ObservationObservation byby satellitesatellite Meteorological-Meteorological- aandnd Research and Development to environmental-observationenvironmental-observation AAdvanceddvanced predictionprediction Improve Desert Environments systemsystem ooff rregionalegional Promoting rainfall waterwater cyclecycle and Create a Sustainable Rainfall Wastewater Atmospheric moisture radar Desert greening collection system treatment by deep-rooted Oasis Network system with seeding air-conditioning equipment
Seawater desalination by solar energy 1 2 and biomass MAKOTO HARADA* RYOHJI OHBA* WATARU KAWAMURA*3 MASAHIKO NAGAI*4
As economic development and urbanization have expanded in the Middle East, so too has desertification. Secur- ing adequate water resources to support economic development and enhance urban environments is critical. Accord- ingly, adopting highly efficient energy-supply equipment and technologies for securing water resources, using water effectively, and implementing desert greening or reforesting projects are important. Mitsubishi Heavy Industries, Ltd. (MHI) aims to contribute to the stable and continuous economic development and environmental improvement of Middle Eastern countries and, in turn, to strengthen the energy security of Japan. Specifically, using its technolo- gies and products, MHI proposes a scenario for creating a sustainable "oasis." This paper introduces some of MHI's efforts to improve desert environments with the goal of creating such a sustainable desert oasis.
academic organizations, MHI has undertaken various 1. Project Overview: Improving Desert Environments engineering studies related to global and regional cli- 1.1 Creating a sustainable oasis network mate change. Middle Eastern countries continue to enjoy remark- Such studies have revealed the possibility of green- able progress in economic development and urbanization. ing the so-called coastal deserts, many of which exist in However, desertification and a lack of water resources western coastal areas of continents. In particular, the are increasingly serious problems for which various so- Red Sea coastal area of Saudi Arabia receives high-hu- lutions are being sought. To help these and other nations midity air from the sea. Various simulations have that are suffering from water deficits, MHI is develop- examined the possibility of greening and have shown that ing a scenario to create a sustainable oasis network. once greening expands to a certain extent in this area, Instead of applying conventional methods that require there is a possibility that the newly established forests large amounts of fossil fuels, which are also limited natu- could promote cloud formation and hence greater rain- ral resources, and pursuing only short-term economic fall. Accordingly, the following hypothetical scenario is efficiency, the scenario that MHI proposes here includes proposed: new and dynamic methods for greening deserts and en- .A greened area of a certain scale would be created in hancing urban infrastructures. These methods a suitable desert region. incorporate active acquisition of sustainable water re- .An increase in rainfall would be spurred by interac- sources and sustainable and renewable energy wherever tions of vegetated land and the climate by which possible. forests promote cloud formation and subsequent pre- MHI hopes that this proposed scenario will help im- cipitation. prove desert environments and promote stable and .The increased rainfall would increase the amount of continuous economic development in the Middle East. It available water in the region, which in turn would is further hoped that the resulting economic and envi- further encourage the expansion of greening. ronmental benefits to the Middle East will help ensure .Finally, a system would be created by which most of the Middle Eastern fossil fuel supply to, and subsequent the water would be supplied from water circulated energy security of, Japan. from the ocean to the atmosphere and then to the greened lands. This cycle would minimize dependence 1.2 Scenario for creating an oasis network on supplemental water sources such as desalinized MHI has participated in the Global Frontier Project seawater or deep subterranean water (non-recharge- of the Ministry of Education, Culture, Sports, Science, able fossil water drawn from biostratigraphic aquifers and Technology of Japan since 1999. As part of the that exist several hundred meters to more than 1 km project, in collaboration with industry, government, and below the ground surface).
*1 Technology Planning Department, Technical Headquarters Mitsubishi Heavy Industries, Ltd. *2 Nagasaki Research & Development Center, Technical Headquarters Technical Review Vol. 42 No. 4 (Nov. 2005) *3 Takasago Research & Development Center, Technical Headquarters 1 *4 Advanced Technology Research Center, Technical Headquarters This system would create a hydrological circulation (1) Investigation of hydrological cycle mechanisms within which the artificially greened lands would in- First, to understand hydrological circulation at glo- crease the moisture content of the winds blowing from bal and regional scales, hydrological circulation coastal areas to the mountains. In the mountains, the mechanisms were investigated to identify the most moisture contained in the winds would be converted to suitable area for greening along the Red Sea coast of clouds that would then precipitate over the mountain Saudi Arabia and to estimate the size of the greened districts. The rainwater would replenish groundwater area required to increase rainfall amounts. These fac- layers located in the comparatively shallow (approxi- tors were examined using observational data and mately several meters deep) underground zones and simulations by the "Earth Simulator" supercomputer. subsequently increase the amount of groundwater Section 2 introduces an example of this research. (Fig.1Fig.1). The oasis MHI envisions would provide a com- (2) Acquiring sustainable water resources and desert fortable living space, would be based on a verified, greening feasible scenario, would minimize the use of deep sub- To create the hydrological circulation mechanism terranean water, and would form a sustainable described above, engineering and agricultural analy- hydrological circulation system. ses, combined with economic, social, and cultural 1.3 Procedure to verify the feasibility of the scenario perspectives, are required. These interdisciplinary The feasibility of the scenario was verified as follows fields were applied to examine methods for acquiring (Fig. 22). sustainable water resources and desert greening.
Cloud and rain High temperature Humid wind Formation of cloud Mountain and high humidity district
Transpiration Grassland Mangrove and forest forest 1.0
Red Sea Recharging underground water Harvested water (shallow layer)
Humidification zone Water efficiently using zone Harvest zone
Fig. 1 Conceptual image of the water circulation system
Research of hydrological Global meteoro- Western Asia meteorological analysis circulation mechanisms in logical analysis coastal areas of Saudi Arabia
Review and evaluation from Securing sustainable Sustainable desert economic, social, and water resources greening cultural perspectives
Creating a sustain- able oasis network
Fig. 2 Research procedures
Mitsubishi Heavy Industries, Ltd. Technical Review Vol. 42 No. 4 (Nov. 2005) 2 The following issues are important. .Identifying the best method presently available to se- 2. Hydrological Circulation Study cure a necessary amount of water. This section describes research on hydrological circu- (Securing sustainable water resources) lation processes ranging from global to local scales; .Identifying the best method to achieve efficient greening results will be applied to securing sustainable water re- Identifying the best method to reduce the amount sources and greening deserts in dry zones. The results of water required for greening were obtained through numerical analyses using obser- (Sustainable greening of deserts) vational data of local weather, the latest weather Section 3 presents two approaches for securing sus- forecasting models, and a large-scale parallel tainable water resources. An example of a technical study supercomputer, the Earth Simulator. related to sustainable desert greening is presented in 2.1 Analysis of global-scale meteorological Section 4. phenomena This study was performed as part of the Research Recent research has revealed that global-scale me- Project for Sustainable Coexistence of Humans, Nature, teorological and hydrological circulation changes are and the Earth entitled "Advanced Prediction System and driven by long-term changes in ocean surface tempera- Counter Measures of Global- and Meso-scale Water ture distributions. Figure 3 illustrates the influence of Cycle" (Global Water Cycle Project: GWCP). Research for changes in the Pacific Ocean surface temperature (El this project is conducted in cooperation with the Japan Nino Southern Oscillation: ENSO) and Indian Ocean Agency for Marine-Earth Science and Technology surface temperature change (Indian Ocean Dipole: IOD) (JAMSTEC), the National Research Institute for Earth on global total rainfall based on analyses of long-term Science and Disaster Prevention, Kyoto University, observation data. The figure reveals that total rainfall Tottori University, Sophia University, and various re- in India decreases during summer when the ENSO is search institutes in Saudi Arabia(1). prevalent, and total rainfall in the Middle East and In- The project began in 2001 and will continue until 2006 dia increases when the IDO is prevalent. (years are based on the Japanese fiscal year). Over the Rainfall in the Red Sea coastal region of Saudi Arabia last 3 years, the MHI project team has nearly completed is characterized by two climatic peaks. One peak is research on the basic technology involved and has be- caused by low atmospheric pressure arriving from over gun preparing the overall plan in parallel with on-site the Mediterranean Sea during winter, while the other verification tests initiated in 2005. peak is caused by the Indian Ocean monsoon during sum- mer, as shown in Fig. 4.4 The mechanism of this rainfall Composite for Pure ENSO Events cm/month phenomenon in winter was first discovered during this research and is referred to as the "Arabian Cyclone" (Yamagata et al., 2005)(2).
70 Average monthly rainfall 60 (1978~2001) 50 40 30
mm/month 20 (a) Impact of ENSO 10 0 Composite for Pure IOD Events cm/month 123456789101112 month (a) City in mountain district (Abha) 70 Average monthly rainfall 60 (1976~2001) 50 40 30
mm/month 20 10 (b) Impact of IOD 0 123456789101112 Fig. 3 Influence of Pacific Ocean surface temperature change month (El Nino Southern Oscillation, ENSO) and Indian Ocean (b) Coastal city (Gizan) surface temperature change (Indian Ocean Dipole; IOD) on global rainfall based on meteorological observation Fig. 4 Observed monthly average rainfall in a city in the data (The gray area shows the increase in rainfall, the mountainous district (Abha) and a coastal city dotted lines show areas of decreased rainfall.) (Gizan) along the Red Sea coast
Mitsubishi Heavy Industries, Ltd. Technical Review Vol. 42 No. 4 (Nov. 2005) 3 In summer and winter, rainfall increases in moun- and number of years required to further clarify the tainous zones higher than 2 000 m in the Red Sea coastal mechanism by which greening deserts could form clouds, region. As shown in Fig. 55, natural forests and agricul- leading to greater rainfall. tural zones have formed in this region known as the To enhance rainfall in the mountainous zone, investi- "Asir." It is important to improve the accuracy of meteo- gations of cloud-seeding techniques using numerous rological analyses by ongoing analyses and simulations balloons are planned in cooperation with Presidency of of meteorological phenomena at both global and regional Meteorology and Environment in Saudi Arabia, as shown scales. Global climate trends such as global warming may in Fig. 77. In those experiments, the launched balloons remarkably alter the global climate in the future and spray moisture-condensing agents in the air and clouds. can also greatly affect regional-scale climates. The U.S. National Center for Atmospheric Research 2.2 Hydrological circulation mechanism of the Red (NCAR) is performing similar experiments using aircraft Sea coastal region of Saudi Arabia in the United Arab Emirates, Saudi Arabia, South Africa, Using the regional weather model, this study then and India. In China, similar technology was examined not quantitatively verified the hypothesis that the greening only to enhance rainfall but also to prevent hail and elimi- and afforestation of deserts along the Red Sea in Saudi nate fog. It is anticipated that results from these studies Arabia would increase the amount of water supplied to will be mutually beneficial and will assist with the Saudi the atmosphere, resulting in enhanced rainfall in the Arabian research project reported here. mountainous zone. For example, if a 75 x 150-km area of desert were (a) Desert (max.: 0.59 g/kg) (b) Grassland (max.: 0.75 g/kg) converted to grassland, the grassland would then sup- ply water vapor to the atmosphere. Increased atmospheric water vapor could increase the water con- tent in clouds over the mountainous zone by approximately 20% [Fig.6(a)(b)]. Thus, the analysis showed that there is a possibility that the amount of rainfall could also increase by approximately 20% [Fig.6(c)(d)]. Current investigations are examining dif- ferences in the types of cultivated plants, vegetated area, (c) Desert (max.: 14.6 mm/hr) (d) Grassland (max.: 19.1 mm/hr)
(a) Natural forest at 3000m altitude (b) Agricultural zone at 2500m Fig. 6 Numerical calculation of areas affected by desert-greening, Fig. 5 Natural conditions at altitudes of approx. 2 500 m and 3 000 m using a regional-scale meteorological model
Balloon
Observation by satellite Airplane (USA) Radar reflection dish Balloon Spraying condensation agent Rocket Parachute (China) Promoting rainfall Rainfall radar GPS sonde Water dam Prediction of diffusion of condensation agent ascending current Equipment loaded with rainfall ppromoter
Ballast
Fig. 7 Technology used to promote rainfall by spraying a condensation agent from balloons (i.e., cloud seeding)
Mitsubishi Heavy Industries, Ltd. Technical Review Vol. 42 No. 4 (Nov. 2005) 4 source. As shown in Fig. 99, current experiments are in- 3. Securing Sustainable Water Resources vestigating the use of both solar energy and biomass for Rapid population growth in the arid Middle Eastern re- seawater desalination. gion has led to vast amounts of water being consumed for As shown in Fig. 1010, an experimental solar electric gen- food production. Much of the water used is pumped from erating system (SEGS) power plant (354 MW) has already deep, subterranean sources, the depletion of which is a se- been built in the Mojave Desert of the U.S. In addition, rious concern. For example, in Saudi Arabia, approximately as shown in Table 11, a number of large-scale experimen- 90% of water use is related to greening efforts and agricul- tal solar thermal power plants are either currently under ture. It is crucial to secure new water resources. This section construction or in the planning stages in several other introduces two approaches for acquiring a sustainable wa- countries. MHI manufactured the steam generators and ter supply using natural energy as the major power source. turbines for the third, fourth, and fifth 90-MW plants built 3.1 Seawater desalination using solar heat and as part of SEGS projects 20 years ago. These facilities are biomass waste still operating smoothly. Three types of solar collectors Compared to Japan, the Middle East receives more are used in solar thermal power plants: the tower type, than two times the annual amount of sunshine (Fig. 88). separate light-collecting (trough) type, and parabola type. Therefore, seawater desalination using solar energy was In this research, the trough type is being investigated for investigated. An on-site survey also showed that a tre- desalination applications, because this type of collector mendous amount of biomass, such as leaves discarded has long actual operating records and is suitable for low- from date palm plantations, is also available as a power temperature (around 100oC) steam generation. By progressively depreciating capital costs, SEGS solar power plants have reduced power generation costs to as low as 5 cents/kWh. The average generation cost since the opera- tions began 20 years ago is estimated to be approximately 8 cents/kWh. (Fig. 111)
14 12 >3600 10 3000- 3600 8 2400- 3000 6
1600- (¢/kWh) 2400 4 Fossil fuel-firing power-generation cost <1600 2 Power generation cost Fig. 8 Distribution of annual sunshine hours 0 1980 1985 1990 1995 2000 2005 2010 2015 2020 2025 Calendar year Solar enegy Evaporator Steam turbine MSF Fig. 11 Cost comparison between a fossil-fuel power plant (Daytime) and the SEGS solar thermal power plant in the U.S.A.
Electric power RO generator Table 1 Solar energy power plants worldwide (Nighttime) Output power Heat Operation MSF: Multi-step flush type Country Location (MW) collector period desalination system California Biomass RO : Reverse osmosis membrane USA Tower type desalinization system (Solar 1) 10 1982 - 88 Fig. 9 Configuration of a desalination system using solar and California 10 Tower 1996 - 99 biomass as power sources (Solar 2) California 354 Trough 1982 - present (SEGS 3)
France Pyrenees 2.5 Tower 1982
Spain Almeria 1 Tower 1983
Sicily 1 Tower 1982 Italy Specchia 12 Trough Planned
Greece Crete 50 Parabola 1998 Fig.Fig. 1100 SSolarolar eelectriclectric ggeneratingenerating ssystemystem (SEGS)(SEGS) ttrough-typerough-type hheateat ccollectorollector ssolarolar Israel Rehobot 250 Tower Planned thermalthermal ppowerower pplantlant wwithith aann ooutpututput ooff 380380 MMWW ((MohaveMohave DDesert,esert, CCA,A, UU.S.A).S.A) Japan Nio1 Tower 1981 - 1985
Mitsubishi Heavy Industries, Ltd. Technical Review Vol. 42 No. 4 (Nov. 2005) 5 250 : RO
200 : MSF
: Average 150 CDM (cents/ton)
100 DDesalinationesalination ccostost bbyy fossilfossil fuelfuel 50
Water production cost (cents/ton) 0 Condensed water Fossil fuel only Solar energy only Solar energy + (Case 1) (Case 2) biomass (Case 3) Desalination method Fig. 12 Cost comparison of seawater desalination by fossil fuel (Case 1), solar Fig. 13 Atmospheric moisture-collecting system energy (Case 2), and a combination of solar energy and biomass (Case 3) using a refrigerating air conditioner (Based on sunshine conditions in California and Saudi Arabia and assuming a water-producing capacity of 40,000 tons/day.)
A drawback of solar-powered desalination plants is that they can only be continuously operated for approxi- 4. Technology to Realize Sustainable Desert Greening mately 8 hours per day. Accordingly, the cost of Saudi Arabia is facing a severe water crisis as rapid desalination is about three times that of fossil-fuel-pow- population growth and increased food demands deplete ered desalination, as shown in Fig. 1212. One way to its deep subterranean water supplies. To solve this prob- address this cost problem is to use biomass from biom- lem, new water resources and more efficient uses of ass as a supplemental fuel. This method makes it possible surface water, soil water (moisture contained in soil lay- to increase the operating hours each day, so that costs ers at a depth of several meters), and sewage waste water can be expected to decrease to those of fossil-fuel-pow- must be developed. ered desalination. Moreover, this method could be The project described here focuses on the creation of considered a Clean Development Mechanism (CDM) and greenbelts that can maintain sustainable plant and crop could thus earn CO2 emission credits. production and provide a comfortable living environment. 3.2 Atmospheric moisture collection system Under examination are the efficient uses of soil and waste Because the relative humidity of the Red Sea coastal water, both of which have been only negligibly utilized. area of Saudi Arabia exceeds 80% in summer, large The research described in this section is currently un- amounts of moisture are carried in the air. The annual derway as a joint project with the Arid Land Research rate of air conditioner use is also high in this area, where Center (ALRC) of Tottori University, Japan. the average temperature often exceeds 30oC for 9 months 4.1 Cultivation of deep-rooted seedlings of the year. This research team focused on these condi- In arid areas, the amount of water near the soil sur- tions and developed the "Atmospheric Moisture face (several tens of cm) is generally insufficient for Collection System" (Fig. 1313), using an MHI packaged air plant cultivation, due to large amounts of evaporation conditioner (power consumption of 12.5 kW) to collect and a lack of rainfall. However, in areas where water is water condensed from the air. The performance of the recharged by hydrological circulation, sufficient unit has been verified. amounts of water are contained at depths from one to In the preliminary test carried out in Nagoya, Japan, in several meters below the soil surface. A new method 2003, approximately 300 L of condensed water per day were called "deep-rooted seedling cultivation" was developed successfully collected under similar weather conditions to to use such deeper soil waters (Fig. 1414). In this cultiva- those in Saudi Arabia. This test unit has now been trans- tion method, water contained in soil can be used directly ferred to the Water Research Center at King Abdul Aziz by seedlings developed to grow long roots (deep-rooted University in Jeddah (KAAU). On-site verification tests seedlings). have begun and are expected to last for 1 year. From the viewpoint of preventing water depletion, Because the unit is usually used as an ordinary air con- however, it is important that this water be replenished ditioner, the costs for producing water are essentially nil. periodically with freshwater from sustainable, hydro- Hence, the unit can serve as an effective alternative source logical circulation in greening areas. It is thus essential for securing domestic-use water in urban areas. It is an- to select a proper site for deep-rooted seedling cultiva- ticipated that the unit can collect approximately 100 L of tion to retain a balance between water supply and water per day, based on the annual average, especially in demand and to cultivate plants at a proper planting cities like Jeddah that are located along the coast. density.
Mitsubishi Heavy Industries, Ltd. Technical Review Vol. 42 No. 4 (Nov. 2005) 6 Transpitation Rainfall Subsurface irrigation (effective use of swage water)
Evaporation Cross section of Approximately 70% of surface (small) root cylinder irrigation water can be reduced by this technology. Approximately 60% of micro Irrigation irrigation can be reduced. Irrigation pipes Root cylinder pipes Culture medium Root Root cylinder
Subsurface irrigation Absorption of soil water Irrigation water can be signifi- cantly reduced through the Longitudinal section of use of rechargeable soil water Deep rooted seeding lower end part of root cylinder
Fig. 14 Deep-rooted seedling cultivation method
Compost
Dry Wastewater Concentrated sludge
Utilization of Pre-treatment cooling energy Air-conditioning equipment Freeze concentration equipment equipment (for removing SS)
Recovery of exhaust heat
Concentrated water Sterilizer
Processed water For plant cultivation Concentrated water-processing system
Fig. 15 Wastewater treatment system based on the freeze-concentration method
The effectiveness of the deep-rooted seedling method when water is frozen; therefore, this method can be used has been verified using soybeans (an annual plant) and to purify water. At the same time, the ice can be used as Japanese black pine (a perennial tree species) as model a cold energy source for air conditioners. The system has plants. Soybeans with roots 95 cm long were success- been tested and verified in Japan, and the following re- fully grown using this method, and it was confirmed that sults were obtained. the soybeans had rooted normally. (1) A verification test using simulated sewage water simi- The deep-rooting method was also confirmed using lar to local sewage in Saudi Arabia demonstrated that Japanese black pine. The main, elongated root of the this system can produce water of suitable quality for deep-rooted black pine seedlings increased up to 2.5 plant cultivation. times faster than by normal methods. In the future, on- Water conditions in inlet (equivalent to sewage): site surveys will be conducted at a suitable site in Saudi Chemical oxygen demand (COD): 300 mg/L, Arabia to confirm the suitability of the deep-rooted seed- Suspended substance (SS): 120 mg/L; ling method for date palm trees, a crop that is in high Processed water qualities: COD < 10 mg/L, demand in the region. SS < 5 mg/L 4.2 Plant cultivation using waste water (2) Sewage water treatment costs can be reduced to as MHI is developing a sewage treatment system based low as approximately 50 yen/m3 by using cold energy on the freeze-concentration method to promote the ef- for air conditioning. However, because the cost of ir- fective use of sewage waste water in Middle Eastern rigation water is approximately 30 yen/m3 or lower countries, where great demand for refrigeration is ex- in Saudi Arabia, additional research is currently at- pected (Fig. 1515). tempting to improve the equipment and further reduce In this system, impurities are eliminated from ice the cost of this processed water.
Mitsubishi Heavy Industries, Ltd. Technical Review Vol. 42 No. 4 (Nov. 2005) 7 5. Conclusions Acknowledgements MHI intends to conduct an on-site demonstration test The authors would like to extend their deepest ap- in Saudi Arabia in fiscal year 2005 (Japan), using the tech- preciation to Dr. Adil Busknak, Chairman of Saudi Arabia nologies verified thus far. The on-site demonstration will Busknak Co., Dr. Hiromasa Ueda, Director General of be performed following detailed and frequent discussions the Acid Rain Research Center (Acid Deposition and with local collaborators. Important factors include the Oxidant Research Center (ADORC)) of the Japan Envi- needs of local residents and the government, social plan- ronmental Sanitation Center, Dr. Toshio Yamagata, ning documents, and large-scale hydrological circulation Program Director of the Japan Agency for Marine-Earth trends. In addition, the present state of water resource Science and Technology, Dr. Tomonori Matsuura, (Sec- conservation and the influence of greening the desert en- tion Chief - Senior Researcher) of the National Research vironment will be evaluated. MHI aims to advance and Institute for Earth Science and Disaster Prevention, clarify knowledge of hydrological circulation mechanisms Professor Shinobu Inanaga of the Arid Land Research and to show that the presented scenario is highly feasible Center of Tottori University, Professor Toru Okamura, through on-site observations, plant cultivation demonstra- Professor of Law at Sophia University, and many others tions, and completing the scenario for an artificial oasis. for their kind cooperation and support.
References (1) Sustainable Coexistence of Human Nature and the Earth "Advanced Prediction System and Counter Measures of Re- gional- and Meso-scale Water Cycle", Report of Research Progress in 2004, March (2005) (2) T. Yamagata et al., Diagnosis of troposphere moisture over Makoto Harada Ryohji Ohba Saudi Arabia and influences of IOD and ENSO, Monthly Weather Review, (to be accepted) 2005
Wataru Kawamura Masahiko Nagai
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