020 study conducted by Peterson Projects & Solutions Singapore states:
“Due to the ongoing growth of demand for palm oil and palm kernel oil, there is an abundance of PKS available, for which there is no use or application of relevant scale or value, except its use as a biofuel, where it offers immense emission reduction potentials, especially in economies, which still rely heavily on fossil fuels, in particular coal.
As was shown, the relative value of PKS compared to the other process outputs has remained constant over the past 20 years and it seems unlikely that mills focus a lot on the palm kernel shell value in their production planning. The risk of palm kernel shell procurement leading to additional deforestation can be minimised through a sustainable sourcing strategy, engaging in supplier screening and considering suppliers’ certificates.
PKS should be seen as a viable input for bioenergy generation, which can significantly reduce the demand for traditional inputs for thermal power plants and provide important baseload power.”
Unlike renewable energy sources such as the sun and wind – which are intermittent, unpredictable, and difficult to handle – electricity from biomass such as PKS is available round the clock, and can be turned on and off as required (in industry parlance, this is referred to as ‘base load’ capacity). Be it their constitution, supply-chain logistics, heating properties, or impact on the environment, there are many reasons why PKS are better than traditional biomass such as rice straw, husk and corn stalks.
Being fibrous in nature, PKS can be collected in mostly uniform sized fragments and small fibres – this facilitates simpler bulk handling and transportation with minimal processing.
Resembling natural biomass pellets, PKS require almost no additional processing to prepare for combustion – all that’s required is screening for foreign matter and drying under the sun or under shelter to the desired moisture specification.
Upon drying, PKS moisture levels go down to 20%, which, coupled with their chemical composition, yields a high calorific value of 3,500kcal/kg – the same as that of low-grade thermal coal!
When used as a substitute for, or in combination with, fossil fuels, PKS slashes pollutants and greenhouse gas emissions.
Moreover, other than the carbon dioxide they produce while being transported, their combustion, too, produces less nitrogen oxide and sulphur oxide than with coal burning.
PKS are rapidly gaining acceptance as a replacement and complementary biomass option in power plants across the globe.