EFB Pellets as Biomass Fuel Transition from PKS to Wood Pellet Energy Plantations?

The high demand for palm kernel shells or PKS makes their availability or supply increasingly limited. The properties of palm kernel shells or PKS which have many similarities to wood pellets make them the main competitor for biomass fuel in the global market. The high demand for palm kernel shells is not only because the price is usually cheaper than wood pellets, but also the large availability can be achieved because of the large number of palm oil mills, also especially the many new biomass power plant developments that can use 100% palm kernel shells, namely biomass power plants with fluidized bed combustion (CFBC or BFBC) technology, read more details here. 

Under these conditions, efforts to obtain new biomass fuel become important. The palm oil industry itself produces a lot of biomass waste so it has potential as raw material for new biomass fuel. One of the biomass wastes that has not yet been utilized and is large in volume and has the potential to pollute the environment is palm oil empty bunches or EFB (empty fruit bunch). Every ton of crude palm oil or CPO production will produce approximately 1 ton of EFB waste. This means that with an average palm oil mill capacity of 45 tonnes of FFB/hour, around 10 tonnes/hour of crude palm oil (CPO) will be produced and 10 tonnes/hour of EFB waste. So, for example, if a palm oil mill operates 20 hours/day, approximately 200 tons of EFB waste will be produced/day. And with the number of palm oil mills in Indonesia estimated at 1,000 units, the amount of EFB waste will also huge.

PKS and EFB are both biomass waste from palm oil mills. Both can be easily obtained from palm oil mills in abundant quantities. PKS can even be used directly as biomass fuel, whereas EFB requires pre-treatment first. The EFB that comes out of the palm oil mill is very wet and the shape and size still need to be adjusted to make the follow-up process easier. EFB pellet production is a solution for EFB waste. But apart from that, so that this EFB pellet product can be used more widely or like wood pellets in general, there is an additional process to reduce the amount of mineral content in the ash.

Meanwhile, wood pellets from energy plantations could become the next source of biomass fuel, although currently someone has already started doing so. Because the raw material for EFB pellets is palm oil mill waste and is abundant, it requires a smaller investment, so EFB pellets can be used as transitional biomass fuel before biomass fuel in the form of wood pellets from energy plantations. Investing in land and its preparation as well as creating an energy plantation costs a lot of money. But the advantage of wood pellets from this energy plantation is that the availability of raw materials, even in very large volumes, can be more guaranteed. Apart from that, there are also other benefits from using the leaves as animal feed, especially ruminants and the flowers for honey bee farming.

Case Study India: Priority of Biomass Pellet Production Over Biomass Briquette

There are dozens of biomass briquette machine manufacturers in India and almost all of these machine manufacturers use mechanical press technology for the production of these briquettes. With this technology, briquettes will be formed due to mechanical press such as repeated strokes every minute (about 220 strokes per minute). This briquette machine manufacturer industry has also existed for decades in India so that biomass briquette products have also been widely known in India. Technically, there are actually 2 other technologies for the production of biomass briquettes, namely screw press and hydraulic press. Based on the briquette production technology, the briquette product output is also slightly different, for more details, read here.

The Indian government launched a decarbonization program at their coal power plants, recently, namely on October 8, 2021 which ordered the use of 5% to 10% biomass pellets for cofiring at all power plants and took effect in October 2022 or one year is the target time set. For example, in the early stages, the Indian government targeted only 5% for the cofiring ratio in their coal power plants, where the 5% figure when translated into biomass pellet production would reach around 50 million tons of biomass pellets per year. A very large number especially with a very short target time. And with a cofiring ratio of 5%, coal power plants also do not need to modify their equipment even though the biomass pellets used come from agricultural wastes, whose quality is below that of woody biomass.

With the number of power plants reaching about 900 units with an average consumption of 50 thousand tons of biomass pellets per year or a total of almost 50 million tons per year, so that a biomass pellet factory with a capacity of around 5 thousand tons / month seems to be suitable, and even if each factory supplying one power plant, the need for a biomass pellet plant will also be the same as the number of power plants, which is 900 units. A huge amount.

Production of biomass briquettes or biomass pellets?
In India, biomass briquette is indeed more popular than biomass pellets, but for the world level pellets are much more popular than briquette, even in 2021 alone, the need for pellets for global power generation alone is estimated to have reached 23 million tons. In addition, the production or pellet factory in general is also larger than the briquette factory. There are many pellet factories with a capacity of 5 thousand tons or even 10 thousand tons per month, while for briquettes it is very rare for a biomass briquette factory to have a capacity like the pellets above. Pelletisers for pellet production for commercial capacity have a capacity of 3 tons/hour or more, while briquette machines are generally less than 2.5 tons per hour, even for the screw press type the average machine capacity is only 300 kg/hour. Technically, even though they are both products of biomass densification technology with the difference that the size of the briquettes is larger than pellets, the production of briquettes is easier than pellets. 

The driving force from the business side makes biomass pellet production more attractive, especially because of its need as cofiring fuel in coal power plants as part of the decarbonization program. The need for biomass pellets can be a driving force for the production of biomass pellets or in general, namely the economy in various regions. The program should also be able to provide three benefits at once, namely environmental, social and economic. In addition, because briquette products are mainly used for boilers in industry, while pellets are for power generation, both of them also have their own market segments so that there is no market competition.

What about the Briquette Machine Manufacturing Industry?
Dozens of industries producing biomass briquette machines should now see this as an opportunity so that they can respond to it. These industries can adapt by creating a new line of business, namely helping the manufacture of a biomass pellet factory. Technically, the biomass briquette production line with biomass pellets also has many similarities (both use biomass densification technology) with the main difference being the pelletiser and briquetter. A number of equipment that can be made themself will reduce imported machines. Pelletisers are almost certain to be imported, so the selection of pelletisers as the heart of the pellet production process must be of high quality so that the pellet production target can be achieved. In the production of large capacity pellets, a number of equipments come from a number of providers, as is common in wood pellet factories with a more detailed explanation here.

In the long term, the goal is to minimize import spending, and even 100% can be made or fabricated by themself. This effort will usually take longer because the complexity of the pelletiser is higher than that of the briquetter. These briquette machine-producing industries can also cooperate with machine manufacturers in Europe who are more experienced and proven with pellet production as an effort to accelerate the transfer of the technology. Within one year as the target was set, it is very difficult to do this, so the practical effort is to buy a 100% complete line from a proven vendor, or sort out a number of equipment that can be produced yourself as above and gradually substitute the imported equipment. This is because achieving the production target for the decarbonization effort is a priority.

In conclusion, at this time India has to maximize efforts to accelerate the construction of biomass pellet factories to achieve this target. However, 1 year to achieve this target is very difficult. With these conditions in the future, it is possible that power plants in India will import biomass fuels such as wood pellets and PKS (palm kernel shell) to meet their needs. With the planned cofiring ratio, which is the lowest target of 5%, the need for biomass pellets reaches around 50 million tons, if only 2% of the biomass fuel needs are imported, both PKS and / or wood pellets, it will reach 1 million tons, a fixed amount still quite big.

Biomass Pellets in India

India has hundreds of millions of biomass waste, especially from agricultural wastes or about 230 million tons per year. Hundreds of millions of tons of biomass waste is of course an environmental problem, especially because most of the waste is simply burned in fields where the smoke pollutes the environment, but on the other hand it will be a solution, namely for decarbonization programs and climate change. Technically, the biomass waste from agricultural waste will be processed into fuel pellets (biomass pellets) which are used for fuel in power plants by cofiring. In the early stages, the Indian government targeted 5% for the cofiring ratio in their coal power plants, where the 5% figure when translated into biomass pellet production would reach around 50 million tons of biomass pellets per year. This is a very large amount, especially with a short time target, which is only one year since it was ordered on October 8, 2021 and will take effect in October 2022 or this year, so hard efforts are needed to achieve this target. Meanwhile, in 2021, the world's demand for wood pellets for power plants will only be around 23 million tons.

The establishment of factories for the production of biomass pellets must be carried out immediately to achieve the production target. These factories must also be supported by logistical readiness to supply raw materials so that the factory can be completed, so that the production of biomass pellets can be carried out as soon as possible. With an average power generation capacity of 275 MW in India, with a cofiring ratio of 5%, the annual need for biomass pellets is estimated at 50 thousand tons or 170 tons per day. With the number of power plants reaching around 900 units with an average consumption of 50 thousand tons of biomass pellets per year or a total of almost 50 million tons per year, the distribution of biomass pellets is also a challenge. A factory with a capacity of around 5 thousand tons/month is likely to be suitable, and even if each factory supplies one power plant, the need for a biomass pellet factories will also be the same as the number of power plants, which is 900 units. A huge amount.

Biomass pellets or agri-waste pellets, namely pellets from agricultural wastes do have a number of differences with wood pellets. Wood itself is also a part of biomass so it can also be called biomass pellet. Biomass has a wider range, including wood pellets and agri-waste pellets. Agri-waste pellets have higher ash content, and some have higher chlorine, potassium and silica content in the ash. The content of these substances is not friendly to the heat exchanger pipes in the boiler which will cause fouling and corrosiveness, so that in addition to decreasing boiler efficiency, the service life of the boiler is shortened. In addition, the harvest of agricultural products usually coincides at certain times, while the pellet factory must continue to produce every day. This is why it is necessary to store and allocate raw materials in the form of agricultural waste for the routine production of these pellets. And because these agricultural wastes cannot be left alone in the agricultural area, they need additional investment in the form of storage warehouses and to be able to store more agricultural waste they need to be temporarily compacted by baling. These things usually don't happen in wood pellet production, so the agri-waste pellet production approach is different.

And because the ash chemistry of agricultural wastes causes many problems in the operation of power plants, their use is also limited. With a cofiring ratio of 5%, the problem can still be tolerated, but when the ratio is enlarged, the impact will be more pronounced. The exception is the CFB (circulating fluidized bed) type plant which can use 100% of the agricultural waste pellets, but in India the power plants using CFB technology are very small, around 1% (9-10 units). Indonesia and Malaysia also produce biomass fuel that is almost similar to pellets and even in the international market is the pellet competitor, namely palm kernel shells or PKS. The volume of PKS also reaches millions of tons, so it can be exported to India to help meet India's needs for biomass pellets, which so far have been mainly for export to Korea and Japan. PKS is also produced by a number of countries in West Africa. But it seems that the Indian government for now will prioritize the use of their agricultural waste first, so it has not provided financial support for the import of the biomass fuel.

Currently, India must make every effort to accelerate the construction of biomass pellet factories to achieve this target. However, 1 year to achieve this target is very difficult. With these conditions in the future, it is possible that power plants in India will import biomass fuels such as wood pellets and PKS to meet their needs. With the currently planned cofiring ratio of 5%, the need for biomass pellets reaches around 50 million tons, if only 2% of the biomass fuel needs are imported, both PKS and/or wood pellets, it will reach 1 million tons, the amount is still very big.

Indonesia National Standard (SNI) of Biomass Pellet and Energy Plantation

Indonesia National Standard (SNI) for Indonesian biomass pellet products has been out and officially used since the end of 2020 or last year. The main objective of implementing SNI for biomass pellets is to respond to the cofiring program at PLN's (state owned electricity company) coal power plants. With this cofiring program, renewable fuels, especially biomass pellets, are used as the main fuel mixture, namely coal. The ratio of the use of renewable fuels in the form of biomass is still small, namely around 1-5% or the equivalent of 9-12 million tons / year of biomass fuel. The total coal power plants as a cofiring target is 114 units spread across 52 locations with a total capacity of 18,154 MW with the target to be completed in 2024. Almost all of the biomass pellets in Indonesia today are wood pellets, all of which also use wastes. sawmills or wood processing industries. In other terms, if you refer to wood pellets, then it must be biomass pellets, whereas if you refer to the term biomass pellets, this is not necessarily wood pellets, but it could be pellets from agricultural wastes (agro-waste pellets). Agricultural wastes which are abundant in Indonesia are also potential as raw material for biomass pellets such as rice husks, empty fruit bunches of palm oil, coconut husk and so on. Below is the table for the SNI biomass pellets:

 

Energy plantations can be a source of woody biomass specifically designed for energy production or specifically for raw materials for the production of biomass pellets or wood pellets. With energy plantations, large production capacities and guaranteed good supply can be achieved. The production of wood pellets from energy plantations takes longer because it needs to prepare and make the energy plantations and wait several years for the wood to be ready to harvest and be processed further into wood pellets. Calliandra and gliricidia are two species of fast rotation and coppice which have been chosen because of their superiority. Another thing that is very important to note is the high heating value and high productivity of wood per hectare. But there is a slight drawback of this type of wood is the content of potassium in ash which is quite high. This makes its use more limited, especially power plants with pulverized combustion (PC) technology.

 

Based on an experiment conducted with calliandra wood from the slopes of Merapi mountain, Central Java; Bangkalan, Madura and Aceh, Sumatera have an average potassium content of above 1000 ppm (0.1%). Indeed, the characteristics of fast-rotating crops tend to produce wood with higher levels of potassium. Meanwhile, from fruit plants, banana trees also have a high potassium content. This potassium has a low melting point and causes fouling in the heat exchanger pipes, thereby reducing the efficiency of the power plant. While chlorine compounds are other compounds that also need attention because they are corrosive at high temperatures, for more details, please read here. And in general, there are significant differences in ash chemistry between biomass and coal. But with a cofiring ratio of 1-5%, power plants generally do not modify their equipment or more specifically on PCs that are most sensitive to ash chemistry problems, because the cofiring percentage is still low.

 

With an average level above 1,000 ppm (0.1%) and still far from 50,000 ppm (5%), there is no problem for wood from energy plantations to be produced into wood pellets and supply to the coal power plants in Indonesia according to SNI the. But if it is exported to foreign countries, especially Japan and Korea, the circulating fluidized bed (CFB) and stoker type power plants are the best market share and the PC type is more limited. With the vast land available and Indonesia's tropical climate, it must further promote energy plantations both to meet domestic needs and to export markets. The energy plantation program also indirectly encourages the ruminant livestock sector, because the leaves can be used as animal feed. 

Water Hyacinth Pellet or Briquette Production?

 

Biomass Briquette

 

Wood pellet

Market absorption or the existence of buyers of the products produced is very important for a production. Certain products are needed because it can be said that they are basic needs such as food, energy and so on. Biomass fuel is a renewable fuel or energy source that is increasingly sought after and needed, especially by industry. Pellets and briquettes are products of biomass densification with use primarily as fuel or energy sources. With this compaction, handling, storage, transportation and use becomes easier, cheaper and safer. As we all know, water hyacinth is an aquatic weed that harms the environment a lot, but how to use this waste so that it is beneficial or minimizes its environmental impact? Is compacting into a pellet or briquette an effective solution? And which is the best made pellet or briquette?

 Water hyacinth is arguably the most invasive aquatic weed in the world today. A number of disadvantages associated with the rampant water hyacinth are real and have a major impact and have been experienced by many countries in the world. In general, the losses of water hyacinth weeds have a major impact on the environmental, health, transportation, energy and economic sectors. More details include:

a. Siltation of water areas namely rivers, lakes, lakes and so on. Silting causes the volume and flow of water to decrease. The reduced volume and flow will certainly have a serious impact on those who use these waters as a source of agricultural irrigation, hydroelectric power, drinking water, industrial processing water and transportation facilities.

b. The dense roots of water hyacinth will not only obstruct the flow of water so that a number of garbage or organic waste collects at the location. In addition, the roots of water hyacinth that absorb nitrogen in the atmosphere will disturb the fish and a number of aquatic biota, because the oxygen supply is disrupted. The source of protein in the form of fish will also be drastically reduced. The location is also a source of disease such as mosquito breeding grounds and is also a home for poisonous snakes.

c. The waters that have been covered by water hyacinth also cannot be used as a means of transportation and a medium for aquaculture. The tourism sector which utilizes the water areas also will decline and stop.

d. With normal volume and flow, these water areas should also be able to control water and flood control which may come at any time, but with the shallower, even water flows become clogged and the surface of the water hyacinth covered waters, the volume and discharge that can be controlled is getting smaller, consequently causing the impact of flooding in a number of places.

e. Water evaporation due to closed water surfaces is also getting higher (evapotranspiration). A number of studies stated that water hyacinth plants resulted in high water evaporation, which is about 3 times normal open water. Lakes or reservoirs as water sources will also be affected due to the decrease in water volume due to high evaporation. In addition, it will also reduce the amount of light in the waters which causes low levels of oxygen solubility. This affects the life of the creatures (aquatic biota or biodiversity) in the water.

Water hyacinth has become a global problem that occurs in five continents with more than 50 countries experiencing it. Africa and Southeast Asia have been particularly hard hit. Egypt, Ghana, Nigeria, Ethiopia, Uganda, Senegal are some of the countries in Africa experiencing the worst water hyacinth problem. Like the second largest lake in Africa, Lake Victoria in Uganda, East Africa has also been filled with water hyacinth. Meanwhile in North Africa the most serious problem in Egypt is in the Nile basins. Likewise in Europe, namely the Guadiana river valley in Spain. Likewise in the Godavari delta and the Brahmaputra river in India. This includes large countries such as the United States and China.

Map of the distribution of water hyacinth attacks globally

Map of distribution of water hyacinth attacks in the United States

 

Map of distribution of water hyacinth attacks in the Hawaiian Islands, United States

 

 

Map of distribution of water hyacinth attacks in China. Black is the worst.

At first, water hyacinth originating from the Amazon river, Brazil was popularized in the mid-19th century as an ornamental plant with beautiful flowers. But not long after that it turned out that water hyacinth had become the fiercest aquatic weed ever. The 80s were the years when a number of countries began to realize the problem of water hyacinth. A similar case as in the golden snail, this animal was originally also similar to ornamental fish in aquariums. But after the leak, the golden snail eggs hatched in the waters and now the golden snail is also a disturbing water pest. Indeed, at first this happened unconsciously or anticipated beforehand, until when the impact of the problem grew bigger and even dangerous, the awareness began to grow. The cases mentioned above should be able to become valuable lessons so that they are not repeated in the future.

Water hyacinth pellet produced in Indonesia, photo taken from here

Ethiopian Ambassador to Indonesia Admasu Tsegaye when meeting with Director Sido Muncul Irwan Hidayat, Photo from here

A number of leading experts and specialists in aquatic weeds around the world have also discussed and tried various countermeasures. A number of frameworks and action plans have been formulated and implemented in these locations. However, the water hyacinth problem cannot be solved completely and permanently. Water hyacinth can also be an indicator of the level of water contamination or eutrophication activity, which is an indication of contamination of aquatic land, by detergents and the like, under normal conditions the growth of water hyacinth takes about 52 days while in polluted water conditions it becomes less than half, which is 22 days only. . The characteristics of plants that can reproduce very easily and whose seeds last for decades are indeed very difficult to eradicate completely, even if it is said to be impossible.

But maximizing the effort so that the water hyacinth is controlled seems more realistic. The speed of eradicating water hyacinth must also be faster than the breeding rate. And it could be that the eradication is done by several combination methods so that the results are effective. Combination of physical / mechanical methods (long arm / short arm excavator, multi-function dredger / dredger, truxor, harvester berky, dump truck, amphibious Long Arm, tugboat, and pontoon), biology (water hyacinth predators and pests) and even chemistry ( such as the use of 2,4-Dimethyl Amine 58% - dose 4 kg / ha) can be done for this effort.

Based on the strategic functions of waters, especially lakes, which are widely available in Indonesia, the prevention of water hyacinth is a national priority, especially since most water hyacinth attacks have even reached 70% of the surface of the water. Among the priority lakes are Lake Toba, Maninjau, Kerinci, Jampang, Rawa Pening, Limboto, Tondano, Tempe, Poso, and Sentani. An indication of the criticality and urgency of these lakes is that some of them can turn into land if not treated immediately. In addition to that in Indonesia, the problem of water hyacinth is also a joint problem across departments or ministries such as the Ministery of Environment, Ministery of Public Works and Human Settlements(subordinat : River, Lake Sector, Directorate General of Water Resources), Fisheries and Marine, Agriculture, and Health, while for the global level Food and The Agriculture Organization (FAO) is one of the institutions that also deals with this problem. This indicates that the water hyacinth problem is not a simple problem and easy to handle.

With the productivity of water hyacinth reaching 300 tons / hectare / year, high speed is needed to reduce the spread of weeds in these waters. For example, with a water hyacinth cleaning speed of 8 hectares / day with a lake area of ​​2000 hectares, 2,400 tons of wet water hyacinth are produced every day, and every month 200 hectares of water hyacinth are cleaned or 2400 hectares per year, which means that periodically the growth of water hyacinth continues to be controlled well. With water hyacinth moisture content reaching 80%, when it is compacted by means of briquettes or pellets, it needs to be dried to about 10% moisture content. Each ton wet of water hyacinth will produce approximately 300 kg of water hyacinth or that means that with the cleaning speed above 720 tons / day of dry water hyacinth or with a moisture content of 10% is obtained. The remaining water that is separated or disposed of per ton of water hyacinth reaches 700 kg per ton or 1,680 tonnes / day. Liquid waste, which is likely to contain a lot or is rich in organic substances, also has the potential to be developed into biogas. The need for energy is indeed very large, plus the use of renewable energy, especially biomass-based, continues to be encouraged. With the production of biomass briquettes as above, namely 720 tonnes per day or 18,000 tonnes / month or 216,000 tonnes / year, of course this is a large enough amount to replace the use of fossil fuels such as coal, oil and gas.

Industrial briquette, puck shape

Although both types of fuel products, both pellets and briquettes, can be produced from water hyacinth waste, which can also depend on the demands of the product users. But technically, briquette production is easier and cheaper than pellets. The density of the briquettes can also be adjusted according to the needs as well as the size of the briquettes. Particle size and moisture content in briquette are also looser than in pellets, for more details can be read here. Even organic waste in the form of sediment (sludge) from the roots and leaves of water hyacinth at the bottom of the water can be taken for briquettes. The sludge briquettes containing humic acid can later be used as organic fertilizer. The preparations for the production of pellets and briquettes can actually be said to be almost the same, such as size reduction / down sizing, mechanical extraction to separate water, drying to 10% moisture content and finally the compaction (biomass densification).

Sludge briquette

Apart from a number of detrimental factors above, there are a number of environmental benefits that can also be obtained from the water hyacinth plant, namely cleaning polluted water (phytoremediation) such as reducing COD, increasing pH, absorbing nitrogen and phosphorus from wastewater. Maximizing benefits and minimizing losses is an approach in overcoming the water hyacinth. With this pattern, the population of water hyacinths must be continuously limited so that there is a good environmental balance. With a comprehensive and accurate statistical analysis, it can be studied in depth the use of water hyacinth as fuel for both briquettes and pellets. Several things that can be compared are fish production before and after water hyacinth infestation, as well as the capacity of electricity generation, tourism and so on. Compensation for economic benefits that are worth it can be a driving force for efforts to use the water hyacinth so that the main mission of saving the environment due to water hyacinth weeds can actually be achieved according to the expected goals. The balance of economic and environmental factors with the production of sustainable briquettes or pellets is expected to be an attractive and effective solution to control the development of water hyacinth.

PKS as the Mainstay Fuel in Cofiring in the Coal Power Plant

Cofiring is the easiest and fastest entry point for coal power plants that will enter the renewable energy sector. With the cofiring mechanism, the percentage of biomass can be increased gradually, even later it is possible if 100% of the power plant's fuel uses biomass. Biomass itself, especially from plants, is a renewable energy source, but if managed properly. Sources of biomass that are obtained carelessly and without regard to environmental aspects are not renewable energy and it will not be sustainable. These activities are contrary to the concept of bioeconomy. And in Indonesia in particular the use of energy from biomass, especially PKS is also in line with government policy which is to encourage the renewable energy mix by 5% in 2025 based on Presidential Regulation No. 5 of 2006. Besides the cofiring method is also listed in the RUKN (National Electricity General Plan) 2019- 2038 which states that the energy conservation roadmap for energy supply activities one of which includes an energy efficiency improvement program on its own use and cofiring.

Among the various biomass sources currently available, PKS (palmkernel shell) is the best biomass fuel. That is because PKS has properties that are close to wood pellets and even in the international biomass fuel market, PKS is the main competitor of wood pellets. PKS has a relatively uniform shape and size, high calories, high bulk density, low ash content and is available in abundant quantities. PKS is palm oil mill (CPO mill) waste  so there is no need for complicated production processes such as wood pellets. It is estimated that there are more than 10 tons / month of PKS produced in Indonesia. Then what about other biomass fuels? Below is a brief comparison with a number of other biomass fuels, namely wood pellets, wood chips, biomass pellets and rice husks.

Wood Pellet

wood pellets have a density of around 700 kg / m3 from the compaction process (wood powder / sawdust densification). In quality wood pellets are better than PKS, this is mainly due to the uniform shape and high level of dryness. Lack of wood pellets is in the price and volume factors. In Indonesia, the price of wood pellets is around 2 times PKS and 3 times coal. Even though the quality is better, with this price, coal power plants certainly will not use a large percentage for cofiring, especially if there are also a number of technical factors as a limitation, such as combustion technology used, chemical ash in wood pellets and so on. Another factor is the volume of availability of wood pellets themselves, which currently produce in Indonesia is still small, which is estimated to be less than 100,000 tons / year. If there is a surge in demand, the selling price of wood pellets increases, following market laws. But with low wood pellet production volumes and relatively expensive prices, wood pellets are less suitable for cofiring.

Wood Chip

Wood chip is a very simple form of biomass fuel, which is made only by size reduction process by using a wood chipper machine. The main problem with wood chips is that they have low bulk density and are expensive to transport. Bulk density wood chip is only about 1/4 of wood pellet or 1/3 PKS. The quality of the wood chip will be exactly the same as the quality of the wood used. Wood chips are only economical if the source of wood chip raw materials is close to the power plant. In simple words if the power plant is surrounded by energy plantation as a source of wood chips, it is probable that the supply of wood chips to the plant will be economical. The energy plantation can also be integrated with livestock businesses. To optimize the potential of the energy plantation, for more details, please read here.

Biomass Pellet / Agro-Waste Pellet

Biomass pellets or pellets from agricultural waste (agro-waste pellets) can also be used to fuel the power plant. These agricultural waste pellets include empty fruit bunch pellets (EFB pellets), rice husk pellets (RH pellets), corn cobs pellets and so on. The quality of the agricultural waste pellets is below wood pellets and it also seems that the producers of these pellet types are still very limited or do not even exist yet in Indonesia. And because it requires industry for its production, the selling price of agro-waste pellets predicted will not too different from wood pellets.

Rice Husk

Rice husks are widely available in rice farming centers or rice barns. Rice husk also has small bulk density (around 100 kg / m3), small caloric value and high ash content can even reach 20%. It also makes it less economical if rice husks are transported over long distances. Another factor is the high level of drought in rice husks so that they are prone to fires that are piled on their storage. Rice husk always comes from dry grain, because the rice milling process can only be done on dry rice. Other technical factors such as high ash content will affect the portion of rice husk use.

Based on the above comparison, it seems that PKS or palm kernel shells are the ideal biomass fuel for cofiring or fullfiring (100% PKS) at the coal powerplant. PKS consumption for the country is estimated to continue to increase and there will even be competition with the export market. In these conditions it could be a number of export restrictions carried out on the grounds of priority domestic needs.