The main products produced by the palm oil mills are crude palm oil and palm kernels. However, it also produces huge quantities of residues such as fibre, shell and empty fruit bunches as shown in Figure 2.2. Dry residues from oil palm wastes can be utilised to produce various types of products. EFB had been studied to convert into paper-making pulp by the researches from MPOB because EFB can be categorized as fibrous crop residues know as lignocellulosic residues. The high number of fibres/unit weight indicates the paper from EFB would have good printing properties and a good formation within paper making. EFB could produce thin, high quality printing paper, speciality papers for example for cigarette and photographic papers and security papers. The total chlorine-free methods had been used to bleach the pulp for producing paper [59,81]. Products such as paper and pulp that are obtained by processing the oil palm wastes can be used in many ways such as cigarette paper and bond papers for writing [82]. Normally, the excess shell are used to cover the surface of the roads in the plantation area.

Various types of wood such as saw-wood and ply-wood or lumber had been produced from oil palm trunk. Oil palm trunks have been chipped and waxed with resin to produce pre formed desk tops and chair seats for schools. The furniture is characterised for resistance against knocks, scratches, ink, termites and fungus The ply-wood or lumber can be utilised as core in producing blackboard. The saw-wood is used for furniture but it is not suitable as building material due to its low specific density. It was found that the strength of the ply­wood made from oil palm trunk was comparable with the commercial ply-wood. The particle board with chemical binders also can be produced from oil palm trunk. Some of the oil palm trunks are mixed with EFB and palm fibres to be combusted to produce energy [81,83,84]. Besides this, the palm shell and palm fibres have been convert of into briquettes in a study [36].

Medium density fibre-boards and blackboards can be produced from EFB and palm fibre [84,85]. Currently, the MDF industry has 14 plants with a total annual installed capacity of 2.9 million. The total export of MDF was RM1.2 billion in 2008. The industry has started utilising acacia mangium and mixed hardwood to produce MDF as alternatives to rubber wood. At present, Malaysia is the world’s third largest exporter of MDF, after Germany and France. MDF from Malaysia has attained international standards such as British (BS), European (EN), Asia-Pacific: Japan Australia and New Zealand (JANS) standards [86]. High-density fiberboard (HDF), also called hardboard, is a type of fiberboard, which is an engineered wood product. It is similar to MDF, but is denser and much harder and stronger because it is made out of exploded wood fibers that have been highly compressed. Agro-Bio Fibre Sdn Bhd in Malaysia holds the patent for the EFB-based MDF over the last 10 years, has invested RM30 million to develop the technology to produce MDF and other products from the oil palm wastes. This company had signed a MoU with the Forest Research Institute of Malaysia (FRIM) to develop HDF used mainly for the production of floorboards that would use 100% EFB as its raw material [87].

Oil palm fibre is non-hazardous biodegradable material extracted from empty fruit bunch that are considered as waste after the extraction oil palm fruits. The fibres are clean, non­carcinogenic, and free from pesticides and soft parenchyma cells. Palm fibres are versatile and stable and can be processed into various dimensional grades to suit specific applications such as erosion control, mattress cushion production, soil stabilization, horticulture and landscaping, ceramic and brick manufacturing, paper production, acoustics control, livestock care, compost, fertilizer and animal feed. Palm fibres can also be used as fillers in thermoplastics and thermoset composites which have wide applications in furniture and automobile components. Production of thermoplastic and thermostat composites has reached commercialization stage when PROTON (Malaysian national car maker) entered into agreement with PORIM (Palm Oil Research Institute of Malaysia) [88,89].

Similar to EFB, according to a study fronds from oil palm trees can be converted into pulp [90]. Oil palm fronds also can be processed as roughage source for ruminants such as cattle and goats [91]. A new product known as oil palm frond based ruminant pellet can be used as balanced diet for fattening beef cattle which is developed by the Malaysian Agricultural Research and Development Institute (MARDI) [91].

11 palm ash (OP A) can be utilised as an absorbent for removing pollutant gases such as nitrogen oxide and sulphur oxide. The combustion of oil palm fibre and shell as boiler fuel to generate steam in palm oil mill will produce OPA. It was found that OPA contains high amount of calcium, silica, potassium and alumina which can be utilised to synthesize active compounds to absorb the pollutant gases into absorbent [92,93]. The presence of some functional groups such as hydroxyl, lactone and carboxylic in oil palm shell have a high affinity towards metal ions. Thus, the charcoal derived from oil palm shell can be coated with chitosan to use as a remover of heavy metal especially chromium from wastewater industry; however, it is still at research stage [94].

Processing the oil palm wastes such as EFB, fibre, shell and palm kernel cake into a uniform and solid fuel through briquetting process will be an attractive option. Palm kernel cake is a by-product of crushing and expelling oil from palm kernel. Briquetting is a process of compacting loose material to form a homogeneous and densified product. The material can be densified into briquettes at high temperature and pressure using screw of extrusion techniques either with or without binder addition. Oil palm briquettes are often favoured for household and industrial heating unit operation such as boiler because of their enhanced physical properties, as well as being easy to handle and feed. According to a study, the equilibrium moisture content for the briquettes made of palm fibre and palm shell is about

12 mf wt.% [36]. It was found that briquettes made from 100% pulverised EFB exhibited good burning properties. It is recommended to blend with sawdust in order to produce better quality briquettes from EFB and palm kernel cake [95]. Oil palm briquettes can be used as fuel in producing steam, district heating and electricity generation for larger commercial scale. The local sawdust briquettes or charcoal briquettes are rarely used in the local market because it could not compete with the availability of cheap fuels such as charcoal and wood which are widely used in the rural areas and restaurants [96]. Therefore, the products are exported for oversea markets [97].

One of the promising technologies which utilise the oil palm wastes or plant matter involves the production of carbon molecular sieve (CMS) from lignocellulosic materials. Production of CMS from oil palm wastes which are cheap and abundant carbon source will enhance the economical feasibility of adsorption process. A CMS is a material containing tiny pores of a precise and uniform size that is used as an adsorbent for gases and liquids, and normally it is used to separate nitrogen from the other gases contained in air. A survey of literature indicated that palm shell have been used the most as the substrate for CMS production by many researcher in Malaysia [97-101]. Basically, there are three steps involve to prepare the CMS from oil palm wastes which are carbonisation of the wastes, activation of the chars produced and pore modification of the activated carbons to obtain CMS. Activated carbon is produced from carbonaceous source materials such as nutshells, oil palm wastes, peat, wood, coir and lignite. Activated carbon also called activated charcoal is a form of carbon that has been processed to make it extremely porous and have a very large surface area, thus available for adsorption or chemical reactions. Activated carbon can be produced by either physical reactivation or chemical activation. In physical reactivation, the precursor is developed into activated carbons using gases by carbonization and/or oxidation process. For chemical activation, prior to carbonization, the raw material is impregnated with certain chemicals such acid, base or salt [102]. According to a study, the optimum conditions for preparing activated carbon from EFB for adsorption of 2,4,6-TCP were found as follows : activation temperature of 814°C, CO2 activation time of 1.9h and IR of 2.8, which resulted in 168.89 mg/g of 2,4,6-TCP uptake and 17.96% of activated carbon yield [103].

Biochar is commonly defined as charred organic matter, produced to abate the enhanced greenhouse effect by sequestering carbon in soils and improve soil properties. Biochar is a stable carbon compound that can be kept in the ground for a long time, until thousands of years. Biochar is created when biomass is heated to temperatures between 300 and 1000"C, under low or zero oxygen concentrations. Universiti Putra Malaysia (UPM) with the collaboration of Nasmech Technology Sdn Bhd have successfully built a plant producing biochar from EFP and also the first large-scale biochar production plant in the region. They have constructed a carbonator — driven plant to produce the biochar from residue materials including the EFB about 20 tonnes daily [104].

Besides converting dried oil palm wastes into various value added products, it also have potential as a source of renewable energy. Utilization of oil palm wastes as a source of energy will bring other environmental benefit like reduction in CO2 .emissions. The greenhouse gases that are present in the atmosphere include water vapor, CO2, methane and ozone, and the increase of greenhouse gases primarily CO2 is the major cause for global warming. Oil palm wastes such as fiber, shell and EFB can be used to produce steam for processing activities and for generating electricity [105]. At present, there are more than 300 palm oil mills operating with self-generated electricity from oil palm wastes. The electricity generated is for their internal consumption and also sufficient for surrounding remote areas [106].

A cement company in Malaysia had used palm shell as fuel in the boiler and they found they the emissions of CO2 can be reduced by 366.26 thousand metric tonnes in the year 2006 alone [107]. Hence, the emission of CO2 in Malaysia can be decreased significantly if all industries in Malaysia can replace or partially replace fossil fuel with oil palm wastes to generate energy without degrading the environment.

Hydrogen is a synthetic fuel, which can be obtained from fossil fuels, nuclear energy and renewable energy sources such as oil palm wastes. In almost any application replacing fossil fuels, hydrogen may be used as fuel especially as feedstock for synthesis of clean transportation fuels or as a gaseous fuel for power generation [108,109]. Gasification is one of the technologies for producing hydrogen. Oil palm wastes such as EFB, fiber, shell, trunks and fronds can be used for gasification [109,110]. The benefits of using hydrogen as transportation fuel are higher engine efficiencies and zero emissions [111]. However, production of hydrogen from oil palm wastes is still at the early stage of research in Malaysia.

3. Conclusions

Malaysia is one of the world’s primary palm oil producers and has been taking steps to promote the use of renewable energy. The utilization of renewable energy resources, in particular oil palm wastes is strategically viable as it can contribute to the country’s sustainability of energy supply while minimizing the negative impacts of energy generation on the environment. It will help the government to achieve its obligation to prolong the fossil fuel reserves. The efficient use of oil palm biomass other than the palm oil itself for food consumption is a promising route to obtain more energy from oil palm plantations. It will also solve the agriculture disposal problem in an environmental friendly manner while recovering energy and higher value chemicals for commercial applications like bio-fuel, coal replacement, building products and many others. The current principle adopted in Malaysia is a cost pass-through mechanism for electricity generation which is the same principle adopted for renewable power generation. This method would result in a small increase in the price of electricity paid by electricity consumers, but at the same time, the consumers may benefit from revenues derived from renewable energy generation. Although this effort pales in comparison to other countries which had become leaders in renewable energy growth, the acceptance of this form of renewable energy contribution calls for a paradigm shift among the people in the realm of sustainable energy. In general, the maturity of the country is marked by an acceptance of the need for the country to wean reliance on a depleting and environmentally damaging fuel source.

Author details

N. Abdullah[1] and F. Sulaiman

School of Physics, Universiti Sains Malaysia, 11800 Minden, Penang, Malaysia

Acknowledgement

The authors would like to acknowledge the three research grants provided by Universiti Sains Malaysia, Penang (1001/PFTZTK/814087, 304/PFIZIK/6310087, 304/PFIZIK/6310073) that has made this research possible.