Besides producing oils and fats, at present there is a continuous increasing interest concerning oil palm renewable energy. One of the major attentions is bio-diesel from palm oil. Bio-diesel implementation is important because of environmental protection and energy supply security reasons. This palm oil bio-diesel is biodegradable, non-toxic, and has significantly fewer emissions than petroleum-based diesel (petro-diesel) when burned. In addition to this oil, palm is also a well-known plant for its other sources of renewable energy, for example huge quantities of biomass by-products are developed to produce value added products such as methane gas, bio-plastic, organic acids, bio-compost, ply-wood, activated carbon, and animal feedstock. Even waste effluent; palm oil mill effluent (POME) has been converted to produce energy. Oil palm has created many opportunities and social benefits for the locals. In the above perspective, the objective of the present work is to give a concise and up- to-date picture of the present status of oil palm industry enhancing sustainable and renewable energy. This work also aims to identify the prospects of oil palm industry towards utilization of oil palm as a source of renewable energy.
The oil palms (Elaeis guineensis) comprise two species of the Arecaceae, or palm family. Mature trees are single-stemmed, and grow up to 20 m tall. The leaves are pinnate, and reach between 3 and 5 m long. The flowers are produced in dense clusters; each individual flower is small, with three sepals and three petals. Unlike, the coconut palm, the oil palm does not produce offshoots; propagation is by sowing the seeds. The fruit takes 5–6 months to mature from pollination to maturity; it comprises an oily, fleshy outer layer (the pericarp), with a single seed (kernel), also rich in oil. Oil palms are commonly used in commercial agriculture in the production of palm oil.
The oil palm is a tropical palm tree originated from West Africa where it was growing wild and later developed into an agricultural crop. Oil palm is the highest yielding oil crop, producing on average about 4–5 tonnes of oil/ ha/year, about 10 times the yield of soybean oil. Soybean oil was a distant second at 19%. Both palm and soybean oils combined, govern almost 48% of global oils and fats consumption in year 2006. Palm oil itself contributes about 33% of the world vegetable oil demand. In terms of the world market, both Malaysia and Indonesia account for 90% of the palm oil world export trade and will likely remain the key players in the palm oil sector, accounting for 28.5MnT or 85% of the world’s palm oil production.
It was forecasted that in years to come, the demand will be higher with the increasing demand of world total oils and fats. It is already very profitable to invest in the industry of oil palm. Oil palm can be used to produce many other downstream oleo-chemical products such as soap, palm fatty acids, palm-methyl esters and many more. Apart from that, huge quantities of biomass by-products such as empty fruit bunch (EFB) fibers, shells, fronds, and trunk are also produced. These biomasses can be converted into many value added product. Hence the objective of this paper will be outlining the contributions of oil palm’s by products as well as its oil as a source of renewable and sustainable energy.
Palm Oil
Palm oil is the second most traded vegetable oil crop in the world after soy and over 90% of the world’s palm oil exports are produced from Malaysia and Indonesia. Palm oil is derived from the fruit flesh of the oil palm. The palm fruit is about the size of a small plum and grows in large bunches weighing 10–20 kg. A bunch can have up to 2000 individual fruits. Each fruit consists of a hard kernel (seed) inside a shell (endocarp), which is surrounded by a fleshy mesocarp. Oil is extracted from both the pulp of the fruit (palm oil—edible oil) and the kernel (palm kernel oil (PKO), used mainly for soap manufacture. Crude palm oil (CPO) is the primary product derived from the red fruits of the oil palm, while PKO, derived from the fruit’s nut is considered to be a secondary product. Hence two types of oils, i.e. CPO and crude palm kernel oil (CPKO) are produced. Although both oils originate from the same fruit, palm oil is chemically and nutritionally different from PKO. Furthermore palm oil is one of the only two mesocarp oils available commercially, the other being olive oil. Palm oil is semi-solid at room temperature; a characteristic brought about by its approx. 50% saturation level. In its virgin form, the oil is bright orange-red in color due to its high content of carotene. Palm oil contains palmitic acid (a fatty acid made by our body), the monounsaturated oleic acid, polyunsaturated linoleic acid (an essential fatty acid) and stearic acid. The typical blend in palm oil is 45% palmitic, 40% oleic, 10% linoleic and 5% stearic. Palm oil (and its products) has good resistance to oxidation and heat at prolonged elevated temperatures; hence, making palm oil an ideal ingredient in frying oil blends. Manufacturers and end-users around the world incorporate high percentages of palm oil in their frying oil blends for both performance and economic reasons. In fact, in many instances, palm oil has been used as 100% replacement for traditional hydrogenated seed oils such as soybean oil and canola. Products fried in palm oil include potato chips, fries, doughnuts, ramen noodles and nuts. The palm oil is also rich in natural chemical compounds important for health and nutrition. Among others, it is a natural source of carotenoids and vitamin E as well as supplying fatty acids and other important fat-soluble micronutrients. It also supplies an abundance of calories that gives us much-needed energy for our daily life. CPO is the richest natural source of tocotrienols which is a fat-soluble vitamins related to the family of tocopherols. In recent studies and research there is now a reasonable and ever-growing body of scientific literature documenting the anti-cancer properties of the tocotrienols and palm oil do attest this properties. Lately, the Malaysian Palm Oil Board (MPOB) has developed a special patented technology for extraction. The latest technology to purify tocotrienols from the fruits of oil palm was developed to produce a superior quality and purity. Refined red palm oil is used for the treatment and prevention of vitamin A deficiency. Palm oil is indeed a nature’s gift to the world.
In terms of energy expression, oil palm is an energy efficient crop that requires less energy input to produce 1 tonne of oil. The energy expressed by the ratio energy output to input is wider for oil palm than any other commercially grown oil crops sources such as soybean and rapeseed. The energy output of oil palm is almost 3 times higher comparatively to soybean and rapeseed oil. Moreover oil palm cultivation and processing requires lower inputs of agrochemicals (pesticides), fertilizers and fossil fuels to produce 1 tonne of oil, with fewer resulting pollutions and emissions.
Palm Oil Bio-Diesel
There is a continuously increasing interest concerning the bio-fuel implementation in Europe and other countries, mainly because of environmental protection and energy supply security reasons. Future shortage in petroleum supply and surging prices for petroleum-based fuels, coupled with the increasing awareness of green house gas emissions increase the shift towards the alternative fuels sector. An alternative fuel must be technically feasible, economically competitive, environmentally acceptable and readily available. One possible alternative to petroleum-based fuels is the use of oils of plant origin like vegetable oils and tree borne oil seeds. Hence this crop oil can be used as renewable resource for fuel energy. This alternative fuel is termed as bio-diesel.
Bio-diesel is chemically defined as a methyl ester, which can be prepared from triglycerides in vegetable oils by transesterification with methanol. This fuel is biodegradable, renewable, clean, non-toxic, and has low emission profile as compared to petroleum diesel.
Bio-diesel is mainly produced from vegetable oils, which are derived from the seeds or the pulp of oil-bearing crops. There are two types of oil crops. It can be annual (rapeseed, groundnut, soybean, and sunflower) or perennials (coconut palms, oil palms, physical nut, and Chinese tallow tree). Oil from the rapeseed was the first type used for bio-diesel production and in Europe rapeseed is still the main feedstock for bio-diesel production. Among the sources, palm oil is the cheapest vegetable oil and has the highest oil yields/ha of plantation.
The following are the advantages of introducing bio-diesel industry which have been outlined in the National Biofuel Policy:
a. mitigating the effects of petroleum price escalation,
b. savings in foreign exchange by reducing the imports of petroleum diesel,
c. environment friendly source of energy by reducing the emissions of greenhouse gases, d. creating new demand for palm oil,
e. mutually beneficial effects on petroleum and palm oil sectors, f. achieving socio-economic safety net, and
g. efficient utilization of raw materials.
Oil Palm Bio-mass
Biomass, in the energy production industry, refers to living and recently living biological material, which can be used as fuel or for industrial production. Biomass conversion systems are arrangements, which can be large and produce electricity (bio-power) and heat; or small—a wood stove or small wood-fired furnace using biomasses. Biomass conversion can also produce bio-fuels, which include ethanol, methanol, bio-oil, and bio-diesel. Biomass energy or bio-energy is the largest source of domestic renewable energy. Many Agricultural industries such as sugar, palm oil, rice, and wood have been utilizing their biomass as a fuel to cover some or all of their energy requirements.
Oil palm mills generally generate numbers of biomass wastes. The amount of biomass produced by an oil palm tree, inclusive of the oil and lignocellulosic materials is on the average of 231.5 kg dry weight/year. Table 5 shows types of biomass produced from oil palm tree and the quantities produced per annum in MnT. These biomasses have high potential of turning into renewable energy. Empty fruit EFB and mesocarp fiber (MF) is the highest contributor of oil palm biomass, whereby about 15.8 and 9.6 MnT, respectively have been produced/year.
Oil palm fronds are available daily throughout the year when the palms are pruned during the harvesting of fresh fruit bunch for the production of oil. Oil palm trunk is obtained during the re-plantation of the oil palm trees. EFB, MF and shells are collected during the pressing of sterilized fruits. Oil palm biomasses can be transformed into three types of biomass energies: i.e. bio-products, bio-fuels, and bio-power.
Bio-products
Palm oil biomasses can be utilized to produce various types value added products. Whereby oil palm biomasses such as the EFB and MF have been modified and processed to produce molded oil palm (MOP) products. MOP product is a unique bio-based material made from oil palm particles and thermoset resin in matched metal disc under heat and pressure. MOP products are extremely versatile and can be used in furniture, building, electronics, packaging, and automobile industries. One of the latest researches by the MPOB onto EFB is to convert EFB into paper-making pulp. The pulp is then bleached using the total chlorine-free (TCF) methods to obtain sheets of paper. Pulp and paper used from oil palm biomass can be used in many ways such as cigarette paper and bond papers for writing. Hence with this advancement from using oil palm biomass. Presently, most of the EFB and MF are used as soil conditioners in estates and plantations and incinerated to obtain oil palm ash (OPA) that can be used as a source of fertilizer due to its high potassium content. Some researches have utilized this OPA to synthesize absorbents for toxic gas removal (sulfur dioxide, SOx). The active compound (silica, alumina, potassium, calcium, and hydrated water) in the absorbent prepared from OPA is believed to be responsible for the high absorption capacity of SOx. EFB and MF also have been used to manufacture medium density fibre-board (MDF) and blackboard. The latest research and output of the local scientists proved that the palm kernels, EFB, palm shells, and stones can be converted into value added products such as oil palm activated carbon. This oil palm activated carbon has been used to treat air toxics such as carbon monoxide (CO) and SOx.
Most of the oil palm trunk is converted into various types of wood such as saw-wood and ply-wood or lumber. Oil palm lumber has been successfully utilized as core in the production of blackboard. The saw-wood produced from oil palm can be used to make furniture but not for building structure due to its low specific density. However, the strength of the ply-wood produced from oil palm was found to be comparable with commercial ply-wood. The excess shells are usually used to cover the surface of the roads in the plantation area. Oil palm trunk also has been used to produce particleboards with chemical binders. Moreover, some of the trunks are mixed with EFB and oil palm fibers to be combusted and produce energy.
Fronds are a source of food for ruminants (cattle and goats). Fronds are also left to rot in between the rows of oil palm trees in the plantation for following reasons: (a) soil conservation; (b) increase the fertility of the soil; (c) increase the amount of water retain in the soil; (d) erosion control; and (e) provide a source of nutrient to the growing oil palm tress (Nutrient is recycled, as a long term benefits).
Besides this, oil palm kernel cake (PKC) has been used to produce animal feed. Some of the waste fatty acids from the kernel and CPO have been used to make fatty acid- based product for animal feed, calcium soap and palm fatty acid distillate (PFAD). In addition to this the oil-production process yields copious amounts of residues that find use in biogas production, as a bio-energy feedstock for co-firing with coal or as base chemicals for the production of bio-plastics and a series of highly valuable biomaterials.
Bio-fuels
Oil palm biomass can be used to make the same products that are created by fossil fuels, sometimes using less energy to do so. Synthetic biofuels are synthetic hydrocarbons or mixtures of synthetic hydrocarbons from biomass, e.g. SynGas (SNG) produced from gasification of forestry biomass or SynDiesel. There are 3 types of bio-fuels that is: bio-ethanol, bio-diesel, and bio-methanol. Bio-ethanol fuels are mainly produced by fermentation from grains rich in sugar or starch. Oil palm waste fibers especially EFB are rich in sugar. Research papers show that EFB have been used to produce glucose and xylose successfully. EFB can be used as a feedstock for second generation ethanol to produce bio-oil and bio-ethanol through pyrolysis and fermentation or hydrolysis, respectively. Flexible-fuel vehicles can run on about 85% ethanol made from these biomasses. Bio-methanol is methanol produced from biomass. A new study patented in Swedish technology concluded that the alcohol fuel methanol can be produced from biomass via black liquor gasification at a cost competitive with that of gasoline and diesel. One of the recent studies on oil palm biomass waste showed that black liquor can be produced from the trunk of oil palm but at present the black liquor is used to produce pulp and paper. With this up-coming research, one day it is predicted that EFB and the waste trunks of oil palm can be used to produce bio-methanol.
Bio-power
Bio-power is the use of biomass to generate electricity. Types of bio-power systems include direct-fired, gasification, anaerobic digestion, pyrolysis, and small, modular systems. Direct-fired systems consist of burning bioenergy feedstocks to produce steam, which is then captured by turbines that spin a generator, eventually creating electricity. EFB and MF are normally used for this process in the existing oil palm factories whereby heat energy is produced through burning or direct combustion and then captured to spin an electric generator. Ligno–cellulosic biomass, i.e. the EFB, can be converted to hydrogen gas through gasification process. On the other hand, the MF and shell contain a small quantity of oil, hence they are used as boiler fuel to generate steam for mill consumption . Most palm oil mills burn all of their fiber and some shells as boiler fuel to produce steam for CPO extraction and a small amount of electricity for internal use.
Recently Chubu Electric Power has announced plans to build two biomass power plants in the eastern province of Sabah, Malaysia. This new biomass plants will use the leftover- disposable palm bunches as renewable energy source to generate the output of a 10,000 kW small-scale electric power plant. The palm biomass power plant will also fulfill CO2 emission trading standards, guidelines set up by EU in 2002 for a trading system for greenhouse gas emission allowances. Chubu aims to reduce CO2 by 2 MnT annually with the new plant, and acquire the CO2 emission trading credits.
Another proposed Project in Malaysia is a biomass power plant with 11.5 MW capacity, which will generate and supply electricity to the fossil fuel intensive Peninsular Malaysia grid. It is fuelled by a renewable source and supplies electricity to a distributor that is supplied by at least one fossil fuel generating unit. In this project EFB will be combusted in a boiler to produce electricity. This project is currently in the progress of building the power plant in Pantai Remis, Perak by Bumibiopower Sdn. Bhd.
Palm Oil Mill Effluent
The major source of wastewater generation from palm oil mill is namely sterilizer condensate, hydrocyclone waste, and separator sludge. On an average 0.9–1.5m3 of POME is generated for each ton of CPO produced. The POME is rich in organic carbon with a biochemical oxygen demand (BOD) value higher than 20 g/L and nitrogen content around 0.2 and 0.5 g/L as ammonia nitrogen and total nitrogen. Currently POME is converted into fertilizers and used in the nearby farm and vegetation area. This data show that POME can be used to produce bio-gas through anaerobic treating system. Anaerobic digestion describes the process by which bacteria in organic matter decompose without the use of oxygen; the result is extractable methane that is used as a source of energy. Therefore the processing of 20 tonnes of fresh fruit bunches, releases 100 tonnes of POME, that yield about 400 m3 of biogas. As the reserves of oil and gas are being depleted, security of energy supply has raised the demand towards the establishment of hydrogen economy. Hence, Malaysian researches have studied the effect of hydrogen production from POME using microflora isolated form the sludge of an anaerobic pond treating POME. It was a successful procedure and the average biogas generation was found to be 0.42 L/g COD destroyed, with a hydrogen content of 5772% at 7 d HRT. The generated biogas was free from methane.
Currently, a company ‘Bumibiopower’ is a renewable energy power plant developer in Malaysia by Mitsubishi Securities Co., Ltd. a Japanese company. This company is in the progress of setting up a plant for methane extraction and power generation using POME near Pantai Remis. The project activity is to install a closed anaerobic system that will produce and collect consistently high quality of methane-rich biogas from POME. This project also includes the installation of a generator, which will be fed by the collected biogas to produce renewable electricity. The size of the generator is expected to be between 1 and 1.5 MW.
Economic land use and social benefits
Oil palm is one of the world’s most efficient bearing crops in terms of land utilization, efficiency and productivity. A single ha produces up to 10 times more oil than other oilseeds. Oil palm yields an average of 3.68tonnes of oil/ha/year (projected to rise to 6tonnes within the next decade) compared to soybean, sunflower seed, and rapeseed. All this comes from a mere 1.84% of the 218 million ha under global oilseeds cultivation. This is done without farming subsidies as in Europe and the US. Income from a ha of oil palm, based on 2005 data, equals about RM 7350/year, compared to RM 6432 for agricultural crops in the UK–of which RM 1837 is from a EU subsidy.
Sustainable oil palm cultivation hosts a win-win situation. Whereby, a surge of oil palm plantations from the 1980s corresponding with higher standard of living through direct and indirect employment. This energy crop provides direct and indirect employment to 860,000 people excluding other multiplying effects and spin-offs activities. Malaysian plantation management is highly developed and government has set up the Federal Land Development Authority (FELDA) to reduced rural poverty through planting of economic crops such as oil palm. The exports of reasonable, healthy, nourishing and high-yielding palm oil now feed some 1.3 billion people in 150 countries. Oil palm is indeed a ‘life’ promoting energy.
Conclusion
The potential utilization of oil palm in various industrial fields has been discussed. Oil palm not only can be used as source of edible oil but also it can be enhanced into excellent renewable energy. Oil palm is one of the most productive bio-diesel crop. Moreover, its waste streams can be used to produce vast amounts of bio-gas and other values added products. This facts proves that oil palm is an energy crop that yields the highest energy balance of all energy crops (‘Energy Returned on Energy Invested’ is between 12 and 14), leaving all other competitors far behind. With this encouraging achievement, oil palm industries will circuitously intensify the economic and revenue growth. In near future CPO, bio-diesel made from oil palm and oil palm by- products could be one of the major contributors of renewable energy in the world, at the same time.
source: Sumanthi, S., Chai S. P., Mohamed, A. R., (2008) Utilization of oil palm as a source of renewable energy in Malaysia
