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Micro-grids project, Part 1: Analysis of rural electrification with high content of renewable energy sources in Senegal
Renewable Energy 34 (2009) 2141–2150
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Micro-grids project, Part 1: Analysis of rural electrification with high content of renewable energy sources in Senegal H. Camblong a, f, *, J. Sarr b, A.T. Niang c,1, O. Curea a, J.A. Alzola d, E.H. Sylla e, M. Santos d a
ˆ le Izarbel, 64210 Bidart, France ESTIA Recherche, Technopo GRTT-LASES, Faculte´ des Sciences de l’Universite´ Cheitk Anta DIOP de Dakar(UCAD), 5005 Dakar-Fann, Senegal c CERER, Center of Studies and Research on Renewable Energies, Hann-Equipe, 476 Daka RPr, Senegal d ´gico, Edificio 202, 48170 Zamudio, Spain Robotiker, Parque Tecnolo e LER, Ecole Supe´rieure Polytechnique, 5085 Dakar Fann/ESP/UCAD, Senegal f Electrical Engineering Department, University of the Basque Country (E.U.P.-D), Europa Plaza 1, 20018 Donostia, San Sebastian, Spain b
a r t i c l e i n f o
a b s t r a c t
Article history: Received 10 December 2007 Accepted 27 January 2009 Available online 28 February 2009
Africa is the poorest continent in the world and this poverty is linked to the lack of access to energy of its population. A big part of inhabitants live in rural zones where the lack of energy and in particular of electricity is still more flagrant. The aim of the Micro-grids project was to promote the electrification of rural regions of Senegal by the installation of micro-grids with high content of renewable energies. This paper presents some results of this project. Surveys have been carried out in three regions of Senegal to study the needs of electrical energy of non-electrified rural villages’ households. These surveys have led to the estimation of electricity needs of the concerned households. The potential in renewable energies of the three regions has also been examined. It has been concluded that the solar energy potential is excellent while the wind energy potential can be interesting in some specific sites. The biomass could also be an efficient source if livestock farming was properly managed in the future. Moreover, many events have been carried out in the three regions to analyse the obstacles for the development of micro-grids in the Senegalese energy context, and to establish suitable solutions to overcome these obstacles. The results presented in this paper have been used to design a rural electrification kit which is described in another paper. Now the Micro-grids’ consortium hopes to set up a new project to apply the designed kit on some rural non-electrified villages. Ó 2009 Elsevier Ltd. All rights reserved.
Keywords: Rural electrification in Senegal Micro-grids Solar PV energy Potential of renewable energies Electricity needs estimation
1. Introduction Africa is the poorest continent in the world. This poverty is linked to the lack of access to energy of African population. Africans consume a mere 0.3–0.6 tonne oil equivalent per capita. By contrast North Americans consume 7.5–9 tonne oil equivalent per capita or between 12 and 30 times more energy on average [1,2]. In brief, nowhere is the per capita level of energy consumption lower than that in Sub-Saharan Africa. It is a clear indicator of how far of wellbeing and comfort parameters they are. The poverty and the lack of access to energy, especially to electrical energy, are still more significant in the rural regions. 70% of the population in sub-Saharan Africa live in rural areas and less than 10% of these have access to reliable sources of electricity. The main advantages of rural electrification are
* Corresponding author. Tel: þ33 5 59438549; fax: þ33 5 59438401. E-mail address: [email protected] (H. Camblong). 1 Tel.: þ221 832 10 53; e-fax: þ33 825 74 86 75. 0960-1481/$ – see front matter Ó 2009 Elsevier Ltd. All rights reserved. doi:10.1016/j.renene.2009.01.015
A better quality of electric light for educational home work, because a good electrical light is a support for education. A better quality of electric light for nocturnal interventions in health institutions. Better working conditions for economic or domestic activities. The access to mass media. A better security (against thefts of livestock, distance of the wild animals). The improvement of the image of villages by the level of electrical equipment. The rural migration reduction by creating activities which generate jobs and sources of revenue. The possibility of improvement of basic services thanks to the local tax revenues generated by the development of economic activities. Environment preservation and protection through the use of renewable energy sources. Rural areas are often far from the national electrical grid, making the connection of remote rural communities to the existing grid too
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costly. In these cases, alternative isolated systems can be used to electrify the community, and consequently to support their socioeconomic development [3]. Local renewable sources, such as solar energy, wind energy or biomass, are often available. In particular, much of Africa is well exposed to sunlight, and solar energy can be used to obtain electricity using PV panels. The use of PV generators could be a vehicle for the development of rural isolated communities [4–6]. Moreover, using renewable energies will prepare the African countries for an energy-efficient and low-pollutant future, which is not only required by International Environmental Conventions, but also essential to any possibility of genuine economic development in a sustainable fashion. Similarly, in Senegal, micro-grids seem to be a good solution for the electrification of rural areas. Even if there is not an official definition, a micro-grid can be defined as a small scale electrical grid where the sources of electricity are placed close to the loads. Moreover, these sources are normally composed by renewable energy systems, such as PV panels, a standard support generator, such as diesel generators, and an energy storage system, such as batteries. These components are well adapted to the socioeconomic reality of Senegal. Although Senegal does not produce oil, 60% of its primary energy comes from oil products. Their growing prices threaten the import–export balance, so their consumption should be limited by the use of renewable energies. The renewable energy potential is significant and varied in Senegal, with 3000 h of sunlight a year, good wind in some sites and important vegetable reserves in Casamance and in the oriental Senegal. Moreover, micro-grids containing renewable energies are suited to the rural context of Senegal. Many villages present a grouped layout, the energy needs are low and the rural households’ incomes are relatively limited. PV installations are well known in the rural electrification field in Senegal. Actually, Senegal has launched for the last 40 years a vast program of experiments and tests of solar energy materials in particular. Senegalese Agency for Rural Electrification (ASER), which has specialized in the diffusion of the photovoltaic solar systems through the country was thus created. However, micro-grids or similar systems have still not been installed on a large scale in Senegal, and the most important rural zones have still no access to electricity. This is why Micro-grids project was carried out, to analyse how micro-grids with high content of renewable energies must be promoted to electrify rural zones of Senegal on a large scale. Section 2 of this paper presents Micro-grids project. Section 3 is dedicated to the description of the methodology used to carry out some surveys for the study of the electricity needs of rural populations. Section 4 gives the results of this survey and an estimation of electrical energy needs in rural regions is made in Section 5. Then, the potential of renewable energies in Senegal is analysed (Section 6) before studying the constraints and solutions for the development of micro-grids in Section 7, and concluding the paper in Section 8. 2. Micro-grids project presentation Micro-grids project has been carried out in the frame of a Coopener project of the Intelligent Energy Europe (IEE) program of Energy and Transport European Commission. IEE is the European Community support program to increase renewable energy sources and energy efficiency by overcoming the non-technological barriers (legal, financial, institutional, cultural, social,.). Coopener is one of the 4 fields of EIE program. It aims at promoting renewable energy sources and energy efficiency in developing countries.
The objective of the project has been the promotion and dissemination of the use of micro-grids with high content of Renewable Energy Sources (RES) for the electrification of villages far away from grid in Senegal [7]. The project has contained six Work Packages (WP): WP 1 – Project Co-ordination (Management) WP 2 – Training in RES and Micro-grids WP 3 – Analysis of local Needs for the Electrification of Rural Areas WP 4 – Definition of a Kit for the Electrification of Rural villages WP 5 – Specific Dissemination Activities WP 6 – Common Dissemination Activities A flow chart showing the interrelation of the different tasks involved in Micro-grids is given in Fig. 1. This paper presents the results of WP 3 and 5. WP 3 has mainly consisted of some surveys carried out in order to study what the energetic needs of rural non-electrified villages are. estimate the electrical power and energy the villages need. assess the potential in renewable energies of these villages. Many events have been organised in WP 5, particularly to identify the barriers which have stopped the development of micro-grids in rural regions of Senegal. Some solutions have been proposed to get over these barriers. The results of these two WPs have been used in WP 4 to design a conceptual optimised and modular kit which would be used to electrify these non-electrified villages. As it was obviously not possible to apply these global analyses to every non-electrified rural villages of Senegal, three target regions have been selected considering the budget of the project. Fig. 2 shows the following three regions: Thie`s (the nearest from Dakar), Fatick and Kaolack (the largest and the more distant from Dakar). Table 1 shows the list of the partners of the Micro-grids project. 3. Methodology for the organisation of the surveys As explained before, some surveys have been carried out in the WP 3 to analyse the electricity needs of rural population. The different steps followed to make the surveys have been: In the preparation of the surveys: BThe definition of different village categories. BThe determination of the number of villages per region. BThe definition of the criteria to select the villages where the surveys would be carried out. BThe drafting of the survey’s questions. BThe sampling of the household surveys. In the organisation of the surveys: BThe preparation of human and material means. BThe training of interviewers.
3.1. The village categories Three categories of villages have been defined in each region: The small villages with less than 500 inhabitants. The medium villages with a population between 500 and 1000 inhabitants. The big villages with more than 1000 inhabitants.
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Fig. 1. Flow chart showing the interrelation of the different tasks involved in Micro-grids.
3.2. Selection of the number of villages per region
3.3. Selection criteria of the villages
The selection of the number of villages per region has been made depending on the demographic size of each region. 34 villages have been selected in the whole:
The villages have been selected from a Database of Semis. The selected villages have to be located farther than 10 km away from the Senelec’s grids. This criterion is defined because the costs to connect villages which are so distant from the Senelec’s grid are high, and then, these villages are specially appropriate for the installation of isolated micro-grids. Moreover, villages have been chosen for the three size categories described before. Concerning the electrified villages, the villages of Thie`s and Kaolack are connected to the Senelec’s grid, while the two electrified villages of Fatick have a hybrid Diesel/Solar power station.
10 non-electrified villages and 1 electrified village in Thie`s. 7 non-electrified villages and 2 electrified villages in Fatick. 13 non-electrified villages and 1 electrified village in Kaolack. The final objective being the electrification of non-electrified villages, the natural target population for the surveys is of course the population of non-electrified villages. However, the surveys carried out in the electrified villages allow measuring the electrical equipment penetration level in the rural electrified villages.
3.4. The type of survey Three kinds of surveys have been made in every selected village: The village surveys, which allow better understanding of the socioeconomic context of the villages, are carried out by interviewing people chosen by the chief of the village. The household surveys to collect data concerning domestic behaviours related to energy consumption are directly addressed to family chiefs.
Table 1 List of the participating organisations. Organisation ROBOTIKER LIPSI-ESTIA Ministry of Energy (including ASER)
Fig. 2. Location of the three target regions in a map of Senegal.
Country Business activity
Spain RTD performer/Technologic Research Centre France RTD performer/university Senegal Target group/public body: energy policy maker and decider Authority with competences in energy issues through all Senegal Regional Council of Dakar Senegal Target group/public body: policy maker CERER-UCAD Senegal RTD performer/university SEMIS Senegal Energy utility PERACOD Senegal Energy professionals ESP (LER) Senegal RTD performer/university
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The technical surveys allow listing the driving forces and the production units (generator set, millet mill,.), and collecting by GPS geographical coordinates of significant infrastructures such as schools, health centres or wells.
3.5. Household surveys sampling With the aim of collecting data from every socioeconomic household category, the surveys have been made considering: The nature of the settlement: grouped or dispersed. The nature of the buildings: standard, in laterite mud, in straw. The size of the sampling depends on the category of the village: 8 households for small villages. 12 households for medium villages. 14 households for big villages.
3.6. The human and material means A team of interviewers has been formed for each region. The teams have been composed by: A supervisor, chosen to carry out the village survey, to supervise the household survey and to coordinate all the teams. He has been the interlocutor of local authorities. Two persons to carry out the household surveys. One person to collect the data of the technical surveys. The activity of the three teams has been coordinated by a socioeconomic expert. Moreover, each team had an all terrain vehicle and a GPS. 4. Results of the surveys Extensive data have been collected during the surveys and they cannot all be included in this paper. This section presents only a synthesis of these data. All the data are available in Ref. [8].
Table 3 Number of residents and of emigrants by household. Type of villages
Mean number of residents by household
Mean number of emigrants by household
Small villages Medium villages Large villages All the villages Small villages Medium villages Large villages All the villages Small villages Medium villages Large villages All the villages
14.18
0.97
16.57
1.75
18.14
2.33
16.02
1.58
11
2.5
13.2
1.75
10.3
2.8
12.4
2.04
13.36
2
14.33
3.22
19.5
3.21
15.33
2.74
Kaolack region
Fatick region
Thie`s region
Table 3 shows the number of residents and emigrants per household. It is important to know the number of residents to estimate the electrical energy needs. Moreover, the emigrants are often the most important financing source of the families. Thus, the number of emigrants is normally linked to the purchasing power of families. It can be seen that, on average, there are more residents in Kaolack than in Fatick and even than in Thie`s. In Kaolack and Thie`s, the number of residents per family increases with the size of villages. Similar conclusions can be made about the number of emigrants per family. There is at least one emigrant per family in the three regions’ villages and the number of emigrants increases with the proximity of the capital of Senegal, Dakar, as it can be verified in the map of Fig. 2.
4.1. Socioeconomic data
4.2. Statistics about the housing
As shown in Table 2, the main activity carried out in the concerned villages is agriculture. In Fatick agriculture is the first activity for all families. Families have often a second, and sometimes a third activity. In general, the second activity is the livestock farming and the third activity is the commerce. The data are rather similar for the three categories of villages.
Table 4 shows some statistics about the housing of the studied regions. It can bee seen that nearly every family has at least a secondary building close to the main building. In Kaolack and Fatick more than half of families have at least four secondary buildings, and three in Thie`s. The table also shows the existing distances between the different buildings. This information is
Table 2 Data about socioeconomic activities in the three regions. Type of villages
Activity 1
Activity 2
Small villages Medium villages Large villages All the villages Small villages Medium villages Large villages All the villages Small villages Medium villages Large villages All the villages
Agriculture (89.8%) Agriculture (94.7%) Agriculture (94.7%) Agriculture (92.5%) Agriculture (100%) Agriculture (100%) Agriculture (100%) Agriculture (100%) Agriculture (92.7%) Agriculture (77.8%) Agriculture (89.3%) Agriculture (84.8%)
Livestock farming (57.1%), commerce (12.2%), agriculture (10.2%), no other activities Livestock farming (36.8%), commerce (21.1%), agriculture (5.3%), no other activities Livestock farming (46.4%), commerce (17.9%), agriculture (7.1%), no other activities Livestock farming (46.3%), Commerce (17.2%), agriculture (7.5%), no other activities Livestock farming (37.5%), commerce (50%), no other activities (12.5%) Livestock farming (31.66%), commerce (14.16%), craft (5.3%), other/no other activities Livestock farming (42.85%), commerce (14.28%), masonry (7.1%), other activities Livestock farming (35.13%), commerce (19%), craft (4%), other/no other activities Livestock farming (31.7%), commerce (17.1%), agriculture (4.9%), no other activities Livestock farming (11.1%), commerce (13.9%), agriculture (19.4%), no other activities Livestock farming (25%), commerce (7.1%), agriculture (10.7%), no other activities (46.4%) Livestock farming (23%), commerce (13.3%), agriculture (11.4%), no other activities
Kaolack region
Fatick region
Thie`s region
H. Camblong et al. / Renewable Energy 34 (2009) 2141–2150 Table 4 Statistics about the housing: number of buildings per family. Building
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Table 6 Statistics about the housing: kind of roof for the main building.
Main Building 1 Building 2 Building 3 Building 4
% of households 100 Mean number of 1.76 rooms by building Mean distance to the 0 main building
98.51 1.25
94.03 1.12
81.34 1.06
61.18 1.08
5.71
6.78
8.79
9.97
% of households 100 Mean number of 1.7 rooms by building Mean distance to the 0 main building
100 1.39
97.29 1.33
64.86 1.03
56.73 1.05
3.13
4.93
5.83
7.35
% of households 100 Mean number of 2.92 rooms by building Mean distance to the 0 main building
95.24 2.13
76.19 1.55
53.33 1.77
32.38 1.27
6.43
7.15
6.13
3.39
Kaolack region
Fatick region
Thie`s region
useful to estimate the length of the electrical cable which would have to be installed if the village is electrified with a micro-grid. The statistics about the number of rooms per building allow estimating the number of bulbs needed to light every room. Tables 5 and 6 show what is the material used to build the main building of the household ant its roof in each region. These data are needed to know if some electrical accessories or PV panels could be installed on the main building. It is obvious that some equipment could not be installed on a too fragile building. It can bee seen that in Thie`s, which is the region nearest from Dakar, the used materials are harder. Actually, 80% of the buildings are built with cement and more than 72% of the main buildings have tin roofing. In Kaolack most of the main buildings are built in laterite mud and the roof is usually thatched. Fatick’s statistics are between the results obtained for the other two regions. The trend is that the farther the village is from Dakar, the more fragile the building is.
Zinc Thatch
22.45% 77.55%
Kaolack region
Zinc Thatch
55.82% 44.18%
Fatick region
Zinc Thatch Flat roof Slate
72.38% 11.43% 1.90% 14.29%
Thie`s region
Table 7 Constraints linked to the supply of energy. Villages from
Mean distance Mean distance to to buy the oil charge the (km) batteries (km)
% of households concerned by the charge of the batteries
Kaolack Fatick Thie`s
6.88 5.84 6.83
13 1.19 33.33
22 13 19.23
families have a black and white television. In Thie`s almost every family has a radio and 84% of the families have black and white televisions. Comparing with non-electrified household, electrified households use in general colour televisions, refrigerators, fans, videos and phones. It can be noticed that in Thie`s, unlike in the other two regions, electricity is also used for power-driven pumps. The surveys have been carried out by different teams in each region, as explained in Section 3. The questions were probably not asked in the same manner in all the three regions. Some differences between data of different regions can be explained like this.
Table 8 Electric equipments in non-electrified and electrified household.
4.3. Energetic aspects Inhabitants of non-electrified villages use three main kinds of lights or energy: Oil-lamps, candles. Batteries for torch, butane gas. Solar PV panels with batteries, feeding bulbs. Some people use batteries charged in another village. As shown in Table 7, more than 5 km have to be covered on average to get oil in the three regions. In Kaolack and Fatick, families who use batteries have to cover about 20 km on average to charge them. Table 8 gives some information about the electric equipments used by families in non-electrified and electrified villages. In non-electrified villages of Kaolack, most of the people use radio-cassettes and radios. In Fatick more or less 10% of the Table 5 Statistics about the housing: kind of building for the main building. Cement Laterite mud Others (straw.)
21.64% 73.88% 4.48%
Kaolack region
Cement Laterite mud Others (straw.)
41.86% 50.38% 7.76%
Fatick region
Cement Laterite mud Others (straw.)
80.00% 18.10% 1.90%
Thie`s region
Equipments
In the non-electrified In the electrified households (%) households (%)
Radio-cassette Radio Black and white TV Colour TV Refrigerator Fan Video Freezer Parabolic antenna Mobile phone
83.58 58.96 3.73 1.49 0.00 0.00 0.00 0.00 0.00 0.00
0.00 40.00 0.00 73.33 60.00 40.00 20.00 13.33 6.67 53.33
Kaolack region
Radio-cassette Radio Black and white TV Colour TV Refrigerator Fan Video Freezer Mobile phone DVD/CD player
33.78 66.22 6.75 0.00 0.00 0.00 0.00 0.00 0.98 0.00
60 26.66 0 80 20 53.33 46.66 6.66 53.33 6.66
Fatick region
Radio-cassette Radio Black and white TV Colour TV Freezer Fan Video Mobile phone Refrigerator Electric pump
43.60 96.00 62.00 20.00 0.00 0.00 0.00 1.00 0.00 0.00
60.00 33.00 26.70 73.30 13.30 26.70 20.00 60.00 6.70 46.70
Thie`s region
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Table 9 Substitutable Energetic Expenses (SEEs) for light. Large villages
Medium villages
Small villages
All the villages
Batteries (Fcfa) Candles (Fcfa)
1244 1898
1654 5148
1528 3000
1522 3495
Oil (Fcfa) Total amount
5002 8144
4467 11,269
3988 8516
4432 9449
Kaolack region
Without With ISS ISS 2026.44 1349.61 1003.13 812.39 9.38 294.64
1635.14 281.35
Oil (Fcfa) 8492.3 Total amount 10156.6 Batteries (Fcfa) 1829 Candles (Fcfa) 155.4
4970.11 7817.94 1515.9 400
64.58 2326.79 1423.57 3624.56 2775 1754 150 312.8
3963.44 5879.93 1740.3 352.3
Oil (Fcfa) Total amount
3482.3 5398.2
2543.7 5468.7
1752.8 3845.4
Batteries (Fcfa) Candles (Fcfa)
1664.3 0
7728.4 9712.8
1244 3310.8
Fatick region
Thie`s region
Fig. 3. Sum the households are Willing To Pay (WTP). Table 10 Definition of service levels. Level 1
Level 2
Level 3
Level 4
2–3 Lamps Radio
3–5 Lamps Radio Black and white TV or radio-cassette
6–8 Lamps Radio Black and white TV or radio-cassette 1 Device
More than 8 lamps Radio Colour TV Video Other devices
Table 9 shows the Substitutable Energetic Expenses (SEE) for lighting. It corresponds to total money that households would save if they were electrified and they could use electricity instead of the other lighting systems they are using today. In Fatick and Thie`s the SEEs decrease with the size of the village. Moreover, taking data as a whole, the trend is that SEEs decrease with the proximity to Dakar. This is probably due to the fact that light systems are cheaper when the distance to Dakar decreases. In some villages, households have Individual Solar Systems (ISS). It can be remarked that in these villages, SEEs are logically lower. Four service levels have been defined to facilitate the estimation of domestic electrical energy needs (see Table 10). The first level considers only 2 or 3 lamps and a radio, while the fourth level takes into account more than 8 lamps, one radio, one colour television, one video and other devices as refrigerator or fans. Table 11 shows the distribution of households per Service Level (SL). In Kaolack the number of families which would like to have an SL 2, 3 or 4 is more or less the same. The collected data are similar in Fatick, even if in general, people of this region are a bit more demanding. The service level demand is much higher in Thie`s where more than 81% of households declare that if their village was electrified, they would take out a subscription corresponding to the fourth level. It can also be noticed that very few households are situated in the first SL whatever the region is.
Table 12 Comparisons of the SEE (for light) and the WTP. SL2
SL3
SL4
SEE WTP
SL1 3952 3833
7079 3298
14,847 6561
14,524 11,429
Kaolack region
SEE WTP
10,444 3000
4715 4600
7129 9500
11,208 14,200
Fatick region
SEE WTP
– –
1987 2250
3972 6929
6305 16,267
Thie`s region
Fig. 3 shows what is the sum the households are Willing To Pay (WTP) per service level. In general, happily, families who want a higher SL are willing to pay more. There is however a small contradiction in Kaolack where families who would like an SL 2 are willing to pay less than those who would like to have an SL 1. A comparison between the SEE for lighting and the WTP is made for each region in Table 12. In Thie`s households declare to be willing to pay more than their substitutable energetic expenses. This declaration seems to be coherent. This fact is also more or less true for Fatick except for families of SL 1 who declare to spend quite a lot for lighting. They are maybe families who spend too much money in comparison with their purchasing capacity. In Kaolack households declare to be willing to spend less money than their SEE. Comparing with the other two regions, it is true that their SEEs are higher and it is probable that their incomes are lower.
Table 11 Distribution of household per Service Level (SL). SL1
SL2
SL3
SL4
Number of households % of households
3 2.30
47 35.30
41 30.80
42 31.60
Kaolack region
Number of households % of households
3 4.06
20 27.03
26 35.13
25 33.78
Fatick region
Number of households % of households
0 0
2 1.69
14 13.21
86 81.13
Thie`s region Fig. 4. Loans taken out by households.
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Table 13 Hypotheses made for the estimation of the subscribed power and the consumed energy per household for each SL Number Economic lamps Radio Total Economic lamps Radio Black and white TV Total Economic lamps Radio Black and white TV Refrigerator Total Economic lamps Radio Black and white TV Video Freezer Total
3 1 5 1 1 8 1 1 1 16 1 1 1 1
Power (W) 11 15 48 11 15 40 110 11 15 40 100 243 11 15 40 50 130 411
Operation time (h/d) 3 5 3 5 5 3 5 5 19 3 5 5 1 18
Some questions of the surveys were prepared to see if households are used to take out loans. Actually, if micro-grids are to be installed in the non-electrified villages, it is important to see whether local population would be willing to take out loans to pay for part of the installation. Fig. 4 shows that some families of the three regions are used to take out loans and that the majority of loans are lesser than 400,000 Francs CFA (656 F CFA ¼ 1 V).
Daily consumption (Wh/d)
Monthly consumption (kWh/month)
99 75 174 165 75 200 440 264 75 200 1900 2439 528 75 200 50 2340 3193
2.97 2.25 5.22 4.95 2.25 6 13.2 7.92 2.25 6 37 73.17 15.84 2.25 6 1.5 70.2 95.79
SL1
SL2
SL3
SL4
5. Estimation of electrical energy needs Some data obtained from the interviews can be used to estimate the electrical energy needs of each village. This estimation is necessary to do a good dimensioning of the micro-grids which would be installed in the concerned villages [9]. The electrical energy needs cannot be directly obtained from the data of the surveys. First, some hypotheses have to be made to
Fig. 5. Loads with priority when the power supply is interrupted.
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Fig. 6. Biogas potential in the three regions.
estimate the subscribed power and the consumed energy per household for each SL. Table 13 gives the list of hypotheses which have been made to do this estimation. Thus, for the SL 1, the subscribed power per household would be of 48 W and the consumed energy in one month is estimated to be 5.22 kWh. For the SL 4, the values are 411 W and 95.79 kWh. The different SLs affect only the energy consumption of the household. They do not take into account other shared loads as
public light or pumping. Other hypotheses have to be made to estimate the electrical consumption of these shared loads, and thus to calculate the overall estimated electrical consumption. Concerning public light, it could be composed by a streetlight of 100 W working 10 h per day, hence consuming 1 kWh per day. Moreover, considering the experience of rural electrification, we can take one streetlight for 15 households. Concerning the social infrastructures (school, health centre, mosque), the shops and those in the same category, the consumption can be estimated to be similar to that of the SL 2, that is, a subscribed power of 243 W and a consumed energy of 2439 kWh per day. For pumping and other uses of motor, the consumption is determined considering a load of 3 kW working 4 h per day, corresponding to a total consumption of 12 kWh per day. These hypotheses, along with those of Table 13 and with data from Table 11 concerning the distribution of household per SL, allow the estimation of the electrical needs for the different sizes of villages in the three regions. The estimated electrical energy needs are lower in Kaolack than in the other regions. The lower estimation is made for a village of 250 inhabitants of Kaolack, where the subscribed power would be 5.97 kW and the consumed energy would be 47.26 kW per day. The highest estimation is made for a village of 1500 inhabitants of Fatick, where the subscribed power
Fig. 7. Solar potential assessment in the three regions.
H. Camblong et al. / Renewable Energy 34 (2009) 2141–2150
would be of 49.34 kW and the consumed energy would be 379.29 kW in a day. The micro-grids which would be installed in these villages should be dimensioned to be as cheap as possible. This cost could be reduced by minimising the storage system (normally batteries) capacity or the power of the additional generator (for instance diesel generator). The risk of this strategy is that sometimes, the available energy could be lower than the demanded energy. Then, when this occurs, the population would have to accept the interruption of the power supply for some loads. Fig. 5 shows the loads having priority of supply for the population of the three regions. The mosque has the priority in Kaolack and Thie`s, followed by the health centre and the pumping. In Fatick, the health centre has the priority followed by the mosque and the public light. It must be underlined that the interviews have been done with the chief of each family and that this person is most of the time a man. This can explain why the mosque has the priority. As seen in different seminars organised in the WP 5, for women, usually, the health centre must have the priority. 6. Renewable energies potential The potential of some renewable energy sources has been estimated by collecting corresponding data in each region. The studied resources are the biogas obtained from the animal wastes, the wind energy and the solar energy. Fig. 6 shows the potential of biogas in the three regions. The main part of biogas would be obtained with bovine wastes. The wastes coming from equines, goats and sheep also show a significant potential for the production of biogas. The global amount of biogas which could be obtained with these animal wastes is really important. For instance, more than 400 m3 of biogas could be obtained per day with cattle wastes in Kaolack. However, these data have to be put into perspective. Because the livestock is dispersed in Senegal, it is difficult to collect the wastes. Moreover, after collecting the wastes, they have to be processed to obtain biogas. Thus, considering all these factors, the use of animal wastes to generate electricity does not still seem to be efficient enough to be considered as a resource for rural electrification. Because of its geographical situation, solar energy potential is very important in Senegal. On average the country gets 3000 h of sunshine a year. It corresponds to a total energy average of 5.8 kWh/m2 per day. Fig. 7 shows the daily radiation in the three regions. The trends are the same: the radiation is maximal in April and May and minimal in December and January, but it is really very high through the year. This solar potential can be used to generate directly electricity with PV panels. This technology is still relatively expensive but very appropriate for isolated sites, such as rural villages distant from the Senelec’s grid. Moreover, the prices of the panels are decreasing. In the future, solar thermodynamic power stations [10] would be able to produce cheaper electrical energy, but this technology is not still mature. Wind energy is the renewable energy that has experienced the highest degree of development during the last two decades [11]. It is now very competitive in relatively windy sites. Some global, but not very precise studies have been carried out in Senegal to analyse the wind energy potential. The average wind speed in the three considered regions is between 3 and 5 m/s, most of the time being more than 4 m/s (Fig. 8). According to these data, wind energy is not very interesting in these regions, but wind speed can be higher locally, near a river, the sea or on a hill. The first wind farm will probably be installed rather soon by a European company in such a site with good wind.
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Thus, contrary to PV panels, wind energy will not be competitive in every non-electrified rural village, but it could be in some locally windy villages.
7. Constraints and solutions to the development of microgrids in Senegal The micro-grid concept is not really new in Senegal. Aside pure PV power stations (Diaoule´ in Fatick and Ndie´bel in Kaolack in the frame of a Senegal–German project, Djirnda in Fatick in the frame of a Senegal–Nippon project), some hybrid PV-diesel generator power stations have been installed in Fatick, precisely in Bassoul–Bassar and Saloum Island. However, despite rural population needs, these kinds of power stations have not still been installed at a large scale. Moreover the already installed power stations have had some operating problems. One of the main objectives of the dissemination activities organised in the WP 5 of the Micro-grids project has been to develop activities to deal with three major challenges for the development of micro-grids in Senegal: The availability: the appropriate offer of energetic services must be increased. The acceptability: adapted energetic equipments which answer to the rural population needs must be created (for the transformation of farm products, for the construction of farm tools and equipments,.). The accessibility: poor people of rural regions must have access to energetic services.
Fig. 8. Wind speed assessment in the three regions.
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Table 14 Estimation of electrical energy needs per size of village and per region. Small villages Population Person/households Households Total power demand (kW) Energy demand (kWh/d)
250 14 18 5.97 47.26
Person/households Households Total power demand (kW) Energy demand (kWh/d) Person/households Households Total power demand (kW) Energy demand (kWh/d)
Medium villages 350 25 7.77 61.45
500 16 31 12.18 94.63
11 23 10.67 77.44
32 13.05 96.78
13.36 19 10.02 75.3
26 12.82 97.66
Large villages
47 16.11 125.67
1000 18 56 21.11 158.01
83 28.09 213.18
Kaolack region
13.2 38 16.17 121.35
57 21.14 161.65
10.3 97 36.6 275.99
146 49.34 379.29
Fatick region
14.33 35 16.5 126.8
52 23.03 178.82
19.5 51 35.37 234.04
77 44.96 310.65
Thie`s region
Below there is a synthesis of the main constraints and the corresponding solutions which have been listed in the different events organised in Senegal: Administrative procedures are heavy. They must be lightened. The tax system is restrictive. Some incentive measures have to be applied for the energetic sector. The local or administrative authorities and the regional committees for the development are not sufficiently implicated upstream of and downstream from the electrification projects. Governors, prefectures and other authorities must be involved in the projects. Beneficiaries, it is to say population of non-electrified villages, are not involved in the financing of the project. They have to take part in the financing to be considered as partners. There are no maintenance systems. The training in maintenance of professionals’ associations must be encouraged to professionalize this field. The spare parts are not available. A toll-house must be created to ease the access to the tools for the technicians in renewable energies. There are not monitoring systems to assess the projects. The partners of the projects must carry out the monitoring and assessment of the project at medium and long term to ease the capitalisation of the projects. There are few continuing education procedures for local expertise. The local expertise must be strengthened through seminars and continuing education sessions. Renewable energies are not included in the training programs. Renewable energies must be included in the school programs, specially in the scientific education. 8. Conclusion The work carried out in the WP 3 and 5 of Micro-grids project and presented in this paper has led to very interesting results. A reliable estimation of the population electrical needs has been obtained in WP 3 by carrying out some surveys. The results from the surveys in the three regions were not always homogenous. This non-homogeneity can be explained in part by the fact that the interviewers’ teams were different in the three regions. Moreover, the results have to be analysed keeping in mind that the questions were asked to the household’s chief who is most of the time a man. Women have a very important place in the domestic activities and their participation in the rural electrification projects is essential. However, the household’s chief being the person who takes the decisions, it was justified to select him to carry out the surveys, specially for the statement about the actual energy spending and the willingness to pay for electrical services. Nevertheless, in the
750
1500
future, it could be interesting to carry out new surveys by involving more people from the households. The presented study has demonstrated that the use of RES for Senegal rural electrification has considerable advantages. There is a huge solar potential and an interesting wind in some sites. Moreover, the technological evolution of RES equipment is linked to the concerns of the users (the supply of electrical energy by micro-grids answers to the energy request for productive activities and increases the contribution of energy to poverty alleviation) (Table 14). This paper presents only one part of the results of Micro-grids project. The results presented in this paper have allowed the design of a rural electrification kit which is described in Ref. [9]. Now, the objective of the Micro-grids’ consortium is to build and install micro-grids in some non-electrified villages of Senegal, on the basis of the designed rural electrification Kit. Acknowledgements This study was carried out with financial support from the Intelligent Energy Europe (IEE) programme managed by the Executive Agency for Competitiveness and Innovation (EACI). The authors of this paper would like to thank all the partners of the Micro-grids project for their significant involvement. References [1] International Energy Agency (IEA) Statistics Division. Energy balances of OECD countries. Energy balances. 2006 ed. Paris: IEA. Available at http://data.iea.org/ ieastore/default.asp; 2006. [2] Population Division of the Department of Economic and Social Affairs of the United Nations Secretariat. World population dataset on CD-ROM. New York: United Nations. Available at http://www.un.org/esa/population/publications/ WPP2004/wpp2004; 2005. [3] Leitch AWR, Scott BJ, Adams JJ. Non-grid electrification of 45 schools in the Eastern Cape, South Africa: an assessment. Renewable Energy 1997;10(2– 3):135–8. [4] Abdeen Mustafa Omer. Solar water pumping clean water for Sudan rural areas. Renewable Energy 2001;24:245–58. [5] PushpendraJain K, Nijegorodov N, Kartha CG. Role of solar energy in development in Botswana. Renewable Energy 1994;4(2):179–88. [6] Othieno H. Photovoltaic technology: most appropriate electricity source for rural tropical Africa. Brighton, UK: World Renewable Energy Congress VI; 2000. p. 1962–5. [7] Project official web site: http://www.microgrids-eie.com. [8] Analysis of local needs for rural zones electrification in Senegal [Analyse des besoins locaux pour l’e´lectrification de zones rurales au Se´ne´gal]. Technical report of Microgrids project WP 3, http://www.microgrids-eie.com; 2007 [in French]. [9] Alzola JA, Vechiu I, Camblong H, Santos M, Sall M, Saw G. Microgrids project, part 2: design of an electrification kit with high content of renewable energy sources in Senegal, Renewable Energy, submitted. [10] Bonnet S, Alaphilippe M, Stouffs P. Thermodynamic solar energy conversion: reflections on the optimal solar concentration ratio. International Journal of Energy, Environment and Economics 2006;12(3):141–52. [11] Yang Ming. Climate change drives wind turbines. Energy Policy 2007;35(12):6546–8.
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Renewable Energy journal homepage: www.elsevier.com/locate/renene
Micro-grids project, Part 1: Analysis of rural electrification with high content of renewable energy sources in Senegal H. Camblong a, f, *, J. Sarr b, A.T. Niang c,1, O. Curea a, J.A. Alzola d, E.H. Sylla e, M. Santos d a
ˆ le Izarbel, 64210 Bidart, France ESTIA Recherche, Technopo GRTT-LASES, Faculte´ des Sciences de l’Universite´ Cheitk Anta DIOP de Dakar(UCAD), 5005 Dakar-Fann, Senegal c CERER, Center of Studies and Research on Renewable Energies, Hann-Equipe, 476 Daka RPr, Senegal d ´gico, Edificio 202, 48170 Zamudio, Spain Robotiker, Parque Tecnolo e LER, Ecole Supe´rieure Polytechnique, 5085 Dakar Fann/ESP/UCAD, Senegal f Electrical Engineering Department, University of the Basque Country (E.U.P.-D), Europa Plaza 1, 20018 Donostia, San Sebastian, Spain b
a r t i c l e i n f o
a b s t r a c t
Article history: Received 10 December 2007 Accepted 27 January 2009 Available online 28 February 2009
Africa is the poorest continent in the world and this poverty is linked to the lack of access to energy of its population. A big part of inhabitants live in rural zones where the lack of energy and in particular of electricity is still more flagrant. The aim of the Micro-grids project was to promote the electrification of rural regions of Senegal by the installation of micro-grids with high content of renewable energies. This paper presents some results of this project. Surveys have been carried out in three regions of Senegal to study the needs of electrical energy of non-electrified rural villages’ households. These surveys have led to the estimation of electricity needs of the concerned households. The potential in renewable energies of the three regions has also been examined. It has been concluded that the solar energy potential is excellent while the wind energy potential can be interesting in some specific sites. The biomass could also be an efficient source if livestock farming was properly managed in the future. Moreover, many events have been carried out in the three regions to analyse the obstacles for the development of micro-grids in the Senegalese energy context, and to establish suitable solutions to overcome these obstacles. The results presented in this paper have been used to design a rural electrification kit which is described in another paper. Now the Micro-grids’ consortium hopes to set up a new project to apply the designed kit on some rural non-electrified villages. Ó 2009 Elsevier Ltd. All rights reserved.
Keywords: Rural electrification in Senegal Micro-grids Solar PV energy Potential of renewable energies Electricity needs estimation
1. Introduction Africa is the poorest continent in the world. This poverty is linked to the lack of access to energy of African population. Africans consume a mere 0.3–0.6 tonne oil equivalent per capita. By contrast North Americans consume 7.5–9 tonne oil equivalent per capita or between 12 and 30 times more energy on average [1,2]. In brief, nowhere is the per capita level of energy consumption lower than that in Sub-Saharan Africa. It is a clear indicator of how far of wellbeing and comfort parameters they are. The poverty and the lack of access to energy, especially to electrical energy, are still more significant in the rural regions. 70% of the population in sub-Saharan Africa live in rural areas and less than 10% of these have access to reliable sources of electricity. The main advantages of rural electrification are
* Corresponding author. Tel: þ33 5 59438549; fax: þ33 5 59438401. E-mail address: [email protected] (H. Camblong). 1 Tel.: þ221 832 10 53; e-fax: þ33 825 74 86 75. 0960-1481/$ – see front matter Ó 2009 Elsevier Ltd. All rights reserved. doi:10.1016/j.renene.2009.01.015
A better quality of electric light for educational home work, because a good electrical light is a support for education. A better quality of electric light for nocturnal interventions in health institutions. Better working conditions for economic or domestic activities. The access to mass media. A better security (against thefts of livestock, distance of the wild animals). The improvement of the image of villages by the level of electrical equipment. The rural migration reduction by creating activities which generate jobs and sources of revenue. The possibility of improvement of basic services thanks to the local tax revenues generated by the development of economic activities. Environment preservation and protection through the use of renewable energy sources. Rural areas are often far from the national electrical grid, making the connection of remote rural communities to the existing grid too
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costly. In these cases, alternative isolated systems can be used to electrify the community, and consequently to support their socioeconomic development [3]. Local renewable sources, such as solar energy, wind energy or biomass, are often available. In particular, much of Africa is well exposed to sunlight, and solar energy can be used to obtain electricity using PV panels. The use of PV generators could be a vehicle for the development of rural isolated communities [4–6]. Moreover, using renewable energies will prepare the African countries for an energy-efficient and low-pollutant future, which is not only required by International Environmental Conventions, but also essential to any possibility of genuine economic development in a sustainable fashion. Similarly, in Senegal, micro-grids seem to be a good solution for the electrification of rural areas. Even if there is not an official definition, a micro-grid can be defined as a small scale electrical grid where the sources of electricity are placed close to the loads. Moreover, these sources are normally composed by renewable energy systems, such as PV panels, a standard support generator, such as diesel generators, and an energy storage system, such as batteries. These components are well adapted to the socioeconomic reality of Senegal. Although Senegal does not produce oil, 60% of its primary energy comes from oil products. Their growing prices threaten the import–export balance, so their consumption should be limited by the use of renewable energies. The renewable energy potential is significant and varied in Senegal, with 3000 h of sunlight a year, good wind in some sites and important vegetable reserves in Casamance and in the oriental Senegal. Moreover, micro-grids containing renewable energies are suited to the rural context of Senegal. Many villages present a grouped layout, the energy needs are low and the rural households’ incomes are relatively limited. PV installations are well known in the rural electrification field in Senegal. Actually, Senegal has launched for the last 40 years a vast program of experiments and tests of solar energy materials in particular. Senegalese Agency for Rural Electrification (ASER), which has specialized in the diffusion of the photovoltaic solar systems through the country was thus created. However, micro-grids or similar systems have still not been installed on a large scale in Senegal, and the most important rural zones have still no access to electricity. This is why Micro-grids project was carried out, to analyse how micro-grids with high content of renewable energies must be promoted to electrify rural zones of Senegal on a large scale. Section 2 of this paper presents Micro-grids project. Section 3 is dedicated to the description of the methodology used to carry out some surveys for the study of the electricity needs of rural populations. Section 4 gives the results of this survey and an estimation of electrical energy needs in rural regions is made in Section 5. Then, the potential of renewable energies in Senegal is analysed (Section 6) before studying the constraints and solutions for the development of micro-grids in Section 7, and concluding the paper in Section 8. 2. Micro-grids project presentation Micro-grids project has been carried out in the frame of a Coopener project of the Intelligent Energy Europe (IEE) program of Energy and Transport European Commission. IEE is the European Community support program to increase renewable energy sources and energy efficiency by overcoming the non-technological barriers (legal, financial, institutional, cultural, social,.). Coopener is one of the 4 fields of EIE program. It aims at promoting renewable energy sources and energy efficiency in developing countries.
The objective of the project has been the promotion and dissemination of the use of micro-grids with high content of Renewable Energy Sources (RES) for the electrification of villages far away from grid in Senegal [7]. The project has contained six Work Packages (WP): WP 1 – Project Co-ordination (Management) WP 2 – Training in RES and Micro-grids WP 3 – Analysis of local Needs for the Electrification of Rural Areas WP 4 – Definition of a Kit for the Electrification of Rural villages WP 5 – Specific Dissemination Activities WP 6 – Common Dissemination Activities A flow chart showing the interrelation of the different tasks involved in Micro-grids is given in Fig. 1. This paper presents the results of WP 3 and 5. WP 3 has mainly consisted of some surveys carried out in order to study what the energetic needs of rural non-electrified villages are. estimate the electrical power and energy the villages need. assess the potential in renewable energies of these villages. Many events have been organised in WP 5, particularly to identify the barriers which have stopped the development of micro-grids in rural regions of Senegal. Some solutions have been proposed to get over these barriers. The results of these two WPs have been used in WP 4 to design a conceptual optimised and modular kit which would be used to electrify these non-electrified villages. As it was obviously not possible to apply these global analyses to every non-electrified rural villages of Senegal, three target regions have been selected considering the budget of the project. Fig. 2 shows the following three regions: Thie`s (the nearest from Dakar), Fatick and Kaolack (the largest and the more distant from Dakar). Table 1 shows the list of the partners of the Micro-grids project. 3. Methodology for the organisation of the surveys As explained before, some surveys have been carried out in the WP 3 to analyse the electricity needs of rural population. The different steps followed to make the surveys have been: In the preparation of the surveys: BThe definition of different village categories. BThe determination of the number of villages per region. BThe definition of the criteria to select the villages where the surveys would be carried out. BThe drafting of the survey’s questions. BThe sampling of the household surveys. In the organisation of the surveys: BThe preparation of human and material means. BThe training of interviewers.
3.1. The village categories Three categories of villages have been defined in each region: The small villages with less than 500 inhabitants. The medium villages with a population between 500 and 1000 inhabitants. The big villages with more than 1000 inhabitants.
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Fig. 1. Flow chart showing the interrelation of the different tasks involved in Micro-grids.
3.2. Selection of the number of villages per region
3.3. Selection criteria of the villages
The selection of the number of villages per region has been made depending on the demographic size of each region. 34 villages have been selected in the whole:
The villages have been selected from a Database of Semis. The selected villages have to be located farther than 10 km away from the Senelec’s grids. This criterion is defined because the costs to connect villages which are so distant from the Senelec’s grid are high, and then, these villages are specially appropriate for the installation of isolated micro-grids. Moreover, villages have been chosen for the three size categories described before. Concerning the electrified villages, the villages of Thie`s and Kaolack are connected to the Senelec’s grid, while the two electrified villages of Fatick have a hybrid Diesel/Solar power station.
10 non-electrified villages and 1 electrified village in Thie`s. 7 non-electrified villages and 2 electrified villages in Fatick. 13 non-electrified villages and 1 electrified village in Kaolack. The final objective being the electrification of non-electrified villages, the natural target population for the surveys is of course the population of non-electrified villages. However, the surveys carried out in the electrified villages allow measuring the electrical equipment penetration level in the rural electrified villages.
3.4. The type of survey Three kinds of surveys have been made in every selected village: The village surveys, which allow better understanding of the socioeconomic context of the villages, are carried out by interviewing people chosen by the chief of the village. The household surveys to collect data concerning domestic behaviours related to energy consumption are directly addressed to family chiefs.
Table 1 List of the participating organisations. Organisation ROBOTIKER LIPSI-ESTIA Ministry of Energy (including ASER)
Fig. 2. Location of the three target regions in a map of Senegal.
Country Business activity
Spain RTD performer/Technologic Research Centre France RTD performer/university Senegal Target group/public body: energy policy maker and decider Authority with competences in energy issues through all Senegal Regional Council of Dakar Senegal Target group/public body: policy maker CERER-UCAD Senegal RTD performer/university SEMIS Senegal Energy utility PERACOD Senegal Energy professionals ESP (LER) Senegal RTD performer/university
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The technical surveys allow listing the driving forces and the production units (generator set, millet mill,.), and collecting by GPS geographical coordinates of significant infrastructures such as schools, health centres or wells.
3.5. Household surveys sampling With the aim of collecting data from every socioeconomic household category, the surveys have been made considering: The nature of the settlement: grouped or dispersed. The nature of the buildings: standard, in laterite mud, in straw. The size of the sampling depends on the category of the village: 8 households for small villages. 12 households for medium villages. 14 households for big villages.
3.6. The human and material means A team of interviewers has been formed for each region. The teams have been composed by: A supervisor, chosen to carry out the village survey, to supervise the household survey and to coordinate all the teams. He has been the interlocutor of local authorities. Two persons to carry out the household surveys. One person to collect the data of the technical surveys. The activity of the three teams has been coordinated by a socioeconomic expert. Moreover, each team had an all terrain vehicle and a GPS. 4. Results of the surveys Extensive data have been collected during the surveys and they cannot all be included in this paper. This section presents only a synthesis of these data. All the data are available in Ref. [8].
Table 3 Number of residents and of emigrants by household. Type of villages
Mean number of residents by household
Mean number of emigrants by household
Small villages Medium villages Large villages All the villages Small villages Medium villages Large villages All the villages Small villages Medium villages Large villages All the villages
14.18
0.97
16.57
1.75
18.14
2.33
16.02
1.58
11
2.5
13.2
1.75
10.3
2.8
12.4
2.04
13.36
2
14.33
3.22
19.5
3.21
15.33
2.74
Kaolack region
Fatick region
Thie`s region
Table 3 shows the number of residents and emigrants per household. It is important to know the number of residents to estimate the electrical energy needs. Moreover, the emigrants are often the most important financing source of the families. Thus, the number of emigrants is normally linked to the purchasing power of families. It can be seen that, on average, there are more residents in Kaolack than in Fatick and even than in Thie`s. In Kaolack and Thie`s, the number of residents per family increases with the size of villages. Similar conclusions can be made about the number of emigrants per family. There is at least one emigrant per family in the three regions’ villages and the number of emigrants increases with the proximity of the capital of Senegal, Dakar, as it can be verified in the map of Fig. 2.
4.1. Socioeconomic data
4.2. Statistics about the housing
As shown in Table 2, the main activity carried out in the concerned villages is agriculture. In Fatick agriculture is the first activity for all families. Families have often a second, and sometimes a third activity. In general, the second activity is the livestock farming and the third activity is the commerce. The data are rather similar for the three categories of villages.
Table 4 shows some statistics about the housing of the studied regions. It can bee seen that nearly every family has at least a secondary building close to the main building. In Kaolack and Fatick more than half of families have at least four secondary buildings, and three in Thie`s. The table also shows the existing distances between the different buildings. This information is
Table 2 Data about socioeconomic activities in the three regions. Type of villages
Activity 1
Activity 2
Small villages Medium villages Large villages All the villages Small villages Medium villages Large villages All the villages Small villages Medium villages Large villages All the villages
Agriculture (89.8%) Agriculture (94.7%) Agriculture (94.7%) Agriculture (92.5%) Agriculture (100%) Agriculture (100%) Agriculture (100%) Agriculture (100%) Agriculture (92.7%) Agriculture (77.8%) Agriculture (89.3%) Agriculture (84.8%)
Livestock farming (57.1%), commerce (12.2%), agriculture (10.2%), no other activities Livestock farming (36.8%), commerce (21.1%), agriculture (5.3%), no other activities Livestock farming (46.4%), commerce (17.9%), agriculture (7.1%), no other activities Livestock farming (46.3%), Commerce (17.2%), agriculture (7.5%), no other activities Livestock farming (37.5%), commerce (50%), no other activities (12.5%) Livestock farming (31.66%), commerce (14.16%), craft (5.3%), other/no other activities Livestock farming (42.85%), commerce (14.28%), masonry (7.1%), other activities Livestock farming (35.13%), commerce (19%), craft (4%), other/no other activities Livestock farming (31.7%), commerce (17.1%), agriculture (4.9%), no other activities Livestock farming (11.1%), commerce (13.9%), agriculture (19.4%), no other activities Livestock farming (25%), commerce (7.1%), agriculture (10.7%), no other activities (46.4%) Livestock farming (23%), commerce (13.3%), agriculture (11.4%), no other activities
Kaolack region
Fatick region
Thie`s region
H. Camblong et al. / Renewable Energy 34 (2009) 2141–2150 Table 4 Statistics about the housing: number of buildings per family. Building
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Table 6 Statistics about the housing: kind of roof for the main building.
Main Building 1 Building 2 Building 3 Building 4
% of households 100 Mean number of 1.76 rooms by building Mean distance to the 0 main building
98.51 1.25
94.03 1.12
81.34 1.06
61.18 1.08
5.71
6.78
8.79
9.97
% of households 100 Mean number of 1.7 rooms by building Mean distance to the 0 main building
100 1.39
97.29 1.33
64.86 1.03
56.73 1.05
3.13
4.93
5.83
7.35
% of households 100 Mean number of 2.92 rooms by building Mean distance to the 0 main building
95.24 2.13
76.19 1.55
53.33 1.77
32.38 1.27
6.43
7.15
6.13
3.39
Kaolack region
Fatick region
Thie`s region
useful to estimate the length of the electrical cable which would have to be installed if the village is electrified with a micro-grid. The statistics about the number of rooms per building allow estimating the number of bulbs needed to light every room. Tables 5 and 6 show what is the material used to build the main building of the household ant its roof in each region. These data are needed to know if some electrical accessories or PV panels could be installed on the main building. It is obvious that some equipment could not be installed on a too fragile building. It can bee seen that in Thie`s, which is the region nearest from Dakar, the used materials are harder. Actually, 80% of the buildings are built with cement and more than 72% of the main buildings have tin roofing. In Kaolack most of the main buildings are built in laterite mud and the roof is usually thatched. Fatick’s statistics are between the results obtained for the other two regions. The trend is that the farther the village is from Dakar, the more fragile the building is.
Zinc Thatch
22.45% 77.55%
Kaolack region
Zinc Thatch
55.82% 44.18%
Fatick region
Zinc Thatch Flat roof Slate
72.38% 11.43% 1.90% 14.29%
Thie`s region
Table 7 Constraints linked to the supply of energy. Villages from
Mean distance Mean distance to to buy the oil charge the (km) batteries (km)
% of households concerned by the charge of the batteries
Kaolack Fatick Thie`s
6.88 5.84 6.83
13 1.19 33.33
22 13 19.23
families have a black and white television. In Thie`s almost every family has a radio and 84% of the families have black and white televisions. Comparing with non-electrified household, electrified households use in general colour televisions, refrigerators, fans, videos and phones. It can be noticed that in Thie`s, unlike in the other two regions, electricity is also used for power-driven pumps. The surveys have been carried out by different teams in each region, as explained in Section 3. The questions were probably not asked in the same manner in all the three regions. Some differences between data of different regions can be explained like this.
Table 8 Electric equipments in non-electrified and electrified household.
4.3. Energetic aspects Inhabitants of non-electrified villages use three main kinds of lights or energy: Oil-lamps, candles. Batteries for torch, butane gas. Solar PV panels with batteries, feeding bulbs. Some people use batteries charged in another village. As shown in Table 7, more than 5 km have to be covered on average to get oil in the three regions. In Kaolack and Fatick, families who use batteries have to cover about 20 km on average to charge them. Table 8 gives some information about the electric equipments used by families in non-electrified and electrified villages. In non-electrified villages of Kaolack, most of the people use radio-cassettes and radios. In Fatick more or less 10% of the Table 5 Statistics about the housing: kind of building for the main building. Cement Laterite mud Others (straw.)
21.64% 73.88% 4.48%
Kaolack region
Cement Laterite mud Others (straw.)
41.86% 50.38% 7.76%
Fatick region
Cement Laterite mud Others (straw.)
80.00% 18.10% 1.90%
Thie`s region
Equipments
In the non-electrified In the electrified households (%) households (%)
Radio-cassette Radio Black and white TV Colour TV Refrigerator Fan Video Freezer Parabolic antenna Mobile phone
83.58 58.96 3.73 1.49 0.00 0.00 0.00 0.00 0.00 0.00
0.00 40.00 0.00 73.33 60.00 40.00 20.00 13.33 6.67 53.33
Kaolack region
Radio-cassette Radio Black and white TV Colour TV Refrigerator Fan Video Freezer Mobile phone DVD/CD player
33.78 66.22 6.75 0.00 0.00 0.00 0.00 0.00 0.98 0.00
60 26.66 0 80 20 53.33 46.66 6.66 53.33 6.66
Fatick region
Radio-cassette Radio Black and white TV Colour TV Freezer Fan Video Mobile phone Refrigerator Electric pump
43.60 96.00 62.00 20.00 0.00 0.00 0.00 1.00 0.00 0.00
60.00 33.00 26.70 73.30 13.30 26.70 20.00 60.00 6.70 46.70
Thie`s region
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Table 9 Substitutable Energetic Expenses (SEEs) for light. Large villages
Medium villages
Small villages
All the villages
Batteries (Fcfa) Candles (Fcfa)
1244 1898
1654 5148
1528 3000
1522 3495
Oil (Fcfa) Total amount
5002 8144
4467 11,269
3988 8516
4432 9449
Kaolack region
Without With ISS ISS 2026.44 1349.61 1003.13 812.39 9.38 294.64
1635.14 281.35
Oil (Fcfa) 8492.3 Total amount 10156.6 Batteries (Fcfa) 1829 Candles (Fcfa) 155.4
4970.11 7817.94 1515.9 400
64.58 2326.79 1423.57 3624.56 2775 1754 150 312.8
3963.44 5879.93 1740.3 352.3
Oil (Fcfa) Total amount
3482.3 5398.2
2543.7 5468.7
1752.8 3845.4
Batteries (Fcfa) Candles (Fcfa)
1664.3 0
7728.4 9712.8
1244 3310.8
Fatick region
Thie`s region
Fig. 3. Sum the households are Willing To Pay (WTP). Table 10 Definition of service levels. Level 1
Level 2
Level 3
Level 4
2–3 Lamps Radio
3–5 Lamps Radio Black and white TV or radio-cassette
6–8 Lamps Radio Black and white TV or radio-cassette 1 Device
More than 8 lamps Radio Colour TV Video Other devices
Table 9 shows the Substitutable Energetic Expenses (SEE) for lighting. It corresponds to total money that households would save if they were electrified and they could use electricity instead of the other lighting systems they are using today. In Fatick and Thie`s the SEEs decrease with the size of the village. Moreover, taking data as a whole, the trend is that SEEs decrease with the proximity to Dakar. This is probably due to the fact that light systems are cheaper when the distance to Dakar decreases. In some villages, households have Individual Solar Systems (ISS). It can be remarked that in these villages, SEEs are logically lower. Four service levels have been defined to facilitate the estimation of domestic electrical energy needs (see Table 10). The first level considers only 2 or 3 lamps and a radio, while the fourth level takes into account more than 8 lamps, one radio, one colour television, one video and other devices as refrigerator or fans. Table 11 shows the distribution of households per Service Level (SL). In Kaolack the number of families which would like to have an SL 2, 3 or 4 is more or less the same. The collected data are similar in Fatick, even if in general, people of this region are a bit more demanding. The service level demand is much higher in Thie`s where more than 81% of households declare that if their village was electrified, they would take out a subscription corresponding to the fourth level. It can also be noticed that very few households are situated in the first SL whatever the region is.
Table 12 Comparisons of the SEE (for light) and the WTP. SL2
SL3
SL4
SEE WTP
SL1 3952 3833
7079 3298
14,847 6561
14,524 11,429
Kaolack region
SEE WTP
10,444 3000
4715 4600
7129 9500
11,208 14,200
Fatick region
SEE WTP
– –
1987 2250
3972 6929
6305 16,267
Thie`s region
Fig. 3 shows what is the sum the households are Willing To Pay (WTP) per service level. In general, happily, families who want a higher SL are willing to pay more. There is however a small contradiction in Kaolack where families who would like an SL 2 are willing to pay less than those who would like to have an SL 1. A comparison between the SEE for lighting and the WTP is made for each region in Table 12. In Thie`s households declare to be willing to pay more than their substitutable energetic expenses. This declaration seems to be coherent. This fact is also more or less true for Fatick except for families of SL 1 who declare to spend quite a lot for lighting. They are maybe families who spend too much money in comparison with their purchasing capacity. In Kaolack households declare to be willing to spend less money than their SEE. Comparing with the other two regions, it is true that their SEEs are higher and it is probable that their incomes are lower.
Table 11 Distribution of household per Service Level (SL). SL1
SL2
SL3
SL4
Number of households % of households
3 2.30
47 35.30
41 30.80
42 31.60
Kaolack region
Number of households % of households
3 4.06
20 27.03
26 35.13
25 33.78
Fatick region
Number of households % of households
0 0
2 1.69
14 13.21
86 81.13
Thie`s region Fig. 4. Loans taken out by households.
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Table 13 Hypotheses made for the estimation of the subscribed power and the consumed energy per household for each SL Number Economic lamps Radio Total Economic lamps Radio Black and white TV Total Economic lamps Radio Black and white TV Refrigerator Total Economic lamps Radio Black and white TV Video Freezer Total
3 1 5 1 1 8 1 1 1 16 1 1 1 1
Power (W) 11 15 48 11 15 40 110 11 15 40 100 243 11 15 40 50 130 411
Operation time (h/d) 3 5 3 5 5 3 5 5 19 3 5 5 1 18
Some questions of the surveys were prepared to see if households are used to take out loans. Actually, if micro-grids are to be installed in the non-electrified villages, it is important to see whether local population would be willing to take out loans to pay for part of the installation. Fig. 4 shows that some families of the three regions are used to take out loans and that the majority of loans are lesser than 400,000 Francs CFA (656 F CFA ¼ 1 V).
Daily consumption (Wh/d)
Monthly consumption (kWh/month)
99 75 174 165 75 200 440 264 75 200 1900 2439 528 75 200 50 2340 3193
2.97 2.25 5.22 4.95 2.25 6 13.2 7.92 2.25 6 37 73.17 15.84 2.25 6 1.5 70.2 95.79
SL1
SL2
SL3
SL4
5. Estimation of electrical energy needs Some data obtained from the interviews can be used to estimate the electrical energy needs of each village. This estimation is necessary to do a good dimensioning of the micro-grids which would be installed in the concerned villages [9]. The electrical energy needs cannot be directly obtained from the data of the surveys. First, some hypotheses have to be made to
Fig. 5. Loads with priority when the power supply is interrupted.
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Fig. 6. Biogas potential in the three regions.
estimate the subscribed power and the consumed energy per household for each SL. Table 13 gives the list of hypotheses which have been made to do this estimation. Thus, for the SL 1, the subscribed power per household would be of 48 W and the consumed energy in one month is estimated to be 5.22 kWh. For the SL 4, the values are 411 W and 95.79 kWh. The different SLs affect only the energy consumption of the household. They do not take into account other shared loads as
public light or pumping. Other hypotheses have to be made to estimate the electrical consumption of these shared loads, and thus to calculate the overall estimated electrical consumption. Concerning public light, it could be composed by a streetlight of 100 W working 10 h per day, hence consuming 1 kWh per day. Moreover, considering the experience of rural electrification, we can take one streetlight for 15 households. Concerning the social infrastructures (school, health centre, mosque), the shops and those in the same category, the consumption can be estimated to be similar to that of the SL 2, that is, a subscribed power of 243 W and a consumed energy of 2439 kWh per day. For pumping and other uses of motor, the consumption is determined considering a load of 3 kW working 4 h per day, corresponding to a total consumption of 12 kWh per day. These hypotheses, along with those of Table 13 and with data from Table 11 concerning the distribution of household per SL, allow the estimation of the electrical needs for the different sizes of villages in the three regions. The estimated electrical energy needs are lower in Kaolack than in the other regions. The lower estimation is made for a village of 250 inhabitants of Kaolack, where the subscribed power would be 5.97 kW and the consumed energy would be 47.26 kW per day. The highest estimation is made for a village of 1500 inhabitants of Fatick, where the subscribed power
Fig. 7. Solar potential assessment in the three regions.
H. Camblong et al. / Renewable Energy 34 (2009) 2141–2150
would be of 49.34 kW and the consumed energy would be 379.29 kW in a day. The micro-grids which would be installed in these villages should be dimensioned to be as cheap as possible. This cost could be reduced by minimising the storage system (normally batteries) capacity or the power of the additional generator (for instance diesel generator). The risk of this strategy is that sometimes, the available energy could be lower than the demanded energy. Then, when this occurs, the population would have to accept the interruption of the power supply for some loads. Fig. 5 shows the loads having priority of supply for the population of the three regions. The mosque has the priority in Kaolack and Thie`s, followed by the health centre and the pumping. In Fatick, the health centre has the priority followed by the mosque and the public light. It must be underlined that the interviews have been done with the chief of each family and that this person is most of the time a man. This can explain why the mosque has the priority. As seen in different seminars organised in the WP 5, for women, usually, the health centre must have the priority. 6. Renewable energies potential The potential of some renewable energy sources has been estimated by collecting corresponding data in each region. The studied resources are the biogas obtained from the animal wastes, the wind energy and the solar energy. Fig. 6 shows the potential of biogas in the three regions. The main part of biogas would be obtained with bovine wastes. The wastes coming from equines, goats and sheep also show a significant potential for the production of biogas. The global amount of biogas which could be obtained with these animal wastes is really important. For instance, more than 400 m3 of biogas could be obtained per day with cattle wastes in Kaolack. However, these data have to be put into perspective. Because the livestock is dispersed in Senegal, it is difficult to collect the wastes. Moreover, after collecting the wastes, they have to be processed to obtain biogas. Thus, considering all these factors, the use of animal wastes to generate electricity does not still seem to be efficient enough to be considered as a resource for rural electrification. Because of its geographical situation, solar energy potential is very important in Senegal. On average the country gets 3000 h of sunshine a year. It corresponds to a total energy average of 5.8 kWh/m2 per day. Fig. 7 shows the daily radiation in the three regions. The trends are the same: the radiation is maximal in April and May and minimal in December and January, but it is really very high through the year. This solar potential can be used to generate directly electricity with PV panels. This technology is still relatively expensive but very appropriate for isolated sites, such as rural villages distant from the Senelec’s grid. Moreover, the prices of the panels are decreasing. In the future, solar thermodynamic power stations [10] would be able to produce cheaper electrical energy, but this technology is not still mature. Wind energy is the renewable energy that has experienced the highest degree of development during the last two decades [11]. It is now very competitive in relatively windy sites. Some global, but not very precise studies have been carried out in Senegal to analyse the wind energy potential. The average wind speed in the three considered regions is between 3 and 5 m/s, most of the time being more than 4 m/s (Fig. 8). According to these data, wind energy is not very interesting in these regions, but wind speed can be higher locally, near a river, the sea or on a hill. The first wind farm will probably be installed rather soon by a European company in such a site with good wind.
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Thus, contrary to PV panels, wind energy will not be competitive in every non-electrified rural village, but it could be in some locally windy villages.
7. Constraints and solutions to the development of microgrids in Senegal The micro-grid concept is not really new in Senegal. Aside pure PV power stations (Diaoule´ in Fatick and Ndie´bel in Kaolack in the frame of a Senegal–German project, Djirnda in Fatick in the frame of a Senegal–Nippon project), some hybrid PV-diesel generator power stations have been installed in Fatick, precisely in Bassoul–Bassar and Saloum Island. However, despite rural population needs, these kinds of power stations have not still been installed at a large scale. Moreover the already installed power stations have had some operating problems. One of the main objectives of the dissemination activities organised in the WP 5 of the Micro-grids project has been to develop activities to deal with three major challenges for the development of micro-grids in Senegal: The availability: the appropriate offer of energetic services must be increased. The acceptability: adapted energetic equipments which answer to the rural population needs must be created (for the transformation of farm products, for the construction of farm tools and equipments,.). The accessibility: poor people of rural regions must have access to energetic services.
Fig. 8. Wind speed assessment in the three regions.
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Table 14 Estimation of electrical energy needs per size of village and per region. Small villages Population Person/households Households Total power demand (kW) Energy demand (kWh/d)
250 14 18 5.97 47.26
Person/households Households Total power demand (kW) Energy demand (kWh/d) Person/households Households Total power demand (kW) Energy demand (kWh/d)
Medium villages 350 25 7.77 61.45
500 16 31 12.18 94.63
11 23 10.67 77.44
32 13.05 96.78
13.36 19 10.02 75.3
26 12.82 97.66
Large villages
47 16.11 125.67
1000 18 56 21.11 158.01
83 28.09 213.18
Kaolack region
13.2 38 16.17 121.35
57 21.14 161.65
10.3 97 36.6 275.99
146 49.34 379.29
Fatick region
14.33 35 16.5 126.8
52 23.03 178.82
19.5 51 35.37 234.04
77 44.96 310.65
Thie`s region
Below there is a synthesis of the main constraints and the corresponding solutions which have been listed in the different events organised in Senegal: Administrative procedures are heavy. They must be lightened. The tax system is restrictive. Some incentive measures have to be applied for the energetic sector. The local or administrative authorities and the regional committees for the development are not sufficiently implicated upstream of and downstream from the electrification projects. Governors, prefectures and other authorities must be involved in the projects. Beneficiaries, it is to say population of non-electrified villages, are not involved in the financing of the project. They have to take part in the financing to be considered as partners. There are no maintenance systems. The training in maintenance of professionals’ associations must be encouraged to professionalize this field. The spare parts are not available. A toll-house must be created to ease the access to the tools for the technicians in renewable energies. There are not monitoring systems to assess the projects. The partners of the projects must carry out the monitoring and assessment of the project at medium and long term to ease the capitalisation of the projects. There are few continuing education procedures for local expertise. The local expertise must be strengthened through seminars and continuing education sessions. Renewable energies are not included in the training programs. Renewable energies must be included in the school programs, specially in the scientific education. 8. Conclusion The work carried out in the WP 3 and 5 of Micro-grids project and presented in this paper has led to very interesting results. A reliable estimation of the population electrical needs has been obtained in WP 3 by carrying out some surveys. The results from the surveys in the three regions were not always homogenous. This non-homogeneity can be explained in part by the fact that the interviewers’ teams were different in the three regions. Moreover, the results have to be analysed keeping in mind that the questions were asked to the household’s chief who is most of the time a man. Women have a very important place in the domestic activities and their participation in the rural electrification projects is essential. However, the household’s chief being the person who takes the decisions, it was justified to select him to carry out the surveys, specially for the statement about the actual energy spending and the willingness to pay for electrical services. Nevertheless, in the
750
1500
future, it could be interesting to carry out new surveys by involving more people from the households. The presented study has demonstrated that the use of RES for Senegal rural electrification has considerable advantages. There is a huge solar potential and an interesting wind in some sites. Moreover, the technological evolution of RES equipment is linked to the concerns of the users (the supply of electrical energy by micro-grids answers to the energy request for productive activities and increases the contribution of energy to poverty alleviation) (Table 14). This paper presents only one part of the results of Micro-grids project. The results presented in this paper have allowed the design of a rural electrification kit which is described in Ref. [9]. Now, the objective of the Micro-grids’ consortium is to build and install micro-grids in some non-electrified villages of Senegal, on the basis of the designed rural electrification Kit. Acknowledgements This study was carried out with financial support from the Intelligent Energy Europe (IEE) programme managed by the Executive Agency for Competitiveness and Innovation (EACI). The authors of this paper would like to thank all the partners of the Micro-grids project for their significant involvement. References [1] International Energy Agency (IEA) Statistics Division. Energy balances of OECD countries. Energy balances. 2006 ed. Paris: IEA. Available at http://data.iea.org/ ieastore/default.asp; 2006. [2] Population Division of the Department of Economic and Social Affairs of the United Nations Secretariat. World population dataset on CD-ROM. New York: United Nations. Available at http://www.un.org/esa/population/publications/ WPP2004/wpp2004; 2005. [3] Leitch AWR, Scott BJ, Adams JJ. Non-grid electrification of 45 schools in the Eastern Cape, South Africa: an assessment. Renewable Energy 1997;10(2– 3):135–8. [4] Abdeen Mustafa Omer. Solar water pumping clean water for Sudan rural areas. Renewable Energy 2001;24:245–58. [5] PushpendraJain K, Nijegorodov N, Kartha CG. Role of solar energy in development in Botswana. Renewable Energy 1994;4(2):179–88. [6] Othieno H. Photovoltaic technology: most appropriate electricity source for rural tropical Africa. Brighton, UK: World Renewable Energy Congress VI; 2000. p. 1962–5. [7] Project official web site: http://www.microgrids-eie.com. [8] Analysis of local needs for rural zones electrification in Senegal [Analyse des besoins locaux pour l’e´lectrification de zones rurales au Se´ne´gal]. Technical report of Microgrids project WP 3, http://www.microgrids-eie.com; 2007 [in French]. [9] Alzola JA, Vechiu I, Camblong H, Santos M, Sall M, Saw G. Microgrids project, part 2: design of an electrification kit with high content of renewable energy sources in Senegal, Renewable Energy, submitted. [10] Bonnet S, Alaphilippe M, Stouffs P. Thermodynamic solar energy conversion: reflections on the optimal solar concentration ratio. International Journal of Energy, Environment and Economics 2006;12(3):141–52. [11] Yang Ming. Climate change drives wind turbines. Energy Policy 2007;35(12):6546–8.