INTRODUCTION TO SMART GRID
The smart grid system is vast collection of technologies to provide an electricity network having the ability to solve the major issues related to reliability, cost effectiveness of electric power and decentralization or grid dependency
The smart grid technology using renewable energy sources transferred electricity towards user side with the concept of integration of renewable energy sources.
1.1.2 Why Smart Grid Technology Adopted
The demand of electricity is increased so much by the passage of time, which creates some major problems related to conventional electricity network. By 2020 energy demand will be doubled from the present demand . Smart grid is the result of such efforts which are performed to make availability of electricity more reliable, economical and user friendly with the concept of decentralized network due to two way communication of electricity through network.
The Architectural model of a 21st century power system that interconnects everyone to affordable, abundant, clean, reliable, and efficient electricity anytime, anywhere. The purpose of Smart Grid is also to integrate several renewable resources with our national Grid and enhances the efficiency; reliability and thus providing a hassle free Transmission of electric power. It also contributes to reduce carbon emissions and providing a pollution free environment.
1.2 Back Ground
1.2.1 The European Development in the Area of Smart Grid
In the next three decades European member state will expend about 750 billion in power infrastructure. This amount will expend on generation and networks. The European Technology plate form was developed in 2005 to solve the problems of Network Owners, operators and users.
1.2.2 Smart Grid Development in USA
In USA the Smart grid developments initiated during first Bush Administration. In 2002 a DOE study describes the hundred of million of Dollar spent In US power systems on transmission practices and results a proposal of construction of transformed national electricity grid upto2030 providing the best and secure transmission of electricity.
1.2.3 Smart Grid Development in Australia
Under the Energy Transformed Flagship the Intelligent Grid Program was launched on 19 Aug, 2008. This Program researched in the fields of Control methodologies and economic modeling for distributed generation, Social impact of Intelligent grid, New housing developments and micro grids.
1.3 Design Description
1.3.1 Features of Smart Grid
The most important features of Smart Grid Technology are:
- Integration of Renewable Sources
- Battery Storage option
- Provide electric power to both AC and DC loads
- Advance Monitoring
1.3.2 Proposed Methodology
Above figure shows prototype modeling of smart grid system at micro level along with the integration of several renewable energy resources such as small wind plant and solar panels. The charge controllers are special devices used for the purpose to control the abrupt change in voltage and stop the reverse flow of current towards PV or wind turbine systems, and also control the charging and discharging of batteries.
An integrator is also one of the most important components of our project. The function of this device to integrate powers from both energy sources in a way that during operating time of the sources loads will directly get power from these sources and at night or the time when these sources are not operating loads are facilitated through battery banks.
1.4 Advantages of Smart Grid
A. Motivates and Includes the Consumer
Smart Grid is a end user device it motivates the consumer to generate a free source of electricity and to utilize it in household appliances when electricity from Grid is not available.
B. Provides Power Quality for 21st Century Needs
It provides power free of disturbance, sags, interruptions and spikes.
C. Markets Opportunities
Smart grid supports energy markets that encourage both investment and innovation.
D. Operates Efficiently and Optimizes Assets
Smart grid is easy to install infrastructure, transmit more power through existing systems and optimizes easily with present grid.
E. Reduction in cost of power infrastructure
When renewable energy sources are infused into the power grid, end-use demands can be adjusted to available power supplies. The ability to manage and reduce peak demands demolishes the need for costly peaking and “just-in-case” power infrastructure.
F. Reduced use of polluting plants
Some existing powerplants are not environment friendly which is adversely affecting the environment around us. Smart grid can produce pollution free generation of electricity.
G. Clean power market
During serious air pollution alerts, power plants and heavy industries sometimes shut down. Smart Grid ensures you clean power options.
H. Energy storage
Smart Grid is also equipped with battery backup options which not only stores energy also used as grid shock absorbers as well.
I. Integrate able with Energy Resources and Storage Options
The system also enables “plug-and-play” interconnection to multiple energy resources and storage devices (e.g. solar, wind, battery storage, etc.)
1.5 Brief Introduction to chapters
This chapter is a survey report about renewable energy sources. Also wind and solar characteristics of Pakistan are given in this chapter. Supply and Demand gap also discussed in this chapter.
This chapter is about PV system. Complete introduction and types of PV system are discussed also given here the architecture model of PV system with design description. And the experimental values also mentioned in this chapter.
This chapter defines the wind turbine specifications. Chapter starts from introduction then history discussed and after that design description is completely described. The experimental values also given in this chapter with advantages and drawbacks of wind turbine technology.
This chapter covers the remaining portion of smart grid technology. First of all integrator is discussed with design after that charge controller and power inverters also discussed with there design and circuitry.
- World Wide Survey of Renewable Energy
- Demand Supply Gap in Pakistan
- Depletion in Oil and Gas
- Energy Sources in Pakistan
- Wind Energy
- Solar Energy
2.1 World Wide Survey of Renewable Energy
Renewable energy has an essential contribution in world energy generation. So many projects are under consideration regarding to renewable energy.
2.1.1 Global Status Report
This report describes the market condition, investment and targets as well as policies. The report doesn’t describe analysis or conclusions, though it reveals some extra ordinary facts regarding the renewable energy . By the end of 2005 only 45 countries were included in the achievement of renewable energy targets which are increased up to 76 in 2009. According to this report last year was the best era for renewable energy. Capacity in developing countries grew to 119GW, or 43% of the total.
Including Pakistan and magnolia less or more than 8-0 countries has started plantation of wind power plants at commercial measures. Some achievements of the year 2008 are:
- In just 1 year the capacity of solar photovoltaic plants tripled to 3 GW from 200 KW.
- Wind power by 29% and solar hot water increased by 15%.
- Grid connected photovoltaic systems increased up to 13GW, wind energy grew up to 250%, 121GW and total power generation capacity from renewable energy boost up to 75%.
- Spain becomes the super power in the field of grid connected PV systems with inclusion of 2.6GW. Germany also takes some handy steps and added 1,5GW in their system.
- Some other developed countries also provide large contributions like USA(3ooMW), Italy ( 300MW) , South Korea ( 270MW) and Japan (240MW) respectively . in total 16GW is the generation of solar including off-grid by 2009 worldwide.
|POWER GENERATION (GW)||RENEWABLE ENERGY RESOURCES IN 2009-2010||RENWABLE ENERGY EXSISTING IN 2009-2010|
|Large Hydro Power||25-30||860|
|Small Hydro Power||6-8||85|
Table2.1 Energy Added and Exists in 2009-2010
2.2 Demand Supply gap in Pakistan
If we give a look at demand supply graph then we will come to know that the difference between demand and supply is becoming wider and wider by the passage of time .the scenario in 3rd world countries is totally discriminated e.g. Pakistan. Needs are increasing exponentially but we are desperately lacking in finding out a good solution. if we have an eye view we may find 3 reasons of demand supply gap.
Increase in prices of oil and gas , increase in population and increase in cost of energy .
2.2.1 Energy Demand
With the increase in population energy requirements are also increasing. All the industry and the production of our daily need in dependent upon electricity .
2.2.2 Energy Supply
Current era’s total production of energy does not meet the current requirement of energy , though the end results are critical in the sense of increase in demand supply gap . Serious steps are needed to be
2.2.3 Energy cost
If we have eye view on last few decades we will come to see the highlighted reduction in the reserves of oil and natural gas, which causes the increase in the cost of per unit production of electricity. This is also the reason of widening the demand supply gap.
2.2.4 Sustainability level
The systems which are to be used for the generation of electricity must be stable, but unfortunately we have not surety of sustainability level of present system and the graph is gradually decreasing according to our present and future demands . This decrease in sustainability may overcome by using alternative techniques.
2.3 Depletion in oil and gas
A large amount of electricity is being produced by fossil fuels and the present value of electricity generated by fossil fuels is increasing. According to the European energy commission and International energy the present reservoirs of oil and gas are not sufficient enough to meet the future requirements. so as the result after 10-12 years we have the depletion in the percentage of Oil using for the generation of electricity as shown in fig 2.2.
As from the above it is obvious that from 1930 to one word till 2010 there is continuous growth in both oil and gas reserves but after 2010 there is deep declined. If the above graph follows the same pattern there is near future we will be totally dependent upon alternates of energy generation.
2.4 ENERGY SOURCES IN PAKISTAN
The primary energy supplies today are not enough to meet even the present demand. More, a very large part of rural area does not have the electricity facilities because they are too expensive to be connected to the national grid. So, Pakistan like other developing countries in the region is facing a severe challenge in energy deficit. The development of renewable energy sources can play an important role in meeting such challenge.
If we see around yourself Pakistan best suits for Solar (PV, thermal), water, wind and Wastes. These are the best renewable sources and Pakistan doesn’t lack these. Pakistan can b benefited from these as substitute energy in areas where these renewable sources exist.
- Renewable energy
- Fossil fuels
- Nuclear power
2.4.1 Renewable energy
It is energy which is produced by natural sources such as wind rain solar and geothermal heat.
18.104.22.168 Types of renewable Energy
- Wave and tidal
These all sources are best placed in Pakistan and we are not lacking in any at all , thus we can produce great amount of energy using these renewable sources , Capturing renewable energy by animals , plants and humans does not permanently deplete the resource. Fossil fuels are renewable but on a very long time-scale, are exploited at rates that may deplete these resources in the near future.
2.4.2 Fossil Fuels
It includes natural gas, oil and coal . fossil fuels are lacking in Pakistan as well the world therefore renewable sources are needed to meet th essential needs
2.5 Wind Energy
Wind energy is one of the best of renewable sources and probably suits Pakistan atmosphere at peak. As our project is related to wind energy as well. In Pakistan wind energy projects are working under the Pakistan Meteorological Dept with the financial collaboration of Ministry of Science and Technology which are accomplishing many such projects in Pakistan.
About 3% of the total Pakistan’s land area is termed as good to excellent for utility scale production of electricity. Fig2.3. shows the variations of wind speeds in different areas of Pakistan
Average wind speed in Lahore is 3m/s as shown in Fig.2.4 . Therefore for the prototype smart Grid system, average wind speed must exceeds the theoretical values as given in.
2.6 Solar energy
Its one of the types of renewable energies, as in our project we are working on solar energy, in photovoltaic system solar cells covert sun radiation to DC electricity. The provinces of Sindh , Punjab and Baluchistan and the Thar desert are specially suited for the utilization of solar energy.
The solar statistics in Pakistan is highly favourable for energy generation. According to Fig2.5. the South western province offers perfect condition for utilization of solar energy. Since Pakistan locates near the equator so it has relatively high UV index as compared to other regions of the World.
The solar characteristics graph in the Lahore region is shown in Fig. 2.6. Lahore city also offers suitable condition for harnessing solar energy The average sunlight hours lies between 7 to 8 hours per day which is approximately 2700 hours per annually. Graph in Fig. 3 shows the UV index of Lahore during a day time in the month of April. Usually the radiation intensity has its maximum value at noon .And value of solar radiation reaches its maximum value during the mid of summers.
Chapter No 3
- Introduction to solar panels
- History of PV system
- Photovoltaic Cell Architecture
- Implementation of PV system
Solar cell or photovoltaic cell is the device use to convert sunlight into electricity. It works on the basic principle of photovoltaic effect.
3.1.1 Photovoltaic effect
When the photons of light falls on the semiconductor material. The photons try to knockout the electrons from the conduction bands. As the energy gap between valence and conduction band increases and when a sufficient amount of energy is projected by the light photons .the electrons knocked out from their respective atom and started to move freely. These free electrons moves towards n-side and holes created due to the deficiency of electrons in this region moves towards p-side to recombine themselves .This difference of potential allows the flow of current.
The PV cell absorbs incoming light photons in p-type. This p-type layer should be synchronized in such a way that it can absorb as many as photons possible and set free as many as electrons possible, to make a radiant flow of current.
In order to make and efficient flow solar cell , the surface of the cell should be kept rough to maximize the absorption of photons while reflection should be minimized in this way maximum conduction can be achieved
The photovoltaic cell was developed in 1954 at Bell Laboratories. The first highly efficient solar cell was developed by Daryl Chapin, Calvin Souther Fuller and Gerald Pearson in year 1954 using a diffused silicon p-n junction. Firstly, cells were developed for toys and other minor uses, as the cost of their production was very high.
Design of solar cells is improved day by day to utilize it for more applications. The applications for that solar panels are used are different and there are three levels of generation
3.2.1 First Generation:
First generation cells are single junction devices and they have large area also having high quality with reduction in production cost
3.2.2 Second Generation:
These materials are developed to address energy requirements and production cost. They reduce high temperature processing as vapour deposition, electroplating and Ultrasonic nozzles.
3.2.3 Third Generation:
The aimof these technologies is to improve poor electrical performance of second generation technologies with low production cost.
3.3 Photovoltaic cell architecture
A PV module consists of a silicon cell .These cell are connected in series or parallel manner in order to produce desired voltage and current .Inside a PV cell a circuit is present that is sealed from the envoi metal protective lamination .A PV panel consists of one or more modules joined together. Finally these panels are combined to make a single PV array which is a complete electricity producing unit.
The performance of a PV array or its modules is rated by its maximum throughput power under S.T.C (Standard Test Condition).STC is defined as when a PV modulecell is operated under 25 °C (77F), with an incident solar irradiation of 1000 W/m2 with the spectral distribution of 1.5 air mass. These are the perfect condition for a PV module to operate in , but in actual the performance of a PV module is almost 80 to 90 percent of its STC rating.
The operating lifetime of a PV module is between 20 to 30 years .Most of the manufactures offers warranty of 20 or more years of its DC output power to a sustainable amount .PV modules are also lice censed under (UL) qualification test for its reliability checks.
3.3.1 Types of Solar Cell
Now a days there are various types of cell materials are developed. Multi junction PV cells
are made in order to increase the cell efficiency while decreasing its volume and weight. But they are far more expensive then an ordinary silicon cells.
The maximum efficiency of a PV cell is achieved almost to 30 percent by doping different intrinsic material together .Example of the exotic materials are Gallium arsenide and Indium serenade etc. However silicon cells are the most common and widely used PV cells.
There are three major types of Silicon cell:
- Amorphous silicon solar Cell or Thin Film Cell
- Mono-crystalline Wafers
- Poly crystalline Cell
Amorphous Silicon Solar Cell
Amorphous technology is often seen in small devices, such as those in garden lamps or calculators, although amorphous panels are also increasingly used in other larger applications. They are formed by depositing a thin film of silicon onto a sheet of different material such as steel. The panel formed as one piece and each cell is not as visible as in other types.
Efficiency of an amorphous solar cell is between 6 and 8%. The Lifetime of an amorphous cell is however shorter than that of crystalline cell. Amorphous cells have current density of about 15 mA/cm2,and the voltage of the cell without any connected load is 0.8 V, which is more as compared to crystalline cells. The efficiency of amorphous solar panels is low as those made from individual solar cells, although improvement has been made over recent years to a point where they can be use as a practical alternative to panels made with crystalline cells.
Crystalline silicon solar cell
The maximum efficiency of silicon solar cell is around 23 %, by adding some other semi-conductor materials it can increase up to 30 %, it depends on wavelength and semiconductor material being used. Crystalline solar cells are made up of wafers like stuff, which has about 0.3 mm thick and diameter of 10 to 15 cm. They can generate approximately 35 mA of current per cm2 of area at voltage of about 550 mV at full illumination.
Crystalline solar cells can be wired in series or parallel to produce a solar panel. As each cell produces a voltage of between 0.5 and 0.6 Volts, 36 cells equipped in series are needed to produce an open-circuit voltage of about 20 Volts. This is enough to charge a 12 Volt battery under certain conditions. Although the efficiency of mono-crystalline cells is slightly higher as compared to that of a polycrystalline cells, but there are some practical difference in their performance. Crystalline cells have longer lifetime than that of amorphous solar cells.
In our project we have used crystalline silicon cell because they are more efficient yet lesser in volume as compared to other types of solar cell, easily available in market and it is more economical.
Polycrystalline silicon, also called poly silicon , consists of small silicon crystals of Polycrystalline cells which can be recognized by a visible grain, a “metal flake effect”. Semiconductor grade (solar grade) polycrystalline silicon then form to “single crystal” silicon, that is randomly associated crystallites of silicon in “polycrystalline silicon” are converted to a large “single” crystal. Single crystal silicon is used in manufacture most of Si-based microelectronic devices. Polycrystalline silicon can be available up to 99.9999% pure.
3.4 Implementation of PV system:
3.4.1 Types of PV system
There are three types of PV system being implemented around the world depending upon its function and integration with other energy resources.
- Standalone PV system
- Grid Connected PV system
- Hybrid Systems
Stand alone PV system
This type of system is usually present in our wrist watches, calculators and in space crafts also. These are dependent totally on its self generated power through solar panels and are directly used by DC loads or AC loads through inverter.
In some system battery bank is also available to store the unused power to facilitate loads during night or under low light conditions.
Further more a charge controller is also required in order to avoid battery from over charging and deep discharging. An inverter is also employed to provide power to AC loads.
Grid Connected PV system
In grid connected type the PV module has also backed up with WAPDA line or Grid connection. In this way if load is not getting enough power from the PV module or its battery, it will switch to the WAPDA line. This type of system is most commonly used around the World. Its applications are found mostly in small industries and homes.
In this type the PV system is also integrated with two or more type of energy resources which may or may not be renewable resources .For example a wind turbine, steam engine or a small hydro plant etc. Other energy sources can also be integrated depending upon climate, geographical location of the place and several other perspectives. These systems are more appropriate for remote applications such as military installation, communication stations and rural villages.
3.4.2 Design Methodology
Our project is based on a Hybrid System Consisting of a PV module and a windmill as two renewable energy resources, we have chosen these sources keeping in mind the climate and terrain of Lahore.
22.214.171.124 Components of Photovoltaic system:
- Solar cell Panel
- Charge Controller
The major component of our system is the integrator .The function of this device is to integrate powers from both energy sources in a way that during operating time of the sources loads will directly get power from these sources and at night or the time when these sources are not operating loads are facilitated through battery banks. A controller is placed in the integrator circuit that is continuously monitoring the voltage level being provided by the sources. If the load can operate single handed by either of the sources the rely will build its connection from load with that source while the energy generated by the second source is being stored in the batteries .If both sources are required to derive a certain load rely opens up its connection of both sources with the load.
When both sources are not providing a sufficient amount of power to the loads the controller will check whether batteries could provide sufficient amount of voltage so, it will start delivering power to load from the battery bank otherwise an LED blinks indicating that system cannot provide sufficient amount of power and will shutdown eventually.
126.96.36.199 Solar Panel Characteristics
|Vpp||1 volt at SOC|
|No. of cells||36|
|Length of each cell||0.15m|
|Width of each cell||0.0513m|
|Area of each cell||0.0077m2|
|Area of total no. of cell||0.278m2|
|o/p per m2||45/0.278=161.6 W/m2|
Table 3.1. Solar Panel Characteristics
188.8.131.52 Experimental Values
This table shows the experimental results of output voltage and output current with respect to different timings and temperature variations in a day.
UV Index watt/m2
DC O/P Voltage
DC O/P Current
DC O/P Power
Table 3.2. Solar Panel Throughput
184.108.40.206 Factors Affecting Output Power
STC(Standard Test Condition)
The electricity produce by solar cell is in DC, the DC output of solar panel is Tested under the STC that is
Cell Temperature= 25°C
Solar Radiation Intensity= 1000 W/m2..
Air Mass= 1.5
These are the standard test condition at which Solar cell gives its Maximum Efficiency, in other conditions there is almost 10 to 15 percent of decrease in the efficiency of cell with respect to its STC rating.
Output power of the solar cell is inversely proportion to the increase in temperature of the cell. For a crystalline module , a typical temperature reduction factor proposed by CEC is 89 percent which means ”95 watts” module will typically provide 85 Watts (95watts*0.89=85watts) under sunlight conditions during summer seasons.
Mismatch and wiring Losses
The performance of the system can be affected due to mismatch of module connections. The loss in power also depends upon the increase in length of wire between source and load. As the distance between source and load increases losses also increases. Therefore the distance should be kept minimal to get maximum power throughput.
DC To AC conversion Losses
Since our system