PKS From Africa Can Fuel Biomass Power Plants in Japan

Japan’s biomass fuel requirement is estimated to be tens of millions of tons each year on account of its projected biomass energy capacity of 6,000MW by the year 2030. To achieve this capacity, more than 20 million tons of biomass fuel will be needed every year which will be mainly met by wood pellets and palm kernel shell (PKS). The similarity of the properties of wood pellets with PKS makes PKS the main competitor of wood pellets in the international biomass fuel market.

PKS-biomass

PKS has emerged as an attractive biomass commodity in Japan

Canada and USA are the biggest suppliers of wood pellets to the Japanese biomass market while PKS mainly comes from Indonesia and Malaysia. With the size of the material almost the same as wood pellets, but at a cheaper price (almost half the wood pellets) and also available in abundance, PKS is the preferred biomass fuel for the Japanese market. PKS can be used 100% in power plants that use fluidized bed combustion technology, while wood pellets are used in pulverized combustion.

Although there is abundant PKS in CPO (crude palm oil) producing countries, but fluctuations in CPO production and increase in domestic demand has led to reduction in PKS exports in Southeast Asia. In palm oil plantations, it is known as the low crop season and peak crop season. When the low crop season usually occurs in the summer or dry season, the supply of fruit to the palm oil mills decreases so that the CPO production decreases and also the supply of PKS automatically reduces, and vice versa in the peak crop season. When demand is high or even stable but supply decreases, the price of PKS tends to rise.

In addition, a wide range of industries in Indonesia and Malaysia have also began to use PKS as an alternative fuel triggering increased domestic demand. In recent years, PKS is also being processed into solid biomass commodities such as torrified PKS, PKS charcoal and PKS activated carbon. Thus, there is very limited scope of increasing PKS supply from Southeast Asia to large-scale biomass consumers like Japan and South Korea.

Palm oil mills process palm oil fruit from palm oil plantations, so the more fruit is processed the greater the PKS produced and also more processors or mills are needed. At present it is estimated that there are more than 1500 palm oil mills in Indonesia and Malaysia. Palm kernel shells from Indonesia and Malaysia is either being exported or used domestically by various industries. On the other hand, in other parts of the world PKS is still considered a waste which tends to pollute the environment and has no economic value.

Palm Oil Producers

Top palm oil producers around the world

West African countries, such Nigeria, Ghana and Togo, are still struggling to find a sustainable business model for utilization of PKS. Keeping in view the tremendous PKS requirements in the Asia-Pacific region, major PKS producers in Africa have an attractive business opportunity to export this much-sought after biomass commodity to the Japan, South Korea and even Europe.

Simply speaking, PKS collected from palm oil mills is dried, cleaned and shipped to the destination country. PKS users have special specifications related to the quality of the biomass fuel used, so PKS needs to be processed before exporting.

PKS-export

PKS exports from Indonesia and Malaysia to Japan are usually  with volume 10 thousand tons / shipment by bulk ship. The greater the volume of the ship or the more cargo the PKS are exported, the transportation costs will generally be cheaper. African countries are located quite far from the Asia-Pacific region may use larger vessels such as the Panamax vessel to export their PKS.

An Introduction to Biomass Harvesting

Biomass harvesting and collection is an important step involving gathering and removal of the biomass from field which is dependent on the state of biomass, i.e. grass, woody, or crop residue. The moisture content and the end use of biomass also affect the way biomass is collected. For crop residues, the operations should be organized in sync with the grain harvest as it occupies the centrestage in farming process.

biomass-harvesting

All of other operations such as residue management and collection take place after so-called grain is in the bin. On the other hand, the harvest and collection dedicated crops (grass and woody) can be staged for recovery of the biomass only. In agricultural processing, straw is the stems and leaves of small cereals while chaff is husks and glumes of seed removed during threshing.

Modern combine-harvesters generally deliver straw and chaff together; other threshing equipment separates them. Stover is the field residues of large cereals, such as maize and sorghum. Stubble is the stumps of the reaped crop, left in the field after harvest. Agro-industrial wastes are by-products of the primary processing of crops, including bran, milling offal, press-cakes and molasses. Bran from on-farm husking of cereals and pulses are fed to livestock or foraged directly by backyard fowls.

The proportion of straw, or stover, to grain varies from crop to crop and according to yield level (very low grain yields have a higher proportion of straw) but is usually slightly over half the harvestable biomass. The height of cutting will also affect how much stubble is left in the field: many combine-harvested crops are cut high; crops on small-scale farms where straw is scarce may be cut at ground level by sickle or uprooted by hand.

Modern combine-harvesters generally deliver straw and chaff together

Collection involves operations pertaining to gathering, packaging, and transporting biomass to a nearby site for temporary storage. The amount of a biomass resource that can be collected at a given time depends on a variety of factors. In case of agricultural residues, these considerations include the type and sequence of collection operations, the efficiency of collection equipment, tillage and crop management practices, and environmental restrictions, such as the need to control erosion, maintain soil productivity, and maintain soil carbon levels.

The Logistics of a Biomass Power Plant

Biomass logistics involves all the unit operations necessary to move biomass wastes from the land to the biomass energy plant. The biomass can be transported directly from farm or from stacks next to the farm to the processing plant. Biomass may be minimally processed before being shipped to the plant, as in case of biomass supply from the stacks. Generally the biomass is trucked directly from farm to the biomass processing facility if no processing is involved.

biomass_logistics

Another option is to transfer the biomass to a central location where the material is accumulated and subsequently dispatched to the energy conversion facility. While in depot, the biomass could be pre-processed minimally (ground) or extensively (pelletized). The depot also provides an opportunity to interface with rail transport if that is an available option. The choice of any of the options depends on the economics and cultural practices. For example in irrigated areas, there is always space on the farm (corner of the land) where quantities of biomass can be stacked.

The key components to reduce costs in harvesting, collecting and transportation of biomass can be summarized as:

  • Reduce the number of passes through the field by amalgamating collection operations.
  • Increase the bulk density of biomass
  • Work with minimal moisture content.
  • Granulation/pelletization is the best option, though the existing technology is expensive.
  • Trucking seems to be the most common mode of biomass transportation option but rail and pipeline may become attractive once the capital costs for these transport modes are reduced.

The logistics of transporting, handling and storing the bulky and variable biomass material for delivery to the biopower plant is a key part of the biomass supply chain that is often overlooked by project developers. Whether the biomass comes from forest residues on hill country, straw residues from cereal crops grown on arable land, or the non-edible components of small scale, subsistence farming systems, the relative cost of collection will be considerable.

Careful development of a system to minimize machinery use, human effort and energy inputs can have a considerable impact on the cost of the biomass as delivered to the biomass processing plant gate.

The logistics of supplying a biomass power plant with consistent and regular volumes of biomass are complex.

Most of the agricultural biomass resources tend to have a relatively low energy density compared with fossil fuels. This often makes handling, storage and transportation more costly per unit of energy carried. Some crop residues are often not competitive because the biomass resource is dispersed over large areas leading to high collection and transport costs.

The costs for long distance haulage of bulky biomass will be minimized if the biomass can be sourced from a location where it is already concentrated, such as sugar mill. It can then be converted in the nearby biomass energy plant to more transportable forms of energy carrier if not to be utilized on-site.

The logistics of supplying a biopower plant with sufficient volumes of biomass from a number of sources at suitable quality specifications and possibly all year round, are complex. Agricultural residues can be stored on the farm until needed. Then they can be collected and delivered directly to the conversion plant on demand. At times this requires considerable logistics to ensure only a few days of supply are available on-site but that the risk of non-supply at any time is low.

Losses of dry matter, and hence of energy content, commonly occur during the harvest transport and storage process. This can either be from physical losses of the biomass material in the field during the harvest operation or dropping off a truck, or by the reduction of dry matter of biomass material which occurs in storage over time as a result of respiration processes and as the product deteriorates. Dry matter loss is normally reduced over time if the moisture content of the biomass can be lowered or oxygen can be excluded in order to constrain pathological action.

To ensure sufficient and consistent biomass supplies, all agents involved with the production, collection, storage, and transportation of biomass require compensation for their share of costs incurred. In addition, a viable biomass production and distribution system must include producer incentives, encouraging them to sell their post-harvest plant residue.