Electrical Technology
Analysis of a Renewable Energy
Project Implementation
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All acclamation and appreciation for almighty Allah the
most beneficent and merciful who is the entire source of
all kind of wisdom and knowledge.
My special praise of the Holy Prophet Hazrat
Muhammad (peace be upon him) the most perfect and
exalted among and of every born on the earth. Who is
forever a torch of guidance and knowledge for humanity
as a whole?
I thanks to Mr. Muhammad Aqeel, Preston University
Lahore for his keen interest, useful suggestion,
consistent encouragement, incentive teaching, and
dynamic supervision throughout the course of his project.
Last but not least, I feel my proud privilege to mention
the feeling of obligations toward my affectionate parents
and family members, who inspired me for higher
education and supported financially and morally
throughout my study.
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TO
OUR WORTHY FATHER
WHO ALWAYS INSPIRE AND
ENCOURAGED
ME FOR WHAT I WANT AND GRAFTED
IN THE
UNTIRING TO GET ON TO HIGHER
IDEAL LIFE
OUR BELOVED MOTHER
&
FAMILY MEMBERS
WHICH I STRONGLY BELIEVE THAT
THEIR PRAYERS ARE WITH ME AND
WILL ALWAYS.
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Electrical Technology
Group Members
Waseem Abbas 16E2-112021
Muhammad Rizwan 16E2-112022
Mudassar Iqbal 16E2-111501
Safeer Ali 16E2-111502
Project Submitted
To
MR Muhammad Aqeel
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CHAPTERS NAME
Chapter 1 Introduction …………………………………..… 09
Chapter 2 Natural Gas .……………………………………... 17
Chapter 3 Bio Gas .……………………………………………. 25
Chapter 4 Design and Analysis ………………….………. 35
Chapter 5 Project Cost and Cost Analysis …………… 50
Chapter 6 Environmental and Social Impact …..…. 52
Chapter 7 Conclusion ………………………………………… 59
Chapter 8 Future Enhancement ………..………..……… 62
Chapter 9 References ……………………………………….. 69
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Table of Contents CHAPTER 1 INTRODUCTION After Reading this Chapter you will be able to:
1.1 Brief History of Pakistan 1.2 Roll of Energy in development of Country 1.3 Energy Requirements in Pakistan 1.4 Energy Crisis of our Country 1.5 Starting a Project to overcome Energy Crisis 1.6 Reason of this project 1.7 Selecting a place to start a project
CHAPTER 2 NATURAL GAS
After reading this Chapter you will be able to: 2.1 Brief History of Natural Gas
2.2 What is the Natural Gas
2.3 The Formation of Natural Gas 2.4 What is CNG and its uses 2.5 Natural Gas Problems and Hazards 2.6 Comparison of Natural gas and Biogas
2.7 Why we are facing the shortage of Natural Gas
CHAPTER 3 BIOGAS
After reading this Chapter you will be able to:
3.1 Brief introduction of Biogas 3.2 Potential of the Biogas Technology 3.3 Biogas Composition, Properties and Utilization as CNG 3.4 Government Roll for Biogas projects 3.5 Biogas Problems and Hazards 3.6 Performance of Biogas Generator
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CHAPTER 4 DESIGN AND ANALYSIS
After reading this Chapter you will be able to: 4.1 Concept of the Biogas project 4.2 The Digestion Process 4.3 The fermentation slurry 4.4 Fermentation Slurry As Fertilizer 4.5 Feed Methods 4.6 Bio GAS Plant types 4.7 Design of Biogas Project 4.8 Analysis of the Biogas Digester Design 4.9 Uses and implementation
4.10 Calculation of the Design and Project
CHAPTER 5 PROJECT COST AND COST ANALYSIS
After reading this Chapter you will be able to:
5.1 Cost of the Bio Digester 5.2 Cost of the Delivery of material 5.3 Cost of the Bio Digester Setup 5.4 Cost of the Labour And Maintenance 5.5 Total Cost of the Project 5.6 Cost Comparison With Natural Gas
CHAPTER 6 ENVIRONMENTAL AND SOCIAL IMPACT After reading this Chapter you will be able to: 6.1 Making a Entire Community on Board 6.2 Environmental Impact of Project 6.3 Social Impact of Project 6.4 Social Implementation of Project 6.5 Effect on the life of People
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CHAPTER 7 CONCLUSION After reading this Chapter you will be able to: 7.1 Bio gas Project Need 7.2 Operational And Financial Benefits
7.3 How it effect on peoples life 7.4 Biogas and Natural Gas Comparison 7.5 Conclusion
CHAPTER 8 FUTURE ENHANCEMENT After reading this Chapter you will be able to: 8.1 Energy Production Potential 8.2 Technical Aspects
8.3 Economic Aspects
8.4 Necessary Framework Conditions
8.5 Costly Benefit Of Biogas Plant In Future
8.6 Difficulties
8.7 Observation of the Development
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INTRODUCTION
1.1 Brief History of Pakistan
Pakistan officially the Islamic Republic of Pakistan, is a sovereign country in South Asia. With a
population exceeding 180 million people, it is the sixth most populous country in the world.
Located at the crossroads of the strategically important regions of South Asia, Central Asia
and Western Asia, Pakistan has a 1,046-kilometre (650 mi) coastline along the Arabian Sea and
the Gulf of Oman in the south and is bordered by India to the east, Afghanistan to the west
and north, Iran to the southwest and China in the far northeast. It is separated from Tajikistan
by Afghanistan's narrow Wakhan Corridor in the north.
The territory of modern Pakistan was home to several ancient cultures, including the Neolithic
Mehrgarh and the Bronze Age Indus Valley Civilization, and has undergone invasions or
settlements by Hindu, Persian, Indo-Greek, Islamic, Turco-Mongol, Afghan and Sikh cultures.
The area has been ruled by numerous empires and dynasties, including the Indian Mauryan
Empire, the Persian Achaemenid Empire, the Arab Umayyad Caliphate, the Mongol Empire,
the Mughal Empire, the Durrani Empire, the Sikh Empire and the British Empire.
As a result of the Pakistan Movement led by Muhammad Ali Jinnah and India's struggle for
independence, Pakistan was created in 1947 as an independent nation for Muslims from the
regions in the east and west of India where there was a Muslim majority. Initially a dominion,
Pakistan adopted a new constitution in 1956, becoming an Islamic republic. A civil war in 1971
resulted in the secession of East Pakistan as the new country of Bangladesh.
Pakistan is a federal parliamentary republic consisting of four provinces and four federal
territories.
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It is an ethnically and linguistically diverse country, with a similar variation in its geography and
wildlife.
A regional and middle power, Pakistan has the seventh largest standing armed forces in the
world and is also a nuclear power as well as a declared nuclear weapons state, being the only
nation in the Muslim world, and the second in South Asia, to have that status. It has a semi-
industrialized economy which is the 27th largest in the world in terms of purchasing power
and 47th largest in terms of nominal GDP.
Pakistan's post-independence history has been characterized by periods of military rule,
political instability and conflicts with neighboring India. The country continues to face
challenging problems, including terrorism, poverty, illiteracy and corruption.
It is a founding member of the Organization of the Islamic Conference (now the Organization
of Islamic Cooperation) and is a member of the United Nations, the Commonwealth of
Nations, the Next Eleven Economies, SAARC, ECO, D8 and the G20 developing nations.
Pakistan’s already strained resources are only going to be stretched further. Almost 42% of the
populations are below the poverty line earning less than $1.25US per day. Access to
substantial shelter can be limited and clean drinking water is particularly difficult to obtain in
rural areas. The compaction of these factors sees the life expectancy in Pakistan at 64 years at
birth compared to 81 years at birth in Australia (UNICEF, 2010)
1.2 Roll of Energy in development of Country
Energy is a foundation stone of the modern industrial economy. Energy provides an essential
ingredient for almost all human activities: it provides services for cooking and space/water
heating, lighting, health, food production and storage, education, mineral extraction, industrial
production and transportation. Modern energy services are a powerful engine of economic
and social development, and no country has managed to develop much beyond a subsistence
economy without ensuring at least minimum access to energy services for a broad section of
its population. Throughout the world, the energy resources available to them and their ability
to pay largely determine the way in which people live their lives. Nevertheless, it is critical to
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recognize that what people want are the services that energy provides, not fuel or electricity
per se.
In developing countries, it is widely accepted that poverty will not be reduced without greater
use of modern forms of energy. Surpassing the 1 toe/capita per year level of energy use seems
to be an important instrument for development and social change. Whilst low energy
consumption is not the only cause of poverty and under-development, it does appear to be a
close proxy for many of its causes. For example, environmental degradation, poor health care,
inadequate water supplies and female and child hardship are often related to low energy
consumption.
1.3 Energy Requirements in Pakistan
Changes in the way that energy is delivered to final consumers are taking place around the
world. Energy generation, distribution and supply are moving from the public to the private
sectors, and governments are now less likely to be directly involved in managing the energy
business. Competition between private utilities is becoming more common, with the
government role reducing to one of policy, oversight and regulation. There is also a move
away from centrally planned generation and supply, with the market determining operational
decisions and the allocation of investment funds. These trends are likely to continue, and are
affecting developing and industrialized countries alike, with implications for investment in
central power generating capacity and grid extensions.
The energy shortfall in Pakistan is currently estimated to lie in the 2500-5000 MW range (with
5000 MW being during peak hour timing) and, according to estimates, this energy crisis cost
the country $6 billion in 2008 while causing losses upwards of 2% of GDP in 2009-10
1.4 Energy Crisis of our Country
Pakistan has been facing an unprecedented energy crisis since the last few years, which has
seriously affected its people. The gap between demand and supply has been constantly
widening. People are spending sleepless nights in summer. Acute power outages have
seriously paralyzed the commercial and economic activities in the country.
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This acute shortage of power reflects the shortsightedness of our policy makers. Shortage of
power supply has assumed the role of a fundamental necessity, becoming a serious policy
dilemma. It needs sustained efforts and long-term policies to overcome this crisis. Sincere
effort is required to ensure sustained and consistent supply of energy.
If we examine the present energy profile of Pakistan, it is meeting its energy requirements
from different sources. Pakistan is generating 48 percent of its electricity from gas, 33 percent
from hydrel, 17 percent from oil, two percent from nuclear and one percent from coal. If we
examine the figures, it is clear that Pakistan is underutilizing its natural resources to generate
electricity.
One of the dilemmas is the non-exploitation of indigenous resources. We have failed to exploit
those resources that nature has bestowed upon us. We have not properly tapped our natural
resources, even though we could have met our energy crisis by doing that. Looking into the
administrative causes of the energy crisis, lack of proper planning is the most important. Lack
of proper conservation methods is another cause of the energy crisis.
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The energy crisis has led to a negative impact on direct foreign investment. Investors require a
sustained, secure and cheap power supply in any country. In Pakistan, no such facility is
available because of which many investors are not willing to come forth. The long-term
solution of the energy crisis is to build mega dams to store water and generate electricity.
Government power bodies like WAPDA and KESC should initiate plans to supply energy.
In a nutshell, energy is the lifeline of a nation and plays a vital role in national progress and
economic development of any country. It needs sincere and dedicated efforts of our policy
makers to find solutions to meet the energy requirements of the nation.
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1.5 Starting a Project to overcome Energy Crisis
Most developing countries have good renewable energy resources, including solar energy,
wind power, geothermal energy, and biomass. These can help developing countries reduce
their dependence on oil and natural gas. Investments in renewable can be less expensive than
fossil fuel energy systems.
Renewable energy can be particularly suitable for developing countries. In rural and remote
areas, transmission and distribution of energy generated from fossil fuels can be difficult and
expensive. Producing renewable energy locally can offer a viable alternative.
Interest in renewable energies has increased in recent years due to environmental concerns
about global warming and air pollution, reduced costs of renewable energy technologies, and
improved efficiency and reliability.
Pakistan an agrarian economy has a population of 140 million. Looking at the nation's energy
demand and living standard of the people, Government of Pakistan is facing an unprecedented
energy crisis. Shortage of energy, including both electricity and gas, is considered to be a major
road block to Pakistan’s rapid economic growth and poverty reduction. Biogas technology is
one of the reliable and renewable energy sources used for cooking and lighting purposes.
In rural areas liquid petroleum gas (LPG) is the only alternative to firewood or coal but LPG
prices have already jumped to Rs100 per kilogram that makes LPG unaffordable to the rural
communities. Biogas technology has proved to be very successful in the country since it not
only produces gas for household purpose but also provides good fertilizer in the form of
digested slurry.
1.6 Reason of this project
Pakistan and most of the developing countries are in energy crisis. Pakistan spends almost 7
billion US$ on import of fossil fuels annually to fulfill its energy needs. The renewable and
sustainable energy resources are best substitute to the conventional fuels and energy sources.
Pakistan takes the opportunity to have almost of its population rural. Having a large amount
of animals that give 652 million kg of manure daily from cattle and buffalo only this can be
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used to generate 16.3 million m3 biogas per day and 21 million tons of bio fertilizer per year.
So by installing the biogas units we can overcome the energy crisis which we are facing too.
They are low-cost and can be run with very small budget. Biogas energy corridor can work as a
good substitute for nearly 70% of country’s population residing in rural areas.
Energy has a very big importance in the development of any country. Unfortunately, our
country is facing a big crisis of Energy since last few years. And we are very keen to find some
renewable method to produce energy which would be cheapest, durable and ecological. One
of such method is “Bio-Gas’’ power plants.
There are almost 159 million animals and their manure can be used for generation of biogas in
rural areas. Energy production by using animal feces is highly sustainable as it is economically
viable, socially acceptable besides being environment friendly. There are almost 35.2million
cattle and buffalo assuming that an average animal can produce 10 kg of manure daily would
account for almost 352 million kg of dung. If 50% of produced feces is collected and used for
biogas production, it will be 176 million kg. According to an estimate about 20 kg wet mass of
manure can generate 1cubic meter (m3) biogas therefore producing almost 8.1 million m3
biogas daily. Almost 112 million people in Pakistan are rural residents and biogas can meet
their cooking and other energy needs in a good way. Pakistan can also explore biogas potential
of citrus pulp, paper industry, slaughter house and street waste as well. Poultry waste is ideal
substrate to produce biogas.
Thus, Pakistan's biogas support program has been considered one of the most successful
programs in the country. This has been the result of standardization of design, an extensive
system of quality control and financial incentive provided to the users for the installation of
biogas plants
The main reasons for starting this project are:
1. To provide clean bio- gaseous fuel mainly for cooking purposes and also for other
applications for reducing use of LPG and other conventional fuels.
2. To meet ‘lifeline energy needs for cooking as envisaged in 'Integrated Energy Policy’.
3. To provide bio-fertilizer organic manure to reduce use of chemical fertilizers.
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4. To mitigate drudgery of rural women, reduce pressure on forests and accentuate social
benefits.
5. To improve sanitation in villages by linking sanitary toilets with biogas plants.
6. To mitigate Climate Change by preventing black carbon and methane emissions.
1.7 Selecting a place to start a project
The town of Kalas Sharif is in South East of Sargodha in the Province of Punjab with a
population of 358 people. Of the 86 households spread across the town, at least 71 live below
the poverty line. The majority of the population here are agricultural workers and every
household owns livestock.
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NATURAL GAS
2.1 Brief History of Natural Gas
From 1947 to the early 1990s, the economy made considerable progress in the transformation
from a wood-burning base to modern energy sources. The process remains incomplete.
Biogases (the woody residue left over from crushed sugarcane), dung, and firewood furnished
about 32 percent of all energy in FY 1988. Some localities had been denuded of firewood,
forcing the local population to use commercial energy sources, such as kerosene or charcoal.
Domestic sources of commercial energy accounted for 77 percent of all commercial energy in
FY 1990. The major domestic energy resources are natural gas, oil, and hydroelectric power.
The remainders of energy requirements are met by imports of oil and oil products.
Crude oil production increased sharply in the 1980s, from almost 4.0 million barrels in FY 1982
to 22.4 million barrels in FY 1992. This increase was the result of the discovery and
development of new oil fields. Despite this expanded production, however, about 28 million
barrels of crude oil were imported annually in the early 1990s. The production from domestic
oil refineries also rose in the 1980s, reaching 42 million barrels annually in the early 1990s.
However, oil products imports accounted for about 30 percent of the value of all oil imports.
Pakistan vigorously pursued oil exploration in the 1980s and early 1990s and made a number
of new discoveries. In the early 1990s, the most productive oil field was at Dhurnal in Punjab,
accounting for 21 percent of total output in FY 1993. The Badin area in southern Sindh was the
site of a number of discoveries in the 1980s, and its proportion of total output has continued
to increase over the years. In the early 1990s, more favorable terms on pricing and
repatriation of profits stimulated the interest of foreign oil companies. About twenty foreign
companies are engaged in oil exploration, but poor security for workers and property in
remote areas of Baluchistan and Sindh remains a significant constraint on foreign investment.
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The large Sui natural gas field in Baluchistan was discovered after independence. Production at
Sui began in 1955 and peaked in 1985. In the early 1990s, it remained the nation's most
productive gas field, accounting for 46 percent of production in FY 1993. The second largest
gas field, also located in Baluchistan at Mari, accounted for 20 percent of all production.
Twenty-five gas fields were operational in FY 1993.
Natural gas pipelines, in which the government owns controlling shares, link the Sui gas field
and a few others to the main population centers and the major crude oil production areas. The
southern pipeline leads from Sui to Hyderabad and Karachi, and a spur supplies Quetta. The
northern pipeline branches at Faisalabad. One branch goes a little farther north of Lahore; the
other branch is connected to the crude oil fields and supplies gas to Islamabad and Peshawar.
There are plans for a new gas pipeline through which Iran would export natural gas to
Pakistan.
2.2 What is the Natural Gas
Natural gas, in itself, might be considered an uninteresting gas - it is colorless, shapeless, and odorless in its pure form.
Natural gas is a combustible mixture of hydrocarbon gases. While natural gas is formed primarily of methane, it can also include ethane, propane, butane and pentane. The composition of natural gas can vary widely, but below is a chart outlining the typical makeup of natural gas before it is refined.
Typical Composition of Natural Gas
Methane CH4 70-90%
Ethane C2H6
0-20% Propane C3H8
Butane C4H10
Carbon Dioxide CO2 0-8%
Oxygen O2 0-0.2%
Nitrogen N2 0-5%
Hydrogen sulphide H2S 0-5%
Rare gases A, He, Ne, Xe trace
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In its purest form, such as the natural gas that is delivered to your home, it is almost pure methane. Methane is a molecule made up of one carbon atom and four hydrogen atoms, and is referred to as CH4. The distinctive “rotten egg” smell that we often associate with natural gas is actually an odorant called mercaptan that is added to the gas before it is delivered to the end-user. Mercaptan aids in detecting any leaks.
Natural gas is considered 'dry' when it is almost pure methane, having had most of the other commonly associated hydrocarbons removed. When other hydrocarbons are present, the natural gas is 'wet'.
Natural gas is considered 'dry' when it is almost pure methane, having had most of the other commonly associated hydrocarbons removed. When other hydrocarbons are present, the natural gas is 'wet.'
Natural gas can be measured in a number of different ways. As a gas, it can be measured by the volume it takes up at normal temperatures and pressures, commonly expressed in cubic feet. Production and distribution companies commonly measure natural gas in thousands of cubic feet (Mcf), millions of cubic feet (MMcf), or trillions of cubic feet (Tcf). While measuring by volume is useful, natural gas can also be measured as a source of energy. Like other forms of energy, natural gas is commonly measured and expressed in British thermal units (Btu). One Btu is the amount of natural gas that will produce enough energy to heat one pound of water by one degree at normal pressure. To give an idea, one cubic foot of natural gas contains about 1,027 Btus. When natural gas is delivered to a residence, it is measured by the gas utility in 'therms' for billing purposes. A therm is equivalent to 100,000 Btu, or just over 97 cubic feet, of natural gas.
2.3 The Formation of Natural Gas
Natural gas is a fossil fuel. Like oil and coal, this means that it is, essentially, the remains of plants and animals and microorganisms that lived millions and millions of years ago. But how do these once living organisms become an inanimate mixture of gases?
There are many different theories as to the origins of fossil fuels. The most widely accepted theory says that fossil fuels are formed when organic matter (such as the remains of a plant or animal) is compressed under the earth, at very high pressure for a very long time. This is
A Methane molecule, CH4
Source: USGS
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referred to as thermogenic methane. Similar to the formation of oil, thermogenic methane is formed from organic particles that are covered in mud and other sediment. Over time, more and more sediment and mud and other debris are piled on top of the organic matter. This sediment and debris puts a great deal of pressure on the organic matter, which compresses it. This compression, combined with high temperatures found deep underneath the earth, breaks down the carbon bonds in the organic matter. As one gets deeper and deeper under the earth’s crust, the temperature gets higher and higher. At low temperatures (shallower deposits), more oil is produced relative to natural gas. At higher temperatures, however, more natural gas is created, as opposed to oil. That is why natural gas is usually associated with oil in deposits that are 1 to 2 miles below the earth's crust. Deeper deposits, very far underground, usually contain primarily natural gas, and in many cases, pure methane.
Natural gas can also be formed through the transformation of organic matter by tiny microorganisms. This type of methane is referred to as biogenic methane. Methanogens, tiny methane-producing microorganisms, chemically break down organic matter to produce methane. These microorganisms are commonly found in areas near the surface of the earth that are void of oxygen. These microorganisms also live in the intestines of most animals, including humans. Formation of methane in this manner usually takes place close to the surface of the earth, and the methane produced is usually lost into the atmosphere. In certain circumstances, however, this methane can be trapped underground, recoverable as natural gas.
A third way in which methane (and natural gas) may be formed is through abiogenic processes. Extremely deep under the earth's crust, there exist hydrogen-rich gases and carbon molecules. As these gases gradually rise towards the surface of the earth, they may interact with minerals that also exist underground, in the absence of oxygen. This interaction may result in a reaction, forming elements and compounds that are found in the atmosphere (including nitrogen, oxygen, carbon dioxide, argon, and water). If these gases are under very high pressure as they move toward the surface of the earth, they are likely to form methane deposits, similar to thermogenic methane.
2.4 What is CNG and its uses CNG is a readily available alternative to gasoline that’s made by compressing natural gas to less than 1% of its volume at standard atmospheric pressure. Consisting mostly of methane, CNG is odorless, colorless and tasteless. It's drawn from domestically drilled natural gas wells or in conjunction with crude oil production.
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Compressed Natural Gas (CNG) is a substitute for gasoline (petrol) or diesel fuel. It is considered to be an environmentally "clean" alternative to those fuels. It is made by compressing methane (CH4) extracted from natural gas. It is stored distributed in hard containers, usually cylinders.
2.5 Natural Gas Advantages and Disadvantages
Advantages:
Natural gas (largely methane) burns more cleanly than the other fossil fuels (45% less carbon dioxide emitted than coal and 30% less than oil)
It is easily transported via pipelines and fairly easily using tankers (land and sea) It can be piped into homes to provide heating and cooking and to run a variety of
appliances. Where homes are not piped, it can be supplied in small tanks. It can be used as a fuel for vehicles (cars, trucks and jet engines) where it is cleaner than
gasoline or diesel. It is used to produce ammonia for fertilizers, and hydrogen, as well as in the production
of some plastics and paints. It's relatively abundant, clean burning and seems easy to distribute. It's also lighter than air, so if there is a leak it will tend to dissipate, unlike propane,
which is heavier than air and pools into explosive pockets. It can be used for heating, cooking, hot water, clothes dryer, backup generator power,
and so forth. Some places will supply it to your house by way of underground pipes. Natural gas is more economical than electricity, it is faster when used in cooking and
water heating and most gas appliances are cheaper than electrical ones. Gas appliances also do not create unhealthy electrical fields in your house.
Disadvantages:
Even though it is cleaner than coal and oil, it still contributes a large amount of carbon dioxide to greenhouse gases.
By itself natural gas is mostly methane, which is 21 times more dangerous for greenhouse warming than carbon dioxide so any leakage of the gas (from animals, landfills, melting tundra, etc) contributes strongly to greenhouse emissions.
If your house is not properly insulated it can be very expensive.
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It can leak, potentially causing an explosion.
2.6 Comparison of Natural gas and Biogas An environmentally friendly and efficient energy source, natural gas is the cleanest-burning conventional fuel, producing lower levels of greenhouse gas emissions than heavier hydrocarbon fuels such as coal and oil. Historically, natural gas also has been one of the most economical energy sources. Natural gas fuels electric power generators, heats buildings and is used as a raw material in many consumer products, such as those made of traditional plastics.
Natural Gas It is obtained in natural form. It is available in large quantities. It is used as a source of power.
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It is also used as raw material in petrochemical industries. It is supplied for household use as LPG (Liquefied petroleum Gas) and also used for
running vehicles as CNG (Compressed Natural Gas).
Biogas It is obtained from shrubs, farm wastes, animal and human wastes. It is available in limited quantities. It is used mostly in rural areas. It is not used as raw material. Decomposition of organic matter yields gas, which has higher thermal efficiency in
comparison to kerosene, dung cake and charcoal. It gives no smoke. Hence, quite useful.
2.7 Why we are facing the shortage of Natural Gas
CNG has grown into one of the major fuel sources used in car engines in Pakistan. The government of Punjab, the most populous province of that country, has mandated that all
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public-transport vehicles will use CNG by 2007. Pakistan is the largest user of CNG in Asia, and third largest in the world, as of 2005. The ongoing crisis took root in 2004, when the government had decided to use natural gas to fuel automobiles. The decision had been taken in order to slash the fuel import bill, which was soaring due to high petrol prices. Another objective behind the use of CNG as a fuel was elimination environmental hazards, because CNG is much more environmentally-friendly then other fuels. However, things have changed. According to sources in Sui Northern Gas Pipelines (SNGPL), the current annual production of CNG is increasing by 7%, against growth in demand of nearly 40%. This shows that the annual shortfall of CNG is more than 400%. Similarly, the total output of gas pipeline companies in the country is around about 2,000 million cubic feet per day (mmcfd), while consumption is 2,800mmcfd. Along with private vehicles, public transportation has also converted from diesel or petrol to CNG since then. Pakistan stands first in the list of countries where CNG is the primary means of fueling vehicles. 22% of all automobiles on the road in Pakistan – 3.5 million in total – run on CNG. Due all above reasons we are facing shortage of Natural Gas.
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BIOGAS
3.1 Brief introduction of Biogas
In the present era of ever-increasing energy consumption and dwindling fossil fuel reserves,
the importance of biomass based, decentralized fuel such as Biogas and Biomass based power
generation has been greatly increased. It is a well established renewable and environment
friendly fuel for rural energy needs. Biogas is ideally suited for rural applications where
required animal or human excreta and agricultural waste are available in plenty. Harnessing
such a resource promotes rural industries, agriculture, dairy and animal farming in a
sustainable way. This will also increase employment in the rural regions and discourage
migration to cities.
Biogas as a renewable energy source could be an alternate means of solving the problems of
energy crisis. Agriculture has the key importance in the economy of Pakistan. Agriculture has
remained the basis of the Pakistan’s Economy as it provides employment to 45 percent
population and provides input for agro based industry. The major limiting factor is energy
which is responsible for impede in developing economies .In Pakistan almost 20% of the
foreign exchange is spent on import of fossil fuels. The given survey shows the increase in the
energy consumption of fuels and electricity in Pakistan of last five years.
Pakistan is currently facing an unprecedented energy crisis. Shortage of energy, including both
electricity and gas, is considered to be a major road block to Pakistan’s rapid economic growth
and poverty reduction. The prices of both continue to increase due to a sharp increase in their
demand, adding to the worries of the crises-hit dwellers. The consumers are facing many
difficulties because of gas load shedding. In rural areas LPG is the only alternative to firewood
or coal but LPG prices have already jumped to Rs100 per kilogram that makes LPG
unaffordable to the rural communities.
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Due to non-consideration of daily production we are now facing the shortage of Natural gas.
The main reason of shortage is the high fuel prices. In response to high fuel prices and
environmental concerns, compressed Natural gas (CNG) is starting to be used in light-duty
passenger vehicles and pickup trucks, medium-duty delivery trucks, and in transit and school
buses.
In present scenario, it is almost impossible for the Government to provide sui-gas facility to
the residents of rural areas. However, the Biogas Plants act as a useful source for providing gas
facility to the households. Pakistan has a great potential for domestic biogas because of the
availability of sufficient animal dung, water, ambient temperature, the availability of
construction materials, enough space for plant installation, freedom from floods, and
availability of human resources for the construction of plant.
Now we are facing the lack of Natural Gas Resources. And the main Reason of shortage of
Natural Gas is that its use as CNG. So now we need to find some renewable method to
produce energy which would be cheapest and ecological. One of such method is “Bio-Gas’’
Using biogas in gas engines promotes proper waste disposal and provides an efficient, profit
able, low-emission energy supply. In addition, the end products of biogas fermentation can be
used as fertilizer.
Biogas typically refers to a gas produced by the biological breakdown of organic matter in the
absence of oxygen. Organic waste such as dead plant and animal material, animal dung, and
kitchen waste can be converted into a gaseous fuel called biogas. Biogas originates from
biogenic material and is a type of bio fuel.
Biogas is produced by the anaerobic digestion or fermentation of biodegradable materials
such as biomass, manure, sewage, municipal waste, green waste, plant material, and crops.
Biogas comprises primarily methane (CH4) and carbon dioxide (CO2) and may have small
amounts of hydrogen sulphide (H2S), moisture and siloxanes.
The gases methane, hydrogen, and carbon monoxide (CO) can be combusted or oxidized with
oxygen. This energy release allows biogas to be used as a fuel. Biogas can be used as a fuel in
any country for any heating purpose, such as cooking. It can also be used in aerobic digesters
where it is typically used in gas engine to convert energy in the gas into electricity and heat.
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Biogas is an environment friendly, clean, cheap and versatile fuel. Biogas is produced by
anaerobic digestion of degradable wastes such as cattle dung, vegetable wastes, sheep and
poultry droppings, municipal solid waste, sewage water, land fill etc. Presently the biogas is
mainly used for cooking and lighting purposes in the rural areas. The use of biogas in
stationary engines used for different agricultural operations is going on. Its utilization is also
feasible in automobiles, used for transportation purposes by enriching and compressing it in
cylinders. Biogas can be converted in bio CNG after enrichment and bottling. It becomes just
like CNG.
Biogas is somewhat lighter than air and has an ignition temperature of approximately 700 °C
(diesel oil 350 °C; petrol and propane about 500 °C). The temperature of the flame is 870 °C.
Biogas consists of about 60 % methane (CH4) and 40 % carbon dioxide (CO2). It also contains
small proportions of other substances, including up to 1% hydrogen sulphide (H2S).
The methane content and hence the calorific value is higher the longer the digestion process.
The methane content falls to as little as 50% if retention time is short. If the methane content
is considerably below 50 %, biogas is no longer combustible. The first gas from a newly filled
biogas plant contains too little methane. The gas formed in the first three to five days must
therefore be discharged unused.
The methane content depends on the digestion temperature. Low digestion temperatures give
high methane content, but less gas is then produced. The methane content depends on the
feed material. Some typical values are as follows:
Cattle manure 65%
Poultry manure 60%
Pig manure 67%
Farmyard manure 55%
Straw 59%
Grass 70%
Leaves 58%
Kitchen waste 50%
Algae 63%
Water hyacinths 52%
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3.2 Potential of the Biogas Technology
So far, biogas has mostly been used as fuel for cooking and running stationary engines.
However, its potential has not fully utilized, yet. There is a great enhancement in its utilization
potential particularly where bigger plants are in operation e.g. institutional biogas plants in
Gaushalas, dairy farms or community biogas plants in villages. Gaushalas are running generally
on charity basis and most of Gaushalas are not in sound financial position. Enrichment and
bottling of biogas will help to improve it.
The family Biogas plants in the country are estimated to be saving 39.6 lakh tones of fuel-
wood per year. Besides, about 9.2 lakh tones of enriched organic manure are being produced
every year from these plants.
There are number of Gaushalas, dairies, village communities having large number of cattle
which have potential of installing biogas enrichment and bottling system. In urban areas, large
quantity of biogas can be produced in sewage treatment plants using anaerobic digestion. Due
to rising cost of petroleum products and environmental concerns it has become imperative to
make use of local resources as an alternate to petroleum fuels. There for it is worldwide trend
to explore and make use of biogas as an alternate fuel in vehicles.
3.3 Biogas Composition, Properties and Utilization as CNG
Biogas comprises of 60-65% methane, 35-40 % carbon dioxide, 0.5-1.0 % hydrogen sulfide and
rests of water vapour. It is almost 20% lighter than air. Biogas, like Liquefied Petroleum Gas
(LPG) cannot be converted to liquid state under normal temperature. Removing carbon
dioxide and compressing it into cylinders makes it easily usable for transport applications, say
three wheelers, cars, pick up vans etc and also for stationary applications at various long
distances. Already, CNG technology has become easily available and therefore, bio-methane
(enriched biogas) which is nearly same as CNG, can be used for all applications for which CNG
are used.
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3.3.1 Conversion Technologies
Biomass can be converted into biogas by anaerobic digestion technology. Anaerobic Digestion
Technology is consisting of three distinct stages.
In the first stage complex biomass material is decomposed by a heterogeneous set of
microorganisms, not necessarily confined to anaerobic environments. These decompositions
comprise mainly of cellulosic material to simple glucose, using enzymes provided by the co-
organisms as catalyst. Similarly proteins are decomposed to amino acids and lipids to long
chain acids. The significant result of the first phrase is the most of the biomass is now water
soluble and in a simpler chemical form suited for the next process step.
The second stage involves dehydrogenation, such as changing glucose into acetic acid,
carboxylation of the amino acids, and breaking down the long chain fatty acids into short chain
acids, again obtaining acetic acid as the final product. These reactions are fermentation
reactions accomplished by a range of acidophilic (acid-forming) bacteria. Their optimum
performance requires a PH environment in the range 6-7 (slightly acidic), but the acid already
formed will lower the PH of the solution, it is sometimes necessary to adjust the PH, for
example by adding the lime.
Finally the third phase is the production of biogas from acetic acid by a second set
of fermentation reactions performed by methanogenic bacteria. These bacteria require a
strictly anaerobic environment. Often, all processes into stages will allow greater efficiencies
to be reached. The third phase takes the order of weeks, the preceding phases on the order of
hours or days, depending on the nature of the feed stock.
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3.3.2 Biogas Enrichment Process
A variety of processes are available for enrichment i.e. removing CO2, H2S and water vapour.
Commonly CO2 removal processes also remove H2S. One of the easiest and cheapest methods
involves is the use of pressurized water as an absorbent liquid. In this method, the biogas is
pressurized and fed to the bottom of a scrubber column where water is sprayed from the top.
In counter-currently operated absorption process, the carbon dioxide and hydrogen sulfide
present in the biogas is absorbed in down going water and methane goes up and collected in
vessel. However, water requirement in this process is high but it is the simplest method of
removing impurities from biogas.
3.3.3 Concept of Alternative Bio-CNG
Biogas contains a large proportion (about 40 % by volume) of carbon dioxide, a heavier and
non combustible gas and some fraction of hydrogen sulphide. Hence it is needed to enrich
biogas by removing these undesirable gases to save compression energy and space in bottle
and corroding effect, which can be done by scrubbing. The scrubbing system is found to enrich
methane about 95 % or more depending upon biogas inlet and water injection pressure.
Biogas can be used for all applications designed for natural gas, assuming sufficient
purification.
3.3.4 Scope of the Technique
Enriched biogas is made moisture free by passing it through filters after that it is compressed
up to 200 bar pressure using a three stage gas compressor. Compressed gas is stored in high
pressure steel cylinders as used for CNG. There is large potential of this technology in buses,
tractors, cars, auto rickshaws, irrigation pump sets and in rural industries. This will help to
meet our energy demand for rural masses thus reduces burden of petroleum demand, moves
towards energy security and will improve economic status by creating employment generation
in rural area.
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3.4 Government Roll for Biogas projects
The Government has formed a council for renewable energy technology named as Pakistan
Council for Renewable Energy technology (PCRET).Which is working for the development of
the biogas plants in the country.
With the energy crisis in Pakistan getting worse day by day, biogas plants in rural areas can
play a major role in decreasing the burden on the national energy grids. Even in the developed
countries like UK, biogas plants are being built and encouraged with the help of government
funds and many other incentives. In our neighboring country India, there are almost two
millions biogas plants
Pakistan’s 70 percent population lives in the rural areas. Most farmers have two or more
cows/buffalos. The dung from these cattle mixed with an equal proportion of water can be
used to produce biogas in a biogas plant. This biogas can then be used for cooking purposes or
to generate electricity through a gas fired engine whereas the residue from this plant can be
used as a fertilizer.
Typically, 50 kg cow dung is required to produce 100 cubic feet of biogas that is sufficient to
fulfill the daily requirements of a family of five or six members. About 4,137 biogas plants were
installed in Pakistan with the help of the government in the period 1974 to 1987. The
government fully funded the first 100 installations and later on withdrew the financial support.
Since then, the growth rate of this technology dropped drastically and only 6,000 biogas plants
were installed till the end of 2006.
Pakistan Centre for Renewable Energy Technologies (PCRET) has already installed and
supported 4,000 biogas plants with only 50 percent financial contribution from beneficiaries.
Now PCRET is going to install 368 biogas plants in rural areas of Pakistan. Also Strategy&
Business Development at KESC to discuss about the upcoming renewable power project base
primarily on animal waste. hay have started the project of producing biogas from animal
manure and the dairy farms honors have signed an agreement of supplying 3000 tons per day
to the KESC and the production power of the plant will be 20-25 MW.
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The Initial Environment Examination (IEE) conducted for the Pakistan Domestic Biogas
Program, proposed to be implemented by the Rural Support Program Network (RSPN),
Pakistan. The program envisions setting up 300,000 domestic biogas plants across Pakistan
within 10 years of time.
3.4.1 Available Feed Stocks
As previously described in the manure of the live stock animals, biogases, field grass, straw,
and different types of cellulosic material and organic wastes are the raw material for the
production of biogas. Urban areas of Pakistan generate over 55000 tones of solid wastes daily.
More than a total of 15 million layer-chicken and 528 broiler chicken birds were approximately
produced in 2003 with a share of 22%, 68%, 3.5% and 6.5% of Sindh, Punjab, Baluchistan and
NWFP Provinces respectively. According to unofficial estimates, hardly 5 to10% poultry farms
have membership of Pakistan Poultry Association (PPA). As per livestock Census 2006 there
are 56.9 million animals (Buffaloes, cow, and bullocks) in Pakistan. . On the average the daily
dung dropping of medium size of animal is estimated15 kg per day. This would Yield 854
million kg dung/day. Assuming 50 % connectivity the availability of fresh dung comes out to be
427million kg/day. Thus 21.35 million m3 Biogas can be produced through bio-methanation. In
addition it will also produce 450 million _ones of bio-fertilizer per day.
3.4.2 Current Capacity and Production
Biogas Technology is an environment friendly technology. It contributes towards eco System
management and biodiversity conservation. It provides soot-free clean gas for meeting
domestic fuel needs as well as enriched bio fertilizer for improvement of Fertility/productivity
of agricultural lands. The dung from animal is the source of biogas. The raw material is
available in Punjab, NWFP, Sindh and some parts of Baluchistan. So far PCRET has installed
3500 biogas plants (with net generation capacity of 14395 M3 / day) on cost sharing basis
throughout Pakistan.
3.5 Biogas Problems and Hazards Biogas is really no more dangerous than other fuels such as wood, gasoline, or bottled gas. But
just as these fuels have their ways of being dangerous, Biogas Face it, anything that can cook
meals and fuel an engine can also burn people.
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It is very important that if a digester is built underground, that it is built in a place that never
floods. If an above ground digester is built in an area that sometimes floods, make sure that
the openings into the digester are above the high water mark.
If a digester is built in an area that does have floods, safety measures should be taken in
advance so that the gas can escape in case the digester and/or the gas storage tank are
flooded. Failure to do so could result in dangerous, uncontrolled release of biogas and if the
digester is a plastic bag, it could float up and away. An upside-down "T" pipe should be placed
at the highest vertical point in the gas pipe line above the gas outlet from the digester. A
vertical pipe and a gate valve should be joined to the stem of the upside-down "T" pipe. The
gate valve can then be opened to release the biogas if a flood threatens to cover either the
digester or the gas storage tank.
The following is a list of safety measures that should be read with great care before a biogas
system is built:
Regularly check the whole system for leaks.
Always maintain a positive pressure in the system.
The engine room floor must be at or above ground level to avoid the buildup of heavier
than air gases.
The engine room roof must be vented at its highest point to allow lighter-than-air gases
to escape. This is also true for greenhouses that have biogas digesters, engines, or
burners in them.
The engine exhaust pipe must be extended so that the dangerous and deadly exhaust
gases are released outside the building.
Metal digesters and gas storage tanks must have wires to lead lightning to the ground.
Gas lines must drain water into condensation traps.
No smoking or open flames should be allowed near biogas digesters and gas storage
tanks, especially when checking for gas leaks.
Methane, the flammable part of biogas, is a lesser danger to life than many other fuels.
However, in the making and using of an invisible fuel, dangerous situations can arise
unexpectedly and swiftly--such as when a gas pipe is accidentally cut. On the other hand,
precaution can be exaggerated.
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When cars first appeared on the roads, a man waving a red flag came first. Remember the
ABC's (Always Be Careful)
3.5.1 Health Hazards
Health hazards are associated with the handling of night soil and with the use of sludge from
untreated human excrete as fertilizer. In general, published data indicate that a digestion time of 14 days at 35 C is effective in killing
(99.9 per cent die-off rate) the enteric bacterial pathogens and the enteric group of viruses.
However, the die-off rate for roundworm (Ascaris lumbricoides) and hookworm (Ancylostoma)
is only 90 per cent, which is still high. In this context, biogas production would provide a public
health benefit beyond that of any other treatment in managing the rural health environment
of developing countries.
3.6 Performance of a Biogas Generator
In the course of past three years, Biogas generators have been installed at a number of user
situations at different sites for more than 300 hours without any trouble. The initial difficulties
experienced during starting have also been eliminated and users have been satisfied with the
field performance of these engines.
On an average, derating to the extent of 50-55% of power output in diesel mode has been
achieved. With manual control, the engine runs stably. It is able to maintain the speed
variation within 10% from no-load to full-load condition. This speed variation does not cause
any tangible deterioration in performance in actual applications. Even with higher
compression ratios as used in diesel engines (16-18) no knocking has been observed with the
present design of the kits. The typical performance of converted biogas engine in terms of
specific fuel consumption for various engine outputs is shown in fig.3 and the comparative
performance of converted biogas engine and the original diesel engine is shown in fig 4. The
derating effect is also indicated. On the basis of these assessments, it is concluded that the
conversion kits are quite satisfactory for field applications.
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DESIGN AND ANALYSIS
4.1 Concept Of The Biogas Project
The concept of a biogas settler is to treat the waste products entering it to create a usable
gas and a safe product to be used for fertilization. The design of a biogas settler is similar to
that of a septic tank, however the design incorporates the ability of biogas to be harnessed
and stored.
The by-products of the fertilization and biogas are possible through a process called
anaerobic digestion. The airtight chamber develops sludge at its bottom and with the lack of
oxygen in the chamber a chemical reaction takes place that creates a methane rich biogas
that is able to be used in household gas appliances such as stoves and lamps. With the lack
of oxygen in the chamber, and as the influent may take 60-80 days to pass through the
system, most harmful pathogens are destroyed and the effluent liquid and slurry are able to
be used for fertilization of the surrounding farmland, reducing the waste and increasing the
sanitation of the area.
The use of a biogas settler is ideal in this situation as the initial cost of the unit is relatively low,
it requires little maintenance, has no energy consumption as opposed to many similar design
that may be affected by flood, the biogas settler will not be affected by its location in such a
wet area. The advantages of the settler far outweigh its negatives, one of which being the
removal of the sludge; approximately every 5 years the sludge will accumulate to a level at
which it will need to be removed and whilst many of the harmful pathogens have been
removed by this stage, it is required to be done by skilled personnel. This sludge will usually
then is placed in a drying bed before it is used for fertilization.
Large retention times on the influent and warmer temperatures of the chamber are ideal in
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the treatment of the effluent to increase the effectiveness of the removal of harmful
products, resulting in by-products higher nutrients and more suitable for uses as
fertilization. Ideally the hydraulic retention time (HRT) would be close to 100 days and
chamber temperature would be close to 55°C to ensure pathogens are destroyed.
By placing the chamber below ground, the temperature can be regulated much more easily
with the chemical reactions inside creating its own heat within the chamber. An expert design
is then required to ensure the HRT is as large as possible whilst still producing a consistent
amount of biogas for the colony’s demands.
Once biogas is initiated, the pressure level within the main chamber is increased, for this
reason a compensation tank is needed. Connected to the lower of the main chamber, as
pressure increases, the sludge is then forced through a pipe into the compensation
chamber, thus reducing the absolute pressure in the main chamber and preventing
fractures in the frame. This compensation tank is then open to atmosphere as the sludge
stored within it is practically harmless and can be placed within the drying beds.
The benefits of a biogas plant seem endless- low construction costs, low running costs and a
clean source of energy. However the system can have some downsides, such as gas loss if
chamber suffers a fracture and the dependence on the community to participate in the use
and production of the biogas plant.
4.2 The Digestion Process
Biogas is produced by putrefactive bacteria, which break down organic material under airless
conditions. This process is called "anaerobic digestion".
The digestion process consists of two main phases:
Acid formation,
Methane formation
In the first phase, protein, carbohydrate and fat give rise to fatty acids, amino acids and
alcohols. Methane, carbon dioxide and ammonia form in the second phase. The slurry
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becomes somewhat thinner during the process of digestion.
The better the two phases merge into each other, the shorter the digestion process. The
conditions for this are particularly favorable in the "fermentation channel" arrangement. The
following types of digestion are distinguished according to the temperature in the digester:
psychrophilic digestion (10-20 °C, retention time over 100 days),
mesophilic digestion (20-35 °C, retention time over 20 days),
thermophilic digestion (50-60 °C, retention time over 8 days).
Thermophilic digestion is not an option for simple plants.
The pH of the fermentation slurry indicates whether the digestion process is proceeding
without disturbance. The pH should be about 7. This means that the slurry should be neither
alkaline nor acid.
Biogas can in principle be obtained from any organic material. Cattle manure can be used as a
"starter". Feed material containing lingn in, such as straw, should be pre composted and
preferably chopped before digestion. More than ten days' preliminary rotting is best for water
hyacinths. Gas production is substantially improved if the preliminary rotting time is twenty
days.
4.3 The Fermentation Slurry
All feed materials consist of
organic solids,
inorganic solids,
water
The biogas is formed by digestion of the organic substances. The inorganic materials (minerals
and metals) are unused ballast, which is unaffected by the digestion process.
Adding water or urine gives the substrate fluid properties. This is important for the operation
of a biogas plant. It is easier for the methane bacteria to come into contact with feed material
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which is still fresh when the slurry is liquid. This accelerates the digestion process. Regular
stirring thus speeds up the gas production.
Slurry with a solids content of 5-10% is particularly well suited to the operation of continuous
biogas plants.
Example:
Fresh cattle manure is made up of 16 % solids and 84% water. The cattle dung is mixed with
water in the proportions of 1:1. The prepared fermentation slurry then has a solids content of
8% and a water content of 92%.
All feed materials consist to a great extent of carbon (C) and also contain nitrogen (N). The C/N
ratio affects gas production. C/N ratios of 20:1 to 30:1 are particularly favorable. Mixtures of
nitrogen-rich feed material (e.g., poultry manure) and carbon-rich feed material (e.g., rice
husks) give high gas production.
4.4 Fermentation Slurry As Fertilizer
During the digestion process, gaseous nitrogen (N) is converted to ammonia (NH3). In this
water-soluble form the nitrogen is available to the plants as a nutrient. A particularly nutrient-
rich fertilizer is obtained if not only dung but also urine is digested.
Compared with solid sludge from fermented straw and grass, the liquid slurry is rich in
nitrogen and potassium. The solid fermentation sludge, on the other hand, is relatively richer
in phosphorus. A mixture of solid and liquid fermented material gives the best yields. The
nutrient ratio is then approximately N:P2O5:K2O= 1:0.5:1. Fermented slurry with a lower C/N
ratio has better fertilizing characteristics. Compared with fresh manure, increases in yield of 5
- 15 % are possible. Particularly good harvests are obtained from the combined use of compost
and fermentation slurry.
The fertilization effect depends on the type of crop and on the soil. Information given in
specialized literature is seldom applicable directly. Tests of one's own are always better.
Reliable information is possible only after three to five years.
When fermentation slurry is used as fertilizer for years, the soil structure is improved. The
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proportion of organic materials in the soil is increased, enabling the soil to store more water.
If fermentation slurry is to be stored before spreading on the field, it should be covered with
earth in layers. This reduces evaporative nitrogen losses even further.
4.5 Feed Methods
A distinction is made between batch and continuous plants.
Batch plants are filled completely and then emptied completely after a fixed retention time.
Each design and each fermentation material is suitable for batch filling.
Large gasholders or a number of digesters are required for uniform gas supply from batch
plants. Continuous plants are filled and emptied regularly -normally daily. Each design is
suitable for continuous operation, but the feed material must be flow able and uniform.
Continuous plants empty automatically through the overflow. Continuous plants are more
suitable for rural households. The necessary work fits better into the daily round. Gas
production is constant, and somewhat higher than in batch plants.
If straw and dung are to be digested together, a biogas plant can be operated on a semi batch
basis. The slowly digested straw-type material is fed in about twice a year as a batch load. The
dung is added and removed regularly.
4.6 Bio GAS Plant Types
Three main types of simple biogas plants can be distinguished (see Figure):
balloon plants,
fixed-dome plants,
Floating-drum plants.
See the figure below.
A. Floating-drum plant
B. Fixed-dome plant
C. Fixed-dome plant with separate gas holder. The gas pressure is kept constant by the
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floating gasholder. The unit can be operated as a continuous overflow-type plant with
no compensating tank. The use of an agitator is recommended.
D. Balloon plant
E. Channel-type digester with folia and sunshade
4.6.1 Balloon Plants
A balloon plant consists of a plastic or rubber digester bag, in the upper part of which the gas
is stored. The inlet and outlet are attached direct to the skin of the balloon. When the gas
space is full, the plant works like a fixed-dome plant - i.e., the balloon is not inflated; it is not
very elastic.
The fermentation slurry is agitated slightly by the movement of the balloon skin. This is
favorable to the digestion process. Even difficult feed materials, such as water hyacinths, can
be used in a balloon plant. The balloon material must be UV-resistant. Materials which have
been used successfully include RMP (red mud plastic), Trivia and butyl.
Advantages:
Low cost, ease of transportation, low construction (important if the water table is high), high
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digester temperatures, uncomplicated cleaning, emptying and maintenance.
Disadvantages:
Short life (about five years), easily damaged, and does not create employment locally, little
scope for self-help. Balloon plants can be recommended wherever the balloon skin is not likely
to be damaged and where the temperature is even and high. One variant of the balloon plant
is the channel-type digester with folia and sunshade.
4.6.2 Fixed-Dome Plants
A fixed-dome plant (Figure) consists of an enclosed digester with a fixed, non-movable gas
space.
Fixed-dome plant
1. Mixing tank with inlet pipe.
2. Digester.
3. Compensating and removal tank.
4. Gasholder.
5. Gas pipe.
6. Entry hatch, with gaslight seal and weighted.
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7. Difference in level = gas pressure in cm WC.
8. Supernatant scum; broken up by varying level.
9. Accumulation of thick sludge.
10. Accumulation of grit and stones.
11. Zero line: filling height without gas pressure.
The gas is stored in the upper part of the digester. When gas production commences, the
slurry is displaced into the compensating tank. Gas pressure increases with the volume of gas
stored; therefore the volume of the digester should not exceed 20 m³. If there is little gas in
the holder, the gas pressure is low.
If the gas is required at constant pressure (e.g., for engines), a gas pressure regulator or a
floating gasholder is required. Engines require a great deal of gas, and hence large gasholders.
The gas pressure then becomes too high if there is no floating gasholder.
Advantages:
Low construction cost, no moving parts, no rusting steel parts, hence long life (20 years or
more), underground construction, affording protection from winter cold and saving space,
creates employment locally.
Disadvantages:
Plants often not gaslight (porosity and cracks), gas pressure fluctuates substantially and is
often very high, low digester temperatures. Fixed-dome plants can be recommended only
where construction can be supervised by experienced biogas technicians.
4.6.3 Floating-Drum Plants
Floating-drum plants (Figure) consist of a digester and a moving gasholder. The gasholder
floats either direct on the fermentation slurry or in a water jacket of its own. The gas collects
in the gas drum, which thereby rises. If gas is drawn off, it falls again. The gas drum is
prevented from tilting by a guide frame.
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Floating-drum plant
1. Mixing tank with inlet pipe.
2. Digester.
3. Overflow on outlet pipe.
4. Gasholder with braces for breaking up surface scum.
5. Gas outlet with main cock.
6. Gas drums guide structure.
7. Difference in level = gas pressure in cm WC.
8. Floating scum in the case of fibrous feed material.
9. Accumulation of thick sludge.
10. Accumulation of grit and stones.
11. Water jacket with oil film.
Advantages:
Simple, easily understood operation, constant gas pressure, volume of stored gas visible
directly, few mistakes in construction.
Disadvantages:
High construction cost of floating-drum, many steel parts liable to corrosion, resulting in short
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life (up to 15 years; in tropical coastal regions about five years for the drum), and regular
maintenance costs due to painting.
In spite of these disadvantages, floating-drum plants are always to be recommended in cases
of doubt. Water-jacket plants are universally applicable and especially easy to maintain. The
drum won't stick, even if the substrate has high solids content.
Floating-drums made of glass-fiber reinforced plastic and high density polyethylene have been
used successfully, but the construction cost is higher than with steel. Floating-drums made of
wire-mesh-reinforced concrete are liable to hairline cracking and are intrinsically porous. They
require a gaslight, elastic internal coating. PVC drums are unsuitable because not resistant to
UV.
The floating gas drum can be replaced by a balloon above the digester. This reduces
construction costs (channel type digester with folia), but in practice problems always arise
with the attachment of the balloon at the edge. Such plants are still being tested under
practical conditions.
4.7 Design of Biogas Project
Biogas settlers involve the construction of carefully calculated chambers in order for them
to produce the biogas efficiently. The following diagram shows a good representation of the
system and how it is hoped to be implemented.
The toilets will be placed in latrines near the villages for which people can use to contribute
to the production of the biogas and the manure mixing chamber allows for farmers and
villagers to dispose of their livestock waste into the biogas plant. Once gas begins to be
produced the sludge can then flow into the compensation chamber and eventually into the
drying bed, where now almost pathogen free is harmless to humans. Once left in the drying
bed for approximately a month, it is then able to be used as a nutrient rich fertilizer.
Many areas are involved in the calculations that make for an effective system, including usage
and production of the biogas itself, as well as the time the waste will spend in the
chamber. The following table outlines the values of which I will be using to develop a
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suitable chamber.
In order to accommodate the entire village, a 200 000 liter tank is required. However, it is
expected that not all the villages will fully cooperate with the idea. Therefore the tank has
been reduced in size by 25% to a 150 000 liter tank. People in the village who have lived
without using toilets ever since were born will require time and education in order for them to
accept the new plan. This can be done by teaching the villagers the many possible benefits
that the plan may provide and that there is nothing wrong with using a toilet.
4.8 Analysis of the Biogas Digester Design
Biogas settlers involve the construction of carefully calculated chambers in order for them
to produce the biogas efficiently. The following diagram shows a good representation of the
system and how it is hoped to be implemented.
The toilets will be placed in latrines near the villages for which people can use to contribute
Figure 3 - The in
to the production of the biogas and the manure mixing chamber allows for farmers and
villagers to dispose of their livestock waste into the biogas plant. Once gas begins to be
produced the sludge can then flow into the compensation chamber and eventually into the
drying bed, where now almost pathogen free is harmless to humans. Once left in the drying
bed for approximately a month, it is then able to be used as a nutrient rich fertilizer.
Many areas are involved in the calculations that make for an effective system, including usage
and production of the biogas itself, as well as the time the waste will spend in the
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chamber. The following table outlines the values of which I will be using to develop a suitable
chamber.
If a digester is built in an area that does have floods, safety measures should be taken in
advance so that the gas can escape in case the digester and/or the gas storage tank are
flooded. Failure to do so could result in dangerous, uncontrolled release of biogas and if the
digester is a plastic bag, it could float up and away.
An upside-down "T" pipe should be placed at the highest vertical point in the gas pipe line
above the gas outlet from the digester. A vertical pipe and a gate valve should be joined to the
stem of the upside-down "T" pipe. The gate valve can then be opened to release the biogas if a
flood threatens to cover either the digester or the gas storage tank.
The following is a list of safety measures that should be read with great care before a biogas
system is built:
1. Regularly check the whole system for leaks.
2. Provide ventilation around all gas lines.
3. Always maintain a positive pressure in the system.
4. The engine room floor must be at or above ground level to avoid the buildup of heavier
than air gases.
5. The engine room roof must be vented at its highest point to allow lighter-than-air gases
to escape. This is also true for greenhouses that have biogas digesters or engines
6. The engine exhaust pipe must be extended so that the dangerous and deadly exhaust
gases are released outside the building.
7. Metal digesters and gas storage tanks must have wires to lead lightning to the ground.
8. Gas lines must drain water into condensation traps.
9. No smoking or open flames should be allowed near biogas digesters and gas storage
tanks, especially when checking for gas leaks.
4.9 Uses and implementation
This proposal aims to provide a solution to the current waste problem in Kalas Sharif where
waste is being left in the open increasing the chance of disease. Currently human faeces are
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deposited behind the houses along with livestock manure where they are left un-buried and
untreated. These unsanitary conditions can lead to the build-up bacteria seeing the
community susceptible to disease.
The proper implementation of a biogas digester would solve this problem while also taking the
load of the local power problem by providing the community with another energy source in
the form of biogas. They would be able to use the biogas for a number of things but primarily
in biogas stoves for cooking which are quite efficient.
The other product made from the bio-digesters is fustigation water. This water when
implemented into the local irrigation systems and farming areas would benefit the crops and
agricultural yield that the area produces.
The Position of Bio-digester in relation to the town is dependent on the size and how the
waste is being collected. Our proposal also includes the construction of central village latrines
and animal manure collection points.
The actual implementation into the community of the bio-digesters would require the
education of how all processes or at least primary functions of the unit would entail, the
precautions needed with the use of the biogas and possibilities of infection with the misuse
and storage of the fustigation water. The way this water can be incorporated into the village is
by adding it to the existing irrigation system which would enrich the towns.
The main objective of our biogas program is to improve the life of people of small villages. We
are trying to improve the quality of farmers in Pakistan by establishing the biogas power plants
commercially. It has been reported that only 7 households have access to a latrine seeing the widespread
practice of open defecation behind homes as the norm. This system not only results in an
unpleasant odour but it is also a health risk. The spread of disease is increased during
monsoon season when these deposits are washed into water sources that in turn become
contaminated.
The use of firewood or kerosene fuelled stoves indoors is everyday practice in most of
Pakistan. In Kalas Sharif in particular, this is the method of choice for all but 7 households. The
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use of such stoves is not only particularly bad for the environment but it also has
detrimental health effects.
4.10 Calculation of the Design and Project
From the information given by the People, the following population statistics can be
estimated.
• 358 People: approx. 131 in village
• 38 households in village
• 4 goats per household in village (75% of households)
• 4 cows per household in village (75% of households)
• 2 goats per household in village (25% of households)
• 2 cows per household in village (25% of households)
These values will form the basis of all following calculations
4.10.1 GAS PRODUCTION
Name
colony households village households Total
No % Quantity No % Quantity
Σ goats 27+23 75 4 38 25 2 169
Σ cows 27+23 75 4 38 25 2 169
Name No yield per day Each Total
Cows 169 250L 42,250L/d 90370L/d
Or
3,760L/hr
Goats 169 200 33,800L/d
Human 169 40L 14,320L/d
4.10.2 GAS USAGE
A community consisting of 8 people used a total of 200L/d of gas in their daily duties including
cooking, making tea and using gas lamps.
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By dividing this by 8, we can get the average usage per person, but multiplying this by 358 will
provide a decent estimation to the energy consumption of the entire Town Kalas Sharif.
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BIOGAS DIGESTER :
Concrete Base 56 x 0.4m x 500 per m (cubed) 11200
Concrete Walls (4/3pi r cubed/2 - inside) x 500 23200
Concrete Base (small tank) 28m (sqrd) x .4 x 500 5600
Concrete Walls (small tank) (1/2)4/3pi r cubed – inside 7130
Corrugated Iron 50m sqrd x 200/m sqrd 10000
Gas Pipes 500m x 500/m 250000
Toilet Room 30000
DELIVERY
Transportation 15500
SETUP
Installation 20000
Connection to Homes 38 x 500 19000
LABOUR
On site engineer 10000
Hourly rate x # of labors 30 x 10 x 40hours 12000
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MAINTENANCE
Labour 10000
Damages 5000
Gas 5000
Fertilizer 2000
__________________________________________________________________
TOTAL COST Rs 435630
Cost Comparison with Natural Gas
If we are using Natural gas for Electricity then per unit cost will be Rs 6.04.
If we are using Bio gas for Electricity then per unit cost will be Rs 4.51
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This chapter presents an introduction to Natural Gas and its Brief History. Then we will explain
the Natural Gas as source of Energy. Then we will describe the compression of Natural gas and
Biogas. After reading this Chapter you will be able to:
6.1 Making a Entire Community on Board
6.2 Environmental Impact of Project
6.3 Social Impact of Project
6.4 Social Implementation of Project
6.5 Effect on the life of People
6.1 Making a Entire Community on Board
For any new program or service to work successfully in rural Pakistan it is important that the
entire community is on board. Forcing a scheme upon the group will result in resistance and
see the scheme fail due to lack of use and support. To ensure that the biogas settler is used to
its full potential a well-developed behavior change program must be created with the views
and values of the community kept in mind.
On a broad scale, the following behavior change models may prove useful in both the planning
and implementation of this project.
6.1.1 Tran theoretical Model (TTM):
Developed by Prochaska and Di Clemente in 1985, this model gives an insight into the thought
process taken when people are faced with change (Department of Transport (Vic), n.d).
As there may be communication barriers and delays between those implementing the
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program and the citizens in the planning stage must be thorough. To make the most of face to
face contact time the TTM model can be used as a planning and understanding tool.
6.1.2 Diffusion of Innovation:
This concept attempts to estimate the rate of take up of change (National Centre of
Sustainability, 2011). This model makes an attempt to understand and analyze the time
difference in innovation acceptance between participants. It will be useful in the planning
stage as it provides further insight into how and more importantly when the group may react
to the innovation.
Diffusion of Innovation Curve
6.1.3 Community Based Social Marketing (CBSM):
Detailed planning and preparedness will assist in implementing a successful program with few
surprises and hitches along the way. The CBSM model will be a valuable tool here, providing a
useful framework for the entire project life time.
The stage which calls for the development of tools to overcome possible change barriers will
be priceless in pre-empting participant resistance and hopefully provide options for
addressing such issues. The key steps in this process are:
a. Identification of the behaviors to change
b. Brainstorming of barriers and drivers
c. Development of tools to overcome barriers and reinforce drivers
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d. Piloting and implementation of the program
e. Evaluation of the program and adjustment of its running accordingly
A Polythene Biogas unit can yield a whole range of benefits for their users, the society and the
environment in general, the chief benefits being.
6.2 Environmental Impact Of Project
As previously mentioned, present day waste management and energy sources in Kalas Sharif
are substandard. This project will have many positive environmental effects seeing a
sustainable shift in the area, these include.
Lower odour due to reduction in open defecation
Reduction in spread of disease due to less waste left openly
Reduction of greenhouse gas emissions of present fuel sources
No external energy source required
Generation of sustainable and cleaner biogas
Generation of sustainable natural fertilizer
Reduced demand on electricity grid
6.2.1 Local Environmental Impacts
The combustion of fossil fuels and traditional wood fuels can create adverse local
environmental effects. In developing countries, the local environmental problems associated
with energy use remain matters of concern that are as, or even more, urgent than they were
in industrialized countries 50 or 100 years ago. Further, it is the poor who suffer most from
such problems; because it is they who are forced to rely upon the most inefficient and
polluting sources of energy services for lack of access to better alternatives. The connection
between wood fuel use, cooking and the epidemiology of respiratory and other illnesses is a
topic of active research. Nevertheless, a consistent pattern linking energy, environment and
health has become clear. Wood fuel combustion in confined, often unventilated indoor areas
and at low thermodynamic efficiency leads to high concentrations of smoke and other
pollutants.
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The World Bank has estimated that the economic costs of air pollution from all sources are
US$ 350B/year, or the equivalent 6% of GNP of all developing countries. Much attention is
now being given to technical and policy measures that can reduce the local environmental
impact of energy use.
6.2.2 Climate Changes
An issue of much relevance to future energy policy is mitigation of the effects of global climate
change. Industrialized countries are responsible for at least 80% of the build-up of greenhouse
gases in the atmosphere, and consumption of fossil-fuel derived energy accounts for the
largest share of anthropogenic emissions of greenhouse gases. Through the UN Framework
Convention on Climate Change and Agenda 21 (UNCED, 1992), the international community
has agreed to work together to meet the problems of climate change, and industrialized
countries are taking steps to reduce or stabilize their emissions of CO2 and other greenhouse
gases.
The implementation of the Kyoto Protocol, once in force, or of any other agreement, which
might develop from the Protocol, will greatly influence energy policy, investment decisions
and the development and deployment of energy technologies. The Protocol assigns legally
binding emission reduction targets and through Joint Implementation and the Clean
Development Mechanism, industrialized countries (listed in Annex 1 to the Protocol) can meet
part of these targets by financing initiatives to reduce greenhouse gas emissions in other
countries. This process may help to lever new financial support for sustainable energy
development projects by providing additional benefits to investors (UNDP, 1998). Dealing with
climate change will require global efforts to control greenhouse gas emissions. Emissions from
developing countries are increasing, and will eventually naturally exceed those of
industrialized countries. The means by which economic growth and increased energy demand
can be reconciled with protection of the local and global environment is central for future
sustainable energy development.
6.3 Social Impact
There are a total of 350 people (86 families) living in Kalas Sharif (2010). The Kalas Sharif
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household occupancy is generally between 4 - 7 people per family. There houses are mostly
hut styles built with either cement or mud floors, walls are usually made from mud or burnt
brick with a thatched roof or one that is made from palm leaf and this is a clear reflection of
their low social status. Most of the houses generally have thatched bathrooms without a
toilet most community members rely on open defecation as the common practice, which
poses a lot of health issues the whole community.
6.4 Social Implementation of Project
There are a number of factors that may hinder the effectiveness or success of this initiative
from technical, cultural and economic standpoints. The first hurdle that must be overcome
pertains to the design of the plant. It is important that the plant is not too large or too small as
both errors will result in underfeeding of the system and consequential failure. Projected
participation rates of householders and the wastes they contribute must be accurate so to
ensure that the most efficient size digester is built. Unexpected events such as drought, flood
and alike must also be factored in to the design as they will all effect the unit directly as well as
the biomass sources.
Construction is also a very important issue to consider. It has been reported in other cases
across Pakistan that prudence when it comes to finding, employing or training skilled workers
has seen the failure of a number of systems.
Government support for such programs can be very difficult to secure and can be unreliable
once secured. This further highlights the need for true support of the community of
Kalas Sharif themselves.
6.5 Effect on the life of People
Persuading the citizens to approve of as well as actively engage in the biogas settler
initiative will be pivotal to the program’s success. It is important that the unique concerns of
the population are understood and addressed as well as any other barriers to this change. In a
town where only three houses own fridges, the installation of a large ‘machine’ may be prove
daunting. There is also the possibility of religious or cultural beliefs reducing the use and
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acceptance of the unit. The following plan has been developed in an attempt to avoid or
overcome some of these barriers and support a successful innovation;
Education:
The citizens must be schooled in how the innovation works in simple to understand terms that
all of them can comprehend and appreciate. This will be most effective if done by a person
who speaks the local language and is from a nearby area as there may be a better sense of
trust between them and more chance of the citizens asking questions and alike. This education
should include the inputs into the system, how the system converts these products and most
importantly the resulting products of the system and the advantages of using them.
Involvement in planning and construction:
as the citizens will have to ‘feed’ the system it is vital that they are satisfied with
placement, layout and construction plans for it. Comments and concerns of citizens should
be taken on board when finalizing the planning stage. Implementing the construction of the
system as a town project and getting as many people as possible involved in some part
of the construction and logistics surrounding it will help to create a sense of ownership
over the system and hopefully increase the chance of take up.
Post installation jobs:
There will be a need for a small amount of citizens to be employed to maintain the system as
well as engage in the de-sludging process. This task will provide jobs for the community or
could even be based on a rotational timetable system.
Examples from other villages:
The voice of other locals who have had biogas settlers installed in their villages will work
wonders in Devikulum. These examples can demonstrate how successful and fruitful the
scheme can be and also help to dampen any concerns the citizens have.
Cultural
There is a concern that cultural values and beliefs may conflict with the use of this system. This
issue has been dealt with in other communities by reinforcing the vision of the revered
Mahatma Gandhi and his belief that one day Indians would live in self-sufficient communities
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obtaining their needs from the local environment and generating income and benefits from
co-operative structures.
There are a number of factors that may hinder the effectiveness or success of this initiative
from technical, cultural and economic standpoints. The first hurdle that must be overcome
pertains to the design of the plant. It is important that the plant is not too large or too small as
both errors will result in underfeeding of the system and consequential failure. Projected
participation rates of householders and the wastes they contribute must be accurate so to
ensure that the most efficient size digester is built. Unexpected events such as drought, flood
and alike must also be factored in to the design as they will all effect the unit directly as well as
the biomass sources.
Construction is also a very important issue to consider. It has been reported in other cases
across Pakistan that prudence when it comes to finding, employing skilled workers has seen
the failure a number of systems.
Government support for such programs can be very difficult to secure and can be unreliable
once secured. This further highlights the need for true support of the community of
Kalas Sharif themselves.
Persuading the citizens to approve of as well as actively engage in the biogas settler
initiative will be pivotal to the program’s success. It is important that the unique concerns of
the population are understood and addressed as well as any other barriers to this change.
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CONCLUSIONS
7.1 Bio gas Project Need
With rapid increase in population and industry, energy needs are on rise. Almost 7million m3
wood is used for commercial and domestic purpose annually in Pakistan. Biogas energy
generation systems are in demand and their number is increasing steadily. They are cheaper
and can be run with very low operating cost. This bio energy corridor can work as a good
substitute for nearly 70% of country’s population residing in rural areas. Installation of plants
to bottle the biogas can be another option.
This will decentralize the source of energy and ensure uninterrupted power supply to the
villages in Pakistan. At present many agencies like PDDC, PCRET and RSPN are working to
disseminate this renewable energy technology. But the need of a National policy is imperative
to bring this technology at farmer’s doorstep and boost its success rate.
Biogas can be used to generate electricity with a combustion engine generator where it would
replace petrol or diesel. Biogas can be sued directly in petrol engines, using the Otto cycle,
where spark plugs are used to ignite the fuel and in modified diesel engine in which biogas are
introduced into the cylinder with the air supply.
A small amount of diesel is required to ignite the mixture in these duel fuel engines. Another
option is to adapt a diesel engine to an Otto cycle by replacing the diesel injector with a spark
plug. There are also some duel fuel generator sets on the market that are specifically aimed at
biogas use.
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7.2 Operational And Financial Benefits
This project has numerous operational, financial and community benefits, including:
1. Saving local businesses money by providing an advanced, local receiving station for wastes
that can reduce fuel and fleet costs associated with trucking the waste to distant locations.
2. Increasing the production of biogas which will be used to generate renewable electricity
for up to 1,000 homes in the region.
3. Utilizing existing waste processing and power generation infrastructure to minimize capital
costs.
4. Eliminating greenhouse gas emissions associated with organic waste in landfills and its
transportation to disposal sites outside the region.
5. Reducing the amount of wastes entering the local sewer collection system.
7.3 Conclusion
Bio energy is one of the primary sources of fuel in Pakistan. The energy utilization in Karnataka considering all types of energy sources and sector wise consumption revealed that traditional fuels such as firewood (7.440 million tons of oil equivalent -43.6%), agro residue (1.510 million tons of oil equivalent -8.85%), biogas, cow dung (0.250 million tons of oil equivalent -1.47%) accounts for 53.20% of the total energy consumption in Karnataka. In rural areas the dependency on the bio energy to meet the domestic energy requirements are as high as 80-85%. The production and use of biogas for domestic purposes can drastically reduce the depletion of natural resources like forests, which are otherwise the prominent and traditional source of energy for cooking and lighting. It removes dependence on forest and enhances greeneries leading to improved environment.
Kolar depends mainly on non-commercial forms of energy. Non-commercial energy constitutes 84%, met mainly by sources like firewood, agricultural residues and cow dung, while commercial energy share is 16%, met mainly by electricity, oil, etc. Availability of animal residues for biogas generation gives a viable alternative for cooking, lighting fuel and a useful fertilizer. Biogas technology is gaining additional upwind through new subsidy programmers for market incentive and development of renewable energies. Biogas potential in Kolar district is good (>60%). Analyses reveals that the domestic energy requirement can be met by biogas option in 301 villages in Kolar district for more than 60% population, 363 villages for 40-60%
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population, 1025 villages for 20-40% population and 1656 villages for less than 20% of the population. However to support the present livestock population fodder from agricultural residues is insufficient in these Taluks, which could be augmented by growing fodder crops during non-agriculture seasons. Various alternatives for improved utilization of bio resources and to enhance bio resource stock in a region are fuel-efficient stoves, biogas, energy plantations, etc.
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FUTURE ENHANCEMENT
8.1 Energy Production Potential
Appropriate feedstock for electricity-generating biogas plants is available in adequate
quantities in many countries. Small and medium-size biogas plants could provide a
considerable contribution to national electricity generation in such countries. However, in
comparison to industrialized countries, only very few small and medium sized biogas plants
are used for electricity generation in Africa, Latin America and even Asia.
Electricity production from biogas can be a very efficient method for producing electricity from
a renewable energy source. However, this applies only if the emerging heat from the power
generator can be used in an economically and ecologically sound way. The average calorific
value of biogas is about 21-23.5 MJ/m³, meaning that 1 m³ of biogas corresponds to 0.5-0.6 l
diesel fuel or an energy content of about 6 kWh. However, due to conversion losses, 1m³ of
biogas can be converted only to around 1.7 kWh el.
Bigger biogas plants are generally more cost-efficient than smaller ones. However, electricity
generation from biogas is a technology appropriate even for relatively small applications in the
range of 10-100kW.
8.2 Technical Aspects
There is mature, reliable high quality technology available on the global market. The techno-
logical difficulties with which small biogas plants were confronted two decades ago have been
resolved.
Different methods of desulphurization have been successfully established and combustion
motors tolerant to biogas that have proven their durability are available in the market.
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Sufficient know-how for planning and constructing reliable biogas power plants is also
available.
Germany is one of the leading countries in terms of high quality components and know-how
required for electricity-generating biogas plants. Know-how and technical components are
also available in China, Thailand and other Asian countries as well as in Brazil. Electricity
generation from biogas in Africa is still limited to a few pilot plants, with Kenya apparently
being one of the centers of development and experience. For the construction of efficient and
reliable biogas power plants, at least some technical core components must be imported from
industrialized countries.
The electricity generation component of a biogas power plant does not require much more
know-how and effort for maintenance than a normal generator set for fossil fuelswith a well
functioning biogas fermentation process as an indispensable prerequisite.
8.3 Economic Aspects
Economically, electricity from biogas must compete with electricity generation from fossil fuels
and other renewable energies such as hydro power. Supporting factors are: • Rising prices of
fossil fuels; • Low reliability of electricity provision from national grids with persistent risk of
power cuts and vulnerability of hydro power to drought.
Inhibiting factors are:
Relatively low prices of fossil fuels;
Need to buy high quality components from industrialized countries;
Unfavorable conditions for selling electricity;
Lack of awareness, capacity and experience preventing the economic operation of
infrastructure components.
The economic feasibility of a biogas plant depends on the economic value of the entire range
of plant outputs. These are:
Electricity or mechanical power;
Biogas;
Heat, co-generated by the combustion engine;
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The sanitation effect with COD and BOD (chemical and biological oxygen demand)
reduction in the runoff of agro-industrial settings;
Slurry used as fertilizer.
Most of the commercially run biogas power plants in developing countries are of medium size
and are installed in industrial contexts, primarily using organic waste material from agro-
industrial production processes such as cow, pig and chicken manure, slaughterhouse waste,
or residues from sisal and coffee processing.
Assessments of economic feasibility are contradictory or inconsistent. Many press releases and
information from biogas power plant producers refer to payback periods of only 1.5 – 2.5
years. In such cases, the electricity from biogas plants can be compared to the price of
electricity provided through the national grid or the price of bottled LPG.
However these figures are unrealistic, except for direct thermal energy use as for cooking
energy, or in very few locations with extremely expensive diesel fuel.
More realistic figures seem to be those calculated by GTZ experts in Kenya for medium and
large plants (>50kW): They anticipate payback periods for plants under the DBFZ tariff scheme
(~0.15 US$/kWh) of 6 years under very favorable conditions, and 9 years for unfavorable but
still economically viable investments.
In spite of this theoretical profitability, recent examples from Africa show that electricity
generation from biogas has not really captured the market as a ‘profitable’ technology. None
of the plants described here could have been installed without international technical and
financial support. This is due to the pilot status of the market and barriers such as a lack of
awareness, experience, local capacity, upfront financing for project development (for own
consumption projects, i.e. where there is no feed-in component) and the existence of policy
barriers in cases where feed-in is required.
Many new studies come to the conclusion that biogas power plants are not commercially
viable without subsidies or guaranteed high prices (~0,20US$) for the produced outputs. In
Germany and other industrialized countries, only guaranteed feed-in tariffs have led to a
breakthrough. Almost all well-known biogas power plants in developing countries depend on
financial support from a third international party.
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We have little experience to draw on concerning the possibility of using biogas power plants to
cover the basic energy needs of the rural population. Most biogas power plants are connected
to agro-industrial facilities and provide electricity only to very few immediate neighbors.
However, calculations show that biogas could play a role in supplying isolated grids, where it
represents a least cost option.
8.4 Necessary Framework Conditions
In Germany, power generation from biogas is only profitable due to grid connection and sup-
porting feed-in tariffs. By contrast, power generation in most developing countries seems to
be especially profitable in settings far away from the national grid and other energy sources,
as the legal framework conditions and the lack of appropriate feed-in tariffs do not support
feeding into the grid. However, there are the first signs of financial and legal support for
feeding in electricity from biogas power plants in countries such as Brazil. Output-oriented
support schemes (such as the German EEG) have proved to be more successful than
investment-oriented financial support.
Direct subsidies and public financial contributions to installation costs have been crucial for
the installation of some pilot plants. However, they have not provided incentives for proper
and efficient operation. By contrast, the establishment of appropriate feed-in tariffs stimulates
the construction of efficient plants and their continuous and efficient operation.
Through its projects and programmers, GTZ therefore recommends the establishment of
guaranteed feed-in price schemes similar to the one in Germany.
However, besides price considerations, there remain many barriers to market penetration and
development of the biogas sector:
Lack of awareness of biogas opportunities;
High upfront costs for potential assessments and feasibility studies;
Lack of access to finance;
Lack of local capacity for project design, construction, operation and maintenance;
Legal framework conditions that complicate alternative energy production and
commercialization: for example, the right to sell electricity at local level has to be in
place.
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As long as the national framework conditions are not favorable, electricity generation from
biogas will remain limited to a few pilot applications.
8.5 Costly Benefit Of Biogas Plant In Future
As soon as the cost and benefit of a biogas plant in plan can be expected, collected and
analyzed, and as soon as a rate of interest for the calculation is determined it can be worked
out with the assistance of a dynamic investment calculation if the plant is economical or not.
Where there are several alternatives relative advantage can be ascertained.
These methods are principally equivalent. The selection is effected according to the purpose
and plausibility, e.g. distinctness of each advantage key. In practice the discounting method is
used most frequently. According to this method the cost and benefit of different periods of
time are concentrated onto one point in time, normally the current value or cash value,
discounted and so made comparable. When comparing alternatives with different economic
lifetimes and investment costs the annuity method is especially suitable.
For the calculation of user fees the annuity method should be used. According to this method
the non-recurring and a periodical investment costs are converted into equal constant annual
amounts for the economic lifetime of the plant and related to the quantity of gas distributed.
This occurs by means of a capital return factor which states the annual amount of depreciation
and interest which has to be used at the end of each year during n years to regain the original
capital with interest and compound interest.
8.6 Difficulties
In order to avoid misinterpretations the basic weakness of efficiency calculations from a micro
as well as macro-economic point of view have to be pointed out. For reasons of operational
ability these calculations extensively comprise monetary effects. This means that cost and
benefit are only determined with a view to monetary aims. There are then, 'intangible' aims
and thus, 'intangible' cost and benefit for which a final valuation lies within the judgment of
the decision maker.
Analysis of a Renewable Energy Project Analysis
Biogas Power Plant 67
Further difficulties arise with the uncertainties combined with the determining of most of the
basic influencing factors involved in the economic and financial profitability of biogas plants.
To pinpoint the importance of possible fluctuations of any exceptions or data for the
profitability calculated, sensitivity analyses should be carried out.
The extent of any effects on the result of the profitability calculation should be investigated
especially for the following factors:
available quantity of substrates
expected gas production, especially the reduction for colder seasons
the proportion of effectively utilizable gas production on total production
type and quantity of replaceable fuels
price of the fuels replaced (also in time-lapse)
type and quantity of the replaced mineral fertilizer
price of the mineral fertilizer (also in time-lapse)
extent of the increase in agricultural production as a result of bio dung
economic lifetime of the plant, respectively its most important components
rate of interest for capital invested
amount and development of the running costs
8.7 Observation of the Development
It would be practical to observe the development of the most important determinants in the
profitability over a period of time and compare them now and again with the assumptions
made at the planning stage. A year after being taken into operation the plant should be
subjected to a renewed assessment concerning the economic advantage and the financial
productivity.
Unlike conventional gas power plants biogas has no environmental hazards and handling
aspects. As it is a renewable energy resource hence it is profitable. It is cheaper than all other
energy resources so it is best fit for the alternate energy resource in future. Mostly countries
Analysis of a Renewable Energy Project Analysis
Biogas Power Plant 68
are installing the biogas plants on commercial level on large scale. In future biogas is going to
be the beneficial sources especially for the rural areas as well as urban areas.
There are significant social, economic and environmental benefits of biogas technology. The
government of Pakistan through PCRET and Alternative Energy Development Board (AEDB)
should take the initiative and announce more funds and support for this proven technology to
be a part of our rural society. In parallel, the media should raise the level of awareness among
the rural community by highlighting the benefits of this technology. NGOs and foreign
investors should been courage to invest in this sector too.
Analysis of a Renewable Energy Project Analysis
Biogas Power Plant 69
REFERENCE
http://creative.com.pk/energy.html
http://rspn.org/our_projects/pdbp.html
http://paksc.org/pk/how-to-make/bioenergy/biogas-plant.html
http://cdn.intechopen.com/pdfs/11474/InTech-
Environmental_technology_assessment_of_natural_gas_compared_to_biogas.pdf
http://www.chevron.com/deliveringenergy/naturalgas/
http://www.photius.com/countries/pakistan/geography/pakistan_geography_ene
rgy.html
http://www.doi.vic.gov.au
http://www.papg.org.pk http://www.buzzle.com/articles/advantages-and-disadvantages-of-natural-
gas.html http://wiki.answers.com/Q/What_are_the_advantages_and_disadvantages_of_n
atural_gas_for_our_planet http://wiki.answers.com/Q/What_are_the_uses_of_CNG http://www.preservearticles.com/201104195606/difference-between-natural-
gas-and-biogas.html http://www.buzza.in
http://www.ewb.org.au/explore/initiatives/ewbchallenge/2011ewbchallenge/ma
ps
http://www.ewb.org.au/explore/initiatives/2011ewbchallenge/transportation
http://www.ewb.org.au/explore/initiatives/2011ewbchallenge/power
http://www.indexmundi.com/australia/life_expectancy_at_birth.html
http://www.ganesha.co.uk/Articles/Biogas%20Technology%20in%20India.htm#Ta
ble
Analysis of a Renewable Energy Project Analysis
Biogas Power Plant 70
http://ilearn.swin.edu.au/webapps/portal/frameset.jsp?tab_group=courses&url=
%2Fwebapps%2Fblackboard%2Fexecute%2FdisplayLearningUnit%3Fcourse_id%3
D_107750_1%26content_id%3D_2252543_1%26framesetWrapped%3Dtrue
http://www.odamindia.org/our- projects/climate-change/charcoal-briquettes/
http://www.povertyactionlab.org/evaluation
http://www.sswm.info/print/1249?tid=854
http://www.sswm.info/category/implementation-tools/reuse-and
recharge/hardware/reuse-energy-products-form-waste-and-was-1
http://www.mekarn.org/procbiod/prest.htm
http://www.unicef.org
Tables List:
Table 01 Total Primary Energy Supply Page 12
Table 02 Total Energy Consumption Page 13
Table 03 Total Energy Sector Utilization Page 13
Table 04 Typical Composition of Natural Gas Page 18
Table 05 Comparison of Natural Gas and Biogas Page 22
Table 06 Natural Gas Consumption Page 23
Table 07 Gas Production Page 48
Table 08 Cost Comparison with Natural Gas Page 51
Figures List
Figure 01 Selecting a place to start a project Page 16
Figure 02 A Methane molecules, CH4 Page 19
Figure 03 Anaerobic Digestion Process Page 29
Figure 04 Bio GAS Plant Types Page 40
Figure 05 Fixed-dome plant Page 41
Figure 06 Floating-drum plant Page 43
Figure 07 Biogas Digester Design Page 45
Figure 08 Diffusion of Innovation Curve Page 53
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