Biomass Energy in Indonesia

With Indonesia’s recovery from the Asian financial crisis of 1998, energy consumption has grown rapidly in past decade. The priority of the Indonesian energy policy is to reduce oil consumption and to use renewable energy. For power generation, it is important to increase electricity power in order to meet national demand and to change fossil fuel consumption by utilization of biomass wastes. The development of renewable energy is one of priority targets in Indonesia.

It is estimated that Indonesia produces 146.7 million tons of biomass per year, equivalent to about 470 GJ/y. Sources of biomass energy in Indonesia are scattered all over the country, but the biggest potential in concentrated scale can be found in the Island of Kalimantan, Sumatera, Irian Jaya and Sulawesi. Studies estimate the electricity generation potential from the roughly 150 Mt of biomass residues produced per year to be about 50 GW or equivalent to roughly 470 GJ/year. These studies assume that the main source of biomass energy in Indonesia will be rice residues with a technical energy potential of 150 GJ/year. Other potential biomass sources are rubber wood residues (120 GJ/year), sugar mill residues (78 GJ/year), palm oil residues (67 GJ/year), and less than 20 GJ/year in total from plywood and veneer residues, logging residues, sawn timber residues, coconut residues, and other agricultural wastes.

Sustainable and renewable natural resources such as biomass can supply potential raw materials for energy conversion. In Indonesia, they comprise variable-sized wood from forests (i.e. natural forests, plantations and community forests that commonly produce small-diameter logs used as firewood by local people), woody residues from logging and wood industries, oil-palm shell waste from crude palm oil factories, coconut shell wastes from coconut plantations, as well as skimmed coconut oil and straw from rice cultivation.

The major crop residues to be considered for power generation in Indonesia are palm oil sugar processing and rice processing residues. Currently, 67 sugar mills are in operation in Indonesia and eight more are under construction or planned. The mills range in size of milling capacity from less than 1,000 tons of cane per day to 12,000 tons of cane per day. Current sugar processing in Indonesia produces 8 millions MT bagasse and 11.5 millions MT canes top and leaves. There are 39 palm oil plantations and mills currently operating in Indonesia, and at least eight new plantations are under construction. Most palm oil mills generate combined heat and power from fibres and shells, making the operations energy self –efficient. However, the use of palm oil residues can still be optimized in more energy efficient systems.

Other potential source of biomass energy can also come from municipal wastes. The quantity of city or municipal wastes in Indonesia is comparable with other big cities of the world. Most of these wastes are originated from household in the form of organic wastes from the kitchen. At present the wastes are either burned at each household or collected by the municipalities and later to be dumped into a designated dumping ground or landfill. Although the government is providing facilities to collect and clean all these wastes, however, due to the increasing number of populations coupled with inadequate number of waste treatment facilities in addition to inadequate amount of allocated budget for waste management, most of big cities in Indonesia had been suffering from the increasing problem of waste disposals.

The current pressure for cost savings and competitiveness in Indonesia’s most important biomass-based industries, along with the continually growing power demands of the country signal opportunities for increased exploitation of biomass wastes for power generation.

Biomass Resources in Malaysia

Malaysia is gifted with conventional energy resources such as oil and gas as well as renewables like hydro, biomass and solar energy. As far as biomass resources in Malaysia are concerned, Malaysia has tremendous agricultural biomass and wood waste resources available for immediate exploitation. This energy potential of biomass resource is yet to be exploited properly in the country.

Taking into account the growing energy consumption and domestic energy supply constraints, Malaysia has set sustainable development and diversification of energy sources, as the economy’s main energy policy goals. The Five-Fuel Strategy recognises renewable energy resources as the economy’s fifth fuel after oil, coal, natural gas and hydro. Being a major agricultural commodity producer in the region Malaysia is well positioned amongst the ASEAN countries to promote the use of biomass as a source of renewable energy.

Major Biomass Resources

Palm Oil Biomass

Malaysia is the world’s leading exporter of palm oil, exporting more than 19.9 million tonnes of palm oil in 2017. The extraction of palm oil from palm fruits results in a large quantity of waste in the form of palm kernel shells, empty fruit bunches and mesocarp fibres. In 2011, more than 80 million tons of oil palm biomass was generated across the country.

13MW biomass power plant at a palm oil mill in Sandakan, Sabah (Malaysia)

Processing crude palm oil generates a foul-smelling effluent, called Palm Oil Mill Effluent or POME, which when treated using anaerobic processes, releases biogas. Around 58 million tons of POME is produced in Malaysia annually, which has the potential to produce an estimated 15 billion m3 of biogas.

Rice Husk

Rice husk is another important agricultural biomass resource in Malaysia with very good energy potential for biomass cogeneration. An example of its attractive energy potential is biomass power plant in the state of Perlis which uses rice husk as the main source of fuel and generates 10 MW power to meet the requirements of 30,000 households.

Municipal Solid Wastes

The per capita generation of solid waste in Malaysia varies from 0.45 to 1.44kg/day depending on the economic status of an area. Malaysian solid wastes contain very high organic waste and consequently high moisture content and bulk density of above 200kg/m3. The high rate of population growth is the country has resulted in rapid increase in solid waste generation which is usually dumped in landfills.

Conclusion

Biomass resources have long been identified as sustainable source of renewable energy particularly in countries where there is abundant agricultural activities. Intensive use of biomass as renewable energy source in Malaysia could reduce dependency on fossil fuels and significant advantage lies in reduction of net carbon dioxide emissions to atmosphere leading to less greenhouse effect. However, increased competitiveness will require large-scale investment and advances in technologies for converting this biomass to energy efficiently and economically.

Biomethane Utilization Pathways

biomethane-transportBiogas can be used in raw (without removal of CO2) or in upgraded form. The main function of upgrading biogas is the removal of CO2 (to increase the energy content) and H2S (to reduce risk of corrosion). After upgrading, biogas possesses identical gas quality properties as  natural gas, and can thus be used as natural gas replacement. The main pathways for biomethane utilization are as follows:

  • Production of heat and/or steam
  • Electricity production / combined heat and power production (CHP)
  • Natural gas replacement (gas grid injection)
  • Compressed natural gas (CNG) & diesel replacement – (bio-CNG for transport fuel usage)
  • Liquid natural gas (LNG) replacement – (bio-LNG for transport fuel usage)

Prior to practically all utilization options, the biogas has to be dried (usually through application of a cooling/condensation step). Furthermore, elements such as hydrogen sulphide and other harmful trace elements must be removed (usually trough application of an activated carbon filter) to prevent adverse effects on downstream processing equipment (such as compressors, piping, boilers and CHP systems).

Although biogas is perfectly suitable to be utilized in boilers (as an environmental friendlier source for heat and steam production), this option is rather obsolete due to the abundance of alternative sources from solid waste origin.

Most Palm Oil Mills are already self-reliant with respect to heat and steam production due to the combustion of their solid waste streams (such as EFB and PKS). Consequently, conversion to electricity (by means of a CHP unit) or utilization as natural gas, CNG or LNG replacement, would be a more sensible solution.

The biogas masterplan as drafted by the Asia Pacific Biogas Alliance foresees a distribution in which 30% of the biomethane is used for power generation, 40% for grid injection and 30% as compressed/liquefied fuel for transportation purpose (Asian Pacific Biogas Alliance, 2015).

For each project, the most optimal option has to be evaluated on a case to case basis. Main decision-making factors will be local energy prices and requirements, available infrastructure (for gas and electricity), incentives and funding.

For the locations where local demand is exceeded, and no electricity or gas infrastructure is available within a reasonable distance (<5-10 km, due to investment cost and power loss), production of CNG could offer a good solution.

Moreover, during the utilization of biogas within a CHP unit only 40-50% of the energetic content of the gas is converted into electricity. The rest of the energy is transformed into heat. For those locations where an abundance of heat is available, such as Palm Oil Mills, this effectively means that 50-60% of the energetic content of the biogas is not utilized. Converting the biogas into biomethane (of gas grid or CNG quality) through upgrading, would facilitate the transportation and commercialisation of over 95%  of the energetic content of the biogas.

Within the CNG utilization route, the raw biogas will be upgraded to a methane content of >96%, compressed to 250 bar and stored in racks with gas bottles. The buffered gas (bottles) will be suitable for transportation by truck or ship. For transportation over large distances (>200km), it will be advised to further reduce the gas volume by converting the gas to LNG (trough liquefaction).

Overall the effects and benefits from anaerobic digestion of POME and utilization of biomethane can be summarized as follows:

  • Reduction of emissions i.e. GHG methane and CO2
  • Reduced land use for POME treatment
  • Enhanced self-sufficiency trough availability of on-site diesel replacement (CNG)
  • Expansion of economic activities/generation of additional revenues
    • Sales of surplus electricity (local or to the grid)
    • Sales of biomethane (injection into the natural gas grid)
    • Replacement of on-site diesel usage by CNG
    • Sales of bottled CNG
  • Reducing global and local environmental impact (through fuel replacement)
  • Reducing dependence on fossil fuel, and enhances fuel diversity and security of energy supply
  • Enhancement of local infrastructure and employment
    • Through electrical and gas supply
    • Through Fuel (CNG) supply

Co-Authors: H. Dekker and E.H.M. Dirkse (DMT Environmental Technology)

Note: This is the second article in the special series on ‘Sustainable Utilization of POME-based Biomethane’ by Langerak et al of DMT Environmental Technology (Holland). The first article can be viewed at this link

POME as a Source of Biomethane

POME-BiogasDuring the production of crude palm oil, large amount of waste and by-products are generated. The solid waste streams consist of empty fruit bunch (EFB), mesocarp fruit fibers (MF) and palm kernel shells (PKS). Reuse of these waste streams in applications for heat, steam, compost and to lesser extent power generation are practised widely across Southeast Asia. POME or Palm Oil Mill Effluent is an underutilized liquid waste stream from palm oil mills which is generated during the palm oil extraction/decanting process and often seen as a serious environmental issue but it is a very good source for biomethane production. Therefore, discharge of POME is subject to increasingly stringent regulations in many palm oil-producing nations.

Anaerobic Digestion of POME

POME is an attractive feedstock for biomethane production and is abundantly available in all palm oil mills. Hence, it ensures continuous supply of substrates at no or low cost for biogas production, positioning it as a great potential source for biomethane production. (Chin May Ji, 2013).

POME is a colloidal suspension containing 95-96% water, 0.6-0.7% oil and 4-5% total solids, which include 2-4% suspended solids. Biological Oxygen Demand (BOD) generally ranges between 25,000 and 65,714 mg/L, Chemical Oxygen Demand (COD) ranges between 44,300 and 102,696 mg/L.

Most palm oil mills and refineries have their own treatment systems for POME, which is easily amenable to biodegradation due to its high organic content. The treatment system usually consists of anaerobic and aerobic ponds. (Sulaiman, 2013).

Open pond systems are still commonly applied. Although relatively cheap to install, these system often fail to meet discharge requirements (due to lack of operational control, long retention time, silting and short circuiting issues).

Moreover, the biogas produced during the anaerobic decomposition of POME in open pond systems is not recovered for utilization. The produced gas dissipates into the atmosphere where it causes adverse environment effects (due to the fact that CH4 is a twenty times stronger greenhouse gas then CO2 (Chin May Ji, 2013).

Biogas capture from POME can be carried out using a number of various technologies ranging in cost and complexity. The closed-tank anaerobic digester system with continuous stirred-tank reactor (CSTR), the methane fermentation system employing special microorganisms and the reversible flow anaerobic baffled reactor (RABR) system are among the technologies offered by technology providers. (Malaysian Palm Oil Board, 2015).

Biogas production largely depends on the method deployed for biomass conversion and capture of the biogas, and can, therefore, approximately range from 5.8 to 12.75 kg of CH4 per cubic meter of POME. Application of enclosed anaerobic digestion will significantly increase the quality of the effluent/ discharge stream as well as the biogas composition, as mentioned in table below.

 Table: Performance comparison between open and closed digester systems

Parameters Open digester system Closed anaerobic digester
COD removal efficiency (%) 81% 97%
HRT (days) 20 10
Methane utilization Released to atmosphere Recoverable
Methane yield (kg CH4/kg COD removed) 0.11 0.2
Methane content (%) 36 55
Solid discharge (g/L) 20 8

*This table has been reproduced from (Alawi Sulaiman, 2007)

A closed anaerobic system is capable of producing and collecting consistently high quality of methane rich biogas from POME. Typical raw biogas composition will be: 50-60 % CH4, 40-50 % CO2, saturated with water and with trace amounts of contaminants (H2S, NH3, volatiles, etc.).

Biomethane Potential in Southeast Asia

The amount of biomethane (defined as methane produced from biomass, with properties close to natural gas) that can be potentially produced from POME (within the Southeast Asian region) exceeds 2.25 billion cubic meter of biomethane (on a yearly basis).

Especially Indonesia and Malaysia, as key producers within the palm oil industry, could generate significant quantities of biomethane. An impression of the biomethane potential of these countries including other feedstock sources is being highlighted below (VIV Asia, 2015).

Indonesia (4.35 billion m3 of biomethane):

  • 25 billion m3 of biomethane from Palm Oil Mill Effluent (POME).
  • 2 billion m3 of bio-methane from Sewage Treatment Plant (STP).
  • 9 billion m3 of bio-methane from Municipal Solid Waste (MSW).

Malaysia (3 billion m3 of biomethane):

  • 1 billion m3 of biomethane from Palm Oil Mill Effluent (POME).
  • 2 billion m3 of biomethane from Sewage Treatment Plant (STP).
  • 8 billion m3 of biomethane from Municipal Solid Waste (MSW).

The Asian Pacific Biogas Alliance estimates that the potential of conversion of biomass to biomethane is sufficient to replace 25 percent of the natural gas demand by renewable biogas (Asian Pacific Biogas Alliance, 2015).

To sum up, due to the high fraction of organic materials, POME has a large energetic potential. By unlocking the energetic potential of these streams through conversion/ digesting and capture of biomethane, plant owners have the opportunity to combine waste management with a profitable business model.

Co-Authors: H. Dekker and E.H.M. Dirkse (DMT Environmental Technology)

References

Alawi Sulaiman, Z. B. (2007). Biomethane production from pal oil mill effluent (POME) in a semi-commercial closed anaerobic digester. Seminar on Sustainable Palm Biomass initiatives. Japan Society on Promotion of Science (JSPS).

Asia Biogas Group. (2015, 08 15). Retrieved from Asia Biogas : http://www.asiabiogas.com

Asian Pacific Biogas Alliance. (2015). Biogas Opportunities in South East Asia. Asian Pacific Biogas Alliance/ICESN.

Chin May Ji, P. P. (2013). Biogas from palm oil mill effluent (POME): Opportunities and challenges from Malysia’s perspective. Renewable and Sustainable Energy Reviews , 717-726.

Malaysian Palm Oil Board. (2015, 08 26). Biogas capture and CMD project implementation for palm oil mills. Retrieved from Official Portal Of Malaysian Palm Oild Board:

Sulaiman, N. A. (2013). The Oil Palm Wastes in Malaysia. In M. D. Matovic, “Biomass Now – Sustainable Growth and Use”. InTech.

VIV Asia. (2015, 08 26). The international platform from feed to food in Asia. Retrieved from http://www.vivasia.nl

Note: This is the first article in the special series on ‘Sustainable Utilization of POME-based Biomethane’ by Langerak et al of DMT Environmental Technology (Holland)

Biomass Wastes from Palm Oil Mills

The Palm Oil industry generates large quantity of wastes whose disposal is a challenging task. In the Palm Oil mill, fresh fruit bunches are sterilized after which the oil fruits can be removed from the branches. The empty fruit bunches (are left as residues, and the fruits are pressed in oil mills. The Palm Oil fruits are then pressed, and the kernel is separated from the press cake (mesocarp fibers). The palm kernels are then crushed and the kernels then transported and pressed in separate mills.

In a typical Palm Oil plantation, almost 70% of the fresh fruit bunches are turned into wastes in the form of empty fruit bunches, fibers and shells, as well as liquid effluent. These by-products can be converted to value-added products or energy to generate additional profit for the Palm Oil Industry.

Palm Kernel Shells (PKS)

Palm kernel shells (or PKS) are the shell fractions left after the nut has been removed after crushing in the Palm Oil mill. Kernel shells are a fibrous material and can be easily handled in bulk directly from the product line to the end use. Large and small shell fractions are mixed with dust-like fractions and small fibres.

Moisture content in kernel shells is low compared to other biomass residues with different sources suggesting values between 11% and 13%. Palm kernel shells contain residues of Palm Oil, which accounts for its slightly higher heating value than average lignocellulosic biomass. Compared to other residues from the industry, it is a good quality biomass fuel with uniform size distribution, easy handling, easy crushing, and limited biological activity due to low moisture content.

Press fibre and shell generated by the Palm Oil mills are traditionally used as solid fuels for steam boilers. The steam generated is used to run turbines for electricity production. These two solid fuels alone are able to generate more than enough energy to meet the energy demands of a Palm Oil mill.

Empty Fruit Bunches (EFBs)

In a typical Palm Oil mill, empty fruit bunches are abundantly available as fibrous material of purely biological origin. EFB contains neither chemical nor mineral additives, and depending on proper handling operations at the mill, it is free from foreign elements such as gravel, nails, wood residues, waste etc. However, it is saturated with water due to the biological growth combined with the steam sterilization at the mill. Since the moisture content in EFB is around 67%, pre-processing is necessary before EFB can be considered as a good fuel.

In contrast to shells and fibers, empty fruit bunches are usually burnt causing air pollution or returned to the plantations as mulch. Empty fruit bunches can be conveniently collected and are available for exploitation in all Palm Oil mills. Since shells and fibres are easy-to-handle, high quality fuels compared to EFB, it will be advantageous to utilize EFB for on-site energy demand while making shells and fibres available for off-site utilization which may bring more revenues as compared to burning on-site.

Palm Oil Mill Effluent (POME)

Palm Oil processing also gives rise to highly polluting waste-water, known as Palm Oil Mill Effluent, which is often discarded in disposal ponds, resulting in the leaching of contaminants that pollute the groundwater and soil, and in the release of methane gas into the atmosphere. POME could be used for biogas production through anaerobic digestion. At many Palm-oil mills this process is already in place to meet water quality standards for industrial effluent. The gas, however, is flared off.

In a conventional Palm Oil mill, 600-700 kg of POME is generated for every ton of processed FFB. Anaerobic digestion is widely adopted in the industry as a primary treatment for POME. Liquid effluents from palm oil mills can be anaerobically converted into biogas which in turn can be used to generate power through gas turbines or gas-fired engines.

Conclusions

Most of the Biomass residues from Palm Oil Mills are either burnt in the open or disposed off in waste ponds. The Palm Oil industry, therefore, contributes significantly to global climate change by emitting carbon dioxide and methane. Like sugar mills, Palm Oil mills have traditionally been designed to cover their own energy needs (process heat and electricity) by utilizing low pressure boilers and back pressure turbo-generators. Efficient energy conversion technologies, especially thermal systems for crop residues, that can utilize all Palm Oil residues, including EFBs, are currently available.

In the Palm Oil value chain there is an overall surplus of by-products and their utilization rate is negligible, especially in the case of POME and EFBs. For other mill by-products the efficiency of the application can be increased. Presently, shells and fibers are used for in-house energy generation in mills but empty fruit bunches is either used for mulching or dumped recklessly. Palm Oil industry has the potential of generating large amounts of electricity for captive consumption as well as export of surplus power to the public grid.

Bioenergy Developments in Malaysia

Malaysia is blessed with abundant renewable sources of energy, especially biomass and solar. Under the Eighth Malaysian Plan, renewable energy was added in the energy mix to unveil a Five-Fuel Strategy to achieve 5 percent contribution by 2005.

Among the various sources of renewable energy, bioenergy seems to be the most promising option for Malaysia. The National Biofuel Policy, launched in 2006 encourages the use of environmentally friendly, sustainable and viable sources of biomass energy. Under the Five Fuel Policy, the government of Malaysia has identified biomass as one of the potential renewable energy. Malaysia produces atleast 168 million tonnes of biomass, including timber and oil palm waste, rice husks, coconut trunk fibres, municipal waste and sugar cane waste annually. Being a major agricultural commodity producer in the region Malaysia is well positioned amongst the ASEAN countries to promote the use of biomass as a renewable energy source.

Malaysia has been one of the world’s largest producers and exporters of palm oil for the last forty years. The Palm Oil industry, besides producing Crude Palm Oil (CPO) and Palm Kernel Oil, produces Palm Shell, Press Fibre, Empty Fruit Bunches (EFB), Palm Oil Mill Effluent (POME), Palm Trunk (during replanting) and Palm Fronds (during pruning).

Malaysia has approximately 4 million hectares of land under oil palm plantation. Over 75% of total area planted is located in just four states, Sabah, Johor, Pahang and Sarawak, each of which has over half a million hectares under cultivation. The total amount of processed FFB (Fresh Fruit Bunches) was estimated to be 75 million tons while the total amount of EFB produced was estimated to be 16.6 million tons. Around 58 million tons of POME is produced in Malaysia annually, which has the potential to produce an estimated 15 billion m3 of biogas can be produced each year.

Malaysia is the world’s second largest producer of crude palm oil. Almost 70% of the volume from the processing of fresh fruit bunch is removed as wastes in the form of empty fruit bunches, palm kernel shells, palm oil mill effluent etc. With more than 423 mills in Malaysia, this palm oil industry generated around 80 million dry tonnes of biomass in 2010. Malaysia has more than 2400 MW of biomass and 410 MW of biogas potential, out of which only 773MW has been harnessed until 2011.

Rice husk is another important agricultural biomass resource in Malaysia with good potential for power cogeneration. An example of its attractive energy potential is biomass power plant in the state of Perlis which uses rice husk as the main source of fuel and generates 10 MW power to meet the requirements of 30,000 households. The US$15 million project has been undertaken by Bio-Renewable Power Sdn Bhd in collaboration with the Perlis state government, while technology provider is Finland’s Foster Wheeler Energia Oy.

Under the EC-ASEAN Cogeneration Program, there are three ongoing Full Scale Demonstration Projects (FSDPs) – Titi Serong, Sungai Dingin Palm Oil Mill and TSH Bioenergy – to promote biomass energy systems in Malaysia. The 1.5MW Titi Serong power plant, located at Parit Buntar (Perak), is based on rice husk while the 2MW Sungai Dingin Palm Oil Mill project make use of palm kernel shell and fibre to generate steam and electricity. The 14MW TSH Bioenergy Sdn Bhd, located at Tawau (Sabah), is the biggest biomass power plant in Malaysia and utilizes empty fruit bunches, palm oil fibre and palm kernel shell as fuel resources.