The Role of Green Energy Systems and Sustainable Development

Authors

• Abdeen Mustafa Omer Energy Research Institute (ERI), Nottingham, UK

Abstract

People are relying upon oil for primary energy and this will continue for a few more decades. Other conventional sources may be more enduring, but are not without serious disadvantages. The renewable energy resources are particularly suited for the provision of rural power supplies and a major advantage is that equipment such as flat plate solar driers, wind machines, etc., can be constructed using local resources. Without the advantage results from the feasibility of local maintenance and the general encouragement such local manufacture gives to the buildup of small-scale rural based industry. This communication comprises a comprehensive review of energy sources, the environment and sustainable development. It includes the renewable energy technologies, energy efficiency systems, energy conservation scenarios, energy savings in greenhouses environment and other mitigation measures necessary to reduce climate change. This study gives some examples of small-scale energy converters, nevertheless it should be noted that small conventional, i.e., engines are currently the major source of power in rural areas and will continue to be so for a long time to come. There is a need for some further development to suit local conditions, to minimise spares holdings, to maximise the interchangeability of the engine parts, and of the engine applications. Emphasis should be placed on full local manufacture. It is concluded that renewable environmentally friendly energy must be encouraged, promoted, implemented and demonstrated by a full-scale plant (device) especially for use in remote rural areas.

Keywords: Renewable energy technologies, energy efficiency, sustainable development, emissions, environment

Introduction

Power from natural resources has always had great appeal. Coal is plentiful, though there is concern about despoliation in winning it and pollution in burning it. Nuclear power has been developed with remarkable timeliness, but is not universally welcomed, construction of the plant is energy-intensive and there is concern about the disposal of its long-lived active wastes. Barrels of oil, lumps of coal, even uranium come from nature but the possibilities of almost limitless power from the atmosphere and the oceans seem to have special attraction. The wind machine provided an early way of developing motive power. The massive increases in fuel prices over the last years have however, made any scheme not requiring fuel appear to be more attractive and to be worth reinvestigation (Cheng, 2010). In considering the atmosphere and the oceans as energy sources, the four main contenders are wind power, wave power, tidal and power from ocean thermal gradients. The sources to alleviate the energy situation in the world are sufficient to supply all foreseeable needs. Conservation of energy and rationing in some form will however have to be practised by most countries, to reduce oil imports and redress balance of payments positions. Meanwhile development and application of nuclear power and some of the traditional solar, wind and water energy alternatives must be set in hand to supplement what remains of the fossil fuels (Kothari, Singal, Rakesh, and Ranjan 2011).

The encouragement of greater energy use is an essential component of development. In the short-term, it requires mechanisms to enable the rapid increase in energy/capita, while in the long-term it may require the use of energy efficiency without environmental and safety concerns. Such programmes should as far as possible be based on renewable energy resources (Cihan, Dursun, Bora, and Erkan, 2009).

Large-scale, conventional, power plant such as hydropower has an important part to play in development although it does not provide a complete solution. There is however an important complementary role for the greater use of small-scale, rural based power plants. Such plants can be employed to assist development since they can be made locally. Renewable resources are particularly suitable for providing the energy for such equipment and its use is also compatible with the long-term aims.

In compiling energy consumption data one can categorise usage according to a number of different schemes:

• Traditional sector- industrial, transportation, etc.
• End-use- space heating, process steam, etc.
• Final demand- total energy consumption related to automobiles, to food, etc.
• Energy source- oil, coal, etc.
• Energy form at point of use- electric drive, low temperature heat, etc.

2. Methods and Materials

The increased availability of reliable and efficient energy services stimulates new development alternatives. This communication discusses the potential for such integrated systems in the stationary and portable power market in response to the critical need for a cleaner energy technology. Anticipated patterns of future energy use and consequent environmental impacts (acid precipitation, ozone depletion and the greenhouse effect or global warming) are comprehensively discussed in this study. Throughout the theme several issues relating to renewable energies, environment, and sustainable development are examined from both current and future perspectives. It is concluded that green energies like wind, solar, ground-source heat pumps, and biomass must be promoted, implemented, and demonstrated from the economic and/or environmental point view. The key factors to reducing and controlling CO₂, which is the major contributor to global warming, are the use of alternative approaches to energy generation and the exploration of how these alternatives are used today and may be used in the future as green energy sources. Even with modest assumptions about the availability of land, comprehensive fuel-wood farming programmes offer significant energy, economic and environmental benefits. These benefits would be dispersed in rural areas where they are greatly needed and can serve as linkages for further rural economic development. There is strong scientific evidence that the average temperature of the earth’s surface is rising. This was a result of the increased concentration of carbon dioxide (CO₂), and other greenhouse gases (GHGs) in the atmosphere as released by burning fossil fuels. This global warming will eventually lead to substantial changes in the world’s climate, which will, in turn, have a major impact on human life and the environment. Energy use reductions can be achieved by minimising the energy demand, by rational energy use, by recovering heat and the use of more green energies. This study was a step towards achieving this goal. The adoption of green or sustainable approaches to the way in which society is run is seen as an important strategy in finding a solution to the energy problem.

3. Renewable Energy Potential

The increased availability of reliable and efficient energy services stimulates new development alternatives (Omer, 1995a). This communication discusses the potential for such integrated systems in the stationary and portable power market in response to the critical need for a cleaner energy technology. Anticipated patterns of future energy use and consequent environmental impacts (acid precipitation, ozone depletion and the greenhouse effect or global warming) are comprehensively discussed in this approach. Throughout the theme several issues relating to renewable energies, environment and sustainable development are examined from both current and future perspectives. It is concluded that renewable environmentally friendly energy must be encouraged, promoted, implemented and demonstrated by full-scale plants (devices) especially for use in remote rural areas. Globally, buildings are responsible for approximately 40% of the total world annual energy consumption. Most of this energy is for the provision of lighting, heating, cooling, and air conditioning. Increasing awareness of the environmental impact of CO₂, NO_x and CFCs emissions triggered a renewed interest in environmentally friendly cooling, and heating technologies. Under the 1997 Montreal Protocol, governments agreed to phase out chemicals used as refrigerants that have the potential to destroy stratospheric ozone. It was therefore considered desirable to reduce energy consumption and decrease the rate of depletion of world energy reserves and pollution of the environment. One way of reducing building energy consumption is to design buildings, which are more economical in their use of energy for heating, lighting, cooling, ventilation and hot water supply.

Passive measures, particularly natural or hybrid ventilation rather than air-conditioning, can dramatically reduce primary energy consumption. However, exploitation of renewable energy in buildings and agricultural greenhouses can, also, significantly contribute towards reducing dependency on fossil fuels. Therefore, promoting innovative renewable applications and reinforcing the renewable energy technologies market will contribute to preservation of the ecosystem by reducing emissions at local and global levels. This will also contribute to the amelioration of environmental conditions by replacing conventional fuels with renewable energies that produce no air pollution or greenhouse gases.

There is strong scientific evidence that the average temperature of the earth’s surface is rising. This is a result of the increased concentration of carbon dioxide and other GHGs in the atmosphere as released by burning fossil fuels. This global warming will eventually lead to substantial changes in the world’s climate, which will, in turn, have a major impact on human life and the built environment. Therefore, effort has to be made to reduce fossil energy use and to promote green energies, particularly in the building sector. Energy use reductions can be achieved by minimising the energy demand, by rational energy use, by recovering heat and the use of more green energies. This study was a step towards achieving that goal. The adoption of green or sustainable approaches to the way in which society is run is seen as an important strategy in finding a solution to the energy problem. The key factors to reducing and controlling CO₂, which is the major contributor to global warming, are the use of alternative approaches to energy generation and the exploration of how these alternatives are used today and may be used in the future as green energy sources (Omer, 1998a). Even with modest assumptions about the availability of land, comprehensive fuel-wood farming programmes offer significant energy, economic and environmental benefits. These benefits would be dispersed in rural areas where they are greatly needed and can serve as linkages for further rural economic development. The nations as a whole would benefit from savings in foreign exchange, improved energy security, and socio-economic improvements. With a nine-fold increase in forest – plantation cover, a nation’s resource base would be greatly improved. The international community would benefit from pollution reduction, climate mitigation, and the increased trading opportunities that arise from new income sources. The non-technical issues, which have recently gained attention, include: (1) Environmental and ecological factors, e.g., carbon sequestration, reforestation and revegetation. (2) Renewables as a CO₂ neutral replacement for fossil fuels. (3) Greater recognition of the importance of renewable energy, particularly modern biomass energy carriers, at the policy and planning levels. (4) Greater recognition of the difficulties of gathering good and reliable renewable energy data, and efforts to improve it. (5) Studies on the detrimental health efforts of biomass energy particularly from traditional energy users. The renewable energy resources are particularly suited for the provision of rural power supplies and a major advantage is that equipment such as flat plate solar driers, wind machines, etc., can be constructed using local resources and with the advantage resulting from the feasibility of local maintenance and the positive influence such local manufacturing has on small-scale rural based industry. This study gives some examples of small-scale energy converters, nevertheless it should be noted that small conventional, i.e., engines are currently the major source of power in rural areas and will continue to be so for a long time to come. There is a need for some further development to suit local conditions, to minimise spares holdings, to maximise the interchangeability of the engine parts and of the engine applications. Emphasis should be placed on full local manufacture.

The renewable energy resources are particularly suited for the provision of rural power supplies and a major advantage is that equipment such as flat plate solar driers, wind machines, etc., can be constructed using local resources and without the high capital cost of more conventional equipment. Further advantage results from the feasibility of local maintenance and flourishing benefits such local manufacturing has on small-scale rural based industry. Table 1 lists the energy sources available.

Table 1. Sources of energy (Omer, 1998a)

Energy source	Energy carrier	Energy end-use
Vegetation	Fuel-wood	CookingWater heatingBuilding materialsAnimal fodder preparation
Oil	Kerosene	LightingIgnition fires
Dry cells	Dry cell batteries	LightingSmall appliances
Muscle power	Animal power	TransportLand preparation for farmingFood preparation (threshing)
Muscle power	Human power	TransportLand preparation for farmingFood preparation (threshing)

Table 2. Renewable applications

Systems	Applications
Water supply systemWastes disposal systemBiogas cooking systemFood productionElectrical demandsSpace heating systemWater heating systemControl systemBuilding fabric	Rain collection, purification, storage and recyclingAnaerobic digestion (CH4)MethaneCultivation of 1 hectare plot and greenhouse for four peopleWind generatorSolar collectorsSolar collectors and excess wind energyUltimately hardwareIntegration of subsystems to cut costs

Currently the ‘non-commercial’ fuels wood, crop residues and animal dung are used in large amounts in the rural areas of developing countries, principally for heating and cooking; the method of use is highly inefficient. Table 2 presented some renewable applications.

Table 3 lists the most important of energy needs.

Table 3. Energy needs in rural areas

Transport, e.g., small vehicles and boatsAgricultural machinery, e.g., two-wheeled tractorsCrop processing, e.g., millingWater pumpingSmall industries, e.g., workshop equipmentElectricity generation, e.g., hospitals and schoolsDomestic, e.g., cooking, heating, and lightingWater supply, e.g., rain collection, purification, and storage and recyclingBuilding fabric, e.g., integration of subsystems to cut costsWastes disposal, e.g., anaerobic digestion (CH4)

Considerations when

selecting power plant include the following:

• Power level- whether continuous or discontinuous.
• Cost- initial cost, total running cost including fuel, maintenance and capital amortised over life.
• Complexity of operation.
• Maintenance and availability of spares.
• Life span of the plant.
• Suitability for local manufacture.

Table 4 listed methods of energy conversion.

Table 4. Methods of energy conversion

Muscle powerInternal combustion engines ReciprocatingRotatingHeat enginesVapour (Rankine)ReciprocatingRotatingGas Stirling (Reciprocating)Gas Brayton (Rotating)Electron gasElectromagnetic radiation Hydraulic engines Wind engines (wind machines)Electrical/mechanical

Man, animalsPetrol- spark ignitionDiesel- compression ignitionHumphrey water pistonGas turbinesSteam engineSteam turbineSteam engineSteam turbineThermionic, thermoelectricPhoto devicesWheels, screws, buckets, turbinesVertical axis, horizontal axisDynamo/alternator, motor

The household wastes for family of four persons, could provide (280 kWh/yr) of methane, but with the addition of vegetable wastes from 0.2 hectare (ha) or wastes from 1 ha cultivated under a complete diet, about 1500 kWh/yr may be obtained by anaerobic digestion (Omer, 1999a). The sludge from the digester may be returned to the land. In hotter climates, this could be used to set up productive biomass utilisation energy cycle (Figure 1).

Figure 1. Biomass energy utilisation cycle.

There is a need for greater attention to be devoted to this field in the development of new designs, the dissemination of information and the encouragement of its use. International and government bodies and independent organisations all have a role to play in renewable energy technologies.

4. Energy Consumption

Over the last decades, natural energy resources such as petroleum and coal have been consumed at high rates. The heavy reliances of the modern economy on these fuels are bound to end, due to their environmental impact, and the fact that conventional sources might eventually run out. The increasing price of oil and instabilities in the oil market has led to search for energy substitutes.

Society and industry in Europe and elsewhere are increasingly dependent on the availability of electricity supply and on the efficient operation of electricity systems. In the European Union (EU), the average rate of growth of electricity demand has been about 1.8% per year since 1990 and is projected to be at least 1.5% yearly up to 2030 (ERI, 1987). Currently, distribution networks generally differ greatly from transmission networks, mainly in terms of role, structure (radial against meshed) and consequent planning and operation philosophies.

In addition to the drain on resources, such an increase in consumption consequences, together with the increased hazards of pollution and the safety problems associated with a large nuclear fission programmes makes this type of energy environment unfriendly. This is a disturbing prospect. It would be equally unacceptable to suggest that the difference in energy between the developed and developing countries. The developed countries to move towards a way of life which, whilst maintaining or even increasing quality of life. This reduces significantly the energy consumption per capita. Such savings can be achieved in a number of ways:

• Improved efficiency of energy use, for example better thermal insulation, energy recovery, and total energy.
• Conservation of energy resources by design for long life and recycling rather than the short life throwaway product.
• Systematic replanning of our way of life, for example in the field of transport.

Energy ratio is defined as the ratio of energy content of the foodproduct/energy input to produce the food.

Er = Ec/Ei(1)

where Er is the energy ratio, Ec is the energy content of the food product, and Ei is the energy input to produce the food.

Currently the non-commercial fuelwood, crop residues and animal dung are used in large amounts in the rural areas of developing countries, principally for heating and cooking, the method of use is highly inefficient. As in the developed countries, the fossil fuels are currently of great importance in the developing countries. Geothermal and tidal energy are less important though, of course, will have local significance where conditions are suitable. Nuclear energy sources are included for completeness, but are not likely to make any effective contribution in the rural areas. Economic importance of environmental issue is increasing, and new technologies are expected to reduce pollution derived both from productive processes and products, with costs that are still unknown.

4.1. Agriculture Sector

During the last decades, agriculture contributed about 41% to the Sudan’s GNP. This share remained stable till 1984/1985 when Sudan was seriously hit by drought and desertification, which led to food shortages, deforestation, and also, socio-economic effects caused by the imposed civil war. The result dropped the agriculture share to about 37%. Recent development due to rehabilitation and improvement in agricultural sector in 1994 has raised the share to 41%. This share was reflected in providing raw materials to local industries and an increased export earning besides raising percentage of employment among population.

4.2. Industrial Sector

The industrial sector is mainly suffering from power shortages, which is the prime mover to the large, medium and small industries. The industrial sector was consuming 5.7% of the total energy consumption, distributed as: 13.8% from petroleum products, 3.4% from biomass and 8% from electricity.

4.3. Domestic Use

Household is the major energy consumer. It consumed 92% of the total biomass consumption in form of firewood and charcoal. From electricity, this sector consumed 60% of the total consumption, and 5.5% of petroleum products.

4.4. Transport Sector

The transportation sector was not being efficient for the last two decades because of serious damage that affected its infrastructure. It consumed 10% of the total energy consumption and utilised 60% of the total petroleum products supplied.

4.5. Energy Sector

The present position for most people in Sudan for obtaining the needed energy forms (heat, light, etc.) is provided by firewood. Cooking is largely done by wood from forests or its derivative, charcoal. Cattle dung and agriculture waste being used to lesser extent. Human, animal, and diesel or gasoline engines provide mechanical power. Some cooking and lighting is done by kerosene. It should be recognised that this situation is unlikely to be charged for the next one or two decades. However, because of the need to increase energy availability and also to find alternatives to the rapidly decreasing wood supplies in many rural areas, other energy alternatives are being sought.

5. Energy Situation

Sudan is the largest country in African continent, with a tropical climate, and an area of approximately 10⁶ square miles (2.5 x 10⁶ km²). It lies between latitudes 3’N and 23’N; and longitudes 21 45’ ’E and 39’E. This large area enjoys a variety of climates, from desert regions in the north, to tropical in the south, and makes it a favourable environment for all activities of integrated agricultural investment from production to processing industries (Omer, 1997a). Sudan is a relatively sparsely populated country. The total population according to the census 2009 was 39 x 10⁶ inhabitants. The annual growth rate is 2.8%, and population density is 12 persons per square kilometre (Omer, 1997a). Sudan is rich in land and water resources (Omer, 1997a). Sudan has a predominately continental climate, which roughly divides, into three climatological regions:

Region 1 is situated north of latitude 19’N. The summers are invariably hot (mean maximum 41C and mean minimum 25C) with large variation; low relative humidity averages. Winters are quite cool. Sunshine is very prevalent. Dust storms occur in summer. The climate is a typical desert climate where rain is infrequent and annual rainfall of 75-300 mm. The annual variation in temperature is large (maximum and minimum pattern corresponding to winter and summer). The fluctuations are due to the dry and rainy seasons.

Region 2 is situated south of latitude 19’N. The climate is a typical tropical continental climate.

Region 3 comprises the areas along the Red Sea coast and eastern slopes of the Red Sea hills. The climate is basically as in region 1, but is affected by the maritime influence of the Red Sea.

Two main air movements determine the general nature of the climate. Firstly, a very dry air movement from the north that prevails throughout the year, but lacks uniformity; and secondly, a major flow of maritime origin that enters Sudan from the south carrying moisture and bringing rain. The extent of penetration into the country by airflow from the south determines the annual rainfall and its monthly distribution. The average monthly rainfall for Sudan indicates the decreasing trend in the rainfall, as well as in the duration as one moves generally from the south towards the north and from east towards west. The total size of the land of Sudan is 6 x 10⁸ Feddans (Feddan = 1.038 acres = 0.42 hectares). The land use in the country is classified into four main categories. There are arable land (8.4 x 10⁶ hectares), pasture (29.94 x 10⁶ hectares), forest (108.3 x 10⁶ hectares), and about 38.22 x 10⁶ hectares used for other purposes. Water resources are estimated at 84 x 10⁹ cubic meters (m³), this including the river Nile and its tributaries. Underground water is estimated at 26 x 10¹⁰ cubic meters, and only 1% of this amount is currently being utilised. The annual average rainfall ranges from about 1 mm in the northern desert to about 1600 mm in the equatorial region. The total annual rainfall estimated at (1093.2 x 10⁹) m³/annum.

Sudan’s economy remains essentially agricultural, with annual agricultural production, estimated as 15 x 10⁶ tonnes mainly sugar, wheat, sorghum, cotton, millet, groundnut, sesame, tobacco, and fruits (Omer, 1997a). Sudan is also viewed as one of the potentially richest nations in livestock (Omer, 1997a), approximately 103 x 10⁶ heads (70 x 10⁶ sheep and goats, 30 x 10⁶ cattle, and 3 x 10⁶ camels) (NEA, 1985). Sudan has a great wealth of the wild life- birds, reptiles, and fishes. Sudan possesses great potentialities for industrialisation since it is rich in agricultural raw materials resources. Since the government realised the importance of industrialisation for economic development, there were many attempts by the state to improve the performance of this sector through different industrial policies. Energy is an essential factor in the development movement, since it stimulates and supports the economic growth, and development. The energy crisis in mid seventies, and substantial increase in oil prices that followed, has put a heavy financial burden on the less developed countries (LDC’s). Sudan is not an exception. The fossil fuels, especially oil and natural gas, are finite in extent, and should be regarded as depleting assets, and since that time the efforts are oriented to search for new sources of energy. Most of the political and resources are directed to establish sources of energy, many of which now face serious environmental and other constraints, rather than the biomass sources which are increasingly being regarded as a central parts of long solutions to the energy environment dilemma. However, increasing energy service levels with the same environmental goals would imply stronger exploitation of biomass energy sources and stronger measures for exploiting the potential of energy conservation. In recent years, Sudan has increased efforts to exploit renewable energy sources and reduce its dependence on oil. Wind, solar and biomass offers a variety of renewable options that are well suited to the African climate. A number of renewable energy initiatives are under way in Sudan that can contribute to rural development while also addressing climate mitigation.

Tables 5 to 10 show energy profile, consumption, and distribution among different sectors in Sudan. Sudan, like most of the oil importing countries, suffered a lot from sharp increase of oil prices in the last decades. The oil bill consumes more than 50% of the income earnings. Sudan meets approximately 87% of its energy needs with biomass, while oil supplies 12%, and the remaining 1% is produced from hydro and thermal power. The household sector consumed 60% of the total electricity supplies (Omer, 1994). The total annual energy consumed is approximately 11 x 10⁹ tonnes of oil, with an estimated 43% lost in the conversion process (Omer, 1996a). The heavy dependence on biomass threatens the health and future of domestic forests, and the large quantities of oil purchased abroad causes Sudan to suffer from serious trade imbalances.

Table 5. Annual energy consumption pattern in Sudan from different energy sources (10 ⁶ MWh)

Sector	Energy	Percent (%)
Residential	4640	77.2%
Transportation	610	10.0%
Industries	340	5.7%
Agricultural	151	2.5%
Others*	277	4.6%
Total	6018	100.0%

*Others are commercial, services, constructions and Quranic schools.

Table 6. Annual biomass energy sources available in Sudan (10 ⁶ m ³ )

Source	Volume of biomass (10 6 m 3 )
Natural and cultivated forestry	2.9
Agricultural residues	5.2
Animal wastes	1.1
Water hyacinth and aquatic weeds	3.2
Total	13.4

Table 7. Annual biomass energy consumption in Sudan (10 ⁶ tonnes)

Sector	Volume of biomass (10 6 m 3 )	Percent of total (%)
Residential	4549	92.0%
Industries	169	3.4%
Others*	209	4.6%
Total	4927	100.0%

*Others are commercial, constructions and Quranic schools.

Table 8. Power output of present hydropower plants (GW)

Station	Energy delivered per pear
Rosaries	275
Sennar	15
Khashm El Girba	13
Total	303

Table 9. Annual electricity consumption in Sudan (10 ⁶ MWh)

Sector	Energy	Percent of total (%)
Transportation	3.2	4%
Agricultural	22.4	28%
Industries	6.4	8%
Residential	48.0	60%
Total	80.0	100%

Table 10. Annual petroleum product consumption in Sudan (10 ⁶ MWh)

Sector	Energy	Percent of total (%)
Transportation	601	60.0%
Industries	138	13.8%
Agricultural	148	14.8%
Residential	55	5.5%
Others*	60	5.9%
Total	1002	100.0%

*Others are commercial and services.

Poverty and iniquity in the basic services are the major components that hindered rural development. Unless being addressed now, none of the great goals of the international and nation community peace, human rights, environment, and sustainable development will be achieved or even progressed.

Energy is a vital prime mover to the development whether in urban or rural areas. The rural energy needs are modest compared to urban. A shift to renewables would therefore help to solve some of these problems while also providing the population with higher quality energy, which will in turn, improve living standards and help reduce poverty. For proper rural development the following must be considered:

• Analyse the key potentials and constraints development of rural energy.
• Assess the socio-technical information needs for decision-makers and planners in rural development.
• Utilise number of techniques and models supporting planning rural energy.
• Design, import and interpret different types of surveys to collect relevant information and analyse them to be an input to planners.

Renewable energy technologies such as solar, wind, etc., become more important since there are local resources, and infinite source of energy. Renewable energy technologies are needed especially in rural areas and small communities. Renewable sources of energy are regional and site specific. The renewable strategy is well integrated in the National Energy Plan (Omer, 1996b), and clearly spelled out in the National Energy Policy, but this is not enough. It has to be integrated in the regional development plans. The role of renewable is big in solving essential life problems especially in rural areas for people and their resource development like the availing of energy for the medical services for people and animals, provision of water, education, communication and rural small industries (Omer, 1995b). A new renewable fuels programme in Sudan aims to improve environmental standards while making better use of domestic resources, providing an economic stimulus to the rural economy, and reducing CO₂ emissions. This

approach discusses Sudan’s current energy system, and describes plans for expanding and improving Sudan’s emerging portfolio of renewable energy options. The poor situations of conventional energy supplies to the Sudanese people are characterised by high dependence on biomass woody fuels (firewood, and charcoal). More than 70% of the total Sudanese populations live in rural and isolated communities characterised by extreme poverty, hunger, and economical activity (NEA, 1983a). The unavailability and the acute shortages of the conventional energy supply (petroleum and electricity) to rural people forced them to use alternatives available energy sources like biomass (NEA, 1983a). This situation caused serious environmental degradation beside the poor unsatisfactory services of some basic needs such as:

• Food security
• Water supply
• Health care
• Communications

In order to raise rural living standards, the per capita energy availability must be increased, through better utilisation of the local available energy resources (Table 11). The rural energy requirements are summarised in Table 12. The suitable energy source, needed for the above rural requirements must be of diffuse low cost types rather than large central installation. Also, those technologies must be appropriate, environmentally, socially and economically acceptable. The urgent problem for rural people development is to increase the energy available per capita. Since it is necessary to rise up the present level of extreme poverty and better basic need services.

Table 11. Percentage of the total annual electricity consumption by states

States	Percent (%)
Khartoum, Central and East states	85.8%
Red Sea state	4.5%
Northern states	4.0%
Darfur states	3.1%
Kordofan states	2.3%
Southern states	0.3%

Table 12. Energy sources for rural area

Source	Form
Solar energy	Solar thermal, and solar PV
Biomass energy	Woody fuels, and non woody fuels
Wind energy	Mechanical types, and electrical types
Mini & micro hydro	A mass water fall, and current flow of water
Geothermal	Hot water

Due to the present limitations, and sharp shortages or unavailability of both electricity and petroleum products to rural people, some renewable energy technologies based on utilising locally available energy; materials and skills are alternate energy options to rural development (Duffie, and Beckman, 1980).

These technologies are not for complete rural electrification (although they can), but they are applied as energies stand alone systems providing energy sources to some rural basic needs. It is necessary that a vigorous program for renewable energies should

be set up immediately (the challenge is to provide a framework enabling markets to evolve along a path that favours environmentally sustainable products and transactions).

5.1. Major Energy Consuming Sectors

Sudan is still considered between the 25 most developing African countries. Agriculture is the backbone of economic and social development in Sudan. About 80% of the populations depend on agriculture, and all other sectors are largely dependent on it. Agriculture contributes to about 41% of the gross national product (GNP) and 95% of all earnings. Agriculture determines for the last 30 years the degree of performance growth of the national economy.

It is necessary that a vigorous programme reaching into alternative renewable energies should be set up immediately. There should be much more realism in formation of such a programme, e.g., it is no use providing a solar powered pump at a price competitive with a diesel for some one who cannot ever offered a diesel engine. The renewable energy technology systems (RETs) are simple, from local materials, clean energy; reliable and sustainable (Table 13). Specialist on their applications carried out socio-economic and environmental studies. The output of the studies pointed out that, they are acceptable to the people and have measured remarkable impacts on the social life, economical activities and rural environment (Kirtikara, 1983; and Omer, 1990).

Table 13. Energy required in Sudan rural area

Rural energy	Activity
Domestic	Lighting, heating, cooking, and cooling
Agricultural process	Land preparation, weaving, harvesting, and sowing
Crop process and storage	Drying, grinding, and refrigeration
Small and medium industries	Power machinery
Water pumping	Domestic use
Transport	Schools, clinics, communications, radio, televisions, etc.

5.2.1. Biomass Resources

Agriculture is the source of a considerable sum of hard currency that is needed for the control of balance of payment in the country’s budget, as well as it is the major source of raw materials for local industry. Biomass resources contributed a significant role in energy supply in Sudan as in all other developing countries. Biomass resources should be divided into residues or dedicated resources, the latter including firewood and charcoal from forest resources as shown in Table 14.

Table 14. Annual biomass energy consumption pattern in Sudan (10 ³ m ³ )

Sector	Firewood	Charcoal	Total	Percent (%)
Residential	6148	6071	12219	88.5%
Industrial	1050	12	1062	7.7%
Commercial	32	284	316	2.3%
Quranic schools	209	0	209	1.5%
Total	7439	6367	13806
Percent (%)	54%	46%		100.0%

Approximately 13 x 10⁶ m³ of biomass are consumed per year as shown in Table 14. To avoid resource depletion, Sudan is currently undergoing a reforestation programme of 1.05 x 10⁶ hectares. Biomass residues are more economically exploitable and more environmentally benign than dedicated biomass resources. There exist a variety of readily available sources in Sudan, including agricultural residues such as sugarcane bagasse, and molasse, cotton stalks, groundnut shells, tree/forest residues, aquatic weeds, and various animal wastes shown in Table 15.

Table 15. Biomass residues, current use and general availability

Type of residue	Current use / availability
Wood industry waste	No residues available
Vegetable crop residues	Animal feed
Food processing residue	Energy needs
Sorghum, millet, and wheat residues	Fodder, and building materials
Groundnut shells	Fodder, brick making, and direct fining oil mills
Cotton stalks	Domestic fuel considerable amounts available for short period
Sugar, bagasse, and molasses	Fodder, energy need, and ethanol production (surplus available)
Manure	Fertiliser, brick making, and plastering (Zibala)

Direct burning of fuel-wood and crop residues constitute the main usage of Sudan biomass, as is the case with many developing countries. However, the direct burning of biomass in an inefficient manner causes economic loss and adversely affects human health. In order to address the problem of inefficiency, research centres around the country have investigated the viability of converting the resource to a more useful form, namely solid briquettes and fuel gas. Briquetting is the formation of a charcoal (an energy-dense solid fuel source) from otherwise wasted agricultural and forestry residues. One of the disadvantages of wood fuel is that it is bulky and therefore requires the transportation of large volumes. Briquette formation allows for a more energy-dense fuel to be delivered, thus reducing the transportation cost and making the resource more competitive. It also adds some uniformity, which makes the fuel more compatible with systems that are sensitive to the specific fuel input (Omer, 1996c).

Briquetting of agricultural residues in Sudan started since 1980, where small entrepreneur constructed a briquetting plant using groundnut shells in Khartoum. The second plant was introduced in Kordofan (western Sudan), and the plant capacity of 2 tonnes per hour with maximum 2000 tonnes per season. Another, prototype unit was brought forth, and worked in Nyala with capacity of 0.5 tonnes per hour (i.e., 600 tonnes per season). In central Sudan, a briquetting plant of cotton stalks was installed at Wad El Shafie with capacity of 2 tonnes per hour (i.e., 2000 tonnes per season). The ongoing project in New Halfa is constructed to produce 1200 tonnes per season of bagasse briquettes (Omer, 1997b; Omer, 1998a; Omer, 1993; Joop, Paul, and Omer, 1987). A number of factories have been built for carbonisation of agricultural residues, namely cotton stalks. The products are now commercialised. More than 2000 families have been trained to produce their cooking charcoal from the cotton stalks.

In Sudan, most urban households has burnt charcoal on traditional square ‘‘Canun’’ stoves that have very low fuel-to-heat conversion efficiencies. The following prototypes were all tried and tested in Sudan:

• The metal clad Kenyan Jiko
• The vermiculite lined traditional Kenyan Jiko
• The all-ceramic Jiko in square metal box
• The open draft Dugga stoves
• The controlled draft Dugga stoves
• The Umeme Jiko ‘‘Canun Al Jadeed’’

Local traditional stoves were tested, improved, invested, and commercially used in Sudan (NEA, 1991): traditional muddy stoves; bucket stoves; and tin stoves

The aim of any modern biomass energy systems must be:

• To maximise yields with minimum inputs.
• Utilisation and selection of adequate plant materials and processes.
• Optimum use of land, water, and fertiliser.
• Create an adequate infrastructure and strong (R & D) base.

Gasification is based on the formation of a fuel gas (mostly CO and H₂) by partially oxidising raw solid fuel at high temperatures in the presence of steam (Elamin, 1995). The technology, initially developed for use with charcoal as fuel input, can also make use of wood chips, groundnut shells, sugarcane bagasse, and other similar fuels to generate capacities from 3 to 100 kW for biomass systems (Omer, 1999a). Three gasifier designs have been developed to make use of the diversity of fuel inputs and to meet the requirements of the product gas output (in terms of degree of cleanliness, composition, heating value, etc.) (Omer, 1998c).

Another area in which rural energy availability could be secured where woody fuels have become scarce, are the improvements of traditional cookers and ovens to raise the efficiency of fuel saving and also, by planting fast growing trees to provide a constant fuel supply. The rural development is essential and economically important since it will eventually lead to better standards of living, people’s settlement, and self sufficient in the following:

• Food and water supplies.
• Better services in education and health care.
• Good communication modes.

Furthermore, Sudan is investigating the potential to make use of more and more of its wastes. Household wastes, vegetable market wastes, and wastes from the cotton stalks, leather, and pulp, and paper industries can be used to produce useful energy either by direct incineration, gasification, digestion (biogas production), fermentation, or cogeneration.

The use of biomass through direct combustion has long been, and still is the most common mode of biomass utilisation as shown in Tables 16, and 17. Examples for dry (thermo-chemical) conversion processes are charcoal making from wood (slow pyrolysis), gasification of forest and agricultural residues (fast pyrolysis), and of course, direct combustion in stoves, furnaces, etc. Wet processes require substantial amount of water to be mixed with the biomass.

Table 16. Effective biomass resource utilisation

Subject	Tools	Constraints
Utilisation and land clearance for agriculture expansion	Stumpage feesControlExtensionConversionTechnology	PolicyFuel-wood planningLack of extensionInstitutional
Utilisation of agricultural residues	BriquettingCarbonisationCarbonisation and briquettingFermentationGasification	CapitalPricingPolicy and legislationSocial acceptability

Table 17. Agricultural residues routes for development

Source	Process	Product	End use
Agricultural residues	DirectProcessingProcessingCarbonisationFermentation	CombustionBriquettesCarbonisation (small scale)BriquettesCarbonisedBiogas	Rural poorUrban householdIndustrial useIndustrial useLimited household useRural household (self sufficiency)Urban fuelEnergy servicesHouseholdIndustry
Agricultural, and animal residues	DirectBriquettesCarbonisationCarbonisationFermentation	CombustionDirect combustionCarbonisedBriquettesBiogas	(Save or less efficiency as wood)(Similar end use devices or improved)UseBriquettes useUse

5.2.2. Biogas Production

Biogas is a generic term for gases generated from the decomposition of organic material. As the material breaks down, methane (CH₄) is produced as shown in Figure 2.

Figure 2. Biogas production process.

Sources that generate biogas are numerous and varied. These include landfill sites, wastewater treatment plants and anaerobic digesters (Omer, 1998d). Landfills and wastewater treatment plants emit biogas from decaying waste. To date, the waste industry has focused on controlling these emissions to our environment and in some cases, tapping this potential source of fuel to power gas turbines, thus generating electricity (Omer, 1998d). The primary components of landfill gas are methane (CH₄), carbon dioxide (CO₂), and nitrogen (N₂). The average concentration of methane is ~45%, CO₂ is ~36% and nitrogen is ~18% (Omer, 1998d). Other components in the gas are oxygen (O₂), water vapour and trace amounts of a wide range of non-methane organic compounds (NMOCs). Landfill gas-to-cogeneration projects present a win-win situation. Emissions of particularly damaging pollutant are avoided, electricity is generated from a free fuel and heat is available for use locally.

Heat tariffs may include a number of components such as: a connection charge, a fixed charge and a variable energy charge. Also, consumers be incentivised to lower the return temperature. Hence, it is difficult to generalise but the heat practice for any domestic heat (DH) company no matter what the ownership structure can be highlighted as follows:

• To develop and maintain a development plan for the connection of new consumers.
• To evaluate the options for least cost production of heat.
• To implement the most competitive solutions by signing agreements with other companies or by implementing own investment projects.
• To monitor all internal costs and with the help of benchmarking, and improve the efficiency of the company.
• To maintain a good relationship with the consumer and deliver heat supply services at a sufficient quality.

Installing DH should be pursued to meet the objectives for improving the environment through the improvement of energy efficiency in the heating sector. At the same time DH can serve the consumer with a reasonable quality of heat at the lowest possible cost. The variety of possible solutions combined with the collaboration between individual companies, the district heating association, the suppliers and consultants can, as it has been in Denmark, be the way forward for developing DH in the United Kingdom. Three scales of combined heat and power (CHP) which were largely implemented in the following chronological order: (1) Large-scale CHP in cities (>50 MWe), industrial and small-scale CHP. (2) Small (5 kWe – 5 MWe) and medium-scale (5-50 MWe). A review of the potential range of recyclables is presented in Table 18.

Table 18. Summary of material recycling practices in the construction sector

Construction and demolition material	Recycling technology options	Recycling product
AsphaltBrickConcreteFerrous metalGlassMasonryNon-ferrous metalPaper and cardboardPlasticTimber	Cold recycling: heat generation; Minnesota process; parallel drum process; elongated drum; microwave asphalt recycling system; finfalt; surface regenerationBurn to ash, crush into aggregateCrush into aggregateMelt; reuse directlyReuse directly; grind to powder; polishing; crush into aggregate; burn to ashCrush into aggregate; heat to 900oC to ashMeltPurificationConvert to powder by cryogenic milling; clopping; crush into aggregate; burn to ashReuse directly; cut into aggregate; blast furnace deoxidisation; gasification or pyrolysis; chipping; moulding by pressurising timber chip under steam and water	Recycling asphalt; asphalt aggregateSlime burn ash; filling material; hardcoreRecycling aggregate; cement replacement; protection of levee; backfilling; filterRecycled steel scrapRecycled window unit; glass fibre; filling material; tile; paving block; asphalt; recycled aggregate; cement replacement; manmade soilThermal insulating concrete; traditional clayRecycled metalRecycled paperPanel; recycled plastic; plastic lumber; recycled aggregate; landfill drainage; asphalt; manmade soilWhole timber; furniture and kitchen utensils; lightweight recycled aggregate; source of energy; chemical production; wood-based panel; plastic lumber; geofibre; insulation board

5.2.3. Hydropower

Hydropower plants are classified by their rated capacity into one of four regimes: micro (< 50 kW); mini (50-500 kW); small (500 kW-5 MW); and large (> 5 MW). The numbers of hydropower plants are given in Table 8, accounting for about 1% of total hydropower available in Sudan.

Hydro potential is promising in Sudan. A number of prospective areas have been identified by surveys and studies carried for exploration of mini-hydropower resources in Sudan. Mini and micro hydro can be utilised or being utilised in Sudan in two ways:

• Using the water falls from 1 m to 100 m; energy can be generated, and small power can be generated up to 100 kW.
• Using the current flow of the Nile water, i.e., the speed of the Nile water. The water speed can be used to run the river turbines (current river turbines), and then water can be pumped from the Nile to the riverside farms. There are more than 200 suitable sites for utilisation of current river turbines along the Blue Nile and the main Nile (WRI, 1994).

The total potential of mini-hydro shows 67000 MWh for southern region, 3785 MWh in Jebel Marra area, and 44895 MWh in El Gezira and El Managil canals. Small-scale hydro plants (< 5 MW) are more environmentally benign than the large-scale hydro projects that often involve huge dams and permanent restructuring of the landscape. These smaller plants

are perfectly suited for some regions of Sudan where there is plenty of rainfall and mountainous or hilly lands cope such as Jebel Marra. Table 11 lists the current distribution of electric power for different states in Sudan (mainly from hydro 55%, and thermal generation 45%).

5.2.4. Solar Energy

The harsh climate in the Red Sea area, for example the Sudan, presents unique challenges in meeting growing demands for water and power. The availability of data on solar radiation is a critical problem. Even in developed countries, very few weather stations have been recording detailed solar radiation data for a period of time long enough to have statistical significance and the Sudan is not an exception.

The country strives hard to make use of technologies related to renewable sources in rural areas where it is appropriate and applicable. Sudan has been considered as one of the best countries for exploiting solar energy. Sunshine duration is ranging from 8.5 to 11 hours per day, with high level of solar radiation regime at an