Palm Oil Mill Effluent

PALM OIL MILL EFFLUENT

Palm oil mill effluent (POME) is the waste water discharged from the sterilization process, crude oil clarification process and cracked mixture separation process. POME produced huge amount of methane gas from its anaerobic process and has 21 times Global Warming Potential (GWP) compared to the other gasses. However it can be solved, if it can be utilized as fuel for power generation and cogeneration. Notwithstanding the huge potential, existence of proven technologies and availability of knowledge and incentives, biogas utilization is still in a very early stage in Malaysia.

Wastewater treatment facility is amongst the most important component in the palm oil mill system. This is because the facility is to treatment palm oil mill effluent (POME) that is being generated in large volume during the production of crude palm oil (CPO). Due to the chemical and physical properties of POME, the most efficient system used in the initial stage of the wastewater plant is the anaerobic treatment. The current systems meet the requirement of the palm oil mill operators to safely discharge the treated POME. However, the systems release one of the green house gases (GHG), CH4 into the atmosphere as the by-products of anaerobic digestion of POME.
 

BIOGAS/METHANE RECOVERY AND POWER GENERATION

Biogas with Methane (CH4) as major gas fraction from the POME could be recovered in the POME treatment facility by changing the anaerobic lagoons to closed/covered digesting ponds or sealed digesting tanks as shown in Figure below. Electric power therefore is generated via the combustion of the CH4 in the gas turbine. Power generated then is supplied to Sarawak Energy.

The overall power generation potential from effluent treatment can be estimated based on the calculated methane yield from anaerobic POME treatment. According to Malaysia Palm Oil Board (MPOB), 0.65 m3 POME is generated from every processed ton of fresh fruit bunch.

Figure: Proposed biogas recovery and power generation

In the following Figure, the composition of biogas from POME has been determined as 62.5 % methane, 37 % Carbon dioxide and 1,500-3,000 vppm hydrogen sulphide. The calorific value for the generated biogas is 22,000 kJ/m3. The heating value (average caloric value) of methane was 36.3 MJ m3 at standard conditions (Matteson and Jenkins, 2005). This corresponds to 10.888 kWh of energy per 1 m3 of methane.

Figure: Schematic diagram of methane recovery from POME

Based on annual production of 9,288,000 tons of FFB process in Sarawak; resulting in an annual effluent generation of 6,037,200 m3 and therefore 150,930,000 m3 of biogas could be harnessed. Assuming that the effluent is treated properly under anaerobic conditions, the total methane production amounted to 94,000,000 m3. The calorific value of methane is stated as 10kWh/m3. The annual energy content of the generated methane gas can be calculated to 940 GWh (~108 MW).

Based on a conversion efficiency of 38 % (gas engine), the potential annual electrical power generation would be 360 GWh. Assuming 100 % availability of the conversion system shall results in an installed power generation capacity of 41 MW from POME derived methane gas. This is summarized in Table below.

Parameters	Value	Unit
FFB	9,288,000	ton/year
POME yield	6,037,200	m3/ton-FFB
Biogas yield from POME	25	m3-biogas/m3-POME
CH4 gas fraction in biogas	0.625	m3-CH4/m3-biogas
CH4 emitted	0.94E+08	m3
Electricity equivalent (38 % eff)	3.6E+08 or (41)	kWh or (MW)

Table: Parameters for estimating CH4 from POME

In spite the substantial potential for biogas utilization in Malaysia especially in palm oil industry, only very few operation biogas utilization applications could be identified in Peninsula Malaysia. Deployment of biogas technology such as anaerobic biogas reactor would furthermore lead to a drastic reduction of GHG emission and also could bring a profitable energy business in the future. There are possibilities to harness this bio-methane from POME for generating “Green” electricity from fuel cell in the future fuel cell applications.

PALM OIL MILL EFFLUENT (POME) - PALM OIL BIOGAS (POB) POWER GENERATION AND COGENERATION TECHNOLOGIES
Since the palm oil mills have abundant biomass waste resources, their energy systems were designed to be cheap rather than efficient. Most of the existing biomass combustion systems in Malaysia utilize low efficiency low-pressure boilers. The average conversion efficiencies in process steam and electricity generation are 35 % and 3 %, respectively. The average overall cogeneration efficiency is 38 %. An additional source of energy in palm oil mills is the biogas produced in the anaerobic decomposition (for wastewater treatment purposes) of POME. Presently, POME-derived biogas is not recovered and used. This CH4 rich (65 %) gas is allowed to dissipate freely into the atmosphere.

Commercially proven technologies are available in the international market for efficient production of power and heat from major biomass resources - bagasse, wood waste, palm oil waste, straw, and rice husk. The state-of-the-art modern technologies utilize efficient high pressure boilers. Some of these boilers are capable of dual fuel burning, utilizing either liquid (e.g., diesel oil) or gas (e.g., natural gas) fuel as supplementary energy source. Dual fired boilers will be used in palm oil waste-fired boilers to facilitate the use of POME-derived biogas as supplementary fuel.

Local manufacturing capacity of efficient high-pressure steam generators in Malaysia is presently low. Most of the equipment for a biomass-based power generation and CHP has to be imported, making the capital cost of a conventional biomass power plant or CHP facility in the country high (typically around US$ 1,500/kW). Moreover, with the market potentials of biomass-based power projects and a suitable government policy on power pricing, the local boiler industry could possibly take up the manufacturing of high-pressure biomass boilers, when the market and demand for efficient biomass power technology takes off.
Technologies for the effective treatment and handling of POME have been applied in several palm oil mills in Malaysia. The present systems typically involve the anaerobic decomposition of the organic components of POME and are sufficient to meet the required final effluent BOD (biochemical oxygen demand) limits imposed by the government. As to the biogas produced during POME treatment, there are no government regulations yet requiring palm oil mills to prevent its release to the atmosphere.

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Palm Oil Biomass

CURRENT UTILIZATION

Today, Sarawak is the last frontier of oil palm development in Malaysia as land resources in Peninsular Malaysia is depleting while in Sabah oil palm development had reached its plateau. The total oil palm planted area in Sarawak Malaysia increased by 23.6 % to 4.49 million hectares in 2008 from 3.63 million tons in 2005. The production of fresh fruit bunch increased further by 43 % to 8.88 million tons in 2008 from 6.20 million tons in 2005.

In the process to extract crude palm oil and palm kernel from the fresh fruit bunch (FFB), considerable amounts of by-products such as fiber, shell, empty fruit bunch (EFB) and palm oil mill effluent are also generated as shown in Table below. These residues are the main energy resources that can be processed and converted to useful energies such as electricity, steam and heat.

Products / Residues	Typical mass produced per ton of FFB processed	Description
Primary products
Palm Oil	220 kg	A fine oil used for cooking and food production, further processing for soap production and olefins
Palm oil Kernel	60 kg	Processed to produce high grade oil
Residual materials
Empty Fruit Bunches (EFB)	220 kg	A woody fibrous biomass in units of approx. 65 by 30 cm. Disposal methods varies by country and region.
Shell	55 kg	A hard, solid biomass with high calorific value. Some used as fuel, some disposed e.g. landfill and road bases.
Fiber	130 kg	A fibrous biomass often used in the palm oil mills for boiler fuel for process steam and electricity.
Palm Oil Mill Effluent (POME)	650 kg	A dilute liquid effluent that requires processing prior to discharge to watercourses.

Table: Typical quantities of products and residues per ton of FFB

Figure below shows the current situation in palm oil mills in Sarawak, where the power generated for the mills are from the fiber and shell only. Even then the amount used is significantly smaller compared to the actual amount produced annually. Apart from producing the electricity to the mill, the steam is also used in the sterilization of fresh fruit bunch. EFB and POME are not being utilized for power generation. Only a small amount of EFB is being returned to the plantation for soil mulching while CH4 from POME is being released to the atmosphere.

Figure: Current utilization of POB in Sarawak

CURRENT AND FUTURE POTENTIAL

Table below illustrates the potential power generation from POB in Sarawak with a total yearly processing capacity of 9,288,000 tons of FFB in 2008 from 41 mills shown in the following Figure.

Production (ton)	Residue	Residue Producr Ratio (%)	Residue Generated (ton)	Total Potential Energy (MJ)	Potential Electricity Generation (MW)
9,288,000	EFB at 65%MC Fiber at 50%MC Shell at 10%MC TOTAL OPW POME	22.0 13.0 5.5 40.5 65.0	2,043,360 1,207,440 510,840 3,761,640 6,037,200	1,406,093 1,258,991 1,098,423 3,763,507 379,048	125 112 98 335 40

Table: Potential power generation from palm oil residues

Figure: Distribution of palm oil mills in Sarawak (2008)

The divisional production of FFB and POB are shown in Figure A and Figure B respectively while the divisional power potential from POB is shown in Figure C. The total power potential from POB can be seen in Figure D where it shows 375 MW is possible including the mills/plants consumption of 1-2 MW per mill. Presently, an additional capacity of 1,074,000 tons of FFB from 8 mills is under planning and construction in which will increase the total potential of biomass for power generation in near future.

Figure A: Production of FFB in Sarawak 2008 (ton/yr)

Figure B: Production of palm oil biomass in Sarawak 2008

Figure C: Potential power from POM in Sarawak 2008

Figure D: Pyrolytic gasification

Year	Area (Ha)	FFB Yield (ton/ha)	FFB Production (ton)	Power Output (MW)				Total Capacity (MW)
				FFB	Fiber	Shell	POME
2008	569,196	16	8,876,540	119	107	93	38	357.95
2009	626,116	17	10,643,972	143	128	112	46	429.22
2010	688,728	18	12,397,104	167	149	130	53	499.92
2011	757,601	19	14,394,419	194	173	151	62	580.46
2012	833,361	20	16,667,220	224	201	175	72	672.12
2013	916,697	21	19,250,637	259	232	202	83	776.29
2014	1,008,367	22	22,184,074	299	267	233	96	894.59
2015	1,109,304	23	25,513,992	343	307	268	110	1,028.87
2016	1,220,234	24	29,285,616	394	353	308	126	1,180.96
2017	1,342,257	25	33,556,425	452	404	353	145	1,353.18
2018	1,476,483	26	38,388,558	517	463	404	165	1,548.04
2019	1,624,131	27	43,851,537	590	528	461	189	1,768.34
2020	1,786,544	28	50,023,232	673	603	526	215	2,017.22

Table: Projection of total power output from palm oil biomass until 2020

Average annual growth in planted areas for the 2006 – 2008 is 11 %. For the computation shown in Table above, 10 % of annual growth is applied. Immature plantation areas are excluded. Only mature plantation areas are accounted for the FFB production. The annual growth of FFB yield is escalated at 1 ton/ha. Sabah recorded a 23 ton/ha yield while Melaka 25.6 ton/ha yield in 2008. According to MPOB, FFB yield could reach 30 %. Conservative thermal efficiency at 32 % and 38 % for POME are assumed throughout the 12 years. A total potential of 500 MW in 2010 and 1,000 MW in 2015 are possible. This will further possess a total potential of 2,000 MW in 2020.
 

EMPTY FRUIT BUNCHES (EFB) AS FUEL FOR POWER GENERATION

There are compelling reasons for supporting the use of empty fruit bunches (EFB) as a source of fuel for renewable energy (RE) power generation. Although the current use of EFB as mulch does have financial benefits, there are better financial gains, with a number of other advantages when used as a fuel for RE power generation. The rapid depletion of fossil fuel needs an alternative replacement and most developed nations are pursuing the development of biomass as an alternative method of power generation.

At 65 % moisture content, EFB has a calorific value of 6028 kJ/kg. The heat content of 1 ton EFB = 6,028 x 1,000 kJ = 6 028 000 kJ. A boiler generating steam at 42 bar absolute (bara) with a high temperature of 500 ºC and a condensing turbine operating in a pressure range between 42 bara and 0.035 bara can give a Rankine efficiency of 39.8 %. The actual thermal efficiency generally is 84 % of this. Even if it is assumed the actual cycle efficiency to be 80 % of the Rankine efficiency, the thermal efficiency is 32 %.

However, in this analysis, the overall thermal efficiency is assumed to be only 25 % for power output. Thus, 1 ton of EFB with 65 % moisture should deliver 6,028,000 x 0.25 kJ = 1,507,000 kJ of energy.

1,507,000 kJ = 1,507,000 / 3,600 kWh = 418.6 kWh

Assuming the minimum price offered by SEB for a unit of electricity is RM 0.21. The gross income will be RM 89.90. Allowing 30 % operational and maintenance cost, the net revenue will be RM 61.50. However, one ton of EFB when used as mulch was found to be RM 14.40. This figure includes all the benefits as a fertilizer as well as the increased FFB yields resulting from using EFB to supplement fertilizer cost.

PALM OIL BIOMASS BRIQUETTES

Palm oil industry generates vast amount of palm biomass. However a considerable portion of this biomass is not feasible to contribute for commercial power generation due to the logistic concerns. Therefore, converting palm biomass from scattered estates into a uniform and solid fuel called “Biomass Briquettes” through condensing process appears to be an attractive solution in upgrading its properties and add value. Palm biomass briquette could be the ideal renewable energy fuel source for co-firing in our coal-fired power plants.

The raw materials including empty fruit bunch (EFB), in powder and fiber forms and palm kernel were compressed into briquettes at high temperature and pressure using screw extrusion technology. It was found that briquettes made either from 100 % pulverized EFB or mixed with sawdust exhibited good burning properties. EFB fiber and palm kernel, due to their physical properties, were recommended to be blended with sawdust in producing quality briquettes. Basically, converting palm biomass into briquettes has increased its energy content and reduced moisture content about minimum of 5 % and 38 % respectively compared to its raw materials.

FOSSIL FUEL REPLACEMENT AND CO2 REDUCTION ANALYSIS

Type of Power Plant	Capacity MWe	Fuel 1	Fuel 2	Coal Replaced (ton/y)	CO2 avoided (ton/y)
	10 (small scale)	Biomass (100%)	Coal (0%)	52,560	118,260
	110**	Coal (100%)	-
		Coal (90%)	Biomass (10%)	50,000	112,500
		Coal (80%)	Biomass (20%)	100,000	225,000

Table: Fossil fuel replacement & CO2 reduction

Calculation derived from the data of SPC Phase 2 (2008) (**) – Generation versus coal consumption is shown in Table 1.5.5. The total coal consumption for 110 MWe Coal-fired plants was about 500,000 tons in 2008 with energy output of about 750,000 MWh. The caloric value (CV) for coal is approximately three times of biomass’s CV (EFB). Therefore, it is anticipated that about three times of biomass volume, in particular EFB will be required to replace each ton of coal. The CO2 emission is 1.5 t CO2/MWh or 2.25 tons of CO2 per ton of coal.

For a typical 10 MW (*) EFB power plant, with 7,884 hours of operation per annum, the total coal shall be replaced is estimated at 52,560 tons per year with 118,260 tons of CO2 could be avoided. The benefits of reducing CO2 emission by replacing proportion amount of coal with biomass are also factoring the feasibility of implementation of co-firing project. Assuming 1 ton CO2 (1 CER) is traded at RM 30, the total revenue from carbon credit through CDM will be ranged from RM 3 million to RM 7 million of revenue per year for 10 % to 20 % of coal replacement with biomass fuel.

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Biomass

INTRODUCTION OF BIOMASS AS ENERGY RESOURCE

Biomass energy is an indirect solar energy and it is the oldest known renewable energy that humans have been using since the discovery of fire. The term biomass refers to vegetative and organic materials coming from agricultural, forestry, urban, and other rural activities, mainly via photosynthetic process capturing some of the solar energy.

Biomass energy is also known as the energy that contained in the plants and organic matter. Historically, biomass has supplied food, feed, fiber, and structural materials needs for humans through metabolism of biological organisms and, over millions of years of geologic time, to form fossil fuels like oil, natural gas, and coal. By category, biomass includes agricultural residues, forest slash and thinning, urban wood wastes, yard wastes, food processing wastes, livestock manure, chaparral, lumber mill waste, municipal solid wastes, and other residues derived there from.

The potential of biomass resources to supply much larger amounts of useful energy with reduced environmental impacts compared to fossil fuels has stimulated substantial research and development of systems to grow, harvest, handle, process, store and convert biomass to electricity, heat, liquid and gaseous fuels, and other chemicals and products. However, the key to accessing the energy content in biomass is converting the raw biomass materials (feedstock) into a usable form, which can be accomplished through three principal routes:

1) Thermo-chemical (combustion and gasification),
2) Biochemical (via anaerobic digestion and fermentation), and
3) Physicochemical (mechanical and chemical extractions).

The first two energy conversion routes are commonly used, and in practice, combinations of two or more of these routes may be used in the generation of final product or products. Electricity from biomass is significant and contributes to the long term targets for electricity generation from renewable sources due to the availability of biomass and also attributed as economic ways to increase renewable energy.

THE OBJECTIVE

The aim of the Renewable Energy Study is to ensure that the state of Sarawak’s biomass resources are properly supported and utilized, and that it delivers additional economical benefits whilst making a contribution to the emissions reduction.

This plan, for the first time, sets out the directions for the coordinated development of the biomass sources in the State. The plan will establish the status of current and future indigenous biomass feedstock and utilization of biomass power generation to meet the renewable energy target in the State of Sarawak.

BIOMASS FOR ELECTRICITY

Electricity can be generated from all types of biomass by several available technologies including the “co-firing” technique that mixes it with coal or natural gas in a combustion chamber.

Large centralized power plants offer the best economic performance, especially if they were also used for heat as in combined heat and power (CHP). Co-firing biomass with coal is a good centralized option in the large power plants. It is more efficient, when electricity is generated from biomass, to make use of the heat that is produced as well particularly for industries consumption.

Smaller decentralized plants burning solid biomass or biogas tend to cost more, but often have advantages for the environment and for rural development. These shall be considered as rural development program in Corporate Social Responsibilities (CSR) scopes. The main concern will be in relation to biomass availability, transport infrastructure and grid connection possible.
In long terms, SEB believes that it is more pragmatic to harness the potential of all cost-effective forms of biomass electricity generation rather than focusing on certain forms alone. Hence, we need to look into variety of options especially when taking into account the future expansion of agriculture and biological sources.

BIOMASS IN SARAWAK

With the abundant of eco-agricultural industries residues, biomass is widely considered as the most viable mean for SEB to achieve the 100 MW renewable energy target by 2015. In line with the Malaysia Plan’s target and the incentives provided, Sarawak Energy envisages grasping the significant potential of biomass power generation to contribute to the renewable energy shares in the state.

The main biomass sources are palm oil biomass and paddy waste. With current production rate of oil palm fresh fruit bunch and paddy at about 9,300,000 tons and 208,000 tons per annum respectively, Sarawak has the theoretical potential of drawing.

Having said that, not all of these potential can be brought to fruition due to the logistic constrains. Hence, strategic approaches are vital to ensure the biomass sources could be efficiently utilized and supported. Power generation from palm oil biomass will be on grid generation whereas the others sources including rice husk and rice straw will be non-grid power generation. The latter shall be planned for community-based rural electrification to partly displace diesel generation at this stage.
Furthermore, the efficiency of the energy-harnessing or conversion technology is becoming an important factor in utilizing most of the biomass available. The conversion technologies include combustion, co-firing, gasification, anaerobic digestion and fermentation where the end-products are used for generating electricity is fairly common nowadays. The electricity efficiency through boiler and gas engine is generally 32% and 38% respectively.

The upgrading and centralization of landfill and sewerage system in Sarawak also possess an opportunity for power generation in future. The waste produced in the process of waste treatment is considered biomass as it involves microorganisms that degrade carbon-based materials.

There are more biomass source options in Sarawak including cocoa husk and sago wastewater but the extent of production is not yet promising for power generation. The algae cultivation for biofuel is seen as a solution to mitigate the CO2 emission as algae are utilizing the CO2 from power plants. Nonetheless, the high production cost associated with the biological engineering is the hindrance to deploy the algae cultivation at this moment.

Definitely, the policies and regulations that directs to the efficient utilization of biomass and the environment conservation as well as appealing incentives for the plants and more attractive electricity price are more importance to spur the development of biomass utilization.

BIOMASS UTILIZATION IN THE STATE

In 2002, the government of Malaysia initiated a project, Biomass Power Generation and Cogeneration in Palm Oil Industry (BIOGEN) to help promote the use of renewable energy, with support from the United Nations Development Program (UNDP), the Global Environment Facility (GEF) and the private sectors. It aims to reduce Greenhouse Gas (GHG) emissions from fossil fuel use and to accredit these reductions for sale through the Clean Development Mechanism (CDM).

The primary objective is to develop and implement activities that will build stakeholders’ capacity and facilitate the greater adoption of renewable energy system. It focuses on palm oil industries and the use of waste material in generating electricity in the mills and selling it to the grid where possible. The importance of Renewable Energy with emphasis towards Energy Efficiency is further reinforced in the 9th Malaysian Plan (9MP) (2006 - 2010) on the production and utilization whilst meeting the environmental objectives. By 2010, Renewable Energy is expected to contribute 350 MW to total energy supply in Malaysia, which is projected to reach 3,128 PJ. Biomass such as rice husks, palm oil and biological waste will be used on a wider basis mainly for power generation.

Under the Small Renewable Energy Power Program (SREP), small power plants utilizing renewable energy are eligible to apply for selling electricity to the utility companies through distribution systems in which applies to all types of renewable energy, including biomass, biogas, municipal waste as well as solar, mini-hydro and wind. This program particularly focuses on biomass wastes as the key renewable energy resources, especially biomass residues from oil palm industries.
The SREP allows renewable projects with up to 10 MW of capacity to sell their electricity output to the utilities. As of July 2009, a total of 43.5 MW has been generated and connected to the grid from projects under SREP program. For off grid power generation, as to 2007, a total capacity of 421 MW of electricity has been generated using biomass waste. For Sarawak, there are possibilities to instigate biomass power plants with capacity more than 10 MW due to the consistent growth of oil palm plantation in the state.

Sarawak is a state with tremendous biomass and bio waste resources available for immediate exploitation. Much of this is readily available waste from the agricultural sector, mainly from oil palm mass plantation. The State of Sarawak is committed in seeking to intensify the development of renewable energy, particularly biomass, as the ‘fifth fuel’ resource under the country’s Fuel Diversification Policy. The policy, which was set out in 2001, had a target of renewable energy providing 5 % of electricity generation by 2005, equal to 100 MW of installed capacity for the state.

Biomass can be the source of hydrogen for new energy conversion techniques such as fuel cells. Therefore, preliminary investigation with a local partner (potentially the Curtin Institute of Technology) shall be carried out to study the gasification of biomass materials/residues.

Technically, the State of Sarawak possesses the potential of generating a total of 425 MW of electricity from the indigenous biomass sources. Palm oil biomass is the main viable source that could contribute about 375 MW of renewable energy electricity based on current biomass yields in the palm oil plantation. Another emerging potential source is paddy residues from the paddy plantation in which could produce substantial amount of electricity in next couple of years with a relatively small capacity of 50 MW presently that does not has the economy of scale at the moment. The estimation of this potential is shown in Table below.

Biomass	Production Rate (ton/year)	Moisture Content (%)	Lower Heating Value (kJ/kg)	Energy Available (MJ)	Potential Electricity, 32% efficiency (MW)
Oil Palm Empty Fruit Bunch Mesocarp Fiber Shell POME	2,043,360 1,207,440 510,840 6,037,200	60 50 10 95	6,028 9,134 18,836 22	1,406,093 1,258,991 1,098,423 379,048	125 112 98 40
TOTAL					375
Paddy Rice Husk Rice Straw	51,893 259,468	13 14	13,395 16,350	79,351 484,281	7 43
TOTAL					50
OVERALL					425

Table: Overall view of electricity potential from biomass in Sarawak

BIOMASS CONVERSION TECHNOLOGIES

As been stated earlier, the conversion technologies can be categorized into thermo, bio and physicochemical routes. The useful end product of the route can be gaseous or liquid that is used in gas engine or turbine to generate electricity. The routes from biomass to electricity are simplified in Figure 1.4.

COMBUSTION

Energy production from biomass through combustion is the most common technology, but is usually economical only when the raw material is available at little or no cost and is burnt near the source. Transportation costs for unprocessed biomass are far greater than for fossil fuels as they contain less energy per unit volume than fossil fuels. Therefore, before being transported, biomass must first be converted into a fuel with higher energy density. This is done by compressing the material. Wood and its residues, for example, can be converted into dense pellets, cubes or briquettes.

ANAEROBIC DIGESTION

Simple biogas producing devices create anaerobic digestion by decomposing organic matter like crop residues or domestic wastes in an oxygen deprived environment. The resulting biogas (mixture of gases) can be burnt to provide energy for cooking and space heating, or create electricity to power other equipment. Since many of the parasites and disease producing organisms in the waste are killed by the relatively high temperature in the digester tanks, the digested material can also be used as fertilizer or fish feed.

GASIFICATION, PYROLYSIS AND PLASMA ARC

These technologies are the other version of combustion where heat is used to degrade biomass into gaseous or liquid form. In gasification, biomass is heated in the presence of oxygen to produce primarily gaseous fuels while pyrolysis involves the heating of biomass in the absence of oxygen to produce a mixture of oils, gases and solid charcoal. Plasma arc on the other hand uses high voltage of electricity to break the feed into its elemental components in gaseous form.

FERMENTATION

Some conventional food crops that are high in starches and sugars, like sugarcane, corn, sorghum, etc. can be fermented to produce ethanol, a relatively clean burning, high-energy fuel. The commercial production of ethanol, however, requires a major surplus of crops or the production of crops specifically energy purposes. Other less expensive biomass feedstocks such as wood or plant wastes can also be used for ethanol production but present conversion techniques in this field are not very efficient, hence overall cost of ethanol produced from these sources is relatively greater.

Figure: Routes of energy conversion from biomass besides combustion

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Solar Energy

INTRODUCTION TO SOLAR ENERGY

The sun creates its energy through a thermonuclear process, which creates heat and electromagnetic radiation. Only small fraction of the total radiation produced reaches the Earth. Insolation is a measure of solar radiation energy received on a given surface area in a given time, and is expressed as average irradiance in watts per square meter or kilowatt-hours per square meter per day. Solar energy is then refers primarily to the use of this solar radiation for practical ends. Solar insolation of the world is well expressed in the map as figured below:

Figure: The amount of solar energy in hours, received each day on an optimally tilted surface during the worst month of the year based on accumulated worldwide solar insolation data
(Source: http://www.altestore.com/howto/Solar-Electric-Power/Reference-Materials/Solar-Insolation-Map-World/a43/)

SOLAR RADIATION IN SARAWAK

Malaysia lies entirely in the equatorial region. The tropical environment has been characterized by heavy rainfall, constantly high temperature and relative humidity and has abundant sunshine and solar radiation. It is however extremely rare to have a clear day even in periods of severe drought. The annual average daily solar irradiations for Malaysia were from 4.21 kWh/m2 to 5.56 kWh/m2. The highest solar radiation was estimated at 6.8 kWh/m2 in August and November while the lowest was 0.61 kWh/m2 in December. The Northern region and a few places in East Malaysia have the highest potential for solar energy application due to its high solar radiation throughout the year. However, it is extremely rare to have a full day with completely clear sky even in periods of severe drought. The cloud cover cuts off a substantial amount of sunshine and thus solar radiation. Seasonal and spatial variations in the amount of sunshine received cannot be ruled out. Areas such as Kuching in Sarawak receive about 4 hours of sunshine per day on an average.

Figure: Estimates of annual averaged daily global solar irradiance for Sarawak
(Source: Daniel Ruoss, 2008)

The solar radiation mapping is based on data from Universiti Kebangsaan Malaysia, Meteonorm V6.1 software and satellite data from Meteotest. It is based on very few ground based data stations - available in Meteonorm V6.1 (www.meteonorm.com), overlapped the semi-completed irradiance map with satellite data from Meteotest in Europe. Satellite images have been identified as an alternative and accurate method for predicting average annual daily solar irradiation of a specific location. These images can be use to predict the performance and sizing of various solar energy systems The satellite data can be averaged over 1 year and provides indication of the irradiance situation in the spots which have no station. Using the statistical data from numerous ground based data gathering stations over 10 years and correlate with satellite data filling in the blanks where no data station is available.

The following Table shows the monthly averaged daily global solar radiation (peak sun hour) and sunshine hour for four observation stations in Sarawak.

	Kuching	Miri	Sibu	Kapit
Jan	3.63	4.98	4.26	4.18
Feb	4.15	4.56	5.08	4.66
Mar	4.38	4.97	5.11	4.74
Apr	4.50	5.55	5.30	4.80
May	4.68	5.39	5.14	4.74
Jun	4.57	4.73	5.14	4.74
Jul	4.80	5.43	5.12	4.83
Aug	4.55	5.44	4.80	4.75
Sep	4.16	5.21	4.50	4.66
Oct	4.73	5.50	4.67	4.59
Nov	3.81	4.45	4.51	4.48
Dec	3.70	4.16	4.22	4.26

Table: Average daily sunshine hour by month for selected cities in Sarawak
(Source: Sarawak Methological Department and KeTTHAIrradiation Data for Malaysia )

Note:
Irradiation - The total quantity of radiant solar energy radiation per unit area received over a given period of time, i.e. the energy of the solar radiation per unit area over that time period. Units in common usage include MJ/m2, kWh/m2 and peak sun hours (PSH). NOTE: 1 kWh/m2 = 1 PSH = 3.6 MJ/m2.

SOLAR IRRADIATION MEASUREMENT

Pyranometers are radiometers designed for measurement of the solar irradiance on a plane surface Pyranometersometimes called a solarimeter, which is used to measure broadband solar irradiance on a planar surface and is a sensor that is designed to measure the solar radiation flux density in W/m2 (watts per metre square) from a field of view of 180 degrees. Not all of the solar energy reaching Earth’s outer atmosphere reaches the surface of the Earth. Some of this energy is reflected back out into space and some of it is absorbed in the atmosphere itself. Pyranometer instrument can be used for measuring solar radiationreceived from a whole hemisphere. It is suitable for measuring global sun plus sky radiation.

Figure: Pyranometer installed on site for solar irradiance measurement
(Source: https://buildingsfieldtest.nrel.gov/solar_irradiance_measurements)

SOLAR ENERGY APPLICATION

To gather and convert the available solar energy to electricity, Photovoltaic (PV) or solar panels are used. Despite the abundant resource, solar PV applications in Malaysia are limited to mainly stand-alone PV systems, especially for rural electrification where the technology costs are highly subsidized. Hybrid systems based on PV and diesel generators have been used for the electrification of remote islands where grid connection is a costly option. Rural electrification projects particularly in Sabah and Sarawak have also incorporated PV systems in places where supply from the grid may not be possible for years to come. Other minor applications being promoted include telecommunication, street and garden lighting and recently, for powering the parking ticket dispensing machines.

Figure: On-site application of PV systems for electricity
(Source: Research and Development Division, Sarawak Energy Berhad)

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For further details log on website :
http://www.sarawakenergy.com.my/index.php/r-d/solar-energy