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SOLAR ENERGY DEVELOPMENT PROGRAMME IN BANGLADESH

 

 

 

 

 

 

 

 

 

 

 

 

Roof-Top Grid-Connected PV Power System in Bangladesh

Developed by - RERC

 

Designed and Developed by -

Dr. Rezaul Karim Mazumder ( Email : rkmeteulabd@yahoo.com )

Dr. Subrata Kumar Aditay    (Email :  skaditya_du@yahoo.com  )

Dr. Saiful Hoque

Dr. Habibur Rahman   ( Email :  habib_ape70@yahoo.com )

And

Dept. of Applied Physics, Electronics and Communication Engineering University of  Dhaka, Dhaka-1000.

Contact Address :

Renewable Energy Research Centre(RERC)
Energy Park, Faculty of Science
Science Library
Campus, University of Dhaka
Dhaka - 1000, Bangladesh

E-mail: rerc@univdhaka.edu
       rercdu@yahoo.com
Ph:  +880-2-9677125, 9661920-73/4570
Fax: +880-2-8615583
Website: http://www.univdhaka.edu/ResearchDetails.php?bodyid=CRE

 

-  Financed by the Ministry of Science and Information & Communication Technology Govt. of the people’s Republic of Bangladesh

 

Introduction : 

Bangladesh is an energy deficit country. Load-shedding and power failure is a daily occurrence. Conventional source of energy in our country is very limited and the supply of energy in the future may not be sufficient for the constant envelopment of the country. Renewable energy resource can be considered as one of the important alternatives and it can play a significant role in the total energy scene of the country.

 

The most important sources of renewable energy, in the country are solar, wind, small hydro, biomass, and biogas. Of all the options, solar energy is the simple, easiest and most viable option. Various private organizations and NGOs like RAHIMAFROZ, Grameen Shakti, CMS, Energy Systems, Solar Bangla, Ananda, Microelectronics, Sunwise, ARMCO etc. have come forward by taking different  projects to utilize solar devices and to provide PV electricity to the villages in Bangladesh.

 

 

Although Solar Home Systems (SHS) are now gradually becoming popular in Bangladesh and have obtained good dimension, Grid-connected PV systems can be good power sources in cities and in remote areas where power generation in the existing grid is needed to be increased.

 

Grid-connected PV power system:

 

During sunny days the DC power generated by the PV modules in the system is converted to AC by power conditioning unit (inverter) and fed into the local loads.

Any excess solar power is supplied to the power line, and any shortfall is made up with grid electricity. During nonsun hours, residence loads are supplied by utility grid alone.

 

In Roof-top Grid-connected PV systems, PV arrays are installed on the roof-tops of buildings.

 

In many countries like Japan, Germany, USA, Australia, Italy government policies are framed to encourage and popularize this power system by providing necessary regulations and incentives. Gridconnected PV power systems in the cities all over the world (where there is sun) will become a small, but important source of electricity generation in the next century. The world market for grid-connected photovoltaic systems is growing rapidly. Fig.1 shows the year wise cumulative installed grid-connected and offgrid PV Power all over the world and Table-1 indicates the installed PV power as of the end of 2005 by Japan, Germany, USA, Australia, Spain, Netherlands and Italy.

 

 

System Design and Development:

 

Realizing the significant potential of this technology a model of 1.1 kW rooftop grid connected photovoltaic system has been designed, developed and successfully commissioned at the rooftop of Renewable Energy Research Centre (RERC), University of Dhaka. A block diagram of the system is shown in Fig.2. In this design the following factors have been taken into consideration.

 

_ Grid interfacing circuitry matching,

_ Effects of voltage fluctuation, harmonic distortion and

stability

_ Over current, over voltage protection and power failure

_ Power conditioning and flickering

_ Safety, bi-directional metering for power tariff

 

 

 

Fig.2 Roof-top Grid connected P

V power system

The designed Roof-top Grid Connected PV system has the following components:

 

PV Array: 20 PV panels (BP Solar, India) are connected in series giving a DC output of 140-400V according to intensity of incident radiation. Orientation and tilt angle: Orientation is south-facing and tilt angle is 24.25N . Area covered by PV array is about  11m2. Fig.3 represents PV array mounted on the roof-top of RERC, DU.

 

Inverter: Inverter (Sunny Boy) that 'inverts' the above DC power from the panels into AC power of 1.1kW/220V/50Hz. The characteristics of the output signal should match the voltage, frequency and power quality limits in the supply network. Fig.4 and Fig.5 shows the photograph of the grid-connected inverter.

 

Load: Appliances in the residence that are fed from the inverter, or, alternatively, from the grid.

Meters: They register the energy being used from the local supply network or fed into local supply network.

Local Supply Network: The single-phase network of local supply line. The supply network acts both as a sink for energy or as a backup for low local generation periods. Fig.6 shows the electric wiring of the system. The overall efficiency of the system depends on the efficiency of the PV array and the efficiency of the inverter. The efficiency of the inverter varies with the load level. High efficiency of the inverter can be obtained by running the inverter near full loads.

 

  

Specifications of the system:

 

PV string:

 

·         No of PV panel (BP) in series-20

·         Open-Circuit Voltage (VOC) : 20V/panel

·         Short-Circuit Current (ISC) : 4A/panel

·         Power Output : 75 Watt/panel

·         Total output of the string: 1.5kWatt

 

Inverter (Sunny Boy):

 

·         Maximum input current : 10A

·         DC input voltage : 139-400V

·         Max. input power : 1.21kW

·         Nominal output power : 1kW

·         Output AC voltage: 220V, 50HZ

 

 

 

Fig.3 PV array of Grid-connected PV system at Roof-Top of RERC-DU

 Fig.4 Grid-connected PV inverter at RERC-DU

 

 

 Fig.5 Grid-connected Inverter

 

 

Practical Results:

 

The system was run for several days in different weather conditions. A representative curve of the generated output power of the system for the input at various time of a day

is shown in Fig.7. Efficiency, Input and Output power of, the system were found to be as follows:

 

·         Efficiency of the inverter: 90-93%

·         Input power (DC): 1000-1300 W

·         (on a typical semi-cloudy day)

·         Output power (AC) : 672-1120W

 

 Fig. 7 Input and output power of the system

 

Cost of unit of electricity Produced:

 

The cost of unit of electricity produced by this system would depend on the overall system efficiency, the resource availability, the lifetime of the system and the interest rate. An economic evaluation of various sizes of roof-top grid connected systems along with the 1.1kW system with and without net-metering of 2 times per unit grid-fed benefit

has been done. The results of the analysis for different interest rates are shown in Fig.8. It is observed from the figure that the cost of unit of energy generated by the various sizes of systems are encouraging with net-metering benefit.

 

Fig.8 Cost of unit of energy versus various sizes of PV systems

 

 

Conclusion:

 

·         Long time performance study of the system is needed to run successfully in Bangladeshi environment.

·         The system will be cost effective for users if Bangladesh Government takes necessary steps to provide subsidy in this field like other foreign countries. Japan and Germany have adopted a form of net metering, whereby customers get paid 2 to 8 times what the power company charges them for any surplus they supply back to the grid.

·         Government regulation for net metering and use of grid-connected PV system should be framed.

·         Extensive demonstration is required to popularize the system.

·         However, further work is needed to evaluate impact on system lifetime, reliability, and economic and environmental cost.

 

Acknowledgement:

 

I would like to express my sincere thanks to Dr. Subrata Kumar Aditay, Dr. Saiful Huque, Dr. Habubur Rahman  Mr. Shamim Kaiser and Mr. Asif Anawar for active  participation and help. I am also grateful to the Ministry of Science and Information & Communication Technology for financial support for the project.

 

Contact persons:

Dr. Rezaul Karim Mazumder rkmeteulabd@yahoo.com

Dr. Subrata Kumar Aditay skaditya_du@yahoo.com

Dr. Habibur Rahman <habib_ape70@yahoo.com>

 

 

 

 

  Last Updated:  23 December, 2008