Urban Density and Energy Efficiency in City Planning: Case Study of Al Ain City

Ahmad Okeil, Mohammed Assem and Ahmed Rashid

Department of Architectural Engineering United Arab Emirates University

Abstract Energy is a critical factor for economic development. Comfort and improved quality of life are generally considered to be consequences of energy expansion programs. In recent years energy expansion plans have forced the consideration of other important issues. Among these issues are the environmental, economic and financial impacts in the national economy resulting from increased energy utilization worldwide. Achieving the same quality of life using less energy means an increase in energy efficiency. For all these reasons we need to fine-tune our cities in order to increase their energy efficiency. The Purpose of this paper is to define areas where energy efficiency of Al Ain city can be improved and to study the influence of urban density on energy efficiency.

Keywords: Urban Density-Energy Efficiency-Domestic Energy Consumption-Renewable Energy-Transportation-Sustainability-Desert Settlement.

1. Introduction The modern development of Al Ain come about with the successful exploitation of oil in the Emirate of Abu Dhabi and the foundation of the United Arab Emirates as a sovereign state in 1971. During the subsequent period, a radical transformation of the area took place, both in urban development and style of living. The introduction of the motor vehicle and electric power made Al Ain both a more accessible and more comfortable place in which to live. As the hometown of the ruling family of the Emirate it benefited from patronage and the desire to see Al Ain develop as a modern garden city, blooming on the edge of the desert. The population jumped from 13,000 in 1968 to 142,000 in 1985, at which time it represented some 80 per cent of the regional population. Major investment programs were initiated in housing, education, health, parks, roads and utilities. These, together with the dramatic increase in population, have radically transformed Al Ain into a modern town. The city buildings are kept low rise and apart from each other. Residential density of Al Ain was 12 persons / hectare in 1985 and is expected to rise to 16 persons / hectare in the year 2000.

The efficiency of electricity use, derived from a measure of peak load attributed per capita to citizens and noncitizens appears to have decreased somewhat in the past few years. Electricity consumption in the Al Ain Region has been increasing at an annual rate of 11.6% between 1980-1992. At the same time, the region's population increased by 6.4% annually. The difference in growth between electricity and population reflects a gradual increase in electricity intensity or use per capita, since 1980. These relationships are shown in Table 1. Table 1 Al Ain Region Growth Rates: Electricity Demand and Population (Int. Bechtel 1996) Electricity Demand Population 1980-1992 11.6% 6.4% 1985-1992 8.5% 5.9% 1990-1992 4.7% 4.3%

By observation and statistical evaluation, it 300 could be said that the most important factor 250 that influences electricity use in Al Ain is the 200 population size. The next most important 150 predictor may be household income by 100 population classification. 50 0

If the economy is continues to be robust, 5 6 7 8 9 0 1 2 3 8 8 8 8 8 9 9 9 9 9 9 9 9 9 9 9 9 9

then the population will expand and living 1 1 1 1 1 1 1 1 1 standards will continue to improve, Fig.1 Al Ain City: Historic Population individuals will require more power and Growth Data (‘000s) water. On the other hand, a recession in the 4000 economy will have an effect on the levels of 3000 expatriate population. A decline in the level 2000 of noncitizen population will cause a decline 1000 in the amount of electricity demand. 0 3 5 7 9 1 7 9 1 3 5 7 Noncitizens consume about 28% of all 3 5 7 8 7 7 7 8 8 8 8 9 9 9 9 9 9 9 9 9 9 9 9 9 9 9 9 9 electricity sold in Al Ain. 1 1 1 1 1 1 1 1 1 1 1 1 1 Fig. 2 Al Ain City: Historic Electricity Although the citizen population is only about Consumption (M kWh) 24% of the total population, it is growing 600 much faster than the noncitizen population. 500 400 The citizen population growth has been very high 300 and stable at about 8% increase per annum. The 200 noncitizen population growth has been about 3% 100 for the years 1988 to 1992. The ratio of noncitizen 0 5 9 7 9 1 3 5 7 9 9 9 0 0 0 0 0 9 9 9 0 to citizen population will decrease dramatically at 0 0 0 0 these differential rates of growth: from 2.7 to 1 in 1 1 1 2 2 2 2 2 Fig.3 Al Ain City: Population Forecast in 1992 and from 1.25 to 1 in 2010. 1000s -Upper Bound Case (Int. Bechtel 1000 1996) The purpose of this paper is to study those factors 800 influencing energy use in Al Ain that are related 600 more to urban density than to population size. It 400 will also define areas where energy efficiency of Al 200 Ain city can be improved. Energy Consumption in 0 5 9 1 5 7 9 7 3 four main sectors will be investigated; Domestic 9 9 9 0 0 0 0 0 9 9 9 0 0 0 0 0 use, street lighting, water desalination and 1 1 1 2 2 2 2 2 Upper Bound Case Lower Bound Case transportation. Fig.4 Al Ain City Power Requirements Forcast in MW (Int. Bechtel 1996) 2. Modes of Energy Consumption related to Urban Density 2.1. Energy Consumption for Domestic Use Statistics indicate that the domestic sector consumes more than one-third of the electricity in Al Ain (citizens and non-citizens). Over half is consumed by the government, schools and commercial, and less than 10 percent is consumed by agriculture and by all other categories. Energy consumed in the residential sector is used either in air-conditioning, lighting, refrigeration, cooking or water heating. The high domestic use of Al Ain City is attributed to housing that is more dispersed and thus requiring more electricity for cooling. Investigations show that 60 % of summer peak load in the domestic sector is accounted for air-conditioning, a situation similar to countries in the cold region where 50% of the energy consumption per household is dedicated to heating. It appears that cooking, lighting, refrigeration, and small appliances are all closely correlated with population size and not with urban density. Energy consumed for air conditioning is the only area that has the potential for important reductions. It is expected that the urban form will have its biggest effect on energy consumed in air-conditioning. Mutual shadowing and extent of exposure to the outer environment are crucial factors influencing energy consumed in air- conditioning.

Residential building types in Al Ain and the expected energy efficiency have been surveyed as shown in table 2. The available building count done in 1992 shows the following numbers: 440 Multistory Buildings, 3171 Villas, 7049 Low Cost Houses, 3300 One Story Houses, 968 Two Story Houses and 4487 Others types. This shows that less than 8% of the residential buildings are more than one story.

2.2. Energy Consumption for Street Lighting More than 30 000 masts (single, double or quad) are used to light all primary, town and district distributors. Due to the low urban density, providing street lighting for local distributors and access roads is not feasible. Considering quality of life this could be a negative point. In some areas fence lighting is used to enhance the feeling of security. Lighting is provided 12 hours each night regardless of time of the year. The amount of energy consumed for street lighting is estimated to be 135 million kWh/a or 450 kWh/ca/a. This is about 5% of total annual per capita consumption, which does not appear in the electricity bill every month. Providing street lighting to local distributors and access roads would increase the energy consumption dramatically. A continuous horizontal expansion of the city using current urban density will be possible only if local distributors and access roads remain unlit. Vertical expansion of the city would allow lighting local distributors and access roads without increasing the per capita energy consumption.

2.3. Energy Consumption for Water Desalination Al Ain Municipality has a policy to create a "garden city". There are numerous public gardens. All major roads are landscaped; the shoulders, medians, and traffic circles are planted with trees, gardens, and grasses. The landscaping on the roadsides extends well beyond the city limits. Al Ain City has been chosen to be the Host City for the final stage of the worldwide competition "Nations in Bloom '98". The international environmental competition seeks to identify those cities that have best adopted landscape management practices to the improvement of the quality of life of all citizens. The water balance for Al Ain region has been estimated as shown in table 3. Table 2 Energy Efficiency of Residential Building Types in Al Ain e e y t p c

Residential Building Type a Photo y n m e T i

Description i l c C i C / f

f r A e E t

u C / O

A o t

e r u s o p x E V / A h w w g o o Low Cost Court House i d L H n

Single story house with courtyard where i

most rooms open to the courtyard. Old W doors and windows are not airtight allowing hot air to flow inside and cooled air to flow outside. l h h a g g r i i

Villa t n H H

Modern 1-2 story single (extended) family e - -

C

- buildings some times with excessive use of m m

t u u

2 i i i glazing. High m /resident ratio. l d d p e e S M M t i m m l u u Multi Family House p i i S d d

- e Found in suburb areas. Accommodating 4 e

M M w

families, 2 at each floor. Upper floor o - protects lower floor from solar radiation d n w i o L W l h a w g r o i

Row House t n L H

2 story row houses with half the units on e -

C

- the ground level and the other half on the m

t u i i first floor. Upper floor protects lower l d p e floor from solar radiation. Side units S protect middle units from outer climate. M Central Air conditioning is used. l h a w g r o i

Multistory House t n L H

4-5 story buildings found only in the CBD. e Ground floor dedicated to commercial use C while upper floors for residential apartments that are some times used as office space. Upper floor protects lower floors from solar radiation Table 3 Water balance for Al Ain Region (Cox 1985, Int. Bechtel 1996) Water Demand Domestic and Trade 45 Mm3/a Large Consumers 18 Mm3/a Landscaping 44 Mm3/a Agriculture 140 Mm3/a Forestry 12 Mm3/a Total 260 Mm3/a

Water Resources Natural Recharge of aquifers 29 Mm3/a Water Reuse (70% of Domestic and Trade) 35 Mm3/a Desalinated Water imports from the coastal zone 23 Mm3/a Total 87 Mm3/a

The demand for landscaping represents about 17% of the total demand or 40% if agriculture and forestry are not taken into consideration. The water demand for landscaping is almost equal to the water demand for domestic and trade use. It is clear that water demand for domestic and trade use is related to population size whereas water demand for landscaping is related to urban density.

Water resources for Al Ain region are also shown in table 3. Fresh groundwater storage capacity of the aquifers of the region is 2 500 Mm3, while total volume of usable groundwater storage including brackish water, is about 20 000 Mm3. The majority of the water that is withdrawn from the aquifer is not recharged. Thus, the aquifer is largely fossil water that has been present from prehistoric days and is now being withdrawn. Groundwater depletion will cause deterioration in water quality as well as a decline in groundwater table. The level of decline of the aquifer is from 10 meters to over 50 meters in Al Ain City itself. While this decline in the water table does not indicate any imminent reduction in total water abstraction potential in the near term, it is an indication that the amount of abstraction exceeds the amount of recharge. At unrestricted rates of groundwater depletion groundwater reserves will be fully exploited within 15-25 years. For this reason, it is the policy recommendation of the Master Plan to depend on seawater desalination for increased water requirements in the Al Ain area and to simultaneously reduce the claim on groundwater. (Bechtel 1996) proposes that the rate of abstraction will be reduced as follows: year abstraction 1995 44 Mm3 2000 33 Mm3 2005 25 Mm3 2010 19 Mm3 As the population continues to grow shortages of water will be covered desalinated water. Desalinated water has a high cost estimated at 10.4 Dh/m3. The 23Mm3 of desalinated water imported yearly from Abu Dhabi require about 23MkWh. Should ground water abstraction be reduced to 33 Mm3 as Bechtel’s proposal, no measures for reducing consumption are taken, and the remaining demand covered by desalinated water, then the energy consumption for desalination could reach about 2200 M kWh almost 66% of the total electricity consumption of Al Ain in 1997. Reused water from the domestic and trade sector represents 70% of the water used for landscaping while the remaining 30% come from underground water (11 Mm3/a).

2.4. Energy Consumption in the Transportation Sector The transportation sector is responsible for an average of one-third of the total energy demand in the majority of countries. In transportation, what is desired is the movement of people and goods. Users are not therefore looking for energy, but for service.

2.4.1. Road Network Al Ain is a car-oriented city with a main road network that has been constructed to a road grid system with a five level road hierarchy. All roads have spare capacity even in peak hours. The primary and town distributors form a two to three kilometer grid around a district. The district distributor roads consist of a finer grid of 500-700 meter spacing and normally border a neighborhood. Local distributor and access roads are provided as loops or cul- de-sac to provide for efficient plot layouts. Fig. 5 Al Ain Road Network. (Cox 1985)

2.4.2. Private Vehicle Ownership In the United States one of every two people owns an automobile. At the other extreme is china, with one privately owned car for every 75,000 people (Energy Efficiency in Transportation 1993). In Low urban density reinforces automobile dependency and promoting Table 4 Modal Variation of Passenger environmental destruction through excess land Transport Energy Intensities for the USA and energy consumption and air pollution.. ((Energy Efficiency in Transportation 1993 Private vehicle (cars, pickups and motor cycles) ownership per head of population in Al Ain has Energy Intensity Mode been growing rapidly in recent years. A clear kWh/passenger-km difference in private vehicle ownership between Auto and light truck citizens (high-income group) and non-citizens 0.6-0.97 Combined (most belong to the low-income group) can be 1.0-1.45 urban seen in figure 6. 0.5-0.62 intercity Bus 2.4.3. Modal Choice and Travel Demand Combined Energy efficiency of a transport system can be Fig. 6 Al Ain car 0.18-0.54Ownership. (Cox 1985) achieved through a modal Shift to 0.48-0.67 urban environmentally more friendly Transport Modes 0.21-0.29 intercity Rail 0.38-0.63 combined 0.3-0.52 transit 0.45-0.82 commuter 0.52-0.64 intercity consuming less energy. As might be expected table 4 shows that private cars have the highest specific energy consumption in kwh/pkm, particularly for short distance transport. Intercity trains and buses are the most efficient energy consumers. Transit has the potential to reduce oil consumption. European cities, which are more transit- oriented, use much less energy per capita than U.S. cities. (Black 1995)

Owning a car does not necessarily mean that owners will use their cars for all trips. Facilities falling within walking distance could be reached on foot or by bicycles and thus saving energy. Low urban densities do not allow available facilities to fall within walking distance for most of the residents they should serve.

Urban development in Al Ain has induced the spatial segregation of working, residential, shopping, service and recreational functions. Development patterns remain highly centralized in the city center, which often contains most of the local administration offices, financial houses, and warehousing activities. Plans for retail- employment decentralization in Al Ain still do not function, probably due to the absence of catchment population sufficient to give a viable turnover. The pattern of shopping in Al Ain is still highly centralized and the population so dispersed that it is difficult to provide economically viable small local shopping centers. This means that long travelling distances to the city center promoted by a street network with plenty of spare capacity remains the only option for most residents of remote districts.

3. Energy Efficiency Improvement: 3.1 Domestic Use Electricity savings from air-conditioning could be achieved through the following strategies: 1. Implementing building codes to reduce the cooling demand through more effective thermal insulation. This has proven success in European countries. Energy consumption in german households has been reduced through building codes from 250 kWh/m2 to 160 kWh/m2 in 1984 to 100 kWh/m2 in 1995 (Solarthemen 1994). In Sweden it was reduced to 70 kWh/m2 to reach the range of a low energy house (Solarthemen 19992). Recent published research work showed that energy consumed for cooling in a two- Story residential building in Al-Ain City, UAE, is estimated as 186 kWh/m2. (AbulNaga 1998) 2. Careful planing of residential building aiming at reducing exposure to outer climate. This is difficult to implement on single story buildings and require an increase in urban density. (Okeil 1993) 3. Replacement of older window units with high-efficiency units. 4. Using high-efficiency central air conditioning units for new construction.. This is difficult to implement on single story buildings and require an increase in urban density.

Taking the Air-condition efficiency and exposure to outer climate as evaluation criteria, it is clear that urban forms with higher density like multi-story houses and Row houses consume less energy for air-condition than lower density urban forms like single-story units. Improving Energy Efficiency in air-conditioning can be achieved in future developments using higher urban density. 3.2. Street lighting Vertical expansion of the city would allow investing resources in lighting available local distributors and access roads instead of expanding the infrastructure beyond the current city boundaries. That is an increase in the quality of life without increasing the per capita energy consumption.

3.3. Water Desalination Reused water from the domestic and trade sector represents 70% of the water used for landscaping and the remaining 30% come from underground water (11 Mm3/a). This means that the current population size on a unit area (density) does not produce enough reused water for landscaping on the same unit area. A balanced ratio between population and landscaping on a unit area requires raising the current population size by a factor of 1.4. This means about 22 persons/hectare which will help protecting the existing plant cover against desertification. Further horizontal expansion with the current level of landscaping will be difficult to sustain. The forecast decrease in noncitizen population size will leave large areas of landscape with less water resource to be reused.

3.4. Transportation Energy conservation in transportation is possible through careful city planning. Two basic strategies are available to the transport planner for achieving higher energy efficiency of a transport system: (a) Reduction of the transport demand through an integrated land use/transportation planning, (b) Modal Shift from less to more environmental friendly transport modes through economic and technical penalizing the car use as well as upgrading alternative transport system.

3.4.1 Modal Choice The financial charges imposed on travelling by car and shipping goods by trucks are simply too low to reflect the real social cost incurred (environmental damages). The real cost including pollution treatment is 6 times the actual cost. The general philosophy of road pricing in cities is to penalize the use of car, if public transport systems are available. The income generated by the road user fees may be invested in improving public transport. For transit to be attractive it should fulfill its objectives which are: (1) to provide transportation that is reliable, comfortable, clean, safe, fast and reasonably priced; (2) to provide transportation that is energy efficient and cost effective; and, (3) to decongest traffic along its route. Traffic calming measures can reduce the convenience of private car use, make it less attractive, and may thus indirectly contribute to modal change. Although the high-income group in Al Ain will still find the service offered by a public transport system below their expectations, the low-income group of noncitizens could create the demand required for a transit system to function. Low urban densities make economical operation of the proposed transit system a difficult task, because scattered trip ends are virtually impossible to serve.

3.4.2. Reducing Travel Demand Industrial plants, public facilities, and offices for business or government all generate the mobility of persons and goods. The amount of mobility generated and the use of various transport modes depend heavily on the characteristics of these facilities and their locations. One promising instrument for reducing car travel is the coordination of land use/infrastructure planning and redistributing densities and functions according to decentralization theory so that each area becomes self sufficient (services and daily needs). Traditionally, this coordination has been tried by encouraging high retail-employment densities near public transportation stations at one end of the trip and high residential densities at the other end (Verroen1992). There is a potential for reducing long-distance commutes by low-to moderate-income households through a policy encouraging multifamily housing construction in the vicinity of suburban retail-employment centers. The "retail-employment/housing balance" approach should be used to develop structures for planning and development that would generate a better geographic match between retail-employment and housing. The geographic matching would presumably obviate the need for much of the intersuburban commuting.

Development patterns based on spatial segregation of working, residential, shopping, service and recreational functions with highly centralized local administration offices, financial houses, and warehousing activities in the city center should be reversed. With the continued expansion of the city at very low densities, there is increasing pressure for decentralization. This could be achieved through: 1) Decentralize retail- employment facilities to district centers, 2) Provide for limited shopping at local level. Retail facilities should be accessible to customers by their preferred mode of transport including transit, located in centers near to similar or complementary shops, located close to residential areas, and should concentrate shops within walking distance together with complementary community facilities. Raising urban density would help implementing plans for decentralization of retail facilities and thus increasing energy efficiency.

4. Utilizing Solar Energy Oil resources are depleting and by the end of the 21st century, no oil will be available. To prolong the life time of oil renewable energy should be utilized. The ecological necessity of using solar energy comes from the fact that is becoming clear that the climatic system is being threatened through carbon dioxide emitted when fossil fuels are burnt to give out their energy. The spread of this gas in the atmosphere causes the green house effect that leads to measurable overheating of the earth atmosphere which affects patterns of rain distribution, rising see level and other phenomena causing worries among scientists. The world climate conference in Montreal 1989 prognosis shows that the world energy consumption will rise 50% in the following 30 years. If fossil fuels continue to be used the emission of CO2 in the atmosphere will rise dramatically. Utilizing renewable energy has become a moral necessity towards the coming generation.

4.1. Solar Energy Potentials in the UAE Although the solar energy potential in the UAE is very high no attempts have been made to utilize it. The utilization of solar energy as an alternative and renewable energy must be taken strongly into consideration in the future. The seasonal variation of global solar radiation over Al Ain varies from winter to summer in a narrow range between 5-8.3 kwh/m2/day, a narrow range if compared to the global solar radiation in Germany 0.5-5 kwh/m2/day. Solar energy in Al Ain can be utilized to cover part of the energy demand in the following sectors:  Air conditioning using passive or active cooling systems.  Street lighting using Photovoltaic  Desalination of water for domestic use and landscaping Electric cars and hydrogen driven cars already exist but still can compete with conventional petrol cars. Solar energy can be utilized in transportation as soon as a break through in these new technologies takes place. This is expected in a few years.

4.2. Feasibility The World Production of Crystalline cells in 1997 was 100 MW with an 15% annual rise. The price of roof systems is 9000 US$/kW. Solar electricity in Europe costs 0.85-1.4 US$/kWh, 25 times higher than nuclear energy. It is expected through mass production of PV cells that solar electricity reaches 0.18 US$/kWh in 10 to 15 years. The current PV efficiency 15-20% (10.5% for the whole system) is expected to rise. According to new calculations performed by Max-Planck-Institute in Stuttgart, the theoretical maximum efficiency of solar cells is 43%. In many European countries governments buy surplus solar electricity for 1.1 US$/kWh to help people investing in solar energy to cover their high costs. Inspite of all efforts in the field of renewable energy, it must be clear that in the near future its contribution will remain low.

4.3. Decentralized Solar Energy Utilization The principle of decentralized solar energy utilization is the uniform distribution of solar radiation, the decentralized energy conversion and its decentralized energy use. A further energy distribution system is not necessary thus reducing the infrastructure system. In Europe many solar settlements are currently being built with detached or row houses each equipped with 20m2 PV panels (2kW) producing 1400-1500 kWh yearly and thus covering about 50% of the household needs. On 500 sunny days in Europe fixed PV 400 panels can produce 3 kWh/m2 300 while sun-tracking panels can produce 5 kWh/m2. If mirrors are 200 used to reflect solar energy to the 100 2 panels, 8.5 kWh/m can be 0 t l r r y g v n b reached. In addition to solar n p c c p u a a u o e e a u e J A O J M J F M A N energy utilization, high thermal S D insulation has been applied to reduce the energy consumption for Fig. 6 Al Ain: Consumption Seasonal Cycle heating to as low as 16 kWh/m2 M kWh built up area. Low energy houses consume less than 80 kWh/m2.

Experiments on zero-energy houses are also being conducted. The energy-autarky solar house by the “Fraunhofer Geselschaft” in Freiburg was built to demonstrate that in Germany with help of solar energy the energy needs of a house could be covered (Stahl et al 1994). Collectors on the roof for warming water and 40m2 PV solar cells for producing electricity are available. For short-term energy storage a lead battery is used. Part of the electric power is used to produce hydrogen and oxygen through electrolysis. Hydrogen is then used as an energy storage medium that could be used directly for cooking and heating but also could be converted again to electricity when the sun does not shine. This system is extremely expensive and is only used to prove that full energy autarky is possible. Designs for Energy surplus houses are being studied The most predominant characteristic of the electricity consumption curve in Al Ain is the seasonal variation. The degree of variation means that power capacity required meeting peak summer loads is not needed for the season from November through April when the large air-conditioning loads are not required. The main advantage of using solar energy for cooling in the hot arid region, contrary to other colder countries, is that the daily and seasonal energy demand cycles show patterns similar to that of the daily and seasonal solar radiation cycle. This means that energy storage problems experienced in colder climates could be eliminated. Increasing the urban density through multistory houses will not prevent utilizing solar energy due to the high solar radiation.

4.4. Centralized Solar Energy Utilization A disadvantage of solar energy is its low energy density per unit used area. A 1300- MW nuclear power station can be replaced by a PV farm covgring an area of more 30 km2. This puts solar electricity on the limits of economic use. Large scale PV farms such as in Sierre-Italy and Essen-Germany with 3 MW peak loads and costing 16-22 Mio. US$ were built. About 70000m2 of land is required to produce 5 MkWh annually covering the needs of 3000 families. Efficiency of such PV farms lies between 10-12%. Thermal Solar power towers are more economic than PV farms. Through the concentration of incident solar energy on a boiler, steam can be generated and through a steam turbine electricity will be generated (1 MW station in Sicily, Italy and the Helio field in France) (Abdelfattah 1997). Centralized solar energy for producing hydrogen over PV farms or thermal plants and electrolysis of water is still too expensive to be used commercially. The high solar radiation over Al Ain suggests an attempt to utilize it through a PV solar farm at the borders of the city.

5. Conclusion Energy Efficiency of Al Ain City can be improved by reducing energy consumed for air conditioning, street lighting, water desalination and Transportation. To increase the energy efficiency of Al Ain city in all these sectors, future development should be: 1. Vertical within the current boundaries without loosing the available efficient road network and pleasant landscaping, 2. Polycentric instead of Monocentric, 3. Mixed use instead of segregated, and 4. Solar energy oriented. 6. References  Abdelfattah A.I.I. and Hassan H.H., Solar Energy and Remote Areas of Developing Countries (Case Study Egypt), Alexandria Engineering Journal, Vol. 36 No. 3, May 1997  AboulNaga, Mohsen M., A Roof Solar Chimney Assisted by Cooling Cavity for Natural Ventilation in Buildings in Hot-Arid Climates: An Energy Conservation Approach in Al-Ain City, Sixth Arab International Energy Conference, AISEC, Oman, 1998  Black, Alan, Urban Mass Transportation Planning, McGraw-Hill, 1995.  Cox, Shankland, Master Plan for the Region of Al Ain, Final Report, Emirate of Abu Dhabi, Town Planning Department in Al Ain, The U.A.E., 1985.  Energy Efficiency in Transportation: Alternatives for the Future, Department of Development Support and Management Services, Energy Branch, United Nations, New York, 1993.  International Bechtel Incorporation, Master Plan for the Power and Water Requirements During the Period 1995-2000 for the Government of Abu Dhabi, Water and Electricity Department, Final Report, 1996.  Okeil, Ahmad, Urban Form and Solar Energy Utilization, Third European Conference on Solar Energy in Architecture and Urban Planning, Florence, 1993.  Praxisinformation Energieeinsparung, Bau und Wohnforschung, No. 04.093, Bonn, 1983.  Solarthemen, Informationszentrale der Elektrizitaetswirtschaft e.V., No. 3,1992  Solarthemen, Informationszentrale der Elektrizitaetswirtschaft e.V., No. 2,1994  Stahl W., Voss, K., and Goetzberger, A., The Self-Sufficient Solar House in Freiburg, Solar Energy, Vol. 52, No. 1, January 1994.  Statistical Yearbook, Department of Water and Electricity, Al Ain, 1997.  Statistical Yearbook, Planning Department, Abu Dhabi, 1996.  Verroen, Erik J. and Jansen Gijsbertus R.M., Location Planning for Companies and Public Facilities: A Promising Policy to Reduce Car Use, Transportation research record, No. 1364, National Academy Press, Washington, 1992.