Bachelor of Science Thesis
KTH School of Industrial Engineering and Management Energy Technology EGI-2017
SE-100 44 STOCKHOLM
Development and Design of a
portable off-grid photovoltaic system with contingency functions for rural
areas (Case study Rwanda)
Shaida Faiqi
Hanna Ma
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Bachelor of Science Thesis EGI-2017
Development and Design of a portable off-grid photovoltaic system with contingency functions for rural areas
(Case study Rwanda)
Shaida Faiqi Hanna Ma
Approved Examiner Supervisor
Commissioner Contact person
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Abstract
This project is initiated by Engineers without Borders at Kungliga Tekniska Högskolan(KTH) in collaboration with the non-governmental organization Rwanda Village Concept Project at the University of Rwanda. It is funded by KTH Opportunities Fund with an amount of 20 000 SEK.
The aim of the project is to design a portable off-grid photovoltaic(PV) system for a typical rural household in Rwanda, more specifically in the village Nyamabuye where there is no access to electricity. The requirements for the system are to have a total cost under 20 000 SEK, a weight under 25 kg and a capacity that meets the energy demand for a rural household. The system consists of PV modules, a battery, a charge controller and a converter. A literature study on off- grid PV systems and the components was conducted. For the case study, an estimation on the energy demand was made based on answers from a survey for locals in Nyamabuye and the current energy situation in Rwanda. To dimension the PV system according to the estimated energy demand, calculations based on a mathematical model for PV systems were conducted in MATLAB. A comparison regarding cost, weight, efficiency etc. of components that currently are available at the market was made. Components could then be chosen to make the system meet the set requirements. The result is a PV system that has a total cost of 10670 SEK and a weight of 13.6 kg. It is dimensioned to meet a daily energy consumption of 1022 Wh. There are several factors that could affect the performance of the system, for example different outdoor temperatures, that were not considered for simplicity. Therefor it is recommended that the system should be tested in different conditions.
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FIGURES ... 5
TABLES ... 6
NOMENCLATURE ... 7
1 INTRODUCTION ... 9
2 OBJECTIVES AND GOALS ... 9
3 BACKGROUND ... 10
3.1 RWANDA ...10
3.1.1 Energy use in Rwanda ...10
3.1.2 Nyamabuye ...11
3.2 ENERGY CONSUMPTION OF HOUSEHOLD APPLIANCES ...13
3.3 PV SYSTEM ...14
3.3.1 PV module ...15
3.3.2 Battery ...15
3.3.3 Inverter and converter ...16
3.3.4 Charge controller ...16
3.3.5 Cables ...17
3.4 COSTS AND MARKET FOR PV SYSTEMS ...17
3.5 EXISTING PV SYSTEMS ...17
3.5.1 Projects ...17
3.5.2 Companies ...18
4 METHOD ... 21
4.1 LIMITATIONS AND ASSUMPTIONS ...22
4.2 DIMENSIONING OF THE PV SYSTEM ...22
5 RESULTS AND DISCUSSION ... 24
5.1 ENERGY DEMAND IN NYAMABUYE ...24
5.2 DIMENSIONING OF THE PV SYSTEM ...25
5.3 SELECTED COMPONENTS FOR THE PV SYSTEM ...26
5.4 COMPARISON WITH EXISTING PV SYSTEMS...27
5.4.1 Projects ...27
5.4.2 Companies ...27
5.5 SENSITIVITY ANALYSIS ...28
5.6 SUSTAINABILITY ...29
6 CONCLUSIONS AND FUTURE WORK ... 30
REFERENCES ... 31
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Figures
Figure 1 Solar radiation map over the world, showing sun peak hours(Altestore, n.d). ... 13 Figure 2 Schematic diagram of the PV system. ... 15 Figure 3 Diagram showing the power for the appliances and during which hours they are used
during a day. ... 25
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Tables
Table 1 Percentage of households possessing various household effects. ... 11
Table 2 Monthly averaged insolation incident on a horizontal surface at indicated GMT times (kW/m2). ... 12
Table 3 Monthly averaged daylight hours (hours) ... 12
Table 4 Advantages and disadvantages of PV systems. ... 14
Table 5 Comparison between lead-acid and lithium-ion batteries. ... 16
Table 6 Temperature, price and usage area for MPPT and PWM charge controllers. ... 16
Table 7 Different systems in Tanzania with including components. ... 18
Table 8 A list of PV systems that are available on the market, arranged after price. ... 19
Table 9 Specification of PV system 1. ... 20
Table 10 Specification of PV system 2. ... 20
Table 11 Specification of PV system 3. ... 21
Table 12 Data for appliances. ... 24
Table 13 Results from calculations. ... 26
Table 14 Specification and price of chosen components. ... 26
Table 15 Specification for the whole PV system. ... 27
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Nomenclature
Abbreviations
AC Altering current
CAD Computer-aided design DC Direct current
EWB Engineers without Boarders GDP Gross domestic product KTH Kungliga Tekniska Högskolan MPPT Maximum power point tracker NGO Non-governmental organization PV Photovoltaic
PWM Pulse width modulation
RVCP Rwanda Village Concept Project SLI Starting, lighting, ignition
Symbols
Symbol Description Unit
𝐸𝐸 Daily energy demand [Wh]
𝑃𝑃𝑖𝑖 Effect of a specific appliance [W]
𝑡𝑡𝑖𝑖 Time a specific appliance is used during a day [h]
𝑊𝑊𝑃𝑃𝑃𝑃 Peak wattage of the array [W]
𝐺𝐺 Daily average peak sun hours [h]
𝜂𝜂𝑆𝑆𝑆𝑆𝑆𝑆 Efficiency for the total system [-]
𝜂𝜂𝑃𝑃𝑃𝑃 Efficiency of PV modules [-]
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𝜂𝜂𝑃𝑃𝑃𝑃−𝐵𝐵𝐵𝐵𝐵𝐵𝐵𝐵 Efficiency of the cables from PV array to battery [-]
𝜂𝜂𝐶𝐶𝐶𝐶 Efficiency of the charge controller [-]
𝜂𝜂𝐷𝐷𝐷𝐷𝑆𝑆𝐵𝐵 Efficiency of distribution cables from PV battery to loads [-]
𝜂𝜂𝐶𝐶𝐶𝐶𝐶𝐶 Efficiency of the converter [-]
𝑄𝑄 Minimum battery required capacity [Ah]
𝐴𝐴 Number of days of storage required [-]
𝑉𝑉 The system DC voltage [V]
𝑇𝑇 Maximum allowable DOD of the battery [-]
𝜂𝜂𝐶𝐶𝐵𝐵𝐵𝐵𝐶𝐶𝐶𝐶 Efficiency of the cables from battery to loads [-]
𝑁𝑁 Number of required PV panels [-]
𝑊𝑊𝑝𝑝 Peak wattage of the selected module [W]
𝐼𝐼𝑜𝑜𝑜𝑜𝑜𝑜 Output current of the PV system [A]
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1 Introduction
In developing countries, such as Rwanda, many people lack access to electricity. Access to electricity is a prerequisite for good living standards as well as development in many areas. In Rwanda, less than 20 % of the households are connected to the national grid (PRnewswire, 2014). There are many on-going projects to increase the number of households that have access to electricity, for example the project Scaling Up Off-Grid Energy in Rwanda(SOGER) by Sweden (Swedenabroad, 2016). Rwanda has large untapped potential for renewable power generation, for example solar energy. Photovoltaic (PV) systems are a good option for making use of solar energy due to their versatility and adaptability to demands. PV systems can be quickly installed and implemented and are sustainable in many aspects. Compared to other renewable energy resources, PV systems generally requires less resources in terms of material and maintenance.
The task of this project is to design a prototype for a portable PV system that is supposed to be implemented in the village Nyamabuye in Rwanda. The project is initiated by Engineers without Borders(EWB) and collaborates with the non-governmental organization (NGO) Rwanda Village Concept Project (RVCP) in Rwanda. RVCP is run by students at the University of Rwanda and have acted as local contact persons for this project. The village has been selected by the NGO RVCP for two main reasons. The first reason is that Nyamabuye has big potential for solar energy while there is no access to electricity, and secondly, due to the proximity to the University of Rwanda.
Several solutions to off-grid mobile PV systems currently exist on the market, but there are still motivations for the development of a new PV system. The main reason is to be able to adapt to the specific demands of Nyamabuye. The goal is to develop a PV system that is able to provide electricity needed for a typical rural household. The desired features for the system are mobility, durability, simplicity and low cost. Compared to existing solutions for mobile PV systems, the advantage of a self-developed system is that factors like the size and cost of the system can be adjusted to a greater extent. The system should have a design that makes it easy to replace the components if needed to avoid the need of replacing the entire system. The reason to develop a system that is mobile is to be able to account for unforeseeable events, for example natural disasters and political instability, that might force immediate relocation.
This project is funded by KTH Opportunities Fund and covers the component costs of the construction of the PV system. The challenge will be to size and select appropriate components in terms of price and function. Since it is also decided that the system need to be portable the weight and cost of the components must also be considered.
2 Objectives and Goals
In rural areas of Rwanda access to grid electricity is very limited or nonexistent. A good option for these areas is to implement autonomous PV systems for power generation, which could improve the living conditions there. The main objective of this project is to design a prototype for a mobile off-grid PV system using conventional PV system technology. The PV system is intended to be implemented in a typical rural household in Rwanda, more specifically in
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Nyamabuye, and should meet several requirements based on the current situation and the potential for solar energy in Rwanda. The energy demand for a typical household in Rwanda needs to be ascertained as well as the components that are suitable for the system. To choose the suitable components for this system several factors, such cost, weight and efficiency need to be taken in to consideration. The system should be lightweight in order to be mobile, the maximum weight of the system is set to 25 kg. The total cost of the system should hold for the budget of 20 000 SEK. Lastly, a comparison between existing PV systems and the system developed in this project will be made to determine the plausibility if the system.
3 Background
3.1 RwandaRwanda is, with an area of 26 338 km², among the smallest countries in Africa and is located in the east central part of the continent. Rwanda has about 12 million inhabitants and a large majority of the population are subsistence farmers. The country is trying to recover from the government-sponsored genocide in the mid -1990s. The background to the genocide is the ethnic tension associated with the traditionally unequal relationship between the Tutsi minority and the majority Hutus.
Many development projects are underway in Rwanda. The focus of these projects is mainly on strengthening the economy, but the government is also very keen to prevent conflicts between ethnic groups. The results of these projects have been very successful and Rwanda is growing quickly in many areas. Despite these successes, Rwanda remains as one of the world’s poorest countries; in the United Nations Development Programme Human Development Index from 2015 Rwanda was ranked in place 163 of 188 countries included.
The rapid increase of the population density and growth affects the degradation of the nature.
Consequently, there is for example soil depletion due to outdated agricultural and reduced availability of water.
3.1.1 Energy use in Rwanda
The primary use for energy in Rwanda is biomass, which is approximately 86 % of the total (EPD, 2003). This is used in the form of firewood, charcoal and agricultural residues for cooking purposes. Agriculture is accounting for a third of Rwanda's Gross domestic product (GDP), and it is also the most important rural income, about 80 % of the population are active in the agriculture.
Fewer than 20 % of the households have access to electricity connected to the national grid, which is one of the lowest electricity consumption per capita in the region. The electricity is mainly generated by hydro and thermal plants, solar sums only to a negligible portion (PRnewswire, 2014).
Table 1 shows the percentage of the households that uses different devices. More than half of the population own a radio, but almost none have access to a refrigerator. Owning a mobile
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telephone is also very common, this number has increased significantly since 2010, when only 40
% owned one (NISR, 2015).
Table 1 Percentage of households possessing various household effects.
Household appliance Urban Rural Total
Radio 67.1 51.9 54.5
Television 38.6 3.6 9.6
Mobile telephone 86.4 54.2 59.8
Non-mobile telephone 1.0 0.1 0.2
Refrigerator 8.4 0.2 1.6
Computer 13.9 1.0 3.2
(NISR, 2015)
3.1.2 Nyamabuye
Nyamabuye is a village located in Rwaniro sector, Huye district, in the southern province in Rwanda. The village is located on top of the Bweramana hill and is surrounded by trees. It has 3499 inhabitants and most of them are agriculturists. Most of the houses in the village are made up of two to three bed rooms with a small farm in the back yard. According to the head of village, there are at least 6 people living in each house.
There is a school in Nyamabuye made up of primary and secondary school. It is the only school in the sector. The average education level in the village is primary school education. There are no people with technical knowledge in the village, such as engineers and technicians.
There is a health centre in Nyamabuye called Rwaniro Health Centre. It offers services such as maternity services, laboratory testing, and vaccination. Due to lack of electricity, there are many services that can not be offered at the health centre.
There is no connection with the national grid in Rwaniro sector. The only source of electricity in Nyamabuye is a solar panel at the primary school, which was provided by a European Union project called IREARPPP (Increase Rural Energy Access in Rwanda Through a Private Partnership). The solar panel is only enough to serve 8 out of 22 classes at the school.
The geographic coordinates for Nyamabuye are -2.33030°(latitude), 29.70930°(longitude). Table 2 shows the monthly average insolation incident on a horizontal surface at this position obtained from NASA.
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Table 2 Monthly averaged insolation incident on a horizontal surface at indicated GMT times (kW/m2).
GMT Time Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec
00 n/a n/a n/a n/a n/a n/a n/a n/a n/a n/a n/a n/a 03 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 06 0.27 0.27 0.28 0.30 0.28 0.26 0.25 0.27 0.32 0.34 0.34 0.31 09 0.67 0.71 0.69 0.66 0.63 0.65 0.70 0.73 0.73 0.68 0.64 0.65 12 0.52 0.55 0.54 0.54 0.54 0.56 0.61 0.61 0.56 0.48 0.47 0.48 15 0.13 0.15 0.14 0.13 0.12 0.13 0.15 0.15 0.11 0.09 0.09 0.11 18 n/a n/a n/a n/a n/a n/a n/a n/a n/a n/a n/a n/a 21 n/a n/a n/a n/a n/a n/a n/a n/a n/a n/a n/a n/a (NASA, n.d.)
Table 3 shows the monthly average hours of daylight in Nyamabuye. The data is obtained from NASA at the coordinates mentioned earlier. It can be concluded that Nyamabuye has approximately 12 hours of daylight per day.
Table 3 Monthly averaged daylight hours (hours)
Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec 12.2 12.1 12.1 12.0 12.0 11.9 12.0 12.0 12.1 12.1 12.2 12.2 (NASA, n.d.)
Figure 1 indicates the number of peak sun hours different areas of the world have. It is shown that countries in Europe, North America and North Asia have around 1-3 hours of sun peak hours, the lighter colors. Meanwhile in Africa, Australia and South America the value can be up to 7 hours, marked with darker red colors. Rwanda has approximately 5 peak sun hours a day (MININFRA, n.d.).
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Figure 1 Solar radiation map over the world, showing sun peak hours(Altestore, n.d).
3.2 Energy consumption of household appliances
The PV system that will be developed should be able to provide power for typical household appliances. The appliances considered in this study are mobile phone charger, lights, radio and refrigerator. The energy consumption for different appliances in a household can vary depending on the year of manufacture, quality etc.
Mobile phone chargers can have energy consumption less than 5 W (Government of South Australia, 2017). This value varies for different brands and phone types, but this is the typical value for a charger.
There are many categories of lights: LED, UV, incandescent GLOBES, gas discharge lamps etc.
All the types have different ranges for energy usage. The variation range can be from 9 W for LED to 60 W for incandescent globes. (Government of South Australia, 2017)
Radio devices do not require much energy consumption; the value is usually approximately 5 W.
Radios also have different values depending on category. (OECD, 2014)
Refrigerators can be manufactured in many sizes, everything from small-scaled minibars to larger refrigerators for restaurant kitchens. They are also equipped with lights that require energy when the refrigerator is open. The refrigeration cycle has different loads of energy consumption during the day to keep it cold inside. The cycle also indicates that the refrigerator is not always on working mode. It does not require the same watts for the whole day, the power goes up and down from hour to hour depending on how often it is used. The range for the energy consumption can be everything between 20 – 200 W, depending on quality and size. (Centre for Sustainable Energy, n.d.) (Warren Recc, n.d.)
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A PV system is an electrical power generating system that generates electricity by using solar energy. There are many different types of PV systems and the application possibilities and size of the PV system can range from small stand-alone systems for households to large gird-connected systems.
The two main types of solar PV systems are grid-connected systems and off-grid/stand-alone systems. Grid-connected systems have alternating current (AC) outputs that matches the capacity of the electric utility grid and can supply the grid with excess power. Stand-alone PV systems work independently and are suitable for areas without access to the electrical grid, such as rural areas. Depending on the application, the system can be configured to provide direct current (DC) or AC. Stand-alone systems generally require batteries for energy storage. Solar hybrid power systems also exist, meaning that a PV system can be connected to another energy source, for example a diesel generator.
PV systems offer various benefits, e.g. low maintenance, environmental friendly, and no need for fuel. They are also competitive regarding costs. The whole life-cycle costs, including costs for operation, fuel, replacement of components etc., are relatively low. The initial cost for PV systems can be relatively high though, but the prices are decreasing (IRENA, 2016). Some advantages and disadvantages of PV systems are shown in Table 4.
Table 4 Advantages and disadvantages of PV systems.
Advantages of PV systems Disadvantages of PV systems
• No emissions
• No need for fuel
• Low maintenance
• The size of the systems can be adjusted depending on the application
• Cost effective for small applications with demands below 3-5 kWh a day.
• High initial cost
• Stand-alone systems usually require batteries which require maintenance and replacement
The fundamental part of the PV system are PV modules which convert sunlight into electricity.
The PV system also consists of several other components which are needed for the system to function as desired. The specific components needed for a specific system depends on the system’s requirements. The main components considered for the PV system in this project are PV modules, battery, charge controller and converter. Figure 2 shows a schematic diagram of the system. These components are described more in detail in the following sections.
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Figure 2 Schematic diagram of the PV system.
3.3.1 PV module
PV modules convert sunlight to electricity through the photovoltaic effect. There are several different types of PV modules. To choose modules that are suitable for a certain application the advantages and disadvantages of the different module types need to be considered.
The most common types of PV modules are monocrystalline and polycrystalline silicon, which together stands for around 90 % of the production (Hankins, 2010). Both module types exhibit long lifetimes, manufacturers usually have guarantees for around 20 years (Kolhe et al., 2015).
Monocrystalline silicon PV cells are the most efficient, around 15 % of the solar energy gets converted into electricity (National Energy Foundation, n.d.). The manufacturing costs for monocrystalline silicon PV are high due to the complicated manufacturing process.
Polycrystalline silicon PV cells generally have a lower cost compared to monocrystalline silicon PV cells, but they have a lower efficiency of around 12 % (National Energy Foundation, n.d.).
Another alternative is thin film PV. Thin PV are lightweight and have lower manufacturing costs.
The disadvantage is that they are generally less efficient than the crystalline silicone ones.
3.3.2 Battery
Batteries are used for storage of the energy produced by the PV modules. This makes it possible to use the energy without sunlight. There are different types of batteries that are suitable for PV systems. The types that are suitable are deep-cycle batteries, which can be discharged down to 80
% before recharging. Some factors that should be taken into consideration when choosing the type of battery are cost, capacity, voltage, cycle life etc. Two of the most common types are lead- acid batteries and lithium-ion batteries, which are the types considered for this project. The advantages and disadvantages for these battery types are shown in Table 5.
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Table 5 Comparison between lead-acid and lithium-ion batteries.
Advantages Disadvantages
Lead-acid • Low cost per watt hour
• Good charge retention
• Good low temperature performance
• Relatively short cycle life
• Lead is not
environmentally friendly
• Low energy density Lithium-ion • Low maintenance
• High energy density, low weight
• High manufacturing costs
3.3.3 Inverter and converter
There are two ways of transferring electric power; namely DC and AC. In DC the electric charge only flows in one direction, while it changes periodically in AC. The electric power from the PV panel is producing DC and a DC-AC inverter in a PV-system converts DC to AC.
There is also a DC-DC converter, which changes the voltage from one level to another while the current is the same. To choose the right converter or inverter for a PV system, the nominal voltage should be the same as the battery connected to the converter or inverter.
3.3.4 Charge controller
A charge controller protects the battery from overcharging and deep discharging by controlling the power flow in and out of the battery bank. There are two kinds of charge controllers for a PV system; Maximum power point tracker (MPPT) and Pulse width modulation (PWM). The difference between these is that a MPPT charge controller make sure that the PV panels are operating optimally while a PWM adapts to the battery voltage. A comparison between the charge controllers can be seen in Table 6. MPPT charge controllers are more expensive but also more effective. Because of these factors the charge controllers are used in different areas when PV systems are used. The MPPT charge controller is more useful when building larger systems that requires more power, while small home systems use the cheaper alternative, i.e. PWM.
(Kalogirou 2009, 490-492)
Table 6 Temperature, price and usage area for MPPT and PWM charge controllers.
Solar cell
temperature (°C) Price Usage area
MPPT Lower than 45 and
higher than 75 High cost Good for higher
power system
PWM 45-75 Low cost Good for smaller
power system (Victron Energy, 2014)
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To connect the components in the PV systems cables are used. These cables must have some properties for DC and they generally need to be light, flexible and UV and water-resistant. They must also be able to handle high temperature and voltage. (Antony, 2010)
It is important that the cables are UV and water resistant since they will be exposed for different kinds of weathers, for example sun and rain. The cables need to be dimensioned by the size of the PV system regarding voltage and volume.
3.4 Costs and market for PV systems
The market for PV systems are growing rapidly due to cost reductions and new business models.
Cost for PV modules have been reduced by 80 % from 2009 to 2015 and are expected to continue falling.
In Africa, the cost per watt for PV systems are higher compared to the cost in developed countries. The reason is that the systems in Africa usually have lower capacities. Solar home systems in developed countries are typically between 3 and 5 kW while they are between 20 to 100 W in Africa. The smaller systems usually need battery and charge controllers for continuous power output, which makes them more expensive.
The cost for solar home systems with capacities under 1 kW are usually between 4 USD and 11.3 USD/W. Cost for the battery and charge controller are between 2.5 USD/W and 6.8 USD/W.
For systems based on DC, the system cost excluding the battery and charge controller typically lies in the range 1.8 USD/W to 13.9 USD/W. For systems based on AC, the costs are higher since they have the need for an inverter and often are larger.
Batteries account for the biggest part of the system cost (around 29 %) and their cost ranges from 1.2 USD/Ah to 3.4 USD/Ah. They also require more maintenance and have relatively short lifetimes compared to the other components in the system. The lifetime for batteries are usually not longer than 5 years, while PV modules can have a lifetime of over 20 years. This makes the replacement of batteries a significant factor of the whole life-cycle cost of a PV system.
(IRENA, 2016)
3.5 Existing PV systems
This section gives an overview of some examples of existing PV systems. PV systems developed through projects are described in section 3.5.1 and systems developed by companies are described in section 3.5.2.
3.5.1 Projects
Many countries use PV systems in rural areas to easily access electricity since it is common that they do not have access to the national electrical grid. In rural areas in Africa there are many projects with the aim to develop off-grid PV systems (SIDA, 2017).The projects consist of both larger and smaller systems.
In the area Holgojo in Kenya there is no connection to the national grid. In a project sponsored by SIDA (Swedish International Development Agency), a solar powered irrigation system was developed. This system makes it possible for water to be extracted from different sources by a
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pump to requested areas for the farmers there. The system was implemented 2014 and has worked well for some years. It has components with high quality. (GIZ, 2015)
Tanzania borders to Rwanda and has the same solar radiation levels as Rwanda. There are many projects with the aim to develop off-grid PV systems in Tanzania. In the rural region Ruvuma in Tanzania there are some examples of PV systems, both at schools and privately owned.
The privately owned PV system has been designed and installed by the owner himself. The system did not have a charge controller. The panels in the system were connected directly to the batteries, which were of the type SLI (starting, lighting and ignition), which is a type of rechargeable lead-acid battery mainly used in automobiles. An inverter was also installed.
The same area in Tanzania also had schools with PV systems. These systems had been designed and installed by technicians. There were one AC/DC system and two DC systems. All of the systems had been built to be protected from rain. The batteries were all of the type deep-cycle.
The systems also had inverters, charge controllers and panels on the roof. The charge controllers had low capacity and if higher capacity is needed, more can be connected together. (Henoch, P., Steen Englund, J., 2015)
The described systems in Tanzania are shown in Table 7.
Table 7 Different systems in Tanzania with including components.
Inverter/converter Panel Charge controller
Battery
Private system Yes Yes No Yes, SLI
DC system Yes Yes Yes Yes, deep-cycle
AC/DC system Yes Yes Yes Yes, deep cycle
3.5.2 Companies
The market for PV systems are growing and more companies are selling these products (Solarserver, 2017). A list of different models of already assembled PV systems is shown in Table 8. The list shows the PV system with the lowest price at the top and the highest on the bottom.
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Table 8 A list of PV systems that are available on the market, arranged after price.
Model Battery Capacity
(W) Weight (kg) Price (SEK) A.B.T
BESTSUN BPS- 800W
AGM 800 130 3 153
TREGOO 10-
50 Extreme Li-Ion 50 3 1 000
HT-S60W-1P
portable solar Sealed lead-acid 60 22 1 500
MTO-SL300 AGM 50 30 4 000
CRG/PI-P300-I Lithium iron phosphate 20 30 5 000 WRM
30200170
AGM 150 45 5 700
Luxen LNSF-
310M Li-ion 310 36 6 000
LVDA Poly 260W
Sealed lead-acid 260 38 8 000
TREGOO 40-
120 Li-ion 120 6 9 000
WRM 30200305 AGM 300 50 9 500
YB-500W AGM 540 60 10 000
A.B.T BESTSUN BFS-3000W-S
Lead-acid AGM 3000 200 15 000
Gecko 500 Li-ion 500 10 15 600
YS1000W-OFF Deep cycle gel 1000 60 16 000
BFS 3000 Deep cycle gel 1500 430 20 000
Storion-S3 Lead-acid AGM 3000 135 28 000
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Tables 9-11 show three different mobile PV systems including all required components from different companies. The tables give information about the various components capacity and the total weight and price. The tables indicate that a larger system results in a higher price.
Table 9 shows a photovoltaic solar kit with 250 W and 24 V. This kit has mainly been designed for applications such as boats, camper vans, cabins and lodges. The design of the system has been developed to make it easy to install and be well protected against damage. (Shopenergia, 2017)
Table 9 Specification of PV system 1.
Panel Inverter Charge controller Battery
Specification Polycrystalline Solar Panel 250 W 12 V/24 V
12/230 V
1000/2000 W Western Charge
Controller 12/24 V 15 A - WRM15
AGM 12 V 100 Ah battery
Dimension (mm)
1650x992x38 350 x 150 x 62 340 x 220 x 163
Weight (kg) 18 2.65 1 30
Total price (SEK)
6000
Total weight
(kg) 52
The second solar kit, shown in Table 10, has been established as a backup system for a household with many electrical appliances. When the power goes out during a shorter period of time this system will work as an emergency kit. The power for the PV system is 30 W and has the capacity to power mobile phones, radios, internet router, LED lantern, computer etc. (Altestore, 2016)
Table 10 Specification of PV system 2.
Panel Inverter Charge
controller Battery Specification Polycrystalline
30 W 12 V
12 V 350 W 33 A
5 A 12/24 V selectable PWM
12 V
Lead-acid Battery 18 Ah
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(mm) 690 x 350 x 25
200 x 150 x 62 65 x 158 x 25 76 x 181 x 167
Weight (kg) 3.2 0.75 0.2 6
Total price
(SEK) 3500
Total weight
(kg) 10.15
Table 11 shows a PV system with high capacity. It is designed to provide energy for cabin households but can also be used for smaller houses (Altestore, 2016).
Table 11 Specification of PV system 3.
Panel Inverter Charge controller Battery
Specification 31.0 V 270 W
24 V 1500 W
35 A 12 V
AGM Batteries 12 V
Dimension
(mm) 1662 x 990 x 46 42 0 x 210 x 12 0 254 x 127 x 635 210 x 130 x 184
Weight (kg) 20 9 1.4 11
Total price
(SEK) 25300
Total weight
(kg) 42
4 Method
The project begins with a literature study on PV systems and on the target village in Rwanda:
Nyamabuye. This thesis is a part of the project by EWB at KTH in collaboration with the NGO RVCP. RVCP provides us with information concerning energy demands for the locals and the current situation there. As described in section 3.1.2, the locals have limited access to electricity.
Therefor a survey including the requirements and demands needed in the rural areas will be used to decide the size of the PV-system. The survey has been developed by KTH and EWB and can be found in Appendix 1. NGO RVCP will be in contact with the locals and provide with required information.
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The result of the information retained from the literature study and the survey will be in consideration when calculation for choosing the right material. The calculations will be made with the computing program MATLAB.
Before selecting the components for the PV system, a comparison with different existing systems will be made. The comparison will be made with both systems that are available on the market and systems that currently are used in rural areas. This to see how components can be placed and to see if the developed PV system meet the requirements usually set for PV systems.
4.1 Limitations and assumptions
• This project only focuses on standalone PV systems for households.
• Since the PV system is mobile, there are several limitations compared to a non-mobile system. The PV panels are assumed to be horizontal since the panels can not be mounted at any angle. The weight and size of the system will be limited in order for it to be mobile.
The maximum weight is set to 25 kg.
• For simplicity, the energy demand is assumed to be constant. The appliances are assumed to be used during the same hours each day. The peak sun hours and sun hours are assumed to be constant, with the average values of 5 hours and 12 hours respectively.
• It is decided that the PV system should be able to provide electricity for 24 hours. Since the average sun hours in Rwanda are 12 hours, the battery is required to store energy for the remaining 12 hours.
• The household appliances are assumed to only require DC. This means that no inverter will be needed for the system, which will make the system smaller.
• The project is funded by KTH Opportunities Fund with an amount of 20 000 SEK, which should cover for the costs of all the components in the PV system. Since the resources are limited, the cost for the components need to be considered.
• The system has a voltage of 12 V.
4.2 Dimensioning of the PV system
The total energy demand during a day, 𝐸𝐸, is calculated according to equation (1),
𝐸𝐸 = ∑𝑚𝑚𝑖𝑖=1𝑃𝑃𝑖𝑖 × 𝑡𝑡𝑖𝑖,
(1Error!
Bookmark defined.) not where 𝑃𝑃𝑖𝑖 is the effect of the 𝑖𝑖:th appliance out of 𝑚𝑚 and 𝑡𝑡𝑖𝑖 is the time the appliance is used during a day.
To dimension the size of the stand-alone PV system equation (2) will be used (Antony 2010). The size of the PV array is dependent on the total energy demand. A higher power requirement results in a higher peak wattage of the array.
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𝑊𝑊𝑃𝑃𝑃𝑃 = 𝐸𝐸 ÷ 𝐺𝐺 ÷ 𝜂𝜂𝑆𝑆𝑆𝑆𝑆𝑆 (2)
𝑊𝑊𝑃𝑃𝑃𝑃 = peak wattage of the array [𝑊𝑊𝑝𝑝] 𝐸𝐸 = the daily energy requirement [𝑊𝑊ℎ]
𝐺𝐺 = the daily average peak sun hours [ℎ]
𝜂𝜂𝑆𝑆𝑆𝑆𝑆𝑆 = efficiency for the total system
Equation (3) can be used to determine the total efficiency of the system.
𝜂𝜂𝑆𝑆𝑆𝑆𝑆𝑆 = 𝜂𝜂𝑃𝑃𝑃𝑃 × 𝜂𝜂𝑃𝑃𝑃𝑃−𝐵𝐵𝐵𝐵𝐵𝐵𝐵𝐵× 𝜂𝜂𝐶𝐶𝐶𝐶 × 𝜂𝜂𝐵𝐵𝐵𝐵𝐵𝐵𝐵𝐵× 𝜂𝜂𝐷𝐷𝐷𝐷𝑆𝑆𝐵𝐵 × 𝜂𝜂𝐶𝐶𝐶𝐶𝐶𝐶 (3)
𝜂𝜂𝑃𝑃𝑃𝑃 = efficiency of PV modules
𝜂𝜂𝑃𝑃𝑃𝑃−𝐵𝐵𝐵𝐵𝐵𝐵𝐵𝐵 = efficiency of the cables from PV array to battery 𝜂𝜂𝐶𝐶𝐶𝐶 = efficiency of the cables from PV array to battery
𝜂𝜂𝐷𝐷𝐷𝐷𝑆𝑆𝐵𝐵 = efficiency of distribution cables from PV battery to loads 𝜂𝜂𝐶𝐶𝐶𝐶𝐶𝐶 = efficiency of the converter
The battery in the PV system must be dimensioned to store the daily energy requirement and the number of hours or days extra, to ensure that the system have enough energy for the energy losses and to cover the hours when the sun is not available. These calculations are made by equation (4). (Antony 2010)
𝑄𝑄 = (𝐸𝐸 × 𝐴𝐴 ) ÷ (𝑉𝑉 × 𝑇𝑇 × 𝜂𝜂𝐷𝐷𝐶𝐶𝑃𝑃 × 𝜂𝜂𝐶𝐶𝐵𝐵𝐵𝐵𝐶𝐶𝐶𝐶 ) (4)
𝑄𝑄 = minimum battery capacity required [ 𝐴𝐴ℎ]
𝐴𝐴 = number of days of storage required 𝑉𝑉 = the system DC voltage [𝑉𝑉]
𝑇𝑇 = the maximum allowable DOD of the battery
𝜂𝜂𝐶𝐶𝐵𝐵𝐵𝐵𝐶𝐶𝐶𝐶 = efficiency of the cables delivering the power from battery to loads
The number of PV panels required, 𝑁𝑁, is given by equation (5).
𝑁𝑁 = 𝑊𝑊𝑊𝑊𝑃𝑃𝑃𝑃
𝑝𝑝, (5)
where 𝑊𝑊𝑝𝑝 is the peak wattage of the selected module.
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The output current of the PV system, 𝐼𝐼𝑜𝑜𝑜𝑜𝑜𝑜, is given by equation (6). (R. Messenger, J. Ventre, 2010)
𝐼𝐼𝑜𝑜𝑜𝑜𝑜𝑜 = 1.25 ×𝑊𝑊𝑃𝑃𝑃𝑃
𝑉𝑉
(6)
Calculations based on the mathematical model presented in this section were carried out in MATLAB. The MATLAB code is presented in Appendix 2.
The selection of the charge controller is based on the voltage of the battery and the PV modules.
The charge controller also need to handle the current from the modules( 𝐼𝐼𝑜𝑜𝑜𝑜𝑜𝑜).
5 Results and Discussion
5.1 Energy demand in Nyamabuye
As mentioned in section 3.1.2, there is no access to electricity in Nyamabuye except for the solar panel at the primary school. This means that no household in the village have the possibility of using any electric appliances, thus there is no existing load power demand. The power requirement of the PV system is therefor based on estimations of the potential energy demand.
The PV system should be able to cover for a radio and a mobile phone, since these are the most common appliances according to the data in Table 1. In addition to this, the PV system should also have the capacity to provide for a potential refrigerator as well as two lamps.
An estimation on the effect and usage per day for the different appliances was made. The result can be found in Table 12.
Table 12 Data for appliances.
Appliance Quantity Usage per
day (h) Effect (W) Total energy consumption per day (Wh)
Mobile phone 1 8 4 32
Lamp 2 5 25 250
Radio 1 4 5 20
Refrigerator 1 30 278
To determine a daily energy profile, the time during the day each appliance is used was estimated.
Figure 3 illustrates the energy profile for a day. It is assumed that the mobile phone is charged between 10 am and 6 pm, the radio is used between 10 am and 2 pm, and the lamps are used between 6 pm to 12 am. The refrigerator has a peak wattage of 30 W but does not have a constant load, as mentioned in the background. But for simplicity, the load is illustrated as constant for 24 hours in the graph.
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Figure 3 Diagram showing the power for the appliances and during which hours they are used during a day.
5.2 Dimensioning of the PV system
The total energy demand for a day was calculated according to equation (1) to 1022 Wh. The input values were taken from Table 12.
The converter was selected after the nominal voltage of the battery, 12V. Specifications for the converter are presented in Appendix 4. The project’s charge controller is a PWM controller with 30 A and 12 V to match the battery and the PV modules, see Appendix 5. The selected components efficiencies were used in order to calculate 𝜂𝜂𝑆𝑆𝑆𝑆𝑆𝑆, from equation (3), to 0.72.
Battery capacity were calculated to 51 Ah from equation (4). Specification for the battery are shown in Appendix 6. The size of the PV panels was calculated according to equation (2). No calculations were made on the optimal tilt angle at the location since the PV panels were assumed to be horizontal. This should not affect the result significantly due to the fact that Rwanda is close to the equator, which means that the optimum tilt angle would be close to zero.
PV modules with 50 W were chosen. The number of modules needed were calculated according to equation (5). The data sheet for one PV module are presented in Appendix 7.
A summary of the calculated values are shown in Table 13.
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Table 13 Results from calculations.
𝐸𝐸 580 Wh
𝑄𝑄 34.6 Ah
𝜂𝜂𝑆𝑆𝑆𝑆𝑆𝑆 0.72
𝑊𝑊𝑃𝑃𝑃𝑃 162 W
𝑁𝑁 3.2
𝐼𝐼𝑜𝑜𝑜𝑜𝑜𝑜 17 A
The number of modules was calculated to 3.2, which gives a minimum of 4 modules.
5.3 Selected components for the PV system
Comparisons between different types of components can be found in Appendix 3.
Table 14 shows the chosen components including specification and price.
Table 14 Specification and price of chosen components.
PV array Battery Charge
controller DC-DC
converter Cables Specification 50 W
12 V
Monocrystalline 𝜂𝜂𝑃𝑃𝑃𝑃= 0.8
12 V 50 Ah Lithium- ion 𝜂𝜂𝐵𝐵𝐵𝐵𝐵𝐵𝐵𝐵= 0.99
30 A 12 V/24 V 𝜂𝜂𝐶𝐶𝐶𝐶 = 0.9
Nominal voltage 12 V 20 A
𝜂𝜂𝐶𝐶𝐶𝐶𝐶𝐶 =0.88
𝜂𝜂𝑃𝑃𝑃𝑃−𝐵𝐵𝐵𝐵𝐵𝐵𝐵𝐵=0.97 𝜂𝜂𝐷𝐷𝐷𝐷𝑆𝑆𝐵𝐵=0.97
Price 3800 SEK (950 SEK/panel)
6000 SEK 700 SEK 700 SEK -
Monocrystalline PV panels were chosen because of the lighter weight.
A lithium-ion battery was chosen because the weight was significantly lighter in comparison to lead-acid batteries, even though it was more expensive.
When selecting a charge controller for the PV system there is two categories: MPPT and PWM.
This project has an economic limitation and the system demands does not require a high capacity system, therefor the PWM charge controller has been selected. The MPPT charge controller is significantly better in utilizing the maximum flow of energy. However, it is more expensive than the PWM.
Table 15 shows the cost and weight for the whole system.
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Table 15 Specification for the whole PV system.
Total cost 10670 SEK
Total weight 13.6 kg
With a power of 162 W and a cost of 10670 SEK, the price per watt becomes 66 SEK/W, which corresponds to around 8 USD/W. This lies within the usual price range for solar home systems under 1kW, which is from 4 USD /W to 11.3 USD /W (as mentioned in section 3.4). The final cost for the system will be higher, since costs for cables, installation, etc. have not been in considered here.
5.4 Comparison with existing PV systems
In this section, the developed PV system is compared to some examples of existing PV systems that were described in section 3.5.
5.4.1 Projects
The system in Holgojo, Kenya, is much bigger than this project’s system and generates much more energy with high quality components. It also has a different usage area, which affects the system requirements.
The private PV system in Tanzania is different from this project’s system in several ways. The batteries in the private system are of the type SLI and in this system it is deep-cycle. The SLI batteries have shorter lifetime but are easier to access and have a lower cost. This project had limitations regarding cost but since the total system cost did not exceed the maximum amount it was possible to invest in more expensive batteries to increase the quality. The private PV system does not have a charge controller that could help the batteries from deep discharging, i.e. there is no regulation when the batteries are charged. This also results in lower lifetime of the batteries.
The private installed system was designed with the chosen components to reduce cost. The people in the area does not have the economic recourses to install and buy PV systems with higher quality and capacity.
The PV systems installed at the schools in Tanzania were made by technicians which makes them safer. The systems all have smaller charge controllers, which makes it easy to add more if expansion of the systems is needed. Charge controllers with a low capacity are also easier to purchase in the area compared to larger charge controller with higher capacity.
The system designed in this project has a larger charge controller with the capacity 30 A. Since this PV system is designed for a rural area, the access to these kind of components is limited.
Therefor it could have been better with smaller charge controllers to make it easier for the user to replace or add more if the energy demand gets higher.
5.4.2 Companies
In Table 8, PV systems that are available on the market are listed. The list shows that some system are better than the PV system in this project in terms of price, capacity and weight.
Companies that mass-produce PV system are in many cases also working with developing the systems regarding these factors, i.e. price, capacity and weight.
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This PV system in this project will be self-built and all the components are from different companies. This will make it easier to change the components if they are damaged. The locals in Nyamabuye might not have the possibility to purchase components from a special kind of brand if the system need to be updated. Therefore, having components from different companies can be considered as an advantage. The PV system in this project is also built after the requirements from the locals in the village Nyamabuye.
The first PV system, presented in Table 9, does not fulfill the requirements of this project concerning weight and capacity. The battery has a weight of 30 kg and is alone exceeding the limit of the weight for the desired system. Apart from the weight, the other requirements are fulfilled.
The second PV system, an emergency solar kit system, is very flexible and appropriate for mobile use since it easily can be carried around. This system is also light weight and economical.
However, the power capacity does not meet the requirements for the appliances in this project.
The third system, presented in Table 11, has the power capacity to meet the requirements for the system desired in this project. But this system has been designed for cabin households and the panel is not flexible for portable use due to the weight and dimension. The cost of this system also exceeds the amount capital that has been provided by KTH Opportunities Fund.
5.5 Sensitivity analysis
Parameters that may affect the results in calculations of the PV system but have not been taken into consideration are rain and dust in the atmosphere. The panels will not work optimally if the dust reaches them. The rain factor will not affect the panel in the same extents, since water resistant material is selected. The rain will however still cover the PV panels and affect the amount of absorbed sunlight. The effects of these factors can be reduced if the panels are cleaned regularly.
Assumptions made in the beginning regarding horizontal PV panels have an impact on the results. In reality the panel might face a house wall or similar. This will result in a higher absorption value of the energy to the PV system. With the correct value a smaller PV system could have been selected and resources could have been placed in other section of the project.
For simplicity, it is assumed that peak sun hours are constant with a value of 5 hours per day. In reality, the number of peak sun hours vary due to for example variation in cloud coverage. This affects the storage energy in the battery. A higher value of the peak sun hours requires less stored energy in the battery and vice versa.
The color of the PV panel has not been considered in the calculations of the system. Different colors reflect and absorb light in diverse amounts. Darker colors absorb more light rays from the sun.
The PV system is dimensioned to be connecting to a refrigerator. A refrigerator is not always on working mode because of the compressor, as described in section 3.2. Due to lack of information for different types of refrigerator in rural areas and their profile load, the system has been oversized. It is assumed that the refrigerator is on maximum capacity the whole day. The
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refrigerator has a big impact on the total capacity, since it contributes with the highest energy consumption per day (see Table 12). The result of this assumption has resulted in a larger system with higher cost and weight.
The population in the village does not have any devices that need electricity, for that reason the number of hours each appliance is used could not be received. The number of hours has been retrieved from assumptions.
5.6 Sustainability
As mentioned in the literature study it is common among the population, especially in the rural areas, to use diesel motors for electricity. These are affecting the environment negatively with emissions to the atmosphere, comparing to PV system that does not have any impact on the environment regarding emissions. The diesel motors also need to be replaced periodically, due to short lifetime, and therefore are in an economically perspective expensive.
The population in Nyamabuye has no access to electricity, presented in the results from the survey. For that reason, Solar Power is a good solution to provide the population with power to charge and run electrical devices. PV system can also quickly be installed in the households, and be used shortly after. Compared to other energy sources like wind- or hydropower the PV system does not require major interventions and investments. These investments can involve high costs and also large-scale interventions in the nature, which are not environmentally friendly. Solar panels are considered to be best alternative at producing large amounts energy. This could cause a problem in big cities; due to the target being a rural household will this not cause any complications.
Access to electricity gives opportunities for increased living standards for the people in Nyamabuye. According to the survey, people use charcoal and wood for cooking. With increased electrification, they could eventually use electricity for cooking instead. This would decrease the emission of greenhouse gases.
The PV system in this project is design for the energy consumption of a household, but it would also be possible to use it for other purposes. For example, it could be used for improvements of the health center and the school in Nyamabuye.
The charge controller selected for this project is a PWM charge controller. As mentioned earlier in this report, MPPT charge controllers have higher energy producing performance than PWM charge controllers. In a sustainability perspective it is better with a charge controller with higher efficiency due to the fact that the maximum energy from the sun will be used. If the system can provide with a higher electricity output, it could reduce costs of the other components. With more electricity other appliances can be used in the households. The MPPT charge controller is however more expansive than the PWM charge controller, and is often used for bigger system.
This project concerns a small PV system for a rural household, therefor a PWM charge controller
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is also a good choice. The population in Nyamabuye does not have any appliances for electricity use and are not connected to the national grid; therefor it would be unnecessary for this PV system to use a MPPT charge controller.
6 Conclusions and future work
Components for a stand-alone PV system were selected to meet set requirements. The next step would be to construct a prototype for the system. To make the system mobile, the components need to be connected and then mounted into a single unit. It should be easy to carry in order for the system to be mobile. A manual for the locals in Nyamabuye could be made to facilitate the usage of the system.
The system design is based on theoretical values, which means that the actual capacity of the PV system could differ from the calculated. There are several factors which were not considered in the calculations that could affect the performance of the system. A few of these factors are, as mentioned in previous sections, temperature, sun hours, and tilt angle of the panels. In order to more accurately evaluate the system performance, the system should be tested. In case it is needed, the system could be re-designed for improvement. After testing, the system will be installed in Nyamabuye. Tests could also be made at the location where the system is going to be used for further performance evaluation.
The components used in this project are ones that are currently available on the market. As mentioned in the background, the market for solar home systems are growing rapidly and the prices are falling. This means that there is potential for cost reductions for PV systems, which could result in a system with higher efficiency for lower costs in the future.
The funding for this project is only sufficient for the production of a single PV system. In order to produce more PV systems, new financiers need to be found. It is also recommended to find manufacturers in Rwanda, so that the PV systems could be produced locally.
As mentioned in the introduction, electricity is prerequisite for good living standards and implementation of PV systems is an attractive option to increase electricity access Rwanda. PV systems, as well as other renewable technologies, could also contribute to sustainability in developing countries, both environmental and socioeconomic. The PV system development in this project could be a step towards increased electrification and sustainability in Rwanda.
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-34- Appendices
Appendix 1: Survey
Appendix 2: MATLAB code
Appendix 3: Component comparison Appendix 4: Data sheet for converter
Appendix 5: Data sheet for charge controller Appendix 6: Data sheet for battery
Appendix 7: Data sheet for PV panels
-35- Appendix 1: Survey
The following information is required in order to clarify the details of the situation of the energy demand and supply characteristics in a village in Rwanda. (Village to be defined prior the completion of this information sheet).
Please indicate with “X” in the column “Yes” if you have the information, or
“No” if you don’t. Provide some comments next to it if you want to provide more information like sources, clarifications, explanations, or something else you consider it is important to have a complete information for the project regarding the item asked.
If there is additional information that you consider important and is not included in the list, please feel free to add it at the end of the document.
1.General data Yes No Comments
1.1 Number of inhabitants of the village
The village is called Nyamabuye it is located in Rwaniro sector, Huye district in the southern province. It is inhabited by 3499 people.
Most of the villagers are agriculturists.
1.2 Position of the village (availability of
maps, coordinates and pictures)
The village is located in Huye district 40 minutes from Huye- Town. The maps are available and the coordinates too
1.3 Political Structure of the village (Local
leaders, major, etc)
The political structure is as follow; head of village:
Executive secretary
SEDO(head of social affairs in the village)
Head of Security Land registrar
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2.Households-related data Yes No Estimated Value
2.1 Average number of inhabitants/house
At least 6 people are found in a house(as indicated by the head of the village)
2.2 Average number of households with a TV
Only 5 houses in the sector have access to electricity.
These houses are not found in the Nyamabuye cell. They got their electricity from MOBISOL which is a company that provides solar energy(not affordable to everyone the cost of an installation is 600000 RWF around 720$)
2.3 Average number of households with a refrigerator (If possible the amperage and voltage or
power of the refrigerator)
2.4 Average number of households with air
conditioning system
No air conditioning system in the village(although the village has a high solar irradiation it is surrounded by trees this makes the weather fresh hence no need of air conditioners)
2.5 Average number of households with an electrical
stove
Most of the villagers use charcoal stoves and firewood there is no household with an electric since there is no electricity
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3.Infrastructres-related data Yes No Comments
3.1 Characteristic of buildings(How many floors,
materials, area,etc.)
The village is located on top of the Bweramana hill most of the houses are made up of two to three bed rooms with a small farm in the back yard.
3.2 Presence of other alternative energy sources
The only source of electric energy they have is a solar panel at the primary school which is not enough itself since it only serves 8 classes out of 22 they have and many services of the sector office are done at the school.
3.3 Possibility to reach the village through paved
roads
The village can not be reached through a paved road it is only half of the trip to the village that has a paved road
3.4 Possibility to reach the village through railway No railway in the village
3.5 Possibility to reach the village by public
transport
The village can be reached using public transport like minibuses and motor bikes
3.6 Presence of school in the village
There is a school in the village called “GROUPE SCOLAIRE SHEKE”
made up of primary and secondary it is the only one found in the sector.
3.7 Presence of health centres in the village
The health centre is called Rwaniro Health centre it offers services such as maternity, laboratory testing, and vaccination but many others are not delivered due lack of
