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Application of a multi-criteria analysis for the selection of the most suitableenergy source and water desalination system in Mauritania

Angel Antonio Bayod Rujula a, Nourou Khalidou Dia b,

a Department of Electrical Engineering, Polytechnic Centre Superior, University of Zaragoza, Spainb Centre of Research for Energy Resources and Consumption, University of Zaragoza, C/Maria de Luna 3, 50015 Zaragoza, Spain

a r t i c l e i n f o

Article history:

Received 8 June 2009Accepted 24 August 2009Available online 20 September 2009

Keywords:

Desalination

Renewable

Scenarios

a b s t r a c t

Water deficits and their associated shortages are serious problems in many areas of the world. The paper

presents a multi-criteria analysis for selection of the most suitable system in Mauritania. Six scenarios,different energy sources, technologies of water desalination processes and water use and five criteria are

analyzed. The multi-criteria analysis shows that the optimal solution is different for each scenario; in

some cases the photovoltaic-reverse osmosis option is preferable; in others, the best option is reverse-

osmosis powered by wind energy or concentrating solar parabolic.

& 2009 Elsevier Ltd. All rights reserved.

1. Introduction

Water deficits and shortages are serious problems in many

areas of the world, but particularly in the Middle East and North

Africa (MENA), the Mediterranean islands of South Europe, (Essam

Mohamed and Papadakis, 2008) and the isolated communities of

the Mauritanian desert. At small scales, the solar desalination

system is applicable in these areas, which have water source

problems and are too remote to access grid electricity (Kalogirou,

2001). Mauritania is a country deficient in basic infrastructure; a

great part of the population currently does not have access to

basic services like water and electricity due to fossil fuel resource

limitations and lack of hydric resources. The Mauritanian govern-

ment indicated that the water deficit will affect 500,000 persons

in urban sectors and 600,000 in rural sectors. Mauritania is,

however, a country with a high rate of solar radiation, approxi-

mately 2020 kWh/m2 year in the case of Nouakchott (NASA, 2008).

The essential problem of the development process in these

regions is a lack of searching techniques, which increase the

potable water potentialities. National water reserves could beexploited. However, this water is hot, brackish and not exploitable

without treatment. Desalination technology is the unique alter-

native for obtaining potable water. This work presents a multi-

criteria analysis for the selection of the most suitable system for

six scenarios in Mauritania, applying technical, economic and

environmental criteria of the renewable resource, water desalina-

tion technology and water consumption.

2. Resources

Energy resources are particularly favorable in Mauritania

(Developpement Energies Renouvelables en Mauritanie, 2004).

Nowadays the majority of electrically energy comes from burning

diesel. In 2003, the oil imported accounted for 16.4% of total

national imports. Clearly, Mauritania is presently energy-dependant

and economically sensitive to variations in the price of petroleum.

The total fuel use during the 19902007 period for each supply is

summarized in Table 1.

Renewable energy offers an alternative solution to decrease the

dependence on fossil fuel. Forms of renewable energy available

are solar throughout the territory, the wind energy in the coast

regions for a length of 800 km and hydraulic potential found

particularly in the southern regions (Senegal River length of

1790 km).

2.1. Solar energy

Mauritania has some of the highest levels of solar radiation in

the world, making it an ideal place for producing solar energy. The

gross solar energy input is estimated at 2 109 GWh/year. Solar

irradiation on the horizontal surface varies between 1900 and

2200 kWh/m2 year (Fig.1) (NASA, 2008). This potential is provided

year-round and for relatively long periods of time. The solar

energy available can be used continuously in an optimal manner

(Bakary, 2008).

For selected sites in Mauritania, monthly series of global

horizontal irradiance and direct normal irradiance were extracted.

These figures are made by application of ARCGIS 9.2 (a geospatial

analysis software package). The data for each city enabled us to

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Contents lists available at ScienceDirect

journal homepage: www.elsevier.com/locate/enpol

Energy Policy

0301-4215/$ - see front matter& 2009 Elsevier Ltd. All rights reserved.

doi:10.1016/j.enpol.2009.08.057

Corresponding author.

E-mail address: [email protected] (N.K. Dia).

Energy Policy 38 (2010) 99115
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use an extrapolation method (natural neighbor). The natural

neighbor tool can efficiently handle large numbers of input points.

The normal direct irradiation received is between 1600 kWh/

m2 year in southeast regions and more than 2600 kWh/m2 year in

coastal regions of Dakhlet Nouadhibou, (Fig. 2) (NASA, 2008).

2.2. Wind energy

Mauritania is the windiest country in West Africa. Wind

potential is considerable, with a capacity for exploitation

estimated at approximately 7644kW/m2year (Bakary, 2008).

Wind potential is ensured by three dominant winds: the maritime

trade, which blows from the northwest all year; the harmattan, a

north-eastern wind that blows in the dry season; and a southern

monsoon that displaces the intertropical face during the wet

season (Bakary, 2008). Wind speeds (at 10 m above ground level)

vary between 3 m/s and more than 9 m/s in the northwest near

the Sahara, (Fig. 3) (Etude strategique, 2004).

2.3. Potential of hybrid systems

Hybrid systems as PVWind, PVDiesel, and PVDiesel

Battery are used in the rural sector or in peripheral zones of great

Table 1

Oil imported by Mauritania between 1990 and 2002.

Quantity (T/year) 1990 1995 2000 2001 2002 2007

Fuel oil 57,304 60,022 87,203 81,778 76,867

Diesel 162,491 207,336 228,649 258,518 280,267

Gasoline 30,334 42,164 26,188 23,315 27,407

Lamp oil 2400 960 356 185 74

Gas butane 59.1 53.3 101.3 89.2 92.4

Total 250,188 310,535 700,513 363,885 384,707 547,775a

a is the total annual consumption of the petroleum product.

Fig. 1. Global solar irradiation for all regions of Mauritania.

A.A. Bayod Rujula, N.K. Dia / Energy Policy 38 (2010) 99115100
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cities. It is difficult to quantify the real potential of hybrid systems

because it depends on the availability of resources in the zone

and the type of combinations, generally. (Many installations of

PVDiesel, PVDieselBattery exists in the interior and PVWind

in the coastal cities (due to a higher potential of these sources).

3. The water consumption

The problem of water supply is crucial in Mauritania. It is the

largest deficit in the countrys infrastructure. The drought hascaused accelerated urbanization, and brought the need for major

water infrastructure improvements. It is estimated that 4 out of 5

Mauritanians do not have a faucet in their homes. They are forced

to consume well water. Since the quality of well water leaves

much to be desired, one of the most common alternatives is to

buy it from a retailer or to try one of the public sources of water

(Mohamed Lemine, 2003).

The internal renewable water resource (IRWR) per capita

in Mauritania was 141.000 hm3 in 2001 (Water resource in

Mauritania, 2001). There are three forms of water use in

Mauritania: domestic, agriculture, and industry consumption,

which used 6%, 92% and 2%, respectively, in 1985. Agriculture

occupies 67% of the active population and contributes 1/3 of GIP


4. Water desalination technologies

There is no fresh water in the north of Mauritania. The use

of desalination might be necessary to provide their cities with

fresh water.

The first desalination technologies developed in the world were

thermal distillation, multi-stage flash (MSF), multi-effect distillation

(MED), and vapor compression (VC). In these processes, salt water is

distilled in steam and condensed as pure water. Subsequently, the

membrane processes such as electrodialysis (ED) and reverse osmosis

(RO) were developed (Martinez and Koo-Oshima, 2004).In Mauritania, two main sources are available for desalination:

the Atlantic Ocean and the brackish groundwater in some basins.

Desalination of sea and brackish water seems to offer a sound

alternative for arid lands bordering seas or salt lakes. The first

experience with seawater desalination in the country is the

Maurelec unit; installed in Nouakchott in 1968, it uses a MSF

process. This unit, with 3000 m3/day of capacity, has operated

since 1974. It was abandoned for technical reasons and cost

problems. The population of many villages, fisherman and women

that reside on the coast between Nouakchott and Nouadhibou

(Imraguens population) have benefited from hundreds of indivi-

dual distillation plants that produce a low amount of desalted

water. These distillation processes have been progressively left

due to persistence of serious technical and maintenance problems

Fig. 2. Normal direct irradiation for all regions of Mauritania.

A.A. Bayod Rujula, N.K. Dia / Energy Policy 38 (2010) 99115 101


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(Bakary, 2006). The reverse osmosis unit of the Mauritanian Society

of Industries and Mines (SNIM) installed in the city of Zouerat

desalts brackish water to produce 16m3/h for the diverse needs of

the Guelbs Society. The brackish water treated by active coal and

filtered by cartridges is pumped at high pressure to 66 modules of

reverse osmosis placed in 11 tubes. The modules are plastic

(cellulose acetate) organized to carry out a selective separation

under the influence of a driving force. These modules produce fresh

water and are maintained in good condition by an adapted

regulation. During the past few years, modules were deteriorated

resulting in an exaggerated consumption of these pieces and

elevated cost of fresh water (Mohamed Lemine, 2003). In January1996, the Canary government (Spain) donated to Mauritania

three seawater desalination plants (Argeuiba 12m3/day, Teichott

12m3/day, Iwik 2 m3/day) and one brackish water plant (Ten-Alloul

25 m3/day) with reverse osmosis technology. From July 2006 to July

2008, the desalination plants produced 1100 m3 of potable water.

These plants are powered by diesel and a hybrid system in the case

of Ten-Alloul village (Experiencia del ITC, 2008). This country has

not used MED, CV and ED technologies yet.

5. Scenarios

Mauritania is a very vast country with a surface area of

1,030,000 km2

(75% desert) and a population of 3,000,000

habitants. The population is very dispersed and has many zones

with very low population levels (north regions, northeast and

southeast regions). The climate is constantly hot, dry and dusty.

During the short rainy season (wintering), from June to October,

annual average precipitation varies from 500 to 600 mm in the far

south to 0100 mm in the northern 2/3rd of the country. In this

study we chose six scenarios (five cities and one village, Fig. 4). In

this figure, the green points represent the six scenarios studied

and the yellow points the capital of all regions of Mauritania.

Other cities and villages, like (Boutilimit, Oualata, Timbedra,

etc.) can be represented by one of these six scenarios; so all zones

in Mauritania are covered. The choice of particular scenarios isbased on a variety of factors, and their selection was conducted

according to existence of:

water (potable, brackish, sea, river)

isolation

other energy sources and desalination technologies

the size of the plant required.

5.1. Scenario I (SI): city of Nouakchott

The capital Nouakchott is located at the edge of the coast

between latitude 181 and 061 north and longitude 151 and 571

west. The city was created on a zone encampment occupied since

Fig. 3. Wind speed at 10 m for all regions of Mauritania.



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1957. The population is estimated to be 800,000 habitants, and the

annual water supply is 16,476,000 m3 (data published by the

National Society of the Water (SNDE), 2004). The reality is otherwise,

because the annual supply is twice as high as this volume. The law

on water resources of November 1989 determines the following

norms for consumptions estimation: 50 l/h/day for localities super-

ior to 5000 habitants, 40 l/h/day for localities situated between 2000

and 5000 habitants and 20 l/h/day for localities situated between

1502000 habitants (Mohamed Lemine, 2003).

5.2. Scenario II (SII): city of Nouadhibou

Nouadhibou is located in the northwest of the country, situated ona white course, between latitude 201 and 561 north and longitude 171

and 021 west. The population is estimated at 100,000 habitants and

the annual water supply is 2,952,000m3. Nouadhibou is the second

city in the country after the Nouakchott capital, as much for the

importance of its population as for its economic impact, characterized

essentially by iron mineral export and fishing industries.

5.3. Scenario III (SIII): the city of Bir Moghrein

Bir Moghrein is a city in the north of Mauritania, close to the

border with West Sahara, between latitude 251 and 231 north

and longitude 111 and 621 west. This is the most forgotten

region of Mauritania. The population was estimated to be 1411

habitants in 2001, but, at present, this population has augmented

(2%/year), due to development of electrical, water and

telecommunication infrastructures. In this region, all test

drilling executed on crystalline rocks found brackish water

at variable depths between 6 and 40m. (Mohamed Lemine,

2003).

5.4. Scenario IV (SIV): the city of Kaedi

The city of Kaedi is situated in the southwest, between latitude

161 and 151 north and longitude 131 and 501 west, and is located

approximately 435 km from Mauritanias capital. The population

is estimated at 60,000 habitants. It is the largest city and

administrative center of the Gorgol region of southern Mauritania.

The annual water supply is 372,000 m3.

5.5. Scenario V (SV): city of Nema

Nema is a town in southeastern Mauritania, close to the border

with Mali. It is situated between latitude 161 and 371 north and

longitude 71 and 151 west. The water consumption for the

domestic sector is 60,000m3/year in 2004, and the urban

population is approximately 60,000 habitants.

5.6. Scenario VI (SVI): the Nebaghuiya village

The Nebaghuiya village is located 120km southeast of

Nouakchott (between latitude 171 and 341 north and longitude

Fig. 4. Location of the six scenarios studied.



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151 and 021 west). The population was estimated at 3077

habitants in 2002 with a total water demand of 160 m3/day in

2004. The analyses realized in the laboratory of the National

Society Rural Development (SONADER) classify the perforations

and wells as brackish water. This village is located in a desert,

mountainous zone where the depth perforations reach 100m

(Informes Consumos Agua, 2005).

6. Planning process

The main objective of this section is to choose systems, based

on combinations of energy sources, desalination technologies and

water consumption, for different scenarios by applying five

criteria (potential, economic costs, O&M costs, environment, and

adequacy). Fig. 5 shows a synthesis of relationships in the

planning process. The problem was divided into different levels

to construct a hierarchical tree. The first level defines the goal to

be achieved, which is the selection of the most suitable system

(based on energy resources, desalination technologies and water

consumption). The second level describes six scenarios (five cities

and one village). The third level outlines the main technologies.

These include energy resources, desalination technologies and

modes of domestic (D), industrial (I) and agricultural (A) water

use. Finally, the fourth level determines the list criteria.

6.1. Determination of the criteria

The criteria represent the tools that enable alternatives from a

specific point of view. It must be remembered that the selection of

criteria is of prime importance in the resolution of a given

Fig. 5. Planning process to multi-criteria decision.



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problem, meaning that it is vital to identify a coherent family of

criteria. This section describes the five criteria selected:

a. Potential: determination of the energy and water potential.

b. Economic costs: determination of the cost/kWh and the

investment costs of these installations for each scenario,

considering construction and transport costs.

c. Operation and maintenance costs: the maintenance costs for

energy sources, desalination technologies installations.d. Environment: in this criterion, we calculate the amount of kg

CO2/year emitted by energy sources and evaluate other

impacts, such as the brine residues, acoustic contamination,

affects on marine ecosystems, corrosion of some materials, and

concentration and chemical discharges to the marine environ-

ment. These impacts are difficult to quantify.

e. Adequacy: this criterion determines the adaptation of energy

sources and the desalination technology with different char-

acteristics of scenarios (adequate, very adequate or little

adequate).

6.2. Stages of the planning process

There are two stages that determine all possible combinations

and assign different coefficients.

The primary stage consists of combining energy resources,

desalination technologies processes and the use of water, and the

second assigns numerical values depending on importance.

6.2.1. Combinations

This stage allows determination of possible combinations for

the water supply, from the different existing energy sources

associated with water desalination technology and with general

uses of water. Five options are considered for generation systems

1: system PV, 2: wind system, 3: diesel system, 4: hybrid system

and 5: CSP system. For each option, it is possible to assign fives

technology types: reverse osmosis (RO), electrodialysis (ED), MSF,

MED and VC.

Each generation system and each desalination technology used

assigns a mode of water use, domestic, industrial and agricultural.X={Xijk, i=1,y, 5, j =1,y,5 and k=1,y, 3}. The element {Xijk},

indicates a system of generation (i) associated with desalination

technology (j) and with a mode of water use (k).

6.2.2. Assigned coefficients

Numerical values are assigned to represent subjective judg-

ments of the relative importance of each part. The value of 0

denotes a null contribution (nonexistent potential energy source,

water or desalination technologies process) while 9 represents an

absolute importance (good potential of all resources, see Table 2).The values of the ranking system used are the following: {0, 1,

2, 3, 4,y,9}.

7. Identification of the most suitable systems

In order to select the most suitable system, appropriate

combinations of energy sources, desalination technologies, type

of water use, various constraints and requirements concerning site

characteristics, technology selection, and operational require-ments were considered.

7.1. Scenario I

The annual solar irradiations on horizontal surface and

direct normal irradiation are estimated to be 2020 and

2248kWh/m2 year, respectively (NASA, 2008). The potential for

wind production of the Mauritanian coast is higher, more than

2800 h/year (Etude strategique, 2004). The nonexistence of other

conventional sources (nuclear, natural gas, hydroelectric) and the

lack of utilization of renewable sources on a large scale obligate

the high use of diesel fuel, at the rate of 4500 h/year in the great

power stations in scenario I (Table 3). The hybrid systems

presented in this work evaluate only PVDiesel, which is asystem not utilized in large cities, except locations within 50 km

of the national electrical grid of Mauritanian Society of Electricity

(SOMELEC). We fixed their value at 3200 h/year.

The approximate cost of a solar kit is inferior to 0.50 h in rural

zones (Developpement Energies Renouvelables en Mauritanie,

2004). The investment costs are very variable and are between 12

and 15h/Wp for the neighboring country, Mali (Ricard Munoz

Martinez, 1998). The wind production cost is 0.06 h in Mauritania

for projects that surpass 10 MW, according to the results of

strategic study of wind energy in Africa (Etude strategique, 2004).

The costs of min-grid diesel (Table 3) is inferior to 0.25 h and

inferior to 0.10 h for national electrical grid (Developpement

Energies Renouvelables en Mauritanie, 2004). For hybrid systems,

the cost depends on the size of the installation. In this case (PVDiesel), we suppose that the economic cost for a hybrid system is

situated between a solar photovoltaic plant and a diesel plant

(0.25 hohybrid costo0.50 h). The Institute for Technical

Thermodynamics of German Aerospace Centre has estimated that

the concentrating solar thermal power (CSP) generation cost in

the North Africa and particularly in Mauritania is 0.120 h/kWh for

the great coastal cities Nouakchott and Nouadhibou (Fig. 6)

(Concentrating Solar Power, 2003).

Mauritania is situated in the desert (Sahara zone), where the

sky is constantly covered with dust. In general, the photovoltaic

maintenance for small units is very limited (cleaning frontal

face of modules, control, etc.), and this cost is established at

0.005 h/kWh (see Table 3). For wind generators (small powers

capacities), the maintenance cost is 0.02h/kWh and is used for

Table 2

Ranking system adopted.

Intensity of

importance

Definition

[89] Great potential (resource, desalination technologies,

water), low costs, null environmental impact

[57] Intermediate potential, low environmental impact

[15] Low potential, high costs, great environmental impact

[00.5] Option does not exist

Table 3

Potential, economic, O&M costs and quantity of CO2 emitted by energy sources for

scenario I.

Scenario I PV Wind Diesel Hybrid CSP

Potential 2020 2800 4500 ffi3200 2248

AC 4.0 5.6 9 6.4 4.5

Economic cost o0.5 0.06 o0.1 0.13 0.120

AC 5 8 7.5 3 6.5

O&M costs 0.005 0.02 40.02 0.005oHo0.02 0.053AC 9 7 5 ffi7 6

kg CO2 emitted/year 85.6 2394 44,775 8000 26.9

AC 8.7 8.1 1 7 9

Adequacy A VA VA LA VA

AC 4 7 9 5 9

AC: associated coefficients, A: adequate, VA: very adequate, LA: little adequate.



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greasing, changing blades, etc. Diesel generators require much

more maintenance (from changes of cartridges to oil and gas

replenishment) and recruitment personnel; the costs are thus

higher, estimated at 0.02h/kWh for Nouakchott (Kellogg and

Nehrir, 1996). The maintenance and operation costs for hybrid

systems depends on several factors such as percentage of

installation of plant photovoltaics and diesel system size, but we

suppose that this cost ranges between photovoltaic and diesel

costs. In the case of a CSP plant, this cost is estimated to be 3% ofthe investment cost. A 100 MW solar power plant with 9 hours of

storage means a present investment of 400 million h, 1000 jobs

during the construction and 100 jobs during the 25 years of

operation (Concentrating Solar Power, 2003). Using these data and

employing the annual direct normal irradiation, we found

maintenance and operation costs to be 0.053 h/kWh.

Generally, sources of renewable energy do not emit great

quantities of CO2 as conventional fossil fuels do. Nevertheless, in

the case of solar photovoltaics, CO2 is produced by silicon

technology applied to manufacture cells. Solar and wind power

are two purely renewable sources. We have considered particu-

larly the mass of CO2 emitted (Table 3), because it represents the

larger percentage of all emissions and is the main cause of the

greenhouse effect. The amounts emitted are 85.6 kg/year for PV,

2394kg/year for wind, 44,715 kg/year for diesel, 8000 kg/year for

hybrid and 26.9kg/year for CSP plants.Great thermal networks generally supply the city of Nouak-

chott. The water comes from 36 perforations of different

capacities in the Idini station, located 70 km from the capital.

The first perforations were installed in 1957 and produce a daily

volume from diesel generators that varies between 53,000 and

58,000m3 (Monographie Eau Potable Mauritanie, 2001). The

populations that do not have access to the conventional electrical

grid (peripheral zones, located up to 40 km from the capital) use

photovoltaic, wind and hybrid systems for their potable water

supplies. Table 3 presents the adequacy of the water use given the

energy sources.

By multiplying the coefficients of the five criteria for scenario I

and for each energy source, we obtain the following weights,

classified in Table 4.

Fig. 6. Generation thermal solar costs for all regions of Mauritania.

Table 4

Weights of energy sources for scenario I.

Energy sources (SI) PV Wind Diesel Hybrid CSP

Weights 6264 17,781 3037 4707 14,215



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Analyzing these results, we observe that the wind source has

the highest weight of 17,781, the CSP source occupied the second

position with a weight of 14,215, and, finally, the diesel had the

lowest weight at 3037 (Fig. 7). This city is provided with

electricity by diesel centrally installed in district peripherals

(Arafat) and the hydroelectric central installed in Mali. This low

weight for the diesel source is due to high costs (economic

and O&M) and to effects on the environment (high kg CO2 emitted

per year).The quality of the raw water and water produced by the

desalination process is fundamental at the time of choosing one

process. The distillation processes consume the same amount

energy independently of water raw salinity; therefore, they are

appropriate for seawater desalination. Pure water needs a specific

process such as ion exchange or post-treatment if the reverse

osmosis process is initially used (Antonio Valero et al., 2001).

Table 5 reviews the types of basic processes in terms of function

of water contributed and the coefficients assigned for each

technology. The cost is between 0.15 and 0.37 h/m3 of brackish

water desalted for reverse osmosis and between 0.16 and

0.30 h for electrodialysis desalination technology. This cost is

augmented for thermal technology due to use of seawater and is

located between 0.73 and 1.07 for MSF, 0.51 and 0.71 for MED

and 0.78 and 1.05 for VC in coastal cities ( Table 6, Antonio Valero

et al., 2001).

The small units need little maintenance, but the required plants

must have a considerable capacity (superior to 30,000m3/day);

therefore it requires at least a group of 20 persons for maintenance

and management. Considering all factors, the average costassociated with personnel and maintenance of a plant can be

estimated to be between 0.10 and 0.48 h/m3 (Antonio Valero et al.,

2001). The maintenance cost for membrane technology is

estimated between 0.06 and 0.13h/m3 (Table 6) and between

0.05 and 0.10 h/m3 for thermal desalination technology.

For environmental aspects, we evaluated the effects caused by

desalination technologies, such as brine residues (Table 6),

acoustic contamination, corrosion of some materials, and finally

the impact on marine ecosystems (Jorge Lechuga et al., 2006).

During the computations of total weights, we have considered

two important factors applied to scenario I: the proximity to the

sea and the desalination process applied as a function of the type

of water use (seawater or brackish water, mentioned in Table 5).

Scenario I is located on the Atlantic coast; we attribute to each

position a variable coefficient between 0 and 9, based on reference

to the sea and distance. In this case, we assign 9 to this scenario.

Finally, the product of the different coefficients of the criteria

allows one to obtain the following weights for each desalination

process, classified in Table 7.

The relative global weight generated for the five desalination

technologies shows the highest ranks of RO and MED, with

relative weights of 6075 and 5685, respectively (Fig. 8). However,

MSF and CV have much lower values of relative weights, 1894 and

1944, respectively.

Water demand is rapidly increasing due to increased develop-

ment and the high rate of population increase.

The mode of water distribution in city of Nouakchott is done in

many manners, including grid distribution, tankers, camions,

terminals, fountains and carters (the water is transported byasses) (Informes Consumos Agua, 2005). There are three modes of

water use:Domestic consumption: high consumption in all zones (more

than 30l/pers./day).Industrial consumption: 90% of the industrial sector is located in

two large cities (Nouakchott and Nouadhibou) and consumes 4%

Potential of energy resources for scenario I

0

2000

4000

6000

8000

10000

12000

14000

16000

18000

20000

PV

Energy resources

Weights

Wind Diesel Hybrid CSP

Fig. 7. Potential of energy resources for scenario I.

Table 5

Desalination process applied in function of the type of water use.

DT BW SW BWAC SWAC

RO YES NO 9 9

ED YES NO 9 0

MSF NO YES 0 9

MED NO YES 0 9

VC NO YES 0 9

BW: brackish water, SW: seawater, BWAC: brackish water associated coefficients,

SWAC: seawater associated coefficients.

Table 6

Economic, maintenance and environmental costs of desalination technologies for scenario I.

Technologies Costs Coefficients O&M Coefficients Environment Coefficients

RO 0.150.37 (a) 7 0.060.13 (b) 5 Fauna and flora 4

0.370.78 4 0.060.13 5 Fauna and flora 3.75

ED 0.160.30 (a0) 7 o(0.060.13) 6 Fauna and flora 4

MSF 0.731.07 1 0.050.10 7.8 Spill of the brine, marine ecosystem 3

MED 0.510.71 3 0.050.10 7.8 Spill of the brine, marine ecosystem 3

VC 0.781.05 1 o0.050.10 8 Spill of the brine, marine ecosystem 3

(a) and (a0) are brackish water costs.

(b) operation and maintenance costs for RO conventional system with production capacity between 1200 to 18,000 m3/day in Asian countries (Lemei and Van der Zaag,

2006).

Table 7

Weights of the seawater desalination technology for scenario I.

Desalination technologies (SI) RO ED MSF MED CV

Weights 6075 0 1894 5685 1944



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of the global consumption of the country (Informe Sectorial

Energas Renovables, 2004). Agriculture consumption: The cultivable superficial area is

120km2 for Nouakchott. These types of grounds are found in

the peripheral zones and are not used for large-scale agriculture,

due to a high salinity of the ground and the advanced of the desert

(Informes Consumos Agua, 2005), Nevertheless, this small

agriculture cover 1% of market demand, like vegetables, rice,

millet, etc. The water produced for a determined use can be high,medium or low, following the zones. The economic costs are

variable and depend on the source of production, the type of

water use, and the location of the zones. They are considered to be

0.8h/m3 for domestic use serving the great cities and less than

0.8h/m3 in isolated zones (Table 8). In the urban sector, the

maintenance costs vary between 0.14 and 0.27h/m3 (water

product for conventional grid, see Table 8).

Spills of water cause a greater preoccupation, because recovery

systems do not exist. In the urban sector, the greatest worries are

the rejection of contaminated waters by the industrial sector in

the great cities and the influence of the marine ecosystem in the

coastal regions. The following weights classified in Table 9 show

each mode of water use for scenario I. The relative global weight

generated for the mode of water use shows the highest ranks of

domestic water use, with a relative weight of 3645 (see Fig. 9). The

industrial sector has a lower value of relative weights of 882, and

much lower values for the agriculture sector, 432.

7.2. Scenario II

The annual solar and direct normal irradiations are estimated

at 2012 and 2777kWh/m2 year, respectively (NASA, 2008). In the

Mauritanian coast, the wind potential is abundant, particularly in

the city of Nouadhibou, at 3400 h/year (Etude strategique, 2004).

Average wind speed reaches a maximum of 9 m/s in May and June.

About 85% of the time, winds blow from northerly directions. The

major part of the city of Nouadhibou is electrified by central diesel

of 75 MW located in Zouerat (a city located 600 km away). This

caused the lower hours of fossil fuels production, 1700 h/year,

approximately (Cadre des Depenses, 2003). As in the anterior

paragraph, we fixed the hybrid systems value at 1700 h/year (see

Table 10).

The economic and maintenance costs of energy sources

are similar to Nouakchotts costs, except the maintenance cost

for CSP, estimated at 0.043 h/kWh. The amounts of CO2 emitted(see Table 10) are 85.3kg/year for a PV source, 2907kg/year for

wind, 12,935 kg/year for diesel, 425 kg/year for hybrid systems

and 33.3 kg/year for CSP.

The following data, classified in Table 11, show each weights

energy source for scenario II.

This situation is similar to scenario I, except that, in this case,

the relative global weights of wind and CSP systems have

increased and achieved values of 27,417 and 17,374, respectively

(Fig. 10). The diesel system has a medium weight, contrary to

scenario I. Scenarios II and I have practically similar characteristics,

as they are located near the sea and are developing the same

desalination process technologies. Therefore the two factors

(localization of the zone and the distance to sea) commented in

scenario I are also applied in scenario II.

The potable water supply of the city of Nouadhibou has

posed serious problems since its creation in 1905 due to urban,

demographic and economic development, as well as due to

the lack of superficial and underground resources. The exploited

water-bearing formation is located 50km from the coast


Seawater desalination technologies for scenarios I and II

0

1000

2000

3000

4000

5000

6000

7000

RO

Desalination technologies

Weights

MSF MED CV

Fig. 8. Relative global weights of the five desalination technologies for scenarios I

and II.

Table 8

Level of water consumption and costs for scenario1 (specific costs for conventional sources).

Uses Level of water

consumed

Coefficients Costs Coefficients O&M Coefficients Environment Coefficients

Domestic High 9 ffi0.8 9 0.140.27 9 Spills waste water 5

Industry High 9 o0.8 7 o(0.140.27) 7 Water contamination reject 2

Agriculture Very low 4 o0.8 6 o(0.140.27) 6 The lands Contamination 3

Mode of water use for scenario I

0

500

1000

1500

2000

2500

3000

3500

4000

Domestic

The water use

Weights

Industries Agrculture

Fig. 9. Relative global weights of the three modes of water use for scenario I.

Table 9

Weights to mode of water use for scenario I.

Mode of water use (SI) Domestic Industry Agriculture

Weights 3645 882 432



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The unique difference between scenarios II and I concerning the

mode of water use is the low water consumption of the agriculture

sector (with a cultivated surface of 17,800 km2 for all region of

Nouadhibou, Informes Consumos Agua, 2005). The product of the

different coefficients of scenario II for agriculture consumption is

540, contrary to scenario I, which was evaluated at 432.

7.3. Scenario III

The annual solar global irradiation in the horizontal surface

and the direct normal irradiation are 2059 and 2359 kWh/m2 year,respectively (Table 12 and Fig. 1, NASA, 2008). Scenario III is not a

wind region; the wind speed is low, inferior to 5.9 m/s,

approximately 1700 h/year of wind production (study realized

by MC2-Eole to a resolution of 50 km) (Etude strategique, 2004).

The inaccessibility to the national electrical grid, the isolation of

the zone, and the non-utilization of renewable sources obligate

high use of diesel generation approximately 3000 h/year

(interpolated from the diesel stations in Mauritania, for example

2920 h/year for Matamoulane village located 60 km from the

capital with 27 kW power). The PV/diesel hybrid system operated

for 2100 h/year.

The transport costs of photovoltaic panels, wind generators,

diesel generators and their components to the zone are very

expensive and drive economic costs too high proportionate to the

size of the installation. In this zone, photovoltaic plants are small,

and the cost is superior to 0.50 h/kWh. The wind production cost

is superior to 0.06h/kWh, and the hybrid system cost, as

mentioned above, is located by hypothesis between photovoltaic

and diesel costs. The transport of combustible cost from

Nouadhibou or Zouerat until Bir Moghrein city is very expensive

due to distance and the complex topography; therefore, the mini-

grid diesel cost is superior to 0.25h/kWh (Developpement

Energies Renouvelables en Mauritanie, 2004) (Table 12). The

concentrating solar thermal power (CSP) generation cost is

0.135 h/kWh for Bir Moghrein city (Concentrating Solar Power,

2003).

The operation and maintenance cost is superior to

0.5Ctsh/kWh for photovoltaic installations with 3.8 kWp power

(Kellogg and Nehrir, 1996) (Table 12). For small wind turbines

(120 kW), with an investment cost of 1700h/kW, the main-

tenance cost is 2 Cts h/kWh. Generally, in rural areas, maintenance

technicians are not found. A problem (damages, technical

problems, etc.), usually requires moving maintenance equipment

from great capitals. These reasons influence much of the

maintenance and operation costs, which are elevated in rural

areas and in isolated cities like Bir Moghrein. The maintenancecost for the CSP system is estimated to be 0.002h/kWh

(calculation effectuated by 100 MW power plant and with an

investment cost of 400 million h).

The amounts of CO2 emitted are 87.3 kg/year for a PV source,

1368 kg/year for the wind system, 27,860kg/year for the diesel

system, 5250 kg/year for the hybrid system and 28.3 kg/year for

CSP (see Table 12).

The diesel system augmented the reverse osmosis utility with

5 m3/h of capacity (Bakary, 2008). The photovoltaic and the wind

energy are widely used for electrification and water pumping. In

this city, the concentrating solar thermal power (CSP) for water

desalination is not adequate, because the water and electric

demand are very low and this city is very far away from the sea

(more than 1000 km), but the possibility of evacuating energyby line transport to the city of Zouerat and Morocco exists.

The hybrid systems, with their different combinations (PVWind,

PVDiesel, etc.) are adequate in this region (Table 12).

The following data classified in Table 13, show weights of each

energy source for scenario III. The relative global weight generated

by a PV source presents the highest value compared to other

sources, with a relative weight of 6741 (see Fig. 11). The hybrid

(PVDiesel) occupied the second position with a relative weight

of 2293. CSP and wind sources have practically the same values

and a much lower value for diesel source with a relative weight

of 1008.

In 2000, the water supply to Bir Moghrein took place by

tankers from a controlled pumping station, located 70 km away.

Actually, this situation has changed. The government, with

Table 11

Weights of energy sources for scenario II.

Eenergy sources (SII) PV Wind Diesel Hybrid CSP

Weights 6264 27,417 5265 2826 17,734

Potential of energy resources for scenario II

0

5000

10000

15000

20000

25000

30000

PV

Energy resources

Weights


Fig. 10. Potential of energy sources for scenario II.

Table 12


scenario III.

Scenario III PV Wind Diesel Hybrid CSP

Potential 2059 o1700 o3000 ffi2100 2359

AC 4.1 3 5.6 4.2 4.7

Economic cost 0.50 40.06 40.25 0.40 0.135

AC 3 7 3 2 5.5

O&M costs b0.005 b0.02 d0.02 0.002AC 7 5 4 ffi5 3

kgCO2 emitted/year 87.3 1368 27,860 5250 28.3

AC 8.7 8.4 3 7.8 9

Adequacy A VA VA LA VA

AC 9 2 5 7 1

Table 10

Potential and quantity of CO2 emitted by energy sources for scenario II.

Scenario II PV Wind Diesel Hybrid CSP

Potential 2012 3400 1300 ffi1700 2777

AC 4.0 6.8 2.6 3.4 5.5

kg CO2 emitted/year 85.6 2394 44,775 8000 26.9

AC 8.7 8.1 1 7 9



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support from a German company (KARCHER), has installed for the

account of Agency of Universal Access to the Controlled Services

(APAUS) a desalination unity with 40 T/day of capacity in the city

of Bir Moghrein in 2005 (reverse osmosis technology with diesel

source, 5 m3/h of capacity (Bakary, 2008). Scenario III is located

more than 1000 km from the sea, and the water is brackish.

Therefore no option exists for thermal desalination technology

(MSF, MED, VC). The costs for RO and ED are similar to those of

scenario I, but with a slight superiority due to isolation and thedisplacement of maintenance personal. The environmental impact

is very limited (Table 14).

Table 15, show weights of each type of desalination process for

scenario III.

For this scenario, we have not studied options for desalination

of seawater because the transportation of water to those areas is

difficult and costly due to distance of the sea (more than

1000 km), low demand and isolation. The weights obtained for

brackish water desalination show that the RO and ED have the

highest rank and are uniquely adequate systems for rural areas

and small city or villages (see Fig. 12).

The mode of water use is identical for all scenarios: domestic,

industrial (industrial sectors do not exist for this scenario) and

agriculture consumption (low for small kitchen gardens supplied

by irrigation and rainwater). In isolated locations, small-scale

agriculture for small kitchen gardens designed by feminine

cooperatives or individuals exists.

For this scenario, we do not have contamination by the industrial

sector, (contrary to scenario I), to include in the costs, (Table 16).

Table 17, show weights of water use for scenario III.

The relative global weight generated for the mode of water use

shows the highest ranks of domestic water use, with relative

weights of 2646 (see Fig. 13), the industry has a null value and

lower values for agriculture, 150.

7.4. Scenario IV

The city is located within the Chemama Riverine zone along the

north bank of the River Senegal where the river connects with the

Gorgol River. This region is one of the few areas of settled

agriculture in the country. Kaedis economy is based on agriculture,

being one of few zones in the country with large arable areas. The

potential agricultural area for the Gorgol region is estimated at

88,300 ha, with a cultivated surface of 53,030ha. The main cultures

are rice and millet. The water consumption for the domestic sector

is 372,000 m3/year in 2004. This city does not have problems of

water consumption, but the rate of electrification is very low.

7.5. Scenario V

The city of Nema is located in the water-bearing region of

Taoudeni, with a surface of 1600 km2 and 100m of depth in one

Potential of energy resources for scenario III

0

1000

2000

3000

4000

5000

6000

7000

8000

PV

Energy resources

Weights


Fig. 11. Potential of energy resources for scenario III.

Table 14

Economic, maintenance and environmental costs of desalination technologies for scenario III.

Technologies Costs Coefficients O&M Coefficients Environment Coefficients

RO 0.150.37 (a) 7 b(0.060.13) 3 Fauna and flora 6

4(0.370.78) 4 2 6

ED (0.160.30) (a0) 6.5 0.060.13 5 Fauna and flora 4

Table 15

Weights of brackish water desalination technology for scenario III.

Desalination technologies SIII RO ED MSF MED CV

Weights 1134 1752 0 0 0

Table 13

Weights of energy sources for scenario III.

Energy sources (SIII) PV Wind Diesel Hybrid CSP

Weights 6741 882 1008 2293 768

Brackish water desalination technologies for scenarios 3 and 6

0

100

200

300

400

500

600

700

800

900

1000

1100

1200

1300

1400

15001600

EDRO

Desalination technologies

Weights

Fig. 12. Relative global weights of two desalination technology for scenarios III

and VI.



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ARTICLE IN PRESS

layer (Mohamed Lemine, 2003). There is one deeper layer towards

the east and Mal. There are formations that present two different

levels:

The old formation that appears in Mauritania reaches widely,

the Adrar, Tagant, Assaba, Hodh el Chargui, and Hodh el Gharbi

regions. The conditions are favorable for the presence of water.

Recent formations that corresponded to the terminal con-

tinental stoneware, exploited solely in the southeastern region

of the country (Dhar de Nema).

When rains supply these reserves abundantly, they produce

water of high quality, but, in this zone, other perforations existwith low volume and with high salinity (salinity superior to

established potability norms).

Scenarios IV and V have been included in this study to

represent many points of the country, but, in reality, they do not

have a water problem. In these scenarios the electrical infra-

structures are very low and the solar irradiation is high.

7.6. Scenario VI

The annual solar irradiation in the horizontal surface and the

direct normal irradiation are 2050 and 2200 kWh/m2 year,

respectively (NASA, 2008). As in the preceding scenario (III),

scenario VI is not a wind region. The inaccessibility to the national

electrical grid and low reliability of some renewable sources bring

about the high use of diesel fuel. The village had five salty

perforations, but only two of them are in use today, and use diesel

generators: a Perkins model P40 with 38 kW, functioning 10 h/day

(3600 h/year, see Table 18), and a second of 13kW power that

serves as support.

The Nebaghuiya village is located 120 km from the capital;therefore, the transport costs do not strongly affect economic

costs. The solar thermal electricity generation cost is 0.125 h/kWh

for Nebaghuiya village (Concentrating Solar Power, 2003), and the

rest is similar to scenario III (see Table 18).

The diesel source needs much maintenance (change of oil and

gasoil cartridges for each 200 h of operation with 8 l of new oil)

and recruitment of two personnel whose monthly salaries are

estimated to 60 and 90 h. The maintenance and operation costs

for the diesel source are elevated (superior to 0.02h/kWh, see

Table 18) and 0.0545h/kWh for the CSP system (calculation

effectuated by 100 MW power plant with investment cost of

400 million h).

The amounts of CO2 emitted are 89 kg/year for PV source,

1453 kg/year for the wind source, 35,820 kg/year for the dieselsystem, 6250 kg/year for the hybrid system and 26.4 kg/year for

CSP (see Table 18).

The following data classified in Table 19 show weights of each

energy source for scenario VI. The relative global weights

generated by energy sources are presented in Fig. 14. For more

detail, see the analysis effectuated in scenario I.

The water desalination technologies for this scenario are similar

to scenario III because the possibility for thermal desalination

technology as MED, MSF, CV does not exist. Therefore the costs are

practically similar, but with a slight inferiority to scenario III due to

the proximity of the capital (diminution of transport costs,

construction costs, maintenance costs, etc.). The weights obtained

for brackish water desalination show that the RO and ED have the

highest rank (1512 and 1755, respectively, see Table 20).

Table 16

Level of water consumption and costs for scenario III (specific costs for conventional source).

Uses Level of water

consumed

Coefficients Costs Coefficients O&M Coefficients Environment Coefficients

Domestic High 9 40.8 7 (0.140.27) 7 Spills waste water 6

Industry High 0.5 0.5 0.5 1

Agriculture Low 1.5 o0.8 5 o(0.140.27) 5 Less land Contamination 4

*No exist industry.

Table 17

Weights to mode of water use for scenario III.

Mode of water use SIII Domestic Industry Agriculture

Weights 2646 0 150

Mode of water use for scenario III

0

500

1000

1500

2000

2500

3000

Water use

Weights

Domestic Agriculture

Fig. 13. Relative global weights of the three modes of water use for scenario III.

Table 18


scenario VI.

Scenario VI PV Wind Diesel Hybrid CSP

Potential 2100 1700 3600 ffi2500 2200

AC 4.2 3.4 7.2 5.0 4.4

Economic cost 0.50 40.06 o0.25 o0.35 0.125

AC 4 7.5 5 2.5 6

O&M costs d0.005 b0.02 d0.02 b0.02

AC 7.5 6.5 4.5 ffi5.5 4

kgCO2 emitted/year 89 1453 35,820 6250 26.4

AC 8.7 8.4 2 7.6 9

Table 19

Weights of energy sources for scenario VI.

Energy sources SVI PV Wind Diesel Hybrid CSP

Weights 9865 1392 2268 3657 1900



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ARTICLE IN PRESS

The mode of water use is identical to scenario III except the

agricultural use.

8. Results and discussion

The results are obtained by the product of total coefficients

associated with sources, by total coefficients associated with

desalination technologies, and by total coefficients associatedwith consumption of the water. During computations we have

considered a special criterion: the possible coupling of

energy sources with desalination process, applied to all scenarios

(Table 21). These coefficients vary between 0 and 9 and depend on

their importance and intensity.

Therefore, with the data used in the calculation procedure, we

obtain relative global weights classified in two Table 22(a and b),

which represent the use of seawater and brackish water,

respectively. The results of these combinations show a great

domination of pairs (WindROD), (CSPROD) and (CSPMED

D) for scenarios I and II (Fig. 15). Therefore, the most suitable

system is the wind powered by reverse osmosis for domestic use

(WindROD) with relative weights of 3.541012 and 5.461012

for scenarios I and II, respectively. The difference in weights is dueto the high wind potential of scenario II; indeed, if we observe the

diagram of energy sources for all scenarios (Fig. 16), we note that

wind energy has the highest ranks for scenarios I and II, with

relative weights of 17,781 and 27,417, respectively. Therefore we

conclude that the wind potential constitutes an important source

for these two scenarios and that the second option is the CSP.

Analyzing the results of the most suitable systems, it was found

that RO desalination technology appears to be the most applied

process. This analysis confirms the results illustrated in Fig. 17,

with relative weights of 6075 for RO and a slight superiority to

MED process with weights of 5685. This analysis is valid for

scenarios I and II because they present the same values. The

particular analysis of scenario I (Fig. 15) shows four dominant

pairs: (WindROD), (CSPROD), (CSPMEDD) and (PVROD).

We observed the presence of the wind source in the first plane; in

this scenario, the wind potential is high and achieved relative

weights of 17,781. CSP also is a good option, with relative weights

Potential of energy resources for scenario VI

0

2000

4000

6000

8000

10000

12000

PV

Energy resources

W

eights


Fig. 14. Potential of energy resources for scenario VI.

Table 20

Weights of brackish water desalination technology for scenario VI.

Desalination technologies SVI RO ED MSF MED CV

Weights 1512 1755 0 0 0

Table 22

(a) Weights of systems for scenarios I and II.

Systems/weights Scenario I Scenario II

PV+ RO+ D 1,24835E+ 12 1.24835E+12

PV+ RO+ I 3.02071E+ 11 3.02071E+11

PV+ RO+ A 1.47953E+ 11 1.84941E+11

PV+ VC+ D 3.10702E+ 11 3.10702E+11

PV+ VC+ I 75,182,131,584 75,182,131,584

PV+ VC+ A 36,823,901,184 46,029,876,480

Wind+RO+ D 3.54358E+ 12 5.46394E+12

Wind+RO+ I 8.57459E+ 11 1.32214E+12

Wind+RO+ A 4.1998E+ 11 8.09473E+11

Diesel +RO+ D 6.05245E+ 11 1.04926E+12

Diesel +RO+ I 1.46454E+ 11 2.53896E+11

Diesel +RO+ A 71732725200 1.55446E+11

Diesel+VC+D 1.50639E+ 11 2.6115E+11

Diesel +VC +I 36,450,851,472 63,191,877,840

Diesel +VC +A 17,853,478,272 38,688,904,800

Hybrid+RO+ D 9.3806E+ 11 5.63195E+11

Hybrid+RO+ I 2.26987E+ 11 1.36279E+11

Hybrid +RO+ A 1.11177E+ 11 83,436,237,000

Hybrid+VC+ D 2.33473E+ 11 1.40173E+11

Hybrid +VC+ I 56,494,618,992 33,918,375,456

Hybrid +VC+ A 27,670,833,792 20,766,352,320

CSP+ RO+ D 2.83291E+ 12 3.46247E+12

CSP+ RO+ I 6.85495E+ 11 8.37832E+11

CSP+ RO+ A 3.35753E+ 11 5.12959E+11

CSP+MED+ D 2.65105E+ 12 3.24019E+12CSP+MED+ I 6.41488E+ 11 7.84046E+11

CSP+MED+ A 3.14198E+ 11 4.80028E+11

CSP+MSF+ D 8.83216E+ 11 1.07949E+12

CSP+MSF+ I 2.13716E+ 11 2.61211E+11

CSP+MSF+ A 1.04677E+ 11 1.59925E+11

Wind+VC+D 8.81958E+ 11 1.35992E+12

Wind+VC+I 2.13412E+ 11 3.29066E +11

Wind+VC+A 1.04528E+ 11 2.01469E +11

(b) Weights of systems for scenarios III and VI

Systems/weights Scenario III Scenario VI

PV+ RO+ D 0.2022E+ 11 0.4529E+11

PV+ RO+ A 0.0114E+ 11 0.0295E+11

PV+ ED+D 0.3130E+ 11 0.5662E+11

PV+ ED+A 0.0177E+ 11 0.0369E+11

Wind+RO+ D 0.0264E+ 11 0.0639E+11

Wind+RO+ A 0.0015E + 11 0.0041E+11

Wind+ED+ D 0.0409E + 11 0.0798E+11

Wind+ED+ A 0.0023E + 11 0.0052E+11

Diesel+ RO+D 0.0302E + 11 0.1041E+11

Diesel+ RO+A 0.0017E + 11 0.0067E+11

Diesel+ ED+ D 0.0468E+ 11 0.1301E+11

Diesel+ ED+ A 0.0468E+ 11 0.0084E+11

Hybrid+ RO+D 0.0688E+ 11 0.1679E+11

Hybrid+ RO+A 0.0039E + 11 0.0109E+11

Hybrid+ ED+D 0.1064E+ 11 0.2099E+11

Hybrid+ ED+A 0.0060E+ 11 0.0136E+11

Table 21

Possible options for coupled energy sources and desalination process (G. Fiorenza

et al, 2003).

Energy sources/

desalination

technologies

RO ED MSF MED CV

PV 9 9 0 0 7

Wind 9 8 0 0 7

Diesel 9 8 0 0 7Hybrid 9 9 0 0 7

CSP 9 0 9 9 9



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of 14,215. For water desalination, RO is the most dominant

desalination process. However, the pairs (HybridVCA) and(dieselVCA) have low likelihood of viability due to low

potential diesel and low water consumption in the agriculture

sector. Finally, it has been demonstrated that, in finding the most

suitable systems for all scenarios, it is always important to

consider water use in the domestic sector. As in the preceding

analysis, the most suitable system for scenario II is reverse

osmosis powered by wind energy (WindROD). Wind energy and

CSP have been dominant generation sources, with relative weights

of 27,417 and 17,374, respectively. However, other important

combinations exist: (CSPROD), (CSPMEDD) and (WindVC

D). Scenarios III and VI are situated more than 1000 and 120 km

from the sea, respectively. Therefore, the possibility of using

seawater does not exist. In these scenarios, the studies have

shown that the water is brackish and the average value of

conductivity of the feed water is around 2200mS/cm. The most

suitable systems are pairs (PVEDD), (PVROD) and (HybridEDD) for scenario III and VI (Fig. 18). The results show that (PV

EDD) has the highest ranks, with a relative weight of 0.561011

for scenario VI, almost double the weights of scenario III. We

deduce that the RO and ED desalination processes offer a viable

option for desalination of brackish water for these scenarios and

that the PV appears as the dominant source.

9. Conclusions

The main goal of this paper was to select the most suitable

system for desalination technologies powered by energy

sources for different scenarios. Evaluations of each scenario were

carried out taking into account several criteria and reaching

Seawater desalination systems for scenarios I and II

0

1E+12

2E+12

3E+12

4E+12

5E+12

6E+12

Scenario I

Scenarios

Weights

PV+RO+D

PV+RO+I

PV+RO+A

PV+VC+D

PV+VC+I

PV+VC+A

Wind+RO+D

Wind+RO+I

Wind+RO+A

Diesel+RO+D

Diesel+RO+I

Diesel+RO+A

Diesel+VC+D

Diesel+VC+I

Diesel+VC+A

Hybrid+RO+D

Hybrid+RO+I

Hybrid+RO+A

Hybrid+VC+D

Hybrid+VC+I

Hybrid+VC+A

CSP+ RO +D

CSP+ RO+I

CSP+ RO+A

CSP+ MED+D

CSP+ MED+I

CSP+ MED+A

CSP+MSF+D

CSP+MSF+I

CSP+MSF+A

Wind+VC+D

Wind+VC+I

Wind+VC+AScenario II

Fig. 15. Seawater desalination systems for scenarios I and II.



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different solutions or alternatives (energy sources+desalinationand technology+mode of water use). This study can conclude

that:

Wind and CSP are the best strategies for scenarios I and II

(coastal cities) and PV is the more important source in other

scenarios (isolated regions).

RO for the desalination of brackish water and seawater is

becoming more important for all scenarios.

RO and the ED desalination process powered by PV are

appropriate solutions for scenarios III and VI (all scenarios

with low demand and with brackish water).

RO powered by wind or CSP is the most suitable system for

great cities located on the coast (scenarios I and II).

References

Antonio Valero, Javier Uche, Luis Serra, 2001. La Desalacion como Alternativa alPHN, realizado por el Centro de Investigacion de Recursos y ConsumosEnergeticos (CIRCE). Universidad de Zaragoza para el Gobierno de Aragon,Spain.

Bakary Mohamed Semega, 2008. Energie eolienne et dessalement dans le contextemauritanien, des modeles de developpement pour le sud. Energie Francopho-nie N179-2ieme trimestre.

Bakary Mohamed Semega, 2006. Le dessalement de leau de mer une alternativepour la desserte du littoral Mauritanien. Universite de Nouakchott, Mauritanie.

Cadre des D epenses en moyenne terme du Secteur de lEnergie en Mauritanie,2003.

Concentrating Solar Power, 2003. A Vision for Sustainable Electricity Generation.Developpement des Energies Renouvelables en Mauritanie, 2004. RevueRenouvelle N16-7.

Essam, Mohamed, Papadakis, G., 2008. A direct coupled photovoltaic seawaterreverse osmosis desalination system toward battery based systemsatechnical and economical experimental comparative study, University ofAthenes, Greece. Desalination 221, 1722.

Etude Strategique de Deploiement de lEnergie Eolienne en Afrique, 2004. Presentepar la Banque Africaine de D eveloppement.

Experiencia del ITC en Proyectos de Cooperacion Internacional, 2008. Suministrode Agua Potable mediante desalacion en Africa, exposicion internacional, Aguay Desarrollo Sostenible.

Fiorenza, G., Sharma, V.K., Braccio, G., 2003. Techno-economic evaluation of a solarpowered water desalination plant, ENEA Centro Ricerche Trisaia, Italy. EnergyConversion and Management 44, 22172240.

Informe Sectorial de las Energas Renovables en Mauritania, Marzo, 2004.Informes sobre Consumos de Agua en Mauritania, 2005.

Jorge Lechuga, A., Marisela Rodrguez, y., Joaqun Lloveras, M., 2006. An alisis de losprocesos para desalinizacion de agua de mar aplicando la inteligencia

competitiva y tecnologica.

Energy resources for four scenarios of Mauritania

0

5

10

15

20

25

30

Scenario I

Scenarios

Weights(10^3)

PV Wind Diesel Hybrid CSP

Scenario II Scenario III Scenario VI

Fig. 16. Energy resources for scenarios I, II, III and VI.

Seawater desalination technologies for scenarios I and II

0

1

2

3

4

5

6

7

Scenario1Scenarios

Weights(10^3)

RO

ED

MSF

MED

VC

Scenario2

Fig. 17. Seawater desalination technologies for scenarios I and II.

Brackish water desalination systems for scenarios III and VI

0

0.1

0.2

0.3

0.4

0.5

0.6

Scenario III

Scenarios

Weights(10^11)

PV+RO+D

PV+RO+A

PV+ED+D

PV+ED+A

Wind+RO+D

Wind+RO+A

Wind+ED+DWind+ED+A

Diesel+RO+D

Diesel+RO+A

Diesel+ED+D

Diesel+ED+A

Hybrid+RO+D

Hybrid+RO+A

Hybrid+ED+DHybrid+ED+A

Scenario VI

Fig. 18. Brackish water desalination systems for scenarios III and VI.



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ARTICLE IN PRESS

Kalogirou, 2001. Effect of fuel cost on the price of desalination water: a case forrenewable, Higher Technical Institute, Cyprus. Desalination 138, 137144.

Kellogg, W., Nehrir, M.H., 1996. Optimal unit sizing for a hybrid wind/photovoltaicgenerating system, department of electrical engineering, Montana StateUniversity, USA. Electric Power Systems Research 39, 3538.

Lemei, A., Van der Zaag, P., 2006. Basic cost equation to estimate unit productioncosts for RO desalination and long-distance piping to supply water to tourism-dominated arid coastal regions of Egypt. Desalination 225, 112.

Martinez Beltan, J., Koo-Oshima, S., 2004. Water desalination for agriculturalapplications. Proceedings of the FAO Expert Consultation on Water Desalina-tion for Agricultural Applications (pp. 2627), 2627 Rome.

Ministere de lHydraulique et de lEnergie de Mauritanie, 2001, Monographie EauPotable.

Mohamed Lemine Ould Fagel, 2003. Tesis, Utilizacion de la Energa Eolica paraDesalacion de Agua en el Norte de Mauritania. Aplicacion a la Wilaya deDakhlet Nouadhibou, Universidad de Las Palmas de Gran Canarias, Spain.

NASA, 2008. /http://eosweb.larc.nasa.gov/SSES.Ricard Munoz Martinez, 1998. Abastecimiento electrico del centro socioeducativo

de jovenes de Niamana, Mal.Societe Nationale des Eaux de Mauritanie (SNDE), 2004. Approvisionnement en

Eau des principales villes de Mauritanie.Water resource in Mauritania, FAO, 2001.

http://eosweb.larc.nasa.gov/SSEhttp://eosweb.larc.nasa.gov/SSE

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