SUMMARY 1. Background of the Study 2. Importance of Energy-Saving

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1 SUMMARY 1. Background of the Study Environmental issue is now gradually revealed by ocean and air pollution in the Gulf States including the State of Qatar. Particularly in Qatar, which has made rapid industrialization, seawater temperature rising is caused by huge volume of industrial water to the coastal sea. In 2000, Supreme Council for Environment and Natural Reserves (SCENR) was established in order to make laws and regulations for ocean and terrestrial environmental protection and to supervise and monitor the execution by the organizations and corporations subject to the regulations. SCENR involves in the projects of industrial facility development from the planning phase in terms of their environmental measures and has authority to issue approval for the implementation of the projects. After the establishment of SCENR, the basic law of environmental policies called Environment Protection Law was made and became in effect in And subsequently in 2005, by-law of Environment Protection Law became in effect and has moved the environmental protection policies forward. SCENR has made and executed more than 7 environment protection-related laws since its establishment, which is an exceptional case in the Gulf region in view of its speed to deliver and ability to enforce the environmental-friendly policy. In order to comply with the strict environmental standards, Qatar Electricity & Water Company (QEWC) set up Safety and Environment Department to deal with environmental issues and measures for the operation and maintenance of power generation and desalination facilities. 2. Importance of Energy-Saving Large amount of heat energy is used for desalination process of the Multi Stage Flash (MSF) desalination plant, which is the major system in the Middle East countries, by combustion of fossil fuel. After utilized for heating seawater for desalination, this heat energy is discharged to the coastal sea as waste warm seawater. Reduction of the energy consumption is very important for the effective utilization of energy, and this reduction also has an effect to reduce environmental impact. As various efforts have been made for higher efficiency for MSF plant since its technology was established in 1970s, further improvement on efficiency is in quite difficult conditions nowadays. Also economic viable way to utilize such low temperature of waste warm seawater (40-50 o C) discharged from MSF plants could not be found out in a long while. In this report, the feasibility study (F/S) is carried out for the water production enhancement project by the desalination system by ocean thermal energy desalination (OTED) technology. This system has been developed with a special focus on utilization of small temperature difference

2 (10-20 o C) so that this system contributes to energy-saving in economic aspect because of utilizing the waste warm seawater as thermal energy source, which is discharged to the coastal sea, for water production. As the consequence of the energy-saving, in environmental aspect this system contributes to reduce not only coastal seawater temperature rising, but also exhaust gas containing CO 2 and NO x because of no use of fuel. 3. Objective The objective of this study is to investigate the feasibility of the Water Production Enhancement project by OTED technology for existing MSF plants in Qatar. We focus on Ras Abu Fontas Station (RAF) which is the largest power generation and desalination station in Qatar. This study investigates the economic efficiency, energy-saving effect and environmental effect of this system and evaluates its possibility of dissemination in Qatar. 4. Outline of Water Production Enhancement System by OTED Technology Principle of the OTED system proposed in this F/S is similar to the self-flash evaporation method which has been widely used in MSF plant. The block diagram of this method is shown in Figure S-1. At first, warm seawater (denoted with 1, waste warm seawater and waste warm brine from existing MSF plant) flows into the depressurized flash chamber (denoted with 2) and makes self-flash evaporation. The vapor condenses at the condenser (denoted with 3), and becomes product water (fresh water) (denoted with 4). The non-vaporized warm seawater in the chamber is discharged from the chamber by the seawater discharge pump (denoted with 5). In existing MSF plants by self-flash evaporation method, a portion of recycle brine, heated in brine heater by steam from external boiler, is used as a portion of the warm seawater mentioned above. However, this project utilizes waste warm seawater from the existing MSF plant. The waste warm seawater evaporates without heating, because its temperature is approximately o C which is higher than that of intake seawater (15-37 o C) In general, the size of plant facility becomes larger to obtain a desired production as lower as the temperature of heat source is, and consequently the economic efficiency becomes lower. Therefore, this system applies plate type heat exchanger to the condenser which is compact and has high efficiency, to minimize the plant size and improve the economic efficiency.

3 Warm Seawater Waste Warm Seawater Stage 20 2 Seawater Discharge Pump 5. Present Status in RAF Station and Model Case Selection 1 Flash Chamber 5 Steam 4 3 Condenser Cooling Seawater (Intake Seawater) Product Water Pump (1) Present status in RAF Station In RAF Station, fourteen (14) units of MSF plants were constructed in RAF-A area at five (5) phases from the end of 1970s to the beginning of 1990s, and five (5) units of MSF plants were constructed in RAF-B area at the end of 1990s. Desalination capacity of RAF-A is 22.5 Thousands m 3 /d per unit and that of RAF-B is 30 Thousands m 3 /d per unit. Discharge rate of waste warm seawater from each plant is around 8 Thousands t/h and 10 Thousands t/h, respectively. (2) Model case selection Case studies are carried out on 8 conditions (Case-A1, A2, A3 and A4 for RAF-A, Case-B1, B2, B3 and B4 for RAF-B). As a result of the case study, it is found that the water production by each of this system is expected to be 5-10% to that for the existing MSF plant as shown in Table S-1. Based on this case study, all cases are evaluated as shown in Table S-2. As a consideration of the results discussed with QEWC, Case-B3 is selected as model case.

4 Case No. Case-A1 Case-A2 Case-A3 Case-A4 Case-B1 Case-B2 Case-B3 Case-B4 Table S-1 Result of case study Operation Condition after Installation of OTED System TBT Same as the present Same as the present Flow Rate of Recycle Brine 3% 1.5% Same as the present 1.5% 4% 1% Same as the present 1% Tempering Period Water Production of OTED System Water Ratio to that of Production the existing (Annual Average MSF None 2,460 m 3 /d % None 2,460 m 3 /d % Decreased by 2 months Decreased by 2 months 1,540 m 3 /d +6.5 % 1,550 m 3 /d +6.6 % None 2,680 m 3 /d +8.9 % None 2,850 m 3 /d +9.5 % Decreased by 2 months Decreased by 2 months 1,660 m 3 /d +5.5 % 1,710 m 3 /d +5.7 % Table S-2 Evaluation of case study Case No. Water Production Capacity Expected Economic Efficiency Evaluation Easiness of Operation Risk by Increase of TBT Availability of Installation Space Total Case-A Case-A Case-A Case-A Case-B Case-B Case-B Case-B Legend 3: Excellent, 2: Good, 1: Fair, 0: Poor

5 6. Result of Study on Model Case (1) Specification of model case plant The specification of this system is designed as listed in Table S-3 Table S-3 Specifications of OTED system in the model case Item Capacity/Specifications Remarks Warm Seawater Flow Rate max. 8,450 t/h Temperature Cooling Seawater Flow Rate 9,700 t/h Temperature Water Production Capacity Summer 1,370 m 3 /d Intake seawater 33 o C Winter 2,000 m 3 /d Intake seawater 20 o C Annual Average 1,660 m 3 /d Required Utility Electricity 340 kw For Pumps etc. Medium Pressure Steam 460 kg/h For Vacuum System o C o C (2) Economic evaluation Using EPC cost, maintenance cost and operation cost estimated for the model case, unit water production cost was estimated as QAR 2.69 (US$ 0.74 /m 3 ) as described in Table S-4.

6 Table S-4 Estimation result of unit water production cost Item Water Production 1, 660 m 3 /d (Annual Average) Remarks (a) Annual Production 589 Thousands m 3 On-stream Factor: 97% (b) EPC Cost QAR 21,300 Thousands (US$ 5,850Thousands) (c) EPC Cost QAR 1.81 /m 3 (US$ 0.50 /m 3 ) per production (d) Maintenance Cost QAR 200 Thousands/y (US$ 55 Thousands/y) (e) Maintenance Cost QAR 0.34 /m 3 (US$ 0.09 /m 3 ) per production (f) Operation Cost QAR 318 Thousands /y (US$ 87 Thousands/y) (g) Operation Cost QAR 0.53 /m 3 (US$ 0.15 /m 3 ) per production (h) Unit Production Cost QAR 2.69 /m 3 (US$ 0.74 /m 3 ) According to the study, price of water is QAR 4.4/m 3 (US$ 1.21/m 3 ) for residential and industrial facilities, QAR 5.2/m 3 (US$ 1.43/m 3 ) for commercial facilities and QAR 7.0/m 3 (1.92 US$/m 3 ) for governmental facilities. Accordingly, the unit production cost by this system is considered to be more economical. 7. Energy-saving and Environmental Effects Qatar, which has been making remarkable progress in industries, has growing concerns about environmental issues accompanied with such rapid industrialization. Especially, having shallow coastal sea and located in the closed Arabian Gulf, Qatar has strict regulations on temperature of and chemical concentration in waste water discharged from industrial plants. With respect to the exhaust gas, as the most of fuel for power plants and boilers is natural gas with less sulfur oxide (SO x ) and nitrogen oxide (NO x ) emission with its combustion, air pollution problem is not so much serious than that in other countries using oil or coals as their main fuel. (refer to Table 3-1). Even in such circumstances, installation of de-nox equipment is planned in vent stacks for gas turbines for power generation and boilers for desalination.in addition, concern about the reduction of carbon dioxide (CO 2 ) emission is also growing, which is critical issue in global. In consideration of these situations, the effect of energy-saving and reduction of CO 2 emission by implementing the project are studied as environmental effect. Influences on waste warm seawater discharged from water production plant such as MSF plants to the coastal sea are also described.

7 (1) Baseline scenario and project scenario To evaluate energy-saving and environmental effects of this project, it is necessary to assume a scenario for the case that this project is not implemented (Baseline Scenario). At first the Baseline Scenario which could most likely happen is estimated on various situations of Qatar, then Project Scenario is estimated on the basis of implementing the model case project. Baseline Scenario 589 Thousands m 3 /y of water, which is corresponding to the annual water production of the model case, is produced by a MSF plant utilizing steam generated by natural gas boiler. Project Scenario 589 Thousands m 3 /y of water is produced by the OTED system which is studied as model case in Chapter 2, utilizing heat energy of waste warm seawater from an existing MSF plant, that is, without utilizing any fuel for heating seawater. (2) Results Study results on the energy-saving effect, the CO 2 emission reduction effect and the effect on reduction of waste heat to the coastal sea are as described in Table S-5, Table S-6 and Table S-7, respectively. Table S-5 Energy-saving effect by this project Item Result Energy consumption in the baseline scenario 236 TJ/y Energy consumption in the project scenario 37 TJ/y Energy-saving effect (annual) 199 TJ/y Table S-6 CO 2 emission reduction effect by this project Item Result CO 2 emission in the baseline scenario 14,000 t-co 2 /y CO 2 emission in the project scenario 2,200 t-co 2 /y CO 2 emission reduction effect (annual) 11,800 t-co 2 /y

8 Table S-7 Effect on reduction of waste heat to the coastal sea by this project Item Result Waste heat discharged in the baseline scenario 183 TJ/y Waste heat discharged in the project scenario 0 TJ/y Effect on reduction of waste heat (annual) 183 TJ/y (3) Environmental Impact Assessment The system in the study utilizes the untapped waste heat source and its environmental impact is quite minimal. The environmental standard applied in the location site such as the temperature of discharged water as well as its quality will be well-considered into the design so that detailed environmental impact assessment will be considered not necessary for the project. Potential in Qatar Potential of this project was estimated as below, in the case that the same system as the model case is applied to all the existing MSF plants in RAF and those in the whole Qatar. Potential at RAF Annual water production 6,700 Thousands m 3 /y (Ratio of enhancement to the existing 6.1 %) Energy-saving effect 2,060 TJ/y (Natural Gas equivalent 2,310 MMSCFA) CO 2 emission reduction effect 121 Thousands t-co 2 /y Potential in Qatar Annual water production 11,000 Thousands m 3 /y (Ratio of enhancement 6.1 %) Energy-saving effect 3,360 TJ/y (Natural Gas equivalent 3,760 MMSCFA) CO 2 emission reduction effect 199 Thousands t-co 2 /y 9. Expectation and Effect by Implementation of the Project The environmental improvement such as energy consumption in existing MSF plants and reduction of coastal seawater temperature rising meets with the national interest of Qatar. Therefore, it is expected that the model plant application of Ocean Thermal Energy Conversion (OTED)

9 technology in QEWC will be model case of energy saving and environmental protection of whole country by demonstration of model plant. In addition, QEWC is well-known worldwidely as the company which is fully supporting the water supply in Qatar. Hence, it is also expected that OTED system has possibility of worldwide dissemination from Qatar by implementation of this project.

10 All rights reserved. The copyright of this material is held by the Agency for Natural Resources and Energy, Ministry of Economy, Trade and Industry (METI). Reproduction of all or part of this material without express permission of the copyright holder is strictly prohibited. The Japan External Trade Organization (JETRO) was commissioned by METI to produce this material. Japan External Trade Organization (JETRO) Industry and Technology Division Industry and Technology Department Ark Mori Building 6F, Akasaka 1-chome, Minato-ku, Tokyo, JAPAN TEL: FAX: