2010 2nd International Conference on Mechanical and Electronics Engineering (ICMEE 2010)

An Analysis & Design on Micro Generation of A Domestic Solar-Wind Hybrid Energy System for Rural & Remote Areas - Perspective Bangladesh

Mir Nahidul Ambial, Md. Kafiul Islam3, Md. Asaduzzaman Shoeb2, Md. Nasimul Islam MaruF, A. S. M. Mohsin2 lLecturer, Dept. of EEE, Eastern University, Dhaka, Bangladesh

2Lecturer, Dept. of EEE, Stamford University Bangladesh, Dhaka, Bangladesh 3Junior Lecturer, SEeS, Independent University, Bangladesh, Dhaka, Bangladesh

Abstract- Utilization of renewable energy resources have been the most important & prospective field to seek new energy sources to meet up the increasing demand in power all over the world specially in a developing country like Bangladesh. Among the renewable resources, wind & solar being the most popular ones due to abundant, ease of accessibility and convertibility to the electricity. This paper presents the analysis and design of a hybrid solar-wind system for micro generation for domestic purpose in the rural & remote areas of our country where continuous power supply from central grid has been a great is problem and sometimes for some remote places it's economically not viable at all as far as our country is concerned. We propose such a hybrid system which is expected to run effectively under a microcontroller to utilize the maximum possible solar & wind resources to reduce the demands on national grid for on-grid region as well as to supply power to those places where there is no grid line (i.e. off-grid region).

Keywords- hybrid system; solar power; wind power; renewable energy; on-grid region; off-grid region

I. INTRODUCTION

In general, we act as having energy with no price or thinking that the energy available is infinite. Lot of times we use the energy do not thinking about where is it produced or originated. Energy is vital for the progress of a nation and it has to be conserved in a most efficient manner. Not only the technologies should be developed to produce energy in a most environment-friendly manner from all varieties of fuels but also enough importance should be given to conserve the energy resources in the most efficient way. Energy is the ultimate factor responsible for both industrial and agricultural development.

Anyway, it is important to prevent scenarios avoiding energy faults or absence. There is energy crisis all over the world. But developing countries like Bangladesh suffer most for very limited resources and technology. There are still lots of area where there are no supplies of electricity and some areas which are grid connected but most of the time they are deprived of continuous supply.

In Bangladesh, a large percentage of villages remain to be un-electrified, most of them are difficult to supply electricity due to inherent problems of location and economy. The costs to install and service the distribution lines are

considerably high for remote areas. Also there will be a substantial increase in transmission line losses in addition to poor power supply reliability. There is a growing interest in harnessing renewable energy sources since they are naturally available, pollution free and inexhaustible.

At present, standalone solar photovoltaic and wind systems have been promoted around the globe on a comparatively larger scale. These independent systems cannot provide continuous source of energy, as they are seasonal. For example, standalone solar photovoltaic energy system cannot provide reliable power during non-sunny days. The standalone wind system cannot satisfy constant load demands due to significant fluctuations in the magnitude of wind speeds from hour to hour throughout the year. Therefore, energy storage systems will be required for each of these systems in order to satisfy the power demands. Usually storage system is expensive and the size has to be reduced to a minimum possible for the renewable energy system to be cost effective. Hybrid power systems can be used to reduce energy storage requirements. In this paper we apply the hybrid system for both on-grid and off-grid areas.

II. THEORY

Although a hybrid wind-solar electric system demands a higher initial investment but the hybrid solution is the best option whenever there is a significant improvement in terms of output and efficiency - which happens when the sun and the wind resources have opposite cycles and intensities during the same day or in some seasons.

A. Solar Power Solar panels are the medium to convert solar power into

the electrical power. Solar panels can convert the energy directly or heat the water with the induced energy. PV (Photo-voltaic) cells are made up from semiconductor structures as in the computer technologies. Sun beam is absorbed with this material and electrons are emitted from the atoms that they are bounded. This release activates a current. Photovoltaic is known as the process between beam absorbed and the electricity induced. With a common principle and individual components, solar power is converted into the electric power.

The solar power generation for any solar radiation can be predicted by using the formula given below:

978-1-4244-7481-3/$26.00 2010 IEEE V2-107 Volume 2

2010 2nd International Conference on Mechanical and Electronics Engineering (ICMEE 2010)

(1)

Where x = solar radiation, P = power generation A, B, C are constants, which can be derived from measured data. The practical values and simulated values for solar power generation are nearly coinciding. By using the above formula, we can predict solar power generation at any solar radiation.

B. Wind Power Wind turbines are used to convert the wind power into

electric power. Electric generator inside the turbine converts the mechanical power into the electric power. The energy production by wind turbines depends on the wind velocity acting on the turbine. Wind power is used to feed both energy production and consumption demand, and transmission lines in the rural areas.

The wind direction is an important factor, because if we have sudden changes in the direction meaning that we have strong winds, it is mandatory to stop the wind energy production to not damage the equipment. Knowing the predominant wind direction we can select the ideal spot for the wind turbine.

In addition, we cannot convert all the wind energy into electricity; we can only convert 59%, according to Betz limit. When using an optimized system, the power available is:

P = ().p. A. v3 (in Watts) (2)

where, A is the area perpendicular to the direction of flow, meter, p, density of air, kgm-\ is approximately 1.2 kg/m\ v, wind velocity, meters per second.

III. SOLAR & WIND RESOURCE ASSESMENT

Bangladesh is situated between 20.30 - 26.38 degrees north latitude and 88.04 -92.44 degrees east which is an ideal location for solar energy utilization. Daily average solar radiation varies between 4 to 6.5 kWh per square meter. Maximum amount of radiation is available on the month of March-April and minimum on December-January.

From collected wind speed data for some sites of our country, the following information about the wind climate in Bangladesh has been found: i) Wind speeds appear to be higher in the east of the

country than the west.

ii) Wind speeds in the coastal areas appear to be higher than inland.

iii) Wind speed exhibits a strong seasonal cycle, lowest in the winter and higher in the summer.

iv) Wind speed exhibits a diurnal cycle, generally peaking at noon and weakest at night.

AvgSolar Radiation kWh/m2/day

7.0 .,------------------6.0 -j-------:=------------5.0 -j---__ r-I _____ ----------4.0 +-______ r-I ______ I--:=-___ --____ ---==_ 3.0 +l1--...... H .... -IIH ..... --1I-____ --I1-2.0 +l1-____ r-I ______ I-I ___ -III-____ -I._ 1.0 +l1-____ r-I ______ I-I ___ -III-____ -I._ 0.0 +-" ..... --.-'-r-''"-r---.-......... --,...L,--,,-..........

6 5 4 3 2 1 o

Figure I. Monthly average solar radiation profile

Avg. Wind Speed (m/s)

Jan Feb Mar Apr MayJun Jul A g Sep Oct Nov Dec

Figure 2. Monthly average wind speed profile

In figure 1 & figure 2 average wind speed and average solar radiation have been shown, which are the overall information of wind speed and solar radiation for Bangladesh in general. By observing the average wind speed we see that the wind speed is not overall the same throughout the whole year. Even wind speed is less than 4m!s during some months for which wind generator cannot produce power. For this purpose we have proposed windsolar hybrid systems so that maximum utilization of renewable energy and production of electricity is ensures. In figure2 average solar radiation has been shown for Bangladesh throughout the whole year. The solar radiation varies with respect to time. So by utilizing both the wind and solar energy we get overall satisfactory data throughout the whole year.

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2010 2nd International Conference on Mechanical and Electronics Engineering (ICMEE 2010)

IV. PROPOSED HYBRID SYSTEM

The designed system has developed for on grid as well as for off grid regions.

A. Off-Grid Hybrid Systems The figure 3 is the block diagram of an off-grid hybrid

system which is very useful in remote places. In the off grid system solar panels and wind generators have been used. The designed system also includes a load controller in order to control the load, batteries and inverter so that we may get both DC and AC loads.

t::::>. DC load

load Batteries

Inverter F} Ch:ge

"----

Wind Generator

Figure 3. Off-grid solar-wind hybrid system

B. On-Grid Hybrid Systems The figure 4 is the block diagram of an on-grid hybrid

system. In this on grid system solar panel and wind generators have been used like the off grid system. In addition, load controller batteries and inverter have been used. A controller has been used in the block diagram which is connected with grid line and the inverter. The output of the controller is again connected with the loads. As the controller has two inputs one from the inverter another from the grid, it choose only one input depending upon the availability of the output of the inverter. The controller will choose the grid line and pass it to the load only when there will not be any input from the inverter.

Wind Generator

".i===>f Load Controler

Solar Panels

Grid Connection

Figure 4. On-grid solar-wind hybrid system

V. SYSTEM FLOW CHART & ALGORITHM

In the wind-solar hybrid system a controller has been developed which is shown in figure 4. The system has been designed in such a way that maximum utilization of wind and solar energy is ensured. This system has been designed for on grid and off grid region especially for rural areas where grid line has been reached but availability of electricity is very less or in a sense supply of electricity is not continuous and there is much interruption. For this reason this system has been designed where we have mainly focused on utilizing renewable energy rather than national grid line. Our main objective is to use the wind energy and solar energy without national grid and if at a period neither wind nor solar energy is available then we would use the national grid.

In the controlled system we have given first priority to the wind turbine which is obvious from the flow chart (figure 5). If the wind energy is greater than 4m1s then we will charge the battery bank 1 which will enable us to supply DC or AC. But if the wind energy is less than 4 mls then we would like to use the solar energy panel. In this case, we will again check whether the radiation is satisfactory enough to produce energy or not. If not then we would use power grid system and check whether the power grid is available or not. If the grid is available then we will take power from the grid and if not then we would again check whether the battery 1 is charged enough to produce electricity or not. If the BB 1 is charged enough then we will take power from BB 1 and if not then we will take power from BB2 which has been charged by solar panel. In this case it should be kept in mind that the battery bank 2 is for emergency case. If the battery 1 fails to supply current then we would use the battery bank 2. So through this controlled system we will ensure maximum utilization of wind and solar energy without connection from grid line.

VI. CONCLUSION

In this paper, the design of an effective and convenient domestic solar-wind hybrid system has been proposed to implement in the rural and remote areas of our country where it's difficult to have continuous power supply from national grid and in some places where we can't even think to bring the grid line because of impracticability and uneconomically. There is a huge opportunity to improve & extend the proposed system in such a way to be able to support national grid [3] by optimal sizing of the whole system [4] as well as by introducing multi-agent control [5] with the optimization of initial cost [6] in the hybrid system.

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Take from B , B 2

Figure 5. Complete flow chart of the proposed hybrid system

VII. REFERENCES [I] Ugur FESL, Raif BAYIR and Mahmut bZER, "Design and

Implementation of a Domestic Solar-Wind Hybrid Energy System" [2] Fontes, N., Roque, A., Maia, 1. : "Micro Generation - Solar and

Wind Hybrid System" [3] Ghassan Halasa, and Johnson A. Asumadu, "Wind-Solar Hybrid

Electrical Power Production To Support National Grid: Case Study -Jordan"

[4] S.C.Gupta, Dr.Y.Kumar and Dr.Gayatri Agnihotri, "Optimal Sizing Of Solar-Wind Hybrid System"

[5] Shuyun jia, jiang chang, "A multi-agent control method and realization in wind-solar hybrid power generation system"

[6] A. M. Jain*, Dr.B. E. Kushare, "Techno-Economics Of Solar Wind Hybrid System In Indian Context: A Case Study"

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[7] 1. Bhagwan Reddy, D.N. Reddy, "Probabilistic Performance Assessment of a Roof Top Wind, Solar Photo Voltaic Hybrid Energy System"

[8] Sultan Ahmmed and M QuamrulIslam, "Wind Power For Rural Areas of Bangladesh"

[9] Shahidul I. Khan, Mohammad Upal Mahfuz, Tareq Aziz, N. M. Zobair, "Prospect of Hybrid Wind System in Bangladesh"

[10] M. Arif Hossain, M. Zakir Hossain, and A.K.M. Sadrul Isalm, "Wind Resource Assessment of the North-WestDivision of Bangladesh"

[II] Mohammad Golam Kibria Khan, Talha Rahman and M.M. Alam, "Wind Energy In Bangladesh: Prospects And Utilization Initiatives"

[12] Abul K. Azad, "A Review on Renewable Power Sources: Prospect of Bangladesh and Scotland"

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