FEASIBILITY STUDY OF A COMBINED ELECTRIC

POWER AND WATER DESALINATION PLANT IN

JORDAN

B. A/K. ABU-HIJLEH,* R. ATALLAH, M. MUSTAFA,M. AL-ASKER and L. EL-MASOUD

Mechanical Engineering Department, Jordan University of Science and Technology, PO Box 3030,Irbid 22110, Jordan

(Received 15 July 1996)

AbstractÐThe rapid growth in Jordan's electrical and water needs cannot be addressed by the currentand planned supply sources. A combined electric power and water desalination plant is proposed andstudied in detail. The plant is designed to cover all of Jordan's electrical and part of its water needs upto the year 2020. Sensitivity analysis of the plant's pro®tability under several ®nancing and fuel pricescenarios was performed. The results show that such a plant represents a good investment opportunityunder a wide range of conditions. # 1998 Elsevier Science Ltd. All rights reserved

Electricity generation Water desalination Jordan Economic feasibility

INTRODUCTION

Jordan is a rapidly growing country. The current population growth rate is around 3.6% and is

expected to drop to only 2.7% by the year 2020 [1]. The growth in the gross national product(GNP) is currently a healthy 6% [2]. The recent political moves toward peace in the region are

expected to maintain or even increase the current GNP growth rate. Until recently, the

Jordanian economy was mainly dominated by the service sector and low technology, light tomedium conversion industries. The current trend in Jordan is toward high technology, medium

to heavy industries and large-scale agricultural projects. A key ingredient to starting and main-

taining such a growth is su�cient supplies of electricity and fresh water.

Until the early 1990 s, the installed electric capacity was appropriate to meet the short term

needs of Jordan. The Jordan Electric Authority (JEA) had expansion plans that were designed

to meet the expected demand in the medium to long term. The second Gulf War, started inAugust 1990, resulted in the return of some 600 000 Jordanians that used to live in the Gulf

countries. The change in the political landscape due to the peace negotiations and the increase

in the quality and quantity of new industries almost doubled the total electric consumption inJordan, from 2875 GWh in 1990 to 4540 GWh in 1995 [3]. In response, the JEA had to step up

the rate of construction of the planned new steam power stations. The growth in electricitydemand was so high that additional gas turbine units were installed to provide 190 MWe of

urgently needed electric power between 1993 and 1996. The last steam unit planned by the JEA

is expected to come on line in early 1999. However, this will not cover the electric needs ofJordan past the year 2005 based on the medium forecast, and will barely meet the needs at the

year 2000 based on the high forecast (see Fig. 1).

Jordan is, in the main, a desert with 81% of the land receiving less than 100 mm of rain peryear and only 2% receiving more than 300 mm of rain per year [4]. The water situation is extre-

mely critical in Jordan. Jordan relies on surface sources for 49% of its water needs. The rest

comes from renewable and non-renewable ground resources (34 and 17%, respectively). Waste-water treatment accounts for less than 1% of the total water supply [4]. Water demand far

exceeds supply, resulting in a de®cit of around 25% (see Fig. 2). This de®cit is currently covered

Energy Convers. Mgmt Vol. 39, No. 11, pp. 1207±1213, 1998# 1998 Elsevier Science Ltd. All rights reserved

Printed in Great Britain0196-8904/98 $19.00+0.00

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*Author to whom correspondence should be addressed.

1207

by pumping water from ground resources in quantities much higher than its capacity to regener-ate. This has already rendered some wells unusable. The Jordan Water Authority (JWA) plansto expand the capacity of current dams and construct new ones. An extensive search is under-way for new ground water resources, but even in the best-case scenario, the water demand willcontinue to exceed all new supplies. Thus, there is an urgent requirement for new waterresources. One option was a proposed fresh water pipeline from Turkey to Jordan. Such a pro-ject is extremely ambitious, especially in political and national security terms. Thus, the need to®nd new local supplies of fresh water is urgent.

Fig. 1. Yearly change in peak and installed electrical capacity in Jordan based on current JEA plansand estimates.

Fig. 2. Yearly change in peak and installed fresh-water capacity in Jordan based on current JWA plansand estimates.

B. A/K. ABU-HIJLEH et al.: COMBINED DESALINATION PLANT1208

In this paper, a study is undertaken to investigate the feasibility of building a combined elec-tric power and water desalination plant in Jordan. The study focuses on the best course ofaction that should be taken in order to meet all of Jordan's electrical and some of its waterneeds up to the year 2020.

LOCATION

Electric power and fresh-water plants share many of the main location considerations, such asproximity to fuel supply, to water supply and to the end user. In the case of Jordan, the ®rsttwo were at complete odds with the last, but were deemed more critical. These two pointsquickly settled the location in which such a plant could be erected. The location was Aqaba, theonly Jordanian port located on the Red Sea. The water supply was, by far, the single most in¯u-ential cause for selecting this location. Jordan is poor in fossil-fuel supply and, thus, dependsmainly on imported fuel. The plant location at Aqaba provides for easy fuel supply by shipsdirectly to the plant's fuel storage tanks. A newly proposed Qatari natural gas pipeline isdesigned to pass through Aqaba. Such a project can supply all the required natural gas fuel tothe plant at minimal transportation costs.

The main JEA steam power units are currently located in Aqaba, mainly because of the needfor a proper supply of cooling water. Thus, the infrastructure for electricity transmission isalready in place. Yet, there will be a need to add new transformers and upgrade the high voltagetransmission network. The systematic layout planning technique (SLP) was used to ®nd the op-timal layout of the plant [5]. The plant was designed for future expansion, which will coverJordan's high forecast electricity needs up to the year 2020.

ELECTRIC POWER GENERATION

Gas turbines were chosen for electricity generation over steam turbines due to their low initialcost, short construction time and high thermal e�ciency in the combined cycle con®guration [6].Gas turbines of 120 MWe capacity were selected for the plant. The use of multiple, medium-sized units allowed for higher availability, increased ¯exibility and smoother incremental expan-sion of the plant capacity. From a technical point of view, the best combination of expansionsteps and size was to start with four 120 MWe gas turbines in the year 2000, subsequently add-ing two or four extra gas turbines every 5 yr up to 2015 for the medium and high forecasts, re-spectively. Both arrangements should cover Jordan's electricity needs up to the year 2020 (seeFig. 3). The excess capacity in both cases is designed to account for the turbines that will be o�-line for maintenance as well as the gradual phasing out of older steam (99 MWe) and Diesel (56MWe) units that entered service in the early 1970 s.

FRESH WATER PRODUCTION

Multi-stage-¯ash (MSF) desalination was chosen over multiple-e�ect as the desalinationmethod. The main reason was the world-wide experience with the operation and maintenance oflarge-scale MSF plants, especially in the Middle East region. The market study showed thesevere shortage in fresh-water supply. Thus, the use of large, 90 000 m3 dayÿ1 (20 MIGD), MSFdesalination trains with each gas turbine is proposed. This is the next generation of large-scaleMSF trains acting as a follow-up to the current 54 000 m3 dayÿ1 (12 MIGD) trains under con-struction at the Al-Taweelah B plant in the UAE [7]. The high-temperature exhaust of the gasturbine is used to provide part of the energy needed to generate steam for the MSF process. Anauxiliary boiler is required to provide the balance of energy to generate the 442 t hÿ1 of steamneeded for each MSF train.

The optimized design conditions for the MSF trains were: top brine temperature(TBT) = 1188C; below brine temperature (BBT) = 388C; performance ratio (PR) = 8.5; 19recovery and three reject stages; and a steam ¯ow rate of 442 t hÿ1. The high TBT could beachieved by the use of acid treatment to reduce scale formation. Acid treatment was abandoneda few decades ago due to safety and high corrosion considerations. Recent advances in materialsas well as operational and control procedures makes the use of acid treatment feasible. The opti-mized value of TBT was obtained by minimizing the cost of water production which was a func-

B. A/K. ABU-HIJLEH et al.: COMBINED DESALINATION PLANT 1209

tion of the acid cost and energy required to recycle the brine ¯ow. The plant overall thermal e�-ciency was calculated to be around 64%. This is better than the 60% e�ciency of the best com-bined cycle electric power generation plants [6]. The main reason is the ability of MSF trains touse steam at lower temperatures than low pressure steam turbines.

Based on the design method proposed, the number of MSF trains erected is the same as thenumber of gas turbines installed. Figure 4 shows the e�ect of adding the MSF trains on thewater situation in Jordan. It is clear that the product of the MSF trains is not su�cient to bal-ance the water demand. The water produced by MSF desalination is of high purity, typically

Fig. 3. Yearly change in peak and installed electrical capacity in Jordan, including the proposed plant.

Fig. 4. Yearly change in peak and installed fresh-water capacity in Jordan, including the proposedplant.

B. A/K. ABU-HIJLEH et al.: COMBINED DESALINATION PLANT1210

less than 10 ppm. The acceptable purity of drinking water is around 500 ppm. Thus, the MSFproduct can be mixed with brackish water to yield a larger volume of drinking water. Largebrackish water reservoirs are available at the Al-Kafrain and Al-Azrak regions [4].

ECONOMIC ANALYSIS

Fourteen di�erent combinations of location, initial capacity and increment steps were studied.Some alternatives were rejected due to technical considerations, e.g. availability of a large watersupply. The two most attractive combinations shared the same location (Aqaba), the same initialcapacity (four units) and the same schedule for capacity upgrade (every 5 yr). A unit is com-posed of a 120 MWe gas turbine, a 90 000 m3 dayÿ1 (20 MIGD) MSF train and all requiredauxiliaries, e.g. transformer and auxiliary boiler. The only di�erence between them was the num-ber of units for future upgrades. Based on the medium forecast of increase in electric powerdemand, the optimal upgrade was two units every 5 yr. For the high forecast, the optimalupgrade was four units every 5 yr.

The ®xed and variable cost of the plant was estimated based on the data available in pro-fessional publications that deal with such issues, such as Modern Power Systems, PowerEngineering International and The International Desalination & Water Reuse Quarterly. Based onthese, fuel cost was estimated at 0.022 USD kWhÿ1 and 0.36 USD mÿ3. The cost of the plantwas amortized over 30 years. The estimated cost, in million USD, of the plant's main com-ponents was as follows: 120 MWe gas turbine (60); auxiliary steam generator (40); MSF desali-nation train (100); transformer (5); control system (20 for the plant); 5 km2 of land (30); andbuildings per unit including storage tanks and workshops (10). The selling price was assumed tobe 0.048 USD kWhÿ1 and 1.25 USD mÿ3. Compare this with the current production cost of0.048 USD kWhÿ1 (JEA) and 1.0 USD mÿ3 (JWA). The higher price for water was a directresult of the high initial and running cost of MSF desalination, compared to the use of dams orground wells. It is assumed that all of the plant's electricity and fresh water production will besold to the JEA and the JWA, respectively, the government agencies responsible for electricityand water distribution in Jordan. Thus, no distribution cost was included. Although the sellingprice of the fresh water produced is higher than the current price reported by the JWA, thewater can be sold at a premium for two reasons: the extreme shortage in water supply and thehigh degree of purity of the desalinated water. Mixing the desalinated water with the low-costbrackish water will reduce the cost of the resulting mixture in terms of USD mÿ3. This is par-ticularly valid for irrigation purposes. The mixing will help reduce the severe shortage in watersupply.

Figure 5 shows the average pro®tability of the plant vs the percentage of ®xed cost ®nancedby a loan. The plant pro®tability was averaged over 20 yr, 2000±2020, and was calculated as theratio between the pro®t from selling all of the plant's electricity and water to the total cost,®xed and running, incurred during the production. Figure 5 includes six curves which corre-spond to the cases of medium- and high-forecast expansion scenarios for three interest rates: 8,10 and 12%. The medium forecast at an interest rate of 8% was the least sensitive to the loanpercentage. The high forecast at an interest rate of 12% was the most sensitive. Figure 6 showsthe e�ect of percentage change in fuel cost, relative to the values assumed above, on the averagepro®tability of the plant. Both the medium- and high-forecast scenarios are included. The inter-est rate was ®xed at 10% and three loan percentages were studied. There was minimal di�erencebetween the curves for the medium- and high-forecast scenarios. The ®gure shows that the plantwill remain pro®table over a relatively wide range of fuel cost ¯uctuations. Should the fuel costincrease dramatically, the selling price will have to be adjusted to re¯ect the increase in pro-duction cost.

Extra water can be produced using reverse osmosis plants (RO) by exploiting the excess elec-tricity production during o�-peak hours. Based on the current load curves [3], the excess electriccapacity ranges between 3 and 12 GW dayÿ1. The lower value occurs just before the scheduled 5yr upgrade, while the high value occurs just after the upgrade. This excess capacity could, theor-etically, be used to produce between 150 000 and 600 000 m3 dayÿ1 (33±133 MIGD). Based onseveral case studies reported in The International Desalination & Water Reuse Quarterly, water

B. A/K. ABU-HIJLEH et al.: COMBINED DESALINATION PLANT 1211

desalination cost using RO ranges between 1.3 and 1.7 USD mÿ3. The advantage of using ROplants is that they can be located closer to the end user. Electricity transmission is much easierand cheaper than water transportation from Aqaba to central Jordan, a distance of 300 km,where the highest demand for water occurs. Several small RO plants can be located near med-ium-sized population centres, subject to the availability of proper brackish water supply. Thiswill further reduce the transportation cost. This option was not included in the current study.Such an option will increase the utilization factor of the plant, and will result in enhancingplant pro®tability and, thus, attractiveness for investment.

Fig. 6. Sensitivity of the plant average pro®t vs changes in fuel cost.

Fig. 5. Sensitivity of the plant average pro®t vs loan interest rate and percentage of ®xed assets ®nancedby loan.

B. A/K. ABU-HIJLEH et al.: COMBINED DESALINATION PLANT1212

CONCLUSIONS

A detailed study of a combined electric power and water desalination plant in Jordan wasundertaken. The plant is made of multiple identical units, each with the capacity of 120 MWeand 90 000 m3 dayÿ1 (20 MIGD). The proposed plant will meet all of Jordan's electricity needsand part of its water needs up to the year 2020. Several alternative combinations were studied.Sensitivity analysis to the loan interest rate, percentage of ®xed cost ®nanced by loan andchanges in fuel cost was performed. The plant is pro®table over a wide range of conditions.Thus, such a plant represents a good opportunity for private investment.

REFERENCES

1. Annual Report of the Jordanian Department of Statistics, 1995.2. Annual Report of the Jordanian Ministry of Planning, 1995.3. Annual Report of the Jordan Electricity Authority, 1995.4. Annual report of the Jordan Water Authority, 1995.5. Black, J. T., The Design of the Factory with a Future, McGraw-Hill, New York, 1991.6. Smith, D. J., Power Engineering International, 1995, 3, 21.7. Borsani, R., Superina, R. and Sommariva, C., The Desalination & Water Reuse Quarterly, 1996, 6, 12.

B. A/K. ABU-HIJLEH et al.: COMBINED DESALINATION PLANT 1213