Abstract

 

The scope of this dissertation project is to develop a sustainable electricity generation model in the St. Martin’s Island. Five renewable resource options have been considered for the detail analysis. The outputs of this model indicate that all the options are capable of fulfilling the requirement but under specific criteria some of them would never payback.

 

This model indicates that it is possible to provide green electricity in the island from only coconut palm biomass, but this option is only financially viable when the energy entrepreneur cultivates the coconut palm and subsidy on the investment is granted.

 

The best option for the St. Martin’s Island has been found as the wind-solar-biomass hybrid system, in spite of purchasing the coconut palms feedstock. On the other hand if the energy entrepreneur cultivates the coconut palm, Wind and Biomass hybrid system will be the best option. 

 

 

 

 Executive summary

 

This dissertation project aims to investigate the feasibility of fulfilling the electricity demand in the St. Martin’s Island of Bangladesh from the available renewable resources and the scope of this research is to develop an excel spreadsheet model to identify the sustainable renewable options for the island. Five different electricity generation options have been considered for the detail analysis.

 

However the coconut palm feedstock is not free. So two basic choices for the biomass have been considered, one is to purchase the coconut palm feedstock and the other is to cultivate the coconut palm. In the second option, the land value and the cost of plantation have been taken into account. Again by-products from the system have been considered for selling. Further more the effect of subsidy on the IRR, NPV and payback periods and the sensitivity of the model have been critically analysed.

 

The main results from this model have been illustrated in table A-1. It is seen that every option is capable of fulfilling the electricity demand in the island but some of them would never payback due to their negative NPV. However the coconut palm cultivation criterion has shown the higher IRR and NPV but the lower payback period in compared with the coconut palm feedstock purchase criterion.

 

This model indicates that it is possible to fulfil the electricity demand in the St. Martin’s Island from only coconut palm biomass, but this option is financially viable when subsidy on the investment is granted and the energy entrepreneur cultivates the coconut palm. Moreover It is seen that this model is very economically sensitive to the cost of coconut palm feedstock, the cost of equipments and the amount of subsidy.

 

The best option for the St. Martin’s Island is found as the Wind-Solar-Biomass hybrid system i.e. option ‘A’, when there is no subsidy but need to purchase of coconut palm feedstock. On the other hand without subsidy but cultivation of coconut palm, option ‘E’ i.e. Wind and Biomass hybrid power generation system has been found the best selection.

 

 

 

 

Table of  Contents

 

								Page
Declaration of originality								I
Abstract								II
Executive summary								III
Contents								V
List of Figures								IX
List of Tables								X
List of Worksheet								XI
Abbreviations								XII
Acknowledgements								XIII
Chapter 1			Introduction					1
		1.1	Background information					1
		1.2	Aims					3
		1.3	Objectives					3
Chapter 2			Renewable Energy resources in the St. Martin’s Island					4
		2.1	Solar energy					4
		2.2	Wind energy					4
		2.3	Biomass energy					4
		2.4	Tidal energy					5
Chapter 3			Energy from Coconut
		3.1	The tree of life					6
		3.2	Making Copra					6
		3.3	Extraction of Coconut oil					7
		3.4	Direct Micro Expelling (DME)					8
Chapter 4			Bio-diesel					9
Chapter 5			Biomass gasification					10
		5.1	Producer gas drive engines					10
Chapter 6			Alternative fuels in the IC engine					12
		6.1	Use of Coconut oil fuel in the IC engine					12
		6.2	Technical difficulties to operate the IC engine by the coconut oil fuel					12
		6.3	Remedies to overcome the problems					12
		6.4	Use of COME, COEE, COIL in the diesel engine					13
								Page
Chapter 7			Spread sheet model for the St. Martin’s Island					14
		7.1	Brief description of the model					14
		7.2	Financial analysis of the model					15
		7.3	How does the model work?					15
Chapter 8			Cultivation of coconut palm					16
		8.1	History of the coconut cultivation					16
		8.2	Coconut cultivation method					16
		8.3	Coconut hybrids for the higher return					16
		8.4	Coconut harvesting					17
Chapter 9			Results					18
Chapter10			Discussion					24
Chapter11			Conclusions					38
References								40
Appendices
Appendix -A			Glossary					51
Appendix-B			Result Appendices					53
		B-1	Calculation for the tidal power in the St. Martin’s Island
		B-2	Recoverable coconut oil and biodiesel per nut
		B-3	Electric energy requirement for the DME process
		B-4	Energy requirement to produce biodiesel
		B-5	Brief description of the worksheets for this dissertation model
		B-6	The model worksheet outputs
						Outputs for the option ‘A’
			B-6.01			Electricity demand for the St. Martin’s Island
			B-6.02			Schematic diagram
			B-6.03			Main result sheet
			B-6.04			Project finance and cash flow
			B-6.05			Brief cost analysis
			B-6.06			Electricity generation from solar energy
			B-6.07			Electricity generation from wind energy
			B-6.08			The battery bank calculation
			B-6.09			Electricity generation from the ‘Coir’
			B-6.10			Electricity generation from the ‘Fronds’
			B-6.11			Electricity generation from the ‘Shells’
			B-6.12			Hybrid calculations
			B-6.13			WSBD -graph
			B-6.14			By-products
						Outputs for the options ‘B’, ‘C’, ‘D’ and ‘E’
		B-7	Items need to purchase or sell
		B-8	By-products and handicrafts made from the coconut sells and fronds
		B-9	Effect of DOD on battery life
			Outputs from the other options (B-E) have been included in the attached CD
Appendix-C			Background information Appendices					78
		C-1	The Maps showing the project locations
		C-2	A Coastal area map of Bangladesh
		C-3	Handicrafts made from the coconut shells and fronds
		C-4	Coconut harvesting methods
		C-5	Brief description of DME steps
		C-6	Advantages of the DME process
		C-7	Properties of coconut oil
		C-8	Chemical composition of coconut oil
		C-9	Advantages and disadvantages of biodiesel
		C-10	Biodiesel production process from coconut oil
		C-11	Biomass gasification process
		C-12	Different types of gas-air mixing methods
		C-13	Basic operation principle of duel-fuel engine
		C-14	Brief description of the remedies to overcome the problems of using coconut oil in the IC engine
		C-15	Engine emissions using coconut oil based fuel
		C-16	Influence of NPV, IRR, Payback period and NPV curve to make decision for selecting a project
		C-17	A map of major coconut producing area of the world
		C-18	A photo illustration of germinated coconut
		C-19	Plantation of coconut seeds in the nursery bed
		C-20	Hybrid coconut palm with hefty bunches
		C-21	Important assumptions and limitations of the model
		C-22	Basic principle of biomass gasification
		C-23	Some panoramic view of the St. Martin’s Island
								Page
Appendix-D			Data Appendices					112
		D-1	Global solar irradiation data for the St. Martin’s Island
		D-2	Wind energy situation at the island, report of BCSIR
		D-3	Month wise hourly average wind data for the island
		D-4	Tidal data obtained form BUET
		D-5	Annual yield of coconut per hectare
		D-6	The major areas of the world under coconut cultivation
		D-7	Annual yield of hybrid coconut palm
		D-8	Analysis of Mature and tender coconut water
		D-9	Ingredients of  copra cake
		D-10	Saponification numbers of common fats and oils
		D-11	Existing flora and fauna in  the St. Martin’s Island
		D-12	Energy density of coconut biomass
		D-13	The composition of COME, COEE and diesel fuel
Appendix E			Additional information Appendices					116
		E-1	Brief description of the copra drying methods
		E-2	Different types of biomass gasifier
		E-3	The major constituents of producer gas
		E-4	Base map of the St. Martin’s Island

 

 List of figures

 

 

Figure number	Description	Page
9.1	Effect of subsidy on the NPV curves-purchase coconut feedstock	22
9.2	Effect of subsidy on the NPV curves-cultivate coconut feedstock	22
9.3	Effect of subsidy on NPV, IRR, Investment and payback period	23
10.1	Effect of investment on the coconut palm cultivation	28
10.2	Model sensitivity to the cost of coconut palm feedstock	37
10.3	Model sensitivity to the increase of  equipment cost	37
10.4	Model sensitivity to the amount of subsidy	38
10.5	Model sensitivity to the electricity selling price	38
10.6	Model sensitivity to the annual operation and maintenance cost	38
C-1	The maps illustrating the project location	78
C-2	A costal area map illustrating the major off-shore islands	79
C-3	Handicrafts made from the coconut shells and fronds	80
C-4.1	Free fall of mature coconuts	81
C-4.2	A Woman harvesting coconut in Vietnam using pole method	81
C-4.3	A man is climbing to harvest coconut	82
C-4.4	Coconut harvesting by trained monkey	82
C-5.1	One DME unit in operation	83
C-10.1	Flowchart of biodiesel production process from coconut oil	91
C-11.1	Block diagram of the gasification system stages	92
C-11.2	Conversion process of biomass into producer gas	93
C-12.1	Gas-air mixing methods	94
C-13.1	Dual-fuel cycle in action	95
C-14.1	The main components of the heat exchanger	96
C-14.2	Specific fuel consumption versus engine speed - graph	97
C-14.3	Brake power versus engine speed - graph	98
C-14.4	Relative emissions versus % of coconut oil- graph	98
C-14.5	Bmep versus engine speed – graph	100
C-14.6	Specific fuel consumption versus speed	100
C-15.1	CO2 concentration versus engine speed - graph	101
C-15.2	CO concentration versus engine speed – graph	101
C-15.3	HC concentration versus engine speed – graph	102
C-15.4	NOx concentration versus engine speed – graph	102
C-15.5	Smoke opacity versus engine speed – graph	103
C-16.1	NPV versus discount rate curve- graph	105
C-17	Coconut producing area of the world	105
C-18.1	Germination of coconut palm	106
C-19.1	Seed coconuts spacing in nursery rows	106
C-19.2	Planting coconuts in seedbeds, Nyimberembe, Tanzania	107
C-19.3	Coconut seedling on the nursery bed	107
C-20.1	Hybrid coconut palm-1	108
C-20.2	Hybrid coconut palm -2	108
C-22	CO2 balance of biomass	110
C-23.1	Panoramic view of the St. Martin’s Island -1	111
C-23.2	Panoramic view of the St. Martin’s Island -2	111
C-23.3	Panoramic view of the St. Martin’s Island -3	111

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

List of tables

 

 

Table number	Description	Page
1.1	Basic elements for the five options in the St. Martin’s Island	2
7.1.1	Energy sharing and dual-fuel mode for the model	14
9.1	Annual electricity generation from the five different options	20
9.2	Effect of subsidy on the IRR, NPV and payback period	20
B-1	Calculation for tidal energy in the St. Martin’s Island	53
B-5	Brief description of the worksheets for the dissertation model	56
B-6	List of model worksheet outputs	58
B-7	Items need to purchase or sell	76
B-8	By-products and coconut handicrafts	76
B-9	Effect of DOD on battery life	76
B-10	Economic sensitivity of the model	77
C-7	Energy related properties of coconut oil	85
C-8.1	Chemical composition of coconut oil	86
C-8.2	Elementary and constitutional formula of coconut oil	86
C-8.3	Melting point and IV for some vegetable oil	88
C-14.1	Fuel compositions of blended coconut oil	97
C-14.2	Properties of coconut blended and ordinary diesel fuel	97
C-14.3	Composition of water-washed coconut oil and diesel fuel	99
C-14.4	Properties of coconut oil and its biodiesel	99
D-1	Global solar irradiation data for the St. Martin’s Island	112
D-3	Month wise hourly average wind speed in the St. Martin’s Island	112
D-5	Annual yield of coconut per hectare	113
D-6	Major areas under coconut cultivation	113
D-7	Annual yield of  hybrid coconut palm	113
D-8	Nutrient values per 100 gm coconut water	114
D-9	Ingredients of copra cake	114
D-10	Saponification value of common fats and oils	114
D-11	Existing flora and fauna in the St. Martin’s Island	115
D-12	Energy density of coconut biomass	115
D-13	Elemental composition of COME, COEE and diesel	115

 

 

List of worksheets

 

Worksheet number	Description	Page
10.1	Comparison among the options- 0% subsidy	30
10.2	Comparison among the options -10% subsidy	31
10.3	Comparison among the options- 50% subsidy	32
B-6.01	Electricity demand in the St. Martin’s Island	59
	Outputs for the option ‘A’
B-6.02	Schematic diagram	60
B-6.03	Main result sheet	61
B-6.04	Project finance and cash flow	62
B-6.05	Brief cost analysis	63
B-6.06	Electricity generation from the solar energy	65
B-6.07	Electricity generation from the wind energy	66
B-6.08	Calculation for the battery bank	69
B-6.09	Electricity generation from the ‘Coir’	70
B-6.10	Electricity generation from the ‘Fronds’	71
B-6.11	Electricity generation from the ‘Coconut Shells’	72
B-6.12	Hybrid calculation	73
B-6.13	Wind-Solar-Biomass hybrid generation  and Demand – graph	74
B-6.14	By-products from the system	75
	Outputs for the options ‘B’, ‘C’, ‘D’ and ‘E’
	Included in the attached CD

  

 

                  

 

 

Abbreviations

 

BCSIR	Bangladesh Council of Scientific and Industrial Research
BPDB	Bangladesh Power Development Board
BUET	Bangladesh University of Engineering and Technology
CFL	Compact Fluorescent Lamp
COEE	Coconut oil ethyl esters
COIL	Water-washed coconut oil
COME	Coconut oil methyl esters
DME	Direct Micro Expelling
DOD	Depth of Discharge
FAME	Fatty Acid Methyl Esters
FFA	Free Fatty Acid
GED	Green Energy Development
GHG	Green House Gases
GOB	Government of Bangladesh
GS	Grameen Shakti
HDL	High Density lipoprotein  (good-cholesterol)
I V	Iodine Value
IRR	Internal Rate of Return
KGOE	Kilogram Oil Equivalent
LCFA	Long Chain Fatty Acids
LDL	Low Density Lipoprotein (bad- cholesterol)
LGED	Local Government Engineering Department
MCFA	Medium Chain Fatty Acids
MOEF	Ministry of Environment and Forest
NEP	National Energy Policy
NPV	Net Present Value
OEE	Oil Extraction Efficiency
PAH	Polycyclic Aromatic Hydrocarbon
PV	Photo Voltaic
RE	Renewable Energy
REB	Rural Electrification Board
REB	Rural Electrification Board
REDA	Renewable Energy Development Agency
SEMP	Sustainable Environment Management Programme
Sp	Species
SRE	Sustainable Rural Energy
UNDP	United Nations Development Programme
WFT	Wildlife Fund of Thailand

 

 

 

Acknowledgements

 

 

The author would like to thank to the Local Government Engineering Department of Bangladesh for nominating him in this MSc taught programme at the University of Reading, UK. Thanks to the SEMP project funded by the UNDP for their sponsorship. Special thank to the Sustainable Rural Energy project for conducting the electricity demand survey in the St. Martin’s Island and providing the huge logistic supports. The author also acknowledge the innovative ideas provided by Dr. David Fulford, Dr. Anne Wheldon, Dr. Maria Vhadati, Mr. David Teal and Dr. Dan Etherington, Managing Director, Kokonut pacific, Australia. Finally the author would like to thank to his family members who had shown a great patience during his study.

 

 

 Introduction

 

 

1.1            Background information

 

St. Martin’s island is the only island in Bangladesh that has coral reef (Coral reefs, 2000). It lies between 92⁰18' and 92⁰21' E longitudes and 20⁰34' and 20⁰39' N latitudes. It is almost flat and is 3.6m above the mean sea level (Banglapedia ). The map illustrating the project location is included in Appendix C-1 and a base map of the island is included in Appendix E-4. The population of the island is 5196 and most of them are fishermen belonging to the 778 families (SRE, 2004). The island is resource rich with the enormous Biodiversity. The existing flora and fauna in the island is listed in appendix D-11.

 

 

The island was named “St. Martin’s” after a British provincial Governor but the local people called it “Narikel Jinjira”. Which means the ‘Coconut Island’ (Holiday, 2004). Coconuts are the important cash crop on the island. Despite considerable fish resources, the island is poorly developed due to the lack of electricity. However every year a significant number of tourists visit the island because of its unique landscape. But the uses of diesel generator and kerosene lamp make the island environmentally fragile and do threaten to the ecosystem and biodiversity.

 

 

The Government of Bangladesh has a noble vision to electrify the whole country by the year 2020 (NEP, 2004). But only 30% of the total population in Bangladesh has received the grid electricity (GS, 2001). There is no possibility in the near future to connect all the remote villages and the offshore islands within the national grid system. Expanding the national grid in those isolated areas are also very expensive and not cost effective. Therefore renewable energy could be an effective alternative to fulfil the electricity demand in the off-grid areas.

 

 

 

 

 The scope of this dissertation project is to develop an excel spreadsheet model to find out the sustainable electricity generation option for the St. Martin’s Island. Therefore NPV, IRR and payback periods of each option need to be analysed. Five different renewable resources options have been considered for the detail analysis. The basic elements of those options have been illustrated in table 1.1

 

 

 

Table 1.1 Basic elements of the five renewable  options  in the St. Martin’s Island

Option	Energy sharing from			Dual-fuel mode in a biomass gasifier
	Solar	Wind	Coconut palm
A	Yes	Yes	Yes	Diesel
B	Yes	Yes	Yes	Bio-diesel
C	No	No	Yes	Coconut oil
D	Yes	Yes	Yes	Coconut oil
E	No	Yes	Yes	Coconut oil

 

 

 

The electricity demand survey in the St. Martin’s Island was conducted by the Sustainable Rural Energy Project of LGED (SRE, 2004). The solar irradiation, wind and tidal data were obtained from the Energy Park (Sumon, 2004), the BCSIR (Zaman et al, 2001) and the BUET (Sadrul, 2004) respectively. All these data have been included in Appendix- D.

 

 

Moreover there are many offshore islands at the southern part of Bangladesh. A Coastal map of Bangladesh illustrating the major offshore islands is included in Appendix C-2.  Similar renewable energy scenario exists in those offshore islands. This model is also applicable to those areas to provide green electricity.

 

 

1.2  Aims 

 

The aims of this dissertation project are to investigate the feasibility of fulfilling the electricity demand in the St. Martin’s Island from the available renewable resources in a sustainable manner, to conserve bio-diversity, to develop eco-tourism and to replicate this model in the other offshore islands of Bangladesh.   

                 

 

1.3  Objectives

 

                        The specific objectives of this dissertation project are:

·        To assess the available renewable resources [Solar, wind, Biomass and Tidal]

·        To make plans for Renewable Energy demonstration unit

·        To make plans for clean electricity to the consumers in a reliable and cost-effective manner

·        To develop an excel spreadsheet model for selecting the components of renewable resources [Wind, Solar, Biomass, and Tidal], which is technically and financially sustainable

·        To calculate NPV, IRR, Payback period and the relevant analysis of each option for selecting the best one suitable for the St. Martin’s Island

 

 

 

2. Renewable Energy resources in the St. Martin’s Island

 

2.1 Solar energy

 

There are good prospect of solar energy resource in the St. Martin’s Island. Average global solar irradiation on the horizontal surface was found 4.8 Kwh m^-2day^-1 and on the 30⁰ inclined surface it was 5.2 Kwh m^-2day^-1 (Sumon, 2004). These data indicate the bright prospect for the solar thermal and photovoltaic application in the Island.  Monthly average solar irradiation data have been illustrated in Appendix D-1.

    

2.2 Wind energy

 

A comprehensive feasibility study has been conducted by the BCSIR to explore wind energy potential in the St. Martin’s Island (Zaman et al, 2001). The report has been included in Appendix D-2. Month wise hourly average wind data have been illustrated in Appendix D-3. It has been obtained that a considerable amount of time wind speed in the island is between 3-4 m/s. Therefore low cut-in speed wind turbine is suitable for the power generation in the island.

 

 

2.3 Biomass energy

 

Coconut palm is the main biomass resource in the St. Martin’s Island. There are 9127 coconut trees in the island, however some of the households cultivate other variety of fruit tree. There are also 467 fruit trees in the island (Stmartinsbd, 2002-a). The coconut fronds, coir and shells have been successfully used as raw materials for a biomass gasifier. Again good quality coconut oil is obtained from the coconut meat. Furthermore Coconut oil methyl or ethyl esters, usually known as biodiesel can be produced from the coconut oil. Coconut oil based fuels have been successfully used to run a diesel engine.

 

 

 

2.4 Tidal energy

 

In order to explore the tidal power in the St. Martin’s Island, seven tidal gauge stations have been established by the BUET (Sadrul, 2004). The tidal data for the island have been included in Appendix D-4. Average power that could be extracted from the each station is illustrated in Appendix B-1. The average tidal heights for the seven gauge stations have been obtained between 1-2 meters. A mean head of at least five meters is usually considered to be the minimum for viable tidal power generation (Boyle Godfrey, 2004). Therefore there is no potential prospect of tidal resource in the St. Martin’s Island.

 

 

3. Energy from Coconut

 

 

3.1 The tree of life

                  

           

The botanical name for the coconut palm is “Cocos nucifera”. Its meaning is described in Appendix-A. Coconut tree has been called the most versatile tree in the world. There is an Indian proverb – “He who plants a coconut tree, plants for food, drink, vessels, clothing, a heat source, habitation for himself and a heritage for his children” (Foodsite, 2003). In Sanskrit the coconut palm is called “Kalpa vriksha” which roughly means “The tree of life” (starship,). Coconut palm is very cold sensitive. The green leaves of tree damaged at -1⁰C, serious damage occurs at -3⁰C, but most death occurs from the tree weakening with the cold and then rotting (Desert, 2003).

 

 

The annual yield of coconut per hectare is illustrated in Appendix D-5. Average yield of coconut oil and biodiesel per nut is about 83ml and 67ml respectively. The detail calculations have been attached in Appendix B-2.

 

  

3.2             Making Copra

 

Copra is the dried coconut meat. It is the commercial form of coconut from which coconut oil is extracted by boiling and pressing. It is an oil-rich pulp with sweet and nutty flavour. Coconut flesh is 50% water, 34% Oil and 16% fats  & proteins whereas copra is 5% moisture and 64% Oils (ICCEPT, 2003). After expelling oil from copra the residue is called as the copra cake. This by-product is valuable protein sources for the animal feed.  

 

 

 

Following are the popular copra making methods

 

• Solar drying

• Direct smoke kiln drying

• Semi-direct smoke kiln drying

• The modified Kukum hot-air drying

• The Cocopugon or the Brick hot air dryer

 

The copra drying methods have been described in Appendix E-1

 

 

3.3 Extraction of Coconut oil

 

Coconut oil extraction from the copra requires large-scale, expensive and energy-intensive equipment. It also needs refining, bleaching and deodorising to create a commercially acceptable product. Oil production from copra needs the following steps (ICCEPT, 2003):

• The copra is chopped into pieces about one centimetre square by copra cutter or milling machine

• Chopped copra passes through extraction machine to ensure all oil is removed

• Heats oil and boils away water

• Oil is then centrifuged to remove any solid particles water and cholesterol

• Oil is then filtered

• Add extra heating to remove moisture

• Storage of coconut oil

• Bi-product can be used as an animal feed

 

The important physical, nutritional and energy related properties of coconut oil have been included in Appendix C-7. The chemical composition of coconut oil is described in Appendix C-8.

 

3.4 Direct Micro Expelling (DME)

Direct Micro Expelling (DME) process has been developed in Australia. This process completely bypasses the tedious copra making stages. The DME process concentrates on small, manageable, daily batches instead of producing large batches of copra, which take many weeks to process and ship. The overall goal of DME is to raise the income levels of poor rural families in the coconut production region (Dan E and Roland L, 1999). It gives direct local employment in rural areas in nut collection and oil production.

 

One DME unit can yield between 30 – 40 litres of virgin coconut oil in a day. The oil extraction efficiency (OEE) is over 85% of available oil (Kokonut,). The DME steps and advantages of the process have been described in Appendix C-5 and Appendix C-6 respectively. To produce one litre virgin coconut oil in the DME process about 0.08 KWh electric energy is needed. The detail calculations have been included in Appendix B-3.

 

  

4. Bio-diesel

 

 

The Fatty Acid Methyl Ester (FAME) or Biodiesel is the biodegradable diesel obtained from the transesterafication of vegetable oil or animal fat. Transesterification is the process in which vegetable oil or animal fat reacts with methanol or ethanol in the presence of a catalyst (Normally NaOH) to produce methyl or ethyl esters and glycerine. Biodiesel can be used in neat form or blended with petroleum diesel to use in unmodified diesel engine (Greentrust, 2000).  Rudolf Diesel developed the first engine to run on peanut oil. He demonstrated the engine at the World exhibition in Paris in 1900. Unfortunately R. Diesel died in 1913 and after his death vegetable oil was forgotten as a renewable source of power (Cyberlipid, ) for long time. The major advantages and disadvantages of biodiesel are included in Appendix C-9. Biodiesel production process from coconut oil has been described in Appendix C-10. To produce biodiesel from one litre coconut oil it needs about 0.104 KWh energy in terms of heat and electricity. The detail calculations have been included in Appendix-B-4

 

 

5. Biomass gasification

 

Solid biomass fuels, which are not convenient to use and have low efficiency of utilization, can be converted in to a high quality gaseous fuel. The process is called biomass gasification. The basic principle of biomass gasification has been briefly discussed in Appendix C-22. A diesel engine can be operated on dual fuel mode by using the producer gas. Alternatively, a gas engine can be operated with producer gas on 100% gas mode with small modification on air/fuel mixing and control system. The gasification process has been described in Appendix C-11. The different types of biomass gasifiers and the major constituents of producer gas have been briefly described in Appendix E-2 and Appendix E-3 respectively.

  

5.1 Producer gas drive engines

 

Producer gas can be used to generate power or electricity in the internal combustion (IC) engine. The IC engines are normally designed to run on diesel or gasoline fuel. The property of producer gas is different from that of diesel or gasoline. Therefore using producer gas in the IC engines affects the performance and the other maintenance features of the engines. There are many ways to use producer gas in the IC engine.

 

Firstly, producer gas can be used as a fuel to run gasoline engine. It needs higher compression ratios, as there are high proportions of inert gasses. Consequently the use of producer gas derates engine performance by 25-50% (Fulford David, 2004).

 

 

Secondly, Gas turbines runs well on producer gas but auto-derivative systems needs higher gas cleanliness (Fulford David, 2004). The main problem is that gas turbine is only economic at large scale (>1 MW) and small gas turbines are expensive in comparison of per KWh power generation.

 

 

 

Thirdly, a slight modification of a diesel engine can make it suitable to run with the producer gas. Therefore it is possible to adapt diesel engine by fitting a spark plug in place of diesel injector (Fulford David, 2004).

 

 

Finally, Dual fuelling is the convenient way to run engine with producer gas. In this method producer gas is mixed with the intake air before the mixture enters into the combustion chamber and a pilot quantity of diesel fuel is injected to ignite the gas-air mixture (Bari Saiful, 1991). Duel fuelling replaces 80-95% of diesel depends on the size of engine (Fulford David, 2004) and hence reduces fuel cost. It has also low emissions than a dedicated diesel engine. The main advantage of this method is that the engine can run on pure diesel whenever there is a shortfall to producer gas. Different types of gas-air mixture and basic operation principle of dual-fuel engine is briefly described in Appendix C-13.

 

 

 

6. Alternative fuels in the IC engine

 

6.1 Use of Coconut oil fuel in the IC engine

 

Coconut oil fuel can be used to run a diesel engine. In Countries with warmer climates, diesel blended coconut oil is often used without transesterification. However as the melting point of coconut oil is 25⁰C (Shortcircuit,), pure coconut oil can only be used at temperature above 25⁰C and some problems may occur below 40⁰C because of its high viscosity (Swain E and Shaheed A, 2000). The calorific value of coconut oil (39 MJ kg^-1K^-1) is slightly lower than the petroleum diesel (43.6 MJ kg^-1K^-1) but this can be easily accommodated with either the engine developing less power or by changing the fuel rack settings.

                        

6.2 Technical difficulties to operate the IC engine by the coconut oil fuel

 

The main problem with the use of coconut fuel oil in diesel engine is that it starts to solidify at a temperature below 22⁰C and by 14⁰C it is close to solid and does not flow at all (Tve, 2001). If engine is started while the temperature is below 22⁰C, the fuel filter is likely to become blocked. Furthermore high viscosity of coconut oil leads to fuel spray and fuel delivery problems and gum content causes fouling of injectors and in cylinder components (Swain E and Shaheed A, 2000)

 

6.3  Remedies to overcome the problems

To overcome the clogging of fuel filter at low temperature the following measures can be taken

 

• To fit a heat exchanger

• Proper filtration of coconut oil

• Blend of coconut oil with petroleum diesel or kerosene

• Water washed coconut oil

• Transesterification

 

Brief descriptions of those processes have been described in the Appendix C-14.

 

6.4  Use of COME, COEE, COIL in the diesel engine

 

An experimental study was done to evaluate the use of coconut oil based fuel as an alternative to diesel oil. The elemental composition, calorific value and Sauter Mean Diameter (SMD) for the water-washed coconut oil (COIL), the Coconut oil methyl esters (COME), the Coconut oil ethyl esters (COEE) and the diesel fuel is included in Appendix D-13. It was found that COME and COEE produced similar brake mean effective pressure (bmep) as diesel fuel. The COIL produces low bmep. Variation of bmep for the different fuel was due to their different calorific value and viscosity. The consumption (g/KWh) of COIL, COME and COEE was higher than that of petroleum diesel due to their lower calorific value (Swain E and Shaheed A, 2000). Graphs showing bmep versus engine speed and specific fuel consumption versus engine speed is illustrated in Appendix C-14. Moreover emissions were also measured while running an engine by the coconut oil based fuels and diesel. It was observed that coconut oil based fuel produces lower emissions than that of diesel. The brief descriptions of the engine emissions using the coconut oil based fuel have been illustrated in Appendix C-15.

 

 

 

 

 

 

7. Spread sheet model for the St. Martin’s Island

 

7.1 Brief description of the model

 

 

The scope of this MSc dissertation project is to develop a sustainable electricity generation model in the St. Martin’s Island. Five renewable resources options have been considered for the detail technical and financial analysis. The basic criterion for each option is to fulfil the present electricity demand in a cost effective way by utilizing the local renewable resources. Energy sharing from the different renewable resources and the dual-fuel mode for each option are illustrated in table 7.1.1 Items need to purchase or sell for a particular option are listed in Appendix B-7

 

 

Table 7.1.1 Energy sharing and dual-fuel mode for the options

Option	Energy sharing from				Dual –fuel mode in a biomass gasifier
	Solar %	Wind %	Biomass (Coconut)  %	Diesel %
A	12	33	53	2	Diesel
B	12	33	55	0	Biodiesel
C	0	0	100	0	Coconut oil
D	12	33	55	0	Coconut oil
E	0	33	67	0	Coconut oil

 

 

 

 

Again coconut is a very expensive tropical fruit. And the coconut palm feedstock is not free. Therefore the two basic criteria for the biomass have been considered. One is to purchase the coconut palm feedstock and the other is to cultivate the coconut palm. The value of land and the cultivation cost have also been taken into account for the second option. Furthermore, sometimes subsidies have been granted to promote renewable energy projects. So the effect of subsidy on IRR, NPV, Investment cost and payback periods have been analysed by using this spreadsheet model. The scope of this project is to analyse five categories of subsidy ranging from 10-50% on the investment cost.

 

 

 

7.2 Financial analysis of the model

 

To evaluate a project or investment, it is important to calculate the Net Present Value (NPV), the Internal Rate of Return (IRR) and the payback periods for that particular project (Andy Baldock, 2004). It is usually stated that projects with the higher IRR are more profitable than projects with the lower IRR. However this is not always true. In some cases, a project with a lower IRR may be better than an investment with a higher IRR (Hadm, 2002). In that particular case the NPV curve helps to make a wise decision. The influence of NPV, IRR, and Payback period is discussed in Appendix C-16. Each of these decision-making parameters have been critically analysed in this spreadsheet model. Moreover the sensitivity analysis of the model has been done and the key influences have been listed in Appendix B-10

 

 

7.3 How does the model work?

 

This dissertation model consists of several interlinked Microsoft excel worksheets. For a particular selection of renewable resources, it calculates the electricity output for that option. Important assumptions and limitations of the model are listed in Appendix C-21. The ultimate outputs from the model are IRR, NPV, Payback period, NPV curve and the brief cost analysis. It can also compare all the possible options in a single graph sheet, which helps to make a concrete decision for selecting a particular option. There is also a provision for updating the model in case of changing the unit rates for the construction materials, the interest rate, the subsidy amount etc. Application and function of each worksheet is described in Appendix B-5. A complete ‘CD’ containing the model and necessary data has been attached with this report.

 

 

 

 

 

 

 

8. Cultivation of coconut palm

 

8.1 History of the coconut cultivation

 

 A Sandy well-drained soil near the coastal areas is the most suitable environment to grow the coconut palm. However, coconuts are adaptable to other soil types including coral atolls and soils with moderate salinity. Philippines has the first position in the world coconut cultivation (Woodroof  J.G., 1979). The major area under coconut cultivation in the world is illustrated in Appendix D-6. Coconut is widely distributed throughout a band of 20⁰N and 20⁰S latitude (Pssc, 2001). This wide distribution is primarily due to floatation of coconut fruit in seawater, where once washed ashore, they readily establishes themselves on the sandy beaches. Additionally, man has contributed to its transportation and cultivation. A map showing major coconut producing area of the world has been illustrated in Appendix C-17

 

 

8.2 Coconut cultivation method

 

Coconut seedlings are normally grown in the nursery bed. It takes about five to six months to germinate (Desert, 2003). A photo illustration of germinated coconut has been included in Appendix C-18. Seed coconuts are placed in rows of 0.25m apart. Distances between the seeds are also kept 0.25m apart (Pssc, 2001). Planting coconut seeds in the nursery bed has been illustrated in Appendix C-19. Coconut seedlings are transplanted to a prepared soil when they are about one- two years old. They need full sun and do not survive very long in shade or inside a house. Depends on the variety within five to six years they will have matured into a graceful coconut palm tree (Starship )

 

8.3 Coconut hybrids for the higher return

 

The first coconut hybrid in the world was developed in India in 1930. It was developed from West Coast Tall as the female parent and Chowghat Green Dwarf as the male parent (Hindu, 2004). In coconut cultivation, special attention should be paid in selecting the appropriate coconut hybrids, which are ideally suited to the agro-climatic conditions of the area. Annual yield of some hybrid coconut palm is illustrated in Appendix D-7. In India, about eleven coconut hybrids have been commercialised for cultivation. The famous coconut hybrids are Chandra Sankara, Kera Sankara, Chandra Laksha, Laksha Ganga, Kera Ganga, Kera Sree, Kera Sowbhaagya, VHC-1, VHC-2 and Godavari Ganga. The photographs of hybrid coconut Palms with hefty bunches are attached in Appendix C-20. Hybrid coconut produces good quality copra with about 70% oil content (Hindu, 2004). 

 

 

8.4 Coconut harvesting

 

The coconut palm produces nuts throughout the year.  Its yield may vary with the season. Generally a mature palm produces at least one mature ready-to-harvest bunch of coconuts every month. Depending on the species, nuts per bunch may vary from five to fifteen. Number of bunches that can be harvested annually from a tall variety tree is about fourteen and that of  a dwarf variety tree is about sixteen. Normally it takes about twelve months for a nut to mature from pollination to harvest ( Fao ). Four popular coconut-harvesting methods are:

• Free fall of mature coconuts

• Pole method

• Climbing method

• Using trained monkey

These methods have been described in Appendix C-4

 

 

 

 

9. Results   

 

The outputs obtained from this dissertation Model have been attached in Appendix B-6. However only the key findings are included in this chapter. The name of reference-worksheet in the model, from where the result has been obtained is shown within the parenthesis.

 

Annual electricity demand

The annual electric energy requirement for the St. Martin’s Island has been obtained about 359MWh [worksheet ‘Electricity demand’]

 

Output from the PVSyst

The detail output from the PVSyst simulation parameters, characteristics of the PV module and the battery have been included in Appendix B-6. However PVSyst suggests that 334 modules, each of 180 Wp are needed to get an annual output of about 47 MWh [worksheet ‘PVSyst’]

 

Output from the wind turbine

It is found that annul 126MWh electricity can be obtained form the two BWC XL.50 turbines, out of which about 68MWh peak and 58MWh off-peak hour power generation [Worksheet ‘Wind energy’].

 

Output from the tidal energy

The tidal heads obtained form the seven tidal gauge stations in the St. Martin’s Island have been varied between 0.7-1.7 meters. The calculations of tidal power have been included in Appendix B-1. Extractable tidal energy from the different gauge stations lies between 96-178 watts [worksheet ‘Tidal energy’].

 

Battery bank

The battery selection has been done with the help of PVSyst software. The tubular plate, vented, lead-acid, Fulmen-CEAC, TXE 1700/OPzS1500 battery has been considered for the battery bank. With the 60% DOD, battery life is found about 3.6 years and with the 80% DOD, battery life is found only 2.2 years. Effect of DOD on the battery life is illustrated in Appendix B-9. Estimated capacity of the battery bank is about 1240 A-h [Worksheet ‘ Battery bank’]

 

Electricity generation from the coir

The annual yield of coir available for the electricity generation is about 62 MT and the amount of electricity that can be generated from this coir is about 25 MWh [Worksheet ‘ Coir energy’]

 

Electricity generation from the coconut fronds

The annual yield of coconut frond available for the electricity generation is about 417 MT and the amount of electricity that can be generated from these fronds is about 174MWh [Worksheet ‘ Frond energy’]

 

Electricity generation from the coconut shell

The annual yield of coconut shell is about 86 MT and the amount of electricity that can be generated from this shell is about 64MWh [Worksheet ‘Shell energy’]

 

Annual yield of coconut oil

The annual yield of coconut oil in the St. Martin’s Island is about 68 thousand litres and the amount of electricity that can be generated from this oil is about 170MWh. The coconut oil production process needs about 0.3 MJ/litre energy in the DME process [Worksheet ‘ Extra fuel’ and Appendix B-3]

 

Annual yield of biodiesel

The annual yield of biodiesel in the St. Martin’s Island is bout 55 thousand litres and the amount of electricity that can be generated from this biodiesel is about 158MWh. The biodiesel production process needs about 0.4MJ/kg extra energy in terms of heat and electricity [Worksheet ‘Extra fuel’ and Appendix B-4]

 

By-products from the model

The amount of by-products i.e. copra cake, crude glycerol, coconut juice etc. and the handicrafts made from the coconut fronds and the shells for the options have been listed in Appendix B-8 [Worksheet by-products]

 

Electricity generation from the different options

Annual electricity generation from the five different options have been summarised in table 9.1 However the key result illustrating the effect of subsidy on the IRR, NPV, Investment and payback period have been included in table 9.2

 

 

Table 9.1  Annual electricity generation from the five different options

Option	Electricity generation from,  (MWh)						Total annual generation In MWh
	Solar	Wind	Biomass
			Coir	Fronds	Shells	Copra
A	42	119	25	174	0	0	360
B	42	119	25	174	0	0	359
C	-	-	25	198	64	72	359
D	42	119	25	174	0	0	359
E	-	110	25	198	26	-	359

Source: Worksheet ‘Results’

 

 

Table 9.2 Effect of subsidy on the IRR, NPV and payback period

 

Option	% of subsidy	Choice for the coconut palm feedstock	% IRR	NPV £000’s	Investment £000’s	Payback period in year
A	0	Purchase	14	66	514	7.2
		Cultivate	20	206	947	5.4
	10