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Prospects for harnessing renewable energy sources in Pakistan
Solar & Wind TechnologyVol. 7, No. 2/3, pp. 321 325,1990
0741 983X/90 $3.00+.00 PergamonPressplc
Printedin Great Britain.
TECHNICAL NOTE Prospects for harnessing renewable energy sources in Pakistan S. M . HASNAIN a n d B. M . GraBS Department of Fuel and Energy, University of Leeds, Leeds LS2 9JT, U.K. (Received 12 October 1988 ; accepted 30 J a n u a r y 1989)
Abstract--Renewable energy resources can provide a viable alternative to the existing energy supply system, particularly in the developing countries. This paper first gives an outline of the conventional energy resources and then discusses in detail the significance of utilization of renewable energy sources in the development of remote areas of Pakistan, which consists of about 75% of its total population. Considering and outlining the indigenous renewable energy potential, and the course of the country's development, some newly established projects and the extent of their application are elucidated. The prospects of renewable energy sources for the remaining 25% urban population of Pakistan are also discussed.
ENERGY STATUS AND P R O S P E C T S Energy has always been a vital and indispensable input to the economical needs of the present age. It functions as a blood stream in production, a fuel for transportation and the power source in electricity generation. Kuljian [1] reported that "despite our still ample coal, oil and gas reserves, at the rate we are depleting them, it behooves us to be thinking about the development of new sources of energy which will be so vital for our energy future". This study [1] depicted that, the future use of world fossil fuels such as coal, gas and oil would be depleted by the year 2030 while the entire non-renewable fossil and fissionable fuel resources will be depleted by the year 2350. Therefore, it has been concluded, that if we are to live and progress on this earth we will have to find alternative, plentiful and reliable energy resources. The world population is presently estimated at about 4.5 billion and increasing at an approximate rate of 2-3% per year so as to double every 20-30 years. In 1980, population of the Third World countries was estimated at over 3.0 billion which may triple by the year 2100. Table 1 lists the growing disparity in population and energy consumption trends between the developed and the developing countries of the world. It can be easily estimated, that in 45 years (19802025), the energy consumption in developing countries would be increased by about 54%. As a result, the effects on the environment will become more severe and resources will continue to deplete. The population o f Pakistan is growing at an alarming rate (about 3.5% per annum), the demands on the existing energy supplies are also increasing, therefore, it is necessary to iden-
tify the alternative energy sources. The country will be in need of larger amounts of energy each year for the expansion of its industrial base, transportation and for mechanized farming. This paper discusses the need for the utilization of renewable energy sources in Pakistan which is compared with existing conventional energy resources. CONVENTIONAL ENERGY RESOURCES Tables 2 and 3, show the magnitude of different energy supply systems in Pakistan. These tables indicate the requirements of conventional energy sources and its production in Pakistan. Notwithstanding the fact that Pakistan has large deposits of coal (estimated about 1.178 million kilograms), which can be classified as highly volatile to sub-bituminous with relatively high ash and sulphur content. In Pakistan, the daily production of oil is around 42,000 barrels (see Table 2), against the demand of 160,000 barrels of oil/day. Pakistan spends more than half of its export earnings on the payment o f oil bills to the Middle East countries, therefore, its foreign exchange resources hampers a substantial increase in oil imports. The case for natural gas, on the other hand is relatively stronger (Table 2). As the natural gas is a precious raw material for fertilizer production and for petrochemical industry, therefore, it is recommended that, consumption should not be allocated for other applications. Recently Pakistan has been facing an acute shortage of electric power. Almost all parts of the country have been subjected to hours of load-shedding each day, particularly during winter. In 1973-1974 the electricity consumption by
Table 1. Global population and energy consumption trends. (P = population, E = energy use) Countries Developed Developing
P(%)
1980 E(%)
P(%)
1985 E(%)
27.7 72.3
80.1 19.9
26.0 74.0
78.7 21.3 321
2000 P(%) E(%) 21.3 78.7
71.9 28.1
2025 P(%) E(%) 15.9 84.1
63.3 36.7
322
Technical Note
Table 2. Oil and gas production in Pakistan. (Data derived from Ref. [2]) Year
Crude oil (barrels per day)
Natural gas (billion cubic metres)
1981 1982 1983 1984 1985 1986
9,564 11,720 12,082 18,000 34,480 41,548
8.93 9.74 9.72 10.04 10.40 11.10
domestic consumers was recorded as 516 million units (kWh), while in March 1985, 4240 million units (kWh) were stated as a maximum demand. It is estimated that about 300 kWh/capita/year electrical energy is required by the domestic user. However, at present it is around only 50 kWh/capita/ year. If these targets were to be achieved by the year 2000, 42,000 GWh of electrical energy will be required. It is envisaged that, the conventional energy sources would contribute only 20,000 GWh (143 kWh/capita/year). Thus alternative sources of energy would need to supply up to 22,000 GWh of electrical energy by the year 2000 in order to fill the gap from 143 to 300 kWh/capita/year [3]. In Table 3 it is depicted that gas and solid sources in Pakistan are depleting with the passage of time. However, it shows that electricity and liquid supply has been relatively improved as compared to previous years. Figure 1, shows a total production and consumption of commercial energy in Pakistan. Solids, liquids, gas and electricity are the main components of the total production and consumption o f commercial energy. This figure reveals a well defined gap between energy production and consumption as it is increasing with the passage of time. All locally produced energy in the form of gas and electricity is being used by the consumers, whereas some solids and liquids fuels have to be imported in order to fulfil the basic necessities of the populace. It seems safe to infer that Pakistan is running out of conventional energy sources very rapidly. A few decades ago nuclear power was envisaged as the final solution to all future energy problems in the world. However, presently, the world's nuclear industry is suffering from power plant cancellation, escalating costs and public opposition. Due to the recent incidences of operational problems, leakages and catastrophic accidents (for instance the Chernobyl disaster) in nuclear plant, the populace is very skeptical about the future of nuclear power. It is, therefore, conceivable to consider the energy resources which are renewable, clean, easily convertable to conventional energy forms with existing technological know how, and zero fuel cost. Table 3. The contribution of commercial energy supply in Pakistan based on percentage of total energy consumption against each source [4] Year
Solids
Liquids
Gas
Electricity
1982 1983 1984 1985
6.90 5.65 6.20 6.78
36.74 40.17 41.38 42.77
50.36 47.74 45.47 42.90
6.00 6.44 6.95 7.55
RENEWABLE ENERGY SOURCES In view of the long term energy requirements of Pakistan, a preliminary assessment of the potential importance of various forms of renewable energy resources (solar, wind, biogas, etc.) needs to be carried out. Geographically, Pakistan is well endowed with natural energy gifts. The north is full of hydro resources, the south has considerable wind and sun, while the central part of the country, being agricultural oriented is extremely appropriate for implementing biogas and solar energy schemes. Pakistan lies in the sun belt area, therefore, the early development of solar energy technologies will have a highly beneficial impact on the nation.
Solar eneryy technoloyies The most tantalizing feature of the sun's energy is its abundance. The total solar power intercepted by the earth is 1.75 x l017 W or an annual total of 5.52 x 1024 J. For comparison, world's total commercial energy consumption in 1982 was 2.86 x 1020 J [5], or some 20,000 times smaller than the solar energy intercepted by the earth. In 220 days we receive as much heat as there is in all the fossil fuels and the fissionable materials in the world put together. If some method can be found to tap this inexhaustible source of energy, it might enable mankind to resolve its energy problems for all time. Solar energy technologies are based on the conversion of solar radiation into heat, mechanical or electrical power, or to directly generate electricity. Solar radiation can be categorized in two types: direct and indirect. Direct solar radiation can be utilized for electrical power generation, using photovoltaic systems. Whereas, examples of indirect solar radiation are biomass, wind and biogas, etc. Utilization of direct solar radiation In this category the incident sunlight is converted directly into the desired form, i.e. heat or electricity, which is indispensable for immediate applications. In Pakistan, lighting and water pumping requirements at village level could be satisfied, if electric power is available readily and cheaply. The magnitude of solar insolation is approximately 8 kWh/m2/day and an average eight hours sunlight per day is available throughout the year [6]. In the rural and far flung areas of Pakistan, electricity requirements have far higher priority than space heating. Therefore, the use of photovoltaic solar panels, can play a vital role by decentralizing electricity generation as well as eliminating the needs for transmission and distribution. In Pakistan, a number of solar village electrification systems with a total capacity of over 300 kW are in progress. In addition, a 5 kW photovoltaic generator is being installed and a photovoltaic and thermal system with a capacity of 120 kW is to be installed in order to energize remote villages [7]. It is also indicated in [8] that in remote areas of Pakistan, the use of photovoltaic system, to produce electricity is prominent, especially in education, hospitals, social animation, lighting, communication and various other applications such as water pumping. Pakistan will be the first country in the ESCAP (Economic and Social Commission for Asia and the Pacific) region to have a solar energy training and demonstration centre, called as the Regional Solar Energy Development and Demonstration centre [9]. Utilization of indirect aolar radiation The process, by which solar energy is transformed indirectly through different steps to convert it into useful
323
Technical Note
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~Production
~
Consumption
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24: 22:
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2o!
0 .,-I 0 0
ta!
161
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.,,.,,,,,l,,,,,,,,,l,,,&,,,,,l,,,,,,,,.l,,,,,,,,,l,&,,,,,,
198t
1982
t983 Number
t984
t9115
1986
1987
of Y e a r s
Fig. 1. Total production and consumption of commercial energy in Pakistan (Ref. [4]). (Quantities in kilograms per capita of coal equivalent and in thousand metric tons).
utilizable energy, are termed as indirect processes. The following examples are a brief description of the utilization of indirect solar radiation in Pakistan.
Biogas Whenever organic wastes decay in anaerobic environment, methane gas is generated which is combustable and can be used as a fuel. As an additional benefit, the slurry left behind in the fermentation chamber after the gas has been generated, is as effective as a fertilizer as the initial manure. This technology is not only cheap but practicable and easy to install. About I0 million biogas plants are successfully operating today in several developing countries. In Pakistan, a number of biogas plants have been demonstrated in 4000 villages and it is hoped that all 27,500 unlit villages can be energized with biogas as a fuel source. It is roughly estimated that approximately 40,000 biogas plants will be needed in the year 2000, which would provide 92 billion cubic feet of gas equivalent to 5 million tonnes o f coal or 2 million tonnes of kerosine. These plants can meet the domestic needs of the projected 100 million rural population in the year 2000, at the present level of per capita of energy consumption. Furthermore each plant will be capable of providing fertilizer equivalent to 2.6 tonnes of nitrogen per year. Thus 40,000 such plants are expected to produce around 100,000 tonnes of nitrogenous energy per year. The implantation of biogas plants might be higher because it has a payback period of only one year. The Energy Resource Cell under Ministry of Petroleum and Pakistan Council of Scientific & Industrial Research (PCSIR) Laboratories under Ministry of Science & Technology are working for the implementation of biogas plants and technology.
Biomass Biomass, which consists o f vegetative matter, can be converted through pyrolysis, hydrolysis and anaerobic digestion into liquid, solid and gaseous fuels. Green plants capture the
sunlight and convert it via photosynthesis into food and fuel. It was photosynthesis that originally gave rise to start point materials for geologic fermentation of oil, natural gas and coal. Now, man can harvest the stored solar energy of present day plants. Dry plant matter has an energy content equivalent to 60% of the energy content of bituminous coal. The fuel obtained from biomass is of good quality, for instance it has sulphur content less than 0.1% and ash content ~ 5 % , whereas coal found in Pakistan has 4-9% sulphur and 1830% ash content. Several countries, on a commercial scale have launched programmes to convert agricultural crops into alcohol. Molasses and Baggas are the byproduct from the processing of cane sugar. Molasses contains over 50% of fermentable sugar from which alcohol can be easily manufactured. It is estimated that 1 tonne o f molasses produces 0.22~).24 m 3 of alcohol (100% by volume). It is assumed that, if in Pakistan 0.5 million tonnes of molasses is produced, it would yield 0.114.12 million cubic meters of alcohol. If petrol and alcohol mixture ratio is kept at 75:25 respectively, 0.11~).12 million cubic meters of petrol would be required to make 0.45/0.47 million cubic meters of alco-petrol. It is generally believed that approximately 1 tonne of cane yields 100 kg of sugar, 40-64 1 of molasses which in turn could produce 14161 of alcohol. Pakistan has an abundance of Molasses, Beet root and Corn, etc., therefore, it would be more economical to install alcohol producing plants with the existing 38 sugar mills rather than to export the molasses at a very cheap rate. Thus, alcohol could easily be produced in vast quantities sufficient to provide all or most o f our transportation fuel requirements. If the production and consumption conditions of the cane sugar are favourable, then it could also be used for the production of alcohol, as it is being produced in Brazil. In future Pakistan might require some sort of substitute of sugar consumption by high fructose syrup, liquid glucose and maltose syrups. These can be manufactured from very cheap quality broken rice or maize by enzymatic
324
Technical Note Table 4. Typical characteristic of refuse components in the city of Karachi [11]
Components
Moisture (wt. %)
Calorific value (Btu/lb)
Sulphur (wt. %)
Ash (wt. %)
15 5 19 45 75
7250 17376 6633 4684 1700
0.39 0.21 0.O4).08 0.11 0.13
11. I 4.5 12.7 21. I 43.6
Paper and hardboard Plastic Cotton and linen Leaves/green food Garbage
technology, as has already been demonstrated in Pakistan [10]. ReJuse power As a partial solution to the shortage of about 800 M W of electricity during winter season in Pakistan, electricity generation is possible through the combustion of refuse. The heat content of refuse varies, but generally 2 tonne of refuse is equal to the heat content of 1 tonne of coal. Roughly it is estimated that per capita refuse generation in Pakistan is around 0.3 tonne per year. For a city like Karachi, about 6000 tGnne of refuse is accumulated each day of which 60% is combustible. A previous study [11] concluded that 1.0 Mt worth of furnace oil for power generator could be saved each year by effective use of refuse. Overall, it is possible that, the total energy supply from refuse could contribute at least a 20% share of the Karachi energy requirement, which is the largest energy consuming zone in Pakistan on per capita consumption basis. The typical fuel characteristics and components in refuse found in Karachi are shown in Tables 4 and 5. These tables show that, the refuse is lower in sulphur and heating value but higher in ash and moisture contents compared to fossil fuels. The refuse calorific content can also be compared with liginite coal (sulphur content 4 - 9 % ) with an advantage of lower sulphur pollution value (0.1~). 16%). Wind power Energy from the wind is derived from solar energy, as a small proportion of the total solar radiation reaching the earth causes movement in the atmosphere, which appears as wind. Traditional wind mills for pumping water and grinding corn have been used for at least 2000 years. Of all the alternatives, wind mills are the most flexible in term of scale of operation. Wind mill technology has developed rapidly in recent years. The United States is spending some $60 million
Table 5. Typical composition of mixed domestic and commercial refuse found in Karachi. (Data derived from Ref. [11]) Components Paper Plastic Cotton Green leaves and food Garbage Metal, glass, debris, etc. (non-combustible inorganics)
wt. % 10.2 4.6 9.8 20.0 36.5 8.5
per a n n u m on various new systems. Currently about 18,000 wind machines with a generation capacity of more than 1.5 GW, have been installed in California and produced enough electricity to supply 50,000 homes. The U.S.A. is relying on this type of power generation for 10% of its total electricity supply by the end of the century [12]. Recent research in the U.K. shows that the wind energy could in principle supply about 20% of its electricity demand in the near future. Wind mills are of different shapes and sizes. A 10 kW power generation capacity wind mill for example, is more suitable in the context of Pakistan rural scene and is sufficient to meet the electricity needs of 200-300 people living in a village. It is observed that the energy generated by a wind mill could be twice as efficient as that obtained from a diesel generator. Wind energy could provide adequate electric power in coastal areas. Preliminary work for most of these areas in Pakistan in the field of data collection [13], as well as experimental investigations is underway [14]. The studies show that wind energy in Karachi could effectively produce over 200 k W h per month. Wave energy Very large energy fluxes can occur in sea waves. The power in the wave is proportional to the square of the amplitude and the period of the motion. The possibility of generating electrical power from these water waves has been realized for many years, and there are countless ideas for machines to extract the power. The vertical travel (amplitude) of these waves can be converted into mechanical energy by placing a combination of platforms, pistons and cylinders to achieve a reciprocating motion and thus mechanical work. The utilization of wave energy for pumping water is considered suitable for desalination purposes in Pakistan [I 3]. New research institutes in Pakistan In order to acquire further insights into the area of silicon technology, a research and development centre, National Institute of Silicon Technology was set up in 1981. This institute has a capacity of assembling and manufacturing 3 million solar cells and would be able to export 250-500 kV solar cells [9]. The Solar Energy Centre (unit of PCSIR), a nucleus for clean energy institute of renewable energy has been established at Hyderabad. This centre will be capable of the product development and dissemination of solar energy technology. The main aim of this establishment, is to launch large scale integrated system for power generation, water desalination and to provides basic living necessities for remote/desert areas. Solar water desalination, solar ponds, solar electrolytic debacterifation, solar passive system, wind
Technical Note energy and wave energy are the major areas of research and development in the Solar Energy Centre [15]. Following the research, development and demonstration projects, educational programmes on utilization of alternative energy resources at all levels are necessary. These educational programmes would facilitate the promotion of indiginous renewable energy technologies (e.g. solar energy). CONCLUDING REMARKS The basic need for utilizing renewable energy resources is of immense importance to mankind. The long term goal to decrease the dependency of mankind on fossil fuels, due to its limited resources, protection against environmental deterioration (caused by use of fossil or nuclear fuels), has become extremely important. The utilization of solar energy and wind power especially in the remote areas, can help in solving the problem of the scarcity of conventional energy sources. For instance, solar heating can be utilized to assist with water supply systems (especially irrigation water supply), household electricity can be obtained from photovoltaics and wind energy. The basic living necessities (drinking water, cooking, bathing, lighting and washing) of people in Pakistan would also be met by considering renewable energy sources. Therefore, their material and cultural living conditions will be greatly improved and a balanced regional development will be attained so as to accelerate the modernization of the country as a whole. In order to get the maximum benefits from renewable energy sources, a number of research institutes have been established in Pakistan. No doubt, the task is difficult, the challenge is great and implementation may be expensive in the early stages. However, long term benefits are much greater and rewarding than just relying on conventional energy sources.
Acknowledgements--The authors wish to acknowledge the assistance of Dr S. W. Ali, Director, Solar Energy Centre,
325
Hyderabad, Pakistan, and Dr N. I. Syed, University of Calgary, Alberta, Canada, in the preparation of this paper.
REFERENCES I. H. A. Kuljian, A look at the world's energy resources. Power Engng, U.S.A. (1954). 2. Petroleum Economist, New discoveries mean increasing oil production in Pakistan. OPEC bulletin, March 1988. 3. S. H. Haq, Futuristics, Pakistan 0984). 4. United Nations, Energy Statistics Year Book (1985). 5. J. C. McVeigh (ed.), Energy Around the World. Pergamon Press, Oxford (1984). 6. R.G. Pallett and T. E. Brabben, Application and experience of photovoltaic pumps for irrigation in Pakistan. 4th E.C. Photovoltaie Solar Energy Conf., Stressa, Italy, May 1982. 7. M. A. Kettani, Solar energy in developing countries, in Solar Worm Forum, Proc. ISES (Edited by D. O. Hall and J. Marton), Vol. 4 (1981). 8. A. Qayyum, J. I. B. Wilson and K. Ibrahim, Application of photovoltaic system in Pakistan in INTERSOL '87. Proc. ISES Worm Conf., Hamburg (1987). 9. R. Akhtar (ed.), Pakistan Year Book (1985-1986). I0. S. Ahmed, Private communication (1988). 11. S. M. Haq, S. N. Sarwar and M. A. Quduss, A case study of generation of electricity from refuse in Karachi. Energy World, No. 149, July 1987. 12. E. A. S. Bokharai, Power Generation: New Hopes, Science Technology and Development, Vol. 4, No. 3 (1984). 13. F. Ahmed, S. A. Hussain and M. Wasim Akhtar, Karachi Univ. J. Sci. 11, No. 2, December 1983. 14. J. A. Khan (ed.), Solar Energy, Engineering Design and Development Projects 1977 1985. NED University of Engineering and Technology, Karachi, Pakistan. 15. S. W. A. Rizvi, Private communication (1986).
0741 983X/90 $3.00+.00 PergamonPressplc
Printedin Great Britain.
TECHNICAL NOTE Prospects for harnessing renewable energy sources in Pakistan S. M . HASNAIN a n d B. M . GraBS Department of Fuel and Energy, University of Leeds, Leeds LS2 9JT, U.K. (Received 12 October 1988 ; accepted 30 J a n u a r y 1989)
Abstract--Renewable energy resources can provide a viable alternative to the existing energy supply system, particularly in the developing countries. This paper first gives an outline of the conventional energy resources and then discusses in detail the significance of utilization of renewable energy sources in the development of remote areas of Pakistan, which consists of about 75% of its total population. Considering and outlining the indigenous renewable energy potential, and the course of the country's development, some newly established projects and the extent of their application are elucidated. The prospects of renewable energy sources for the remaining 25% urban population of Pakistan are also discussed.
ENERGY STATUS AND P R O S P E C T S Energy has always been a vital and indispensable input to the economical needs of the present age. It functions as a blood stream in production, a fuel for transportation and the power source in electricity generation. Kuljian [1] reported that "despite our still ample coal, oil and gas reserves, at the rate we are depleting them, it behooves us to be thinking about the development of new sources of energy which will be so vital for our energy future". This study [1] depicted that, the future use of world fossil fuels such as coal, gas and oil would be depleted by the year 2030 while the entire non-renewable fossil and fissionable fuel resources will be depleted by the year 2350. Therefore, it has been concluded, that if we are to live and progress on this earth we will have to find alternative, plentiful and reliable energy resources. The world population is presently estimated at about 4.5 billion and increasing at an approximate rate of 2-3% per year so as to double every 20-30 years. In 1980, population of the Third World countries was estimated at over 3.0 billion which may triple by the year 2100. Table 1 lists the growing disparity in population and energy consumption trends between the developed and the developing countries of the world. It can be easily estimated, that in 45 years (19802025), the energy consumption in developing countries would be increased by about 54%. As a result, the effects on the environment will become more severe and resources will continue to deplete. The population o f Pakistan is growing at an alarming rate (about 3.5% per annum), the demands on the existing energy supplies are also increasing, therefore, it is necessary to iden-
tify the alternative energy sources. The country will be in need of larger amounts of energy each year for the expansion of its industrial base, transportation and for mechanized farming. This paper discusses the need for the utilization of renewable energy sources in Pakistan which is compared with existing conventional energy resources. CONVENTIONAL ENERGY RESOURCES Tables 2 and 3, show the magnitude of different energy supply systems in Pakistan. These tables indicate the requirements of conventional energy sources and its production in Pakistan. Notwithstanding the fact that Pakistan has large deposits of coal (estimated about 1.178 million kilograms), which can be classified as highly volatile to sub-bituminous with relatively high ash and sulphur content. In Pakistan, the daily production of oil is around 42,000 barrels (see Table 2), against the demand of 160,000 barrels of oil/day. Pakistan spends more than half of its export earnings on the payment o f oil bills to the Middle East countries, therefore, its foreign exchange resources hampers a substantial increase in oil imports. The case for natural gas, on the other hand is relatively stronger (Table 2). As the natural gas is a precious raw material for fertilizer production and for petrochemical industry, therefore, it is recommended that, consumption should not be allocated for other applications. Recently Pakistan has been facing an acute shortage of electric power. Almost all parts of the country have been subjected to hours of load-shedding each day, particularly during winter. In 1973-1974 the electricity consumption by
Table 1. Global population and energy consumption trends. (P = population, E = energy use) Countries Developed Developing
P(%)
1980 E(%)
P(%)
1985 E(%)
27.7 72.3
80.1 19.9
26.0 74.0
78.7 21.3 321
2000 P(%) E(%) 21.3 78.7
71.9 28.1
2025 P(%) E(%) 15.9 84.1
63.3 36.7
322
Technical Note
Table 2. Oil and gas production in Pakistan. (Data derived from Ref. [2]) Year
Crude oil (barrels per day)
Natural gas (billion cubic metres)
1981 1982 1983 1984 1985 1986
9,564 11,720 12,082 18,000 34,480 41,548
8.93 9.74 9.72 10.04 10.40 11.10
domestic consumers was recorded as 516 million units (kWh), while in March 1985, 4240 million units (kWh) were stated as a maximum demand. It is estimated that about 300 kWh/capita/year electrical energy is required by the domestic user. However, at present it is around only 50 kWh/capita/ year. If these targets were to be achieved by the year 2000, 42,000 GWh of electrical energy will be required. It is envisaged that, the conventional energy sources would contribute only 20,000 GWh (143 kWh/capita/year). Thus alternative sources of energy would need to supply up to 22,000 GWh of electrical energy by the year 2000 in order to fill the gap from 143 to 300 kWh/capita/year [3]. In Table 3 it is depicted that gas and solid sources in Pakistan are depleting with the passage of time. However, it shows that electricity and liquid supply has been relatively improved as compared to previous years. Figure 1, shows a total production and consumption of commercial energy in Pakistan. Solids, liquids, gas and electricity are the main components of the total production and consumption o f commercial energy. This figure reveals a well defined gap between energy production and consumption as it is increasing with the passage of time. All locally produced energy in the form of gas and electricity is being used by the consumers, whereas some solids and liquids fuels have to be imported in order to fulfil the basic necessities of the populace. It seems safe to infer that Pakistan is running out of conventional energy sources very rapidly. A few decades ago nuclear power was envisaged as the final solution to all future energy problems in the world. However, presently, the world's nuclear industry is suffering from power plant cancellation, escalating costs and public opposition. Due to the recent incidences of operational problems, leakages and catastrophic accidents (for instance the Chernobyl disaster) in nuclear plant, the populace is very skeptical about the future of nuclear power. It is, therefore, conceivable to consider the energy resources which are renewable, clean, easily convertable to conventional energy forms with existing technological know how, and zero fuel cost. Table 3. The contribution of commercial energy supply in Pakistan based on percentage of total energy consumption against each source [4] Year
Solids
Liquids
Gas
Electricity
1982 1983 1984 1985
6.90 5.65 6.20 6.78
36.74 40.17 41.38 42.77
50.36 47.74 45.47 42.90
6.00 6.44 6.95 7.55
RENEWABLE ENERGY SOURCES In view of the long term energy requirements of Pakistan, a preliminary assessment of the potential importance of various forms of renewable energy resources (solar, wind, biogas, etc.) needs to be carried out. Geographically, Pakistan is well endowed with natural energy gifts. The north is full of hydro resources, the south has considerable wind and sun, while the central part of the country, being agricultural oriented is extremely appropriate for implementing biogas and solar energy schemes. Pakistan lies in the sun belt area, therefore, the early development of solar energy technologies will have a highly beneficial impact on the nation.
Solar eneryy technoloyies The most tantalizing feature of the sun's energy is its abundance. The total solar power intercepted by the earth is 1.75 x l017 W or an annual total of 5.52 x 1024 J. For comparison, world's total commercial energy consumption in 1982 was 2.86 x 1020 J [5], or some 20,000 times smaller than the solar energy intercepted by the earth. In 220 days we receive as much heat as there is in all the fossil fuels and the fissionable materials in the world put together. If some method can be found to tap this inexhaustible source of energy, it might enable mankind to resolve its energy problems for all time. Solar energy technologies are based on the conversion of solar radiation into heat, mechanical or electrical power, or to directly generate electricity. Solar radiation can be categorized in two types: direct and indirect. Direct solar radiation can be utilized for electrical power generation, using photovoltaic systems. Whereas, examples of indirect solar radiation are biomass, wind and biogas, etc. Utilization of direct solar radiation In this category the incident sunlight is converted directly into the desired form, i.e. heat or electricity, which is indispensable for immediate applications. In Pakistan, lighting and water pumping requirements at village level could be satisfied, if electric power is available readily and cheaply. The magnitude of solar insolation is approximately 8 kWh/m2/day and an average eight hours sunlight per day is available throughout the year [6]. In the rural and far flung areas of Pakistan, electricity requirements have far higher priority than space heating. Therefore, the use of photovoltaic solar panels, can play a vital role by decentralizing electricity generation as well as eliminating the needs for transmission and distribution. In Pakistan, a number of solar village electrification systems with a total capacity of over 300 kW are in progress. In addition, a 5 kW photovoltaic generator is being installed and a photovoltaic and thermal system with a capacity of 120 kW is to be installed in order to energize remote villages [7]. It is also indicated in [8] that in remote areas of Pakistan, the use of photovoltaic system, to produce electricity is prominent, especially in education, hospitals, social animation, lighting, communication and various other applications such as water pumping. Pakistan will be the first country in the ESCAP (Economic and Social Commission for Asia and the Pacific) region to have a solar energy training and demonstration centre, called as the Regional Solar Energy Development and Demonstration centre [9]. Utilization of indirect aolar radiation The process, by which solar energy is transformed indirectly through different steps to convert it into useful
323
Technical Note
XlO3
~Production
~
Consumption
'1 O 43 c~
E
24: 22:
O
[..)
2o!
0 .,-I 0 0
ta!
161
>a Da
.,,.,,,,,l,,,,,,,,,l,,,&,,,,,l,,,,,,,,.l,,,,,,,,,l,&,,,,,,
198t
1982
t983 Number
t984
t9115
1986
1987
of Y e a r s
Fig. 1. Total production and consumption of commercial energy in Pakistan (Ref. [4]). (Quantities in kilograms per capita of coal equivalent and in thousand metric tons).
utilizable energy, are termed as indirect processes. The following examples are a brief description of the utilization of indirect solar radiation in Pakistan.
Biogas Whenever organic wastes decay in anaerobic environment, methane gas is generated which is combustable and can be used as a fuel. As an additional benefit, the slurry left behind in the fermentation chamber after the gas has been generated, is as effective as a fertilizer as the initial manure. This technology is not only cheap but practicable and easy to install. About I0 million biogas plants are successfully operating today in several developing countries. In Pakistan, a number of biogas plants have been demonstrated in 4000 villages and it is hoped that all 27,500 unlit villages can be energized with biogas as a fuel source. It is roughly estimated that approximately 40,000 biogas plants will be needed in the year 2000, which would provide 92 billion cubic feet of gas equivalent to 5 million tonnes o f coal or 2 million tonnes of kerosine. These plants can meet the domestic needs of the projected 100 million rural population in the year 2000, at the present level of per capita of energy consumption. Furthermore each plant will be capable of providing fertilizer equivalent to 2.6 tonnes of nitrogen per year. Thus 40,000 such plants are expected to produce around 100,000 tonnes of nitrogenous energy per year. The implantation of biogas plants might be higher because it has a payback period of only one year. The Energy Resource Cell under Ministry of Petroleum and Pakistan Council of Scientific & Industrial Research (PCSIR) Laboratories under Ministry of Science & Technology are working for the implementation of biogas plants and technology.
Biomass Biomass, which consists o f vegetative matter, can be converted through pyrolysis, hydrolysis and anaerobic digestion into liquid, solid and gaseous fuels. Green plants capture the
sunlight and convert it via photosynthesis into food and fuel. It was photosynthesis that originally gave rise to start point materials for geologic fermentation of oil, natural gas and coal. Now, man can harvest the stored solar energy of present day plants. Dry plant matter has an energy content equivalent to 60% of the energy content of bituminous coal. The fuel obtained from biomass is of good quality, for instance it has sulphur content less than 0.1% and ash content ~ 5 % , whereas coal found in Pakistan has 4-9% sulphur and 1830% ash content. Several countries, on a commercial scale have launched programmes to convert agricultural crops into alcohol. Molasses and Baggas are the byproduct from the processing of cane sugar. Molasses contains over 50% of fermentable sugar from which alcohol can be easily manufactured. It is estimated that 1 tonne o f molasses produces 0.22~).24 m 3 of alcohol (100% by volume). It is assumed that, if in Pakistan 0.5 million tonnes of molasses is produced, it would yield 0.114.12 million cubic meters of alcohol. If petrol and alcohol mixture ratio is kept at 75:25 respectively, 0.11~).12 million cubic meters of petrol would be required to make 0.45/0.47 million cubic meters of alco-petrol. It is generally believed that approximately 1 tonne of cane yields 100 kg of sugar, 40-64 1 of molasses which in turn could produce 14161 of alcohol. Pakistan has an abundance of Molasses, Beet root and Corn, etc., therefore, it would be more economical to install alcohol producing plants with the existing 38 sugar mills rather than to export the molasses at a very cheap rate. Thus, alcohol could easily be produced in vast quantities sufficient to provide all or most o f our transportation fuel requirements. If the production and consumption conditions of the cane sugar are favourable, then it could also be used for the production of alcohol, as it is being produced in Brazil. In future Pakistan might require some sort of substitute of sugar consumption by high fructose syrup, liquid glucose and maltose syrups. These can be manufactured from very cheap quality broken rice or maize by enzymatic
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Technical Note Table 4. Typical characteristic of refuse components in the city of Karachi [11]
Components
Moisture (wt. %)
Calorific value (Btu/lb)
Sulphur (wt. %)
Ash (wt. %)
15 5 19 45 75
7250 17376 6633 4684 1700
0.39 0.21 0.O4).08 0.11 0.13
11. I 4.5 12.7 21. I 43.6
Paper and hardboard Plastic Cotton and linen Leaves/green food Garbage
technology, as has already been demonstrated in Pakistan [10]. ReJuse power As a partial solution to the shortage of about 800 M W of electricity during winter season in Pakistan, electricity generation is possible through the combustion of refuse. The heat content of refuse varies, but generally 2 tonne of refuse is equal to the heat content of 1 tonne of coal. Roughly it is estimated that per capita refuse generation in Pakistan is around 0.3 tonne per year. For a city like Karachi, about 6000 tGnne of refuse is accumulated each day of which 60% is combustible. A previous study [11] concluded that 1.0 Mt worth of furnace oil for power generator could be saved each year by effective use of refuse. Overall, it is possible that, the total energy supply from refuse could contribute at least a 20% share of the Karachi energy requirement, which is the largest energy consuming zone in Pakistan on per capita consumption basis. The typical fuel characteristics and components in refuse found in Karachi are shown in Tables 4 and 5. These tables show that, the refuse is lower in sulphur and heating value but higher in ash and moisture contents compared to fossil fuels. The refuse calorific content can also be compared with liginite coal (sulphur content 4 - 9 % ) with an advantage of lower sulphur pollution value (0.1~). 16%). Wind power Energy from the wind is derived from solar energy, as a small proportion of the total solar radiation reaching the earth causes movement in the atmosphere, which appears as wind. Traditional wind mills for pumping water and grinding corn have been used for at least 2000 years. Of all the alternatives, wind mills are the most flexible in term of scale of operation. Wind mill technology has developed rapidly in recent years. The United States is spending some $60 million
Table 5. Typical composition of mixed domestic and commercial refuse found in Karachi. (Data derived from Ref. [11]) Components Paper Plastic Cotton Green leaves and food Garbage Metal, glass, debris, etc. (non-combustible inorganics)
wt. % 10.2 4.6 9.8 20.0 36.5 8.5
per a n n u m on various new systems. Currently about 18,000 wind machines with a generation capacity of more than 1.5 GW, have been installed in California and produced enough electricity to supply 50,000 homes. The U.S.A. is relying on this type of power generation for 10% of its total electricity supply by the end of the century [12]. Recent research in the U.K. shows that the wind energy could in principle supply about 20% of its electricity demand in the near future. Wind mills are of different shapes and sizes. A 10 kW power generation capacity wind mill for example, is more suitable in the context of Pakistan rural scene and is sufficient to meet the electricity needs of 200-300 people living in a village. It is observed that the energy generated by a wind mill could be twice as efficient as that obtained from a diesel generator. Wind energy could provide adequate electric power in coastal areas. Preliminary work for most of these areas in Pakistan in the field of data collection [13], as well as experimental investigations is underway [14]. The studies show that wind energy in Karachi could effectively produce over 200 k W h per month. Wave energy Very large energy fluxes can occur in sea waves. The power in the wave is proportional to the square of the amplitude and the period of the motion. The possibility of generating electrical power from these water waves has been realized for many years, and there are countless ideas for machines to extract the power. The vertical travel (amplitude) of these waves can be converted into mechanical energy by placing a combination of platforms, pistons and cylinders to achieve a reciprocating motion and thus mechanical work. The utilization of wave energy for pumping water is considered suitable for desalination purposes in Pakistan [I 3]. New research institutes in Pakistan In order to acquire further insights into the area of silicon technology, a research and development centre, National Institute of Silicon Technology was set up in 1981. This institute has a capacity of assembling and manufacturing 3 million solar cells and would be able to export 250-500 kV solar cells [9]. The Solar Energy Centre (unit of PCSIR), a nucleus for clean energy institute of renewable energy has been established at Hyderabad. This centre will be capable of the product development and dissemination of solar energy technology. The main aim of this establishment, is to launch large scale integrated system for power generation, water desalination and to provides basic living necessities for remote/desert areas. Solar water desalination, solar ponds, solar electrolytic debacterifation, solar passive system, wind
Technical Note energy and wave energy are the major areas of research and development in the Solar Energy Centre [15]. Following the research, development and demonstration projects, educational programmes on utilization of alternative energy resources at all levels are necessary. These educational programmes would facilitate the promotion of indiginous renewable energy technologies (e.g. solar energy). CONCLUDING REMARKS The basic need for utilizing renewable energy resources is of immense importance to mankind. The long term goal to decrease the dependency of mankind on fossil fuels, due to its limited resources, protection against environmental deterioration (caused by use of fossil or nuclear fuels), has become extremely important. The utilization of solar energy and wind power especially in the remote areas, can help in solving the problem of the scarcity of conventional energy sources. For instance, solar heating can be utilized to assist with water supply systems (especially irrigation water supply), household electricity can be obtained from photovoltaics and wind energy. The basic living necessities (drinking water, cooking, bathing, lighting and washing) of people in Pakistan would also be met by considering renewable energy sources. Therefore, their material and cultural living conditions will be greatly improved and a balanced regional development will be attained so as to accelerate the modernization of the country as a whole. In order to get the maximum benefits from renewable energy sources, a number of research institutes have been established in Pakistan. No doubt, the task is difficult, the challenge is great and implementation may be expensive in the early stages. However, long term benefits are much greater and rewarding than just relying on conventional energy sources.
Acknowledgements--The authors wish to acknowledge the assistance of Dr S. W. Ali, Director, Solar Energy Centre,
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Hyderabad, Pakistan, and Dr N. I. Syed, University of Calgary, Alberta, Canada, in the preparation of this paper.
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