30-05-2011, 08:14 AM
DISTRIBUTED GENERATION FOR RURAL AREAS ELECTRIFICATION BASED UPON RENEWABLE ENERGY RESOURCES USING MATLAB
Abstract
Currently, the world is facing energy crisis and many advance researches are in progress to
overcome these energy crisis. Distributed generation is getting much importance in this scenario.
Distributed generation means to generate energy (electricity) from any available renewable
energy resource and distribute that electricity at the spot. The generated power can be integrated
with national grid if suitable. Pakistan has wide spectrum of high potential of renewable energy
sources, conventional and non-conventional as well, which have not been adequately explored,
exploited or developed. As a result, the primary energy supplies today are not enough to meet
even the present demand. Moreover, a very large part of the rural areas does not have the
electrification facilities because they are either too remote and/or too expensive to connect to the
national grid. So, Pakistan, like other developing countries of the region, is facing a serious
challenge of energy deficit. The development of the renewable energy resources can play an
important role in meeting this challenge. Distributed generation has many advantages. These
benefits include line loss reduction, reduced environmental impacts, peak shaving, increased
overall energy efficiency, relieved transmission and distribution congestion, voltage support, and
deferred investments to upgrade existing generation, transmission, and distribution systems.
During this research work, three major renewable energy resources namely solar, wind and
micro-hydro have been selected for rural areas/ village electrification. For this purpose, three
different locations have been selected for proper design calculation of locally available
renewable energy resources. Finally, the three independent stand-alone systems have been
simulated in MATLAB software to run the loads of different capacity.
Chapter No. 01
Introduction
1.1 - Introduction
Distributed generation, also called on-site generation, generates electricity from many small
energy sources called renewable energy resources.
Several recent developments have encouraged the entry of power generation and energy storage
at the distribution level. A distributed resource (DR) is a term that encompasses both distributed
generation (DG) and distributed energy storage (DS). A distributed utility will use both
distributed resources and load management to achieve its goal. In addition, several compact
distributed generation technologies are fast becoming economically viable. Integration of DG
into an existing utility can result in several benefits. These benefits include line loss reduction,
reduced environmental impacts, peak shaving, increased overall energy efficiency, relieved
transmission and distribution congestion, voltage support, and deferred investments to upgrade
existing generation, transmission, and distribution systems. Benefits are not limited to utility.
Customers also benefit from DG in term of better quality of supply at lower cost. Among the
many benefits of distributed generation is a reduced line loss [1].
Distributed generation units with small energy sources, such as fuel cells, micro-turbines, and
photovoltaic devices, can be connected to utility grid as alternative energy sources besides
providing power to their local loads. The distributed generation units are interfaced with utility
grid using three phase inverters. With inverter control, both active and reactive power pumped
into the utility grid from the distributed generation units can be controlled. Reactive power flow
control allows the distributed generation units to be used as static VAR compensation units
besides energy sources [2].
Distributed Energy Resource (DER) systems are small-scale power generation technologies
(typically in the range of 3 kW to 10,000 kW) used to provide an alternative to or an
enhancement of the traditional electric power system. The usual problem with distributed
generators is their high cost [3], [4].
1.2 - Worldwide Importance of Renewable Energy Resources
Importance of Renewable Energy Resources is increasing with every passing day. The
International Renewable Energy Agency (IRENA) is an intergovernmental organization for
promoting the adoption of renewable energy worldwide. It aims to provide concrete policy
advice and facilitate capacity building and technology transfer. IRENA was formed on January
26, 2009, by 75 countries signing the charter of IRENA [5].
Renewable energy resources have numerous advantages; some of them are described below:
Chapter No. 02
Scope of
Renewable
Energy Resources
In Pakistan
Scope of Renewable Energy Resources in Pakistan Chapter No. 02
Page 6
2.1 - Renewable Energy Resources in Pakistan
Pakistan has wide spectrum of high potential of renewable energy sources, conventional and
non-conventional as well, which have not been adequately explored, exploited or developed. As
a result, the primary energy supplies today are not enough to meet even the present demand.
Moreover, a very large part of the rural areas does not have the electrification facilities because
they are either too remote and/or too expensive to connect to the national grid. So, Pakistan, like
other developing countries of the region, is facing a serious challenge of energy deficit. The
development of the renewable energy sources can play an important role in meeting this
challenge.
In 2005, only 85,000 villages were connected to the national grid out of a total of 125,000 unelectrified
villages. The remaining 40,000 villages, comprising over 3 million households,
therefore, rely on firewood, cow dung, coal, kerosene, petroleum, LPG, cell batteries etc[7].
7876 of these un-electrified villages cannot be connected to the national gird for another 20 years
due to their distance from the national grid, which rendered these villages technically and
economically unavailable.
Like any other citizens of Pakistan, the inhabitants of these villages also deserved access to the
basic amenities of life. Hence, the Government of Pakistan (GOP) tasked Alternative Energy
Development Board (AEDB) to provide the basic energy services to these villages [7].
There are many renewable energy resources available in Pakistan, the most common that are
being explored recently are following:
- Micro-hydro
- Photovoltaic (Solar Electricity)
- Wind Energy
- Biodiesel
- Biomass
- Biogas
Currently, Pakistan is taking much interest in the generation of electricity from renewable energy
resources. Alternative Energy Development Board (AEDB) Pakistan is working on the
renewable energy resources. In this chapter we have described the current status of renewable
energy resources in Pakistan [7].
Scope of Renewable Energy Resources in Pakistan Chapter No. 02
Page 7
2.2 - Micro-Hydro
In Pakistan, hydel power is available in access in the form of sea water, rivers, canals etc. that
hydel power can be used to generate electricity in different areas of country using small microhydel
projects.
In Pakistan, Gilgit Baltistan has maximum hydro electricity resources as compared to anywhere
in the country. The region has an area of 72000 square kilometers and a population of nearly two
million. It is a mountainous region and the population is widely scattered. A large number of
micro hydro power station units have been established in the area. Some small i.e. up to 18 MW
hydro power stations have been established on Naltar Nulla during the past forty years in the
region mostly relying on foreign aid. Acute shortage of electricity and long periods of load
shedding especially in the cold winter months is a common phenomenon.
Generation from the hydroelectric power stations rapidly falls due to decrease in the flow in the
winter season. This leads to severe power crises and shortages.
Due to non availability of reliable and continuous power supply, establishment of industries have
not been possible. Unemployment is on the rise giving fears of social unrest as in other areas of
adjoining Khyber Pakhtoonkhwa. Adequate availability of power will usher in industrial activity
and the demand of energy and revenues both will then rise rapidly in near future. Gilgit is now
Pakistan’s gateway to China along the Karakoram Highway.
Micro-Hydro has the potential of about 30,000MW in Pakistan [7].
2.2.1 - Resource Potential of Micro-Hydro
Pakistan has an installed hydroelectric capacity of 5,928 MW of large (>250 MW), 437 MW of
medium (>50 MW and <250 MW), and 253 MW of small to micro (<50 MW) plants, mostly in
the northern parts of the country [7].
2.2.2 - Current Status of Micro-Hydro
AEDB is actively working with Aga Khan Rural Support Program (AKRSP) to install 103
Mini/Micro hydro power plants at Chitral and other places in Gilgit Baltistan [7].
2.3 - Photovoltaic (Solar Electricity)
Solar PV cells convert solar energy in to electricity that is used to charge batteries to provide
lights during night. Solar energy has excellent potential in Pakistan that receives high levels of
solar radiation throughout the year. Solar Energy is available at a rate of 1000 watts per square
meter in Pakistan. This can be converted to DC electricity with the help of Solar Photovoltaic
cells, which may be used to pump water, operate fans, TV and telecommunications directly
during daytime. The electrical energy generated during the day time (5-8 hours of sunshine), can
Scope of Renewable Energy Resources in Pakistan Chapter No. 02
Page 8
also be stored in deep cycle lead acid batteries which can be used at night to provide power for
lighting, radio, Television and fans. The system will be user-friendly and designed as a standalone
system for each household, who will be trained to operate and maintain it. The user will
only be required to switch on/off the system, as is done in normal home lighting systems [7].
Solar energy is a potentially available renewable energy source in this region. This source can be
utilized as an excellent alternative to fossil fuels for these areas. Solar energy resource is planned
to successfully utilize for household applications and electrification of remotest villages of these
areas. The outcomes of this program are social uplift, betterment and provision of basic
amenities of life [7].
2.3.1 - Resource Potential of Solar Photovoltaic
Pakistan covers 796,095 square kilometers of land between latitudes 24° and 36°north and
longitudes 61° and 76° east. At present, it faces serious energy problems: 95 percent of its
electricity generation comes from hydropower, which becomes less productive during the driest,
hottest months of the year and cannot keep pace with the sharp rise in energy demand. Also,
about 70 per cent of the population lives in some 50,000 villages dispersed around the country.
Many of these villages are far from the main transmission lines of the national grid and, because
of their relatively small populations; it is usually not economically viable to connect these
villages to the grid. Solar energy, on the other hand, has excellent potential in areas of Pakistan
that receive high levels of solar radiation throughout the year. Every day, for example, the
country receives an average of about 19 Mega Joules per square meter of solar energy [7].
2.4 - Wind Energy
Electricity can be generated in many ways. In each case, a fuel is used to turn a turbine which
drives a generator which feeds the grid. The turbines are designed to suit the particular
characteristics of the fuel. Wind generated electricity is no different. The wind is the fuel –
unlike fossil fuels it is both free and clean, but otherwise it is just the same. It drives the turbine
which generates electricity into a grid.
2.4.1 - Resource Potential of Wind Energy
Pakistan has a considerable potential of wind energy in the coastal belt of Sindh, Baluchistan and
as well as in the desert areas of Punjab and Sindh. This renewable source of energy has however,
not so far been utilized significantly. The Wind Data of all Pakistan has been collected from
Pakistan Metrological Department and analyzed by AEDB [7].
As per the collected data, the coastal belt of Pakistan is blessed with a God gifted wind corridor
that is 60 km wide (Gharo ~ Kati Bandar) and 180 km long (up to Hyderabad). This corridor has
the exploitable potential of 50,000 MW of electricity generation through wind energy. AEDB
has made a wind resource study to setup the benchmark wind speed values at different levels
Scope of Renewable Energy Resources in Pakistan Chapter No. 02
Page 9
from Gharo and Jhimpir regions at present. In addition to that there have been some other wind
sites have been exploited in coastal area of Baluchistan and some Northern areas. Most of the
remote villages in the south can be electrified through micro wind turbines. It is estimated that
more than 5000 villages can be electrified through wind energy in Sindh, Baluchistan and
Northern areas [7].
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