Pakistan faces an energy crisis as demand rises, but biogas can help meet rural energy needs. Biogas is a renewable resource that can be produced from agricultural waste like livestock manure and sugarcane bagasse. Pakistan has the potential to generate thousands of megawatts of power from biogas, helping its large rural population and reducing foreign exchange spent on fossil fuel imports. There are different types of biogas digesters that convert biomass into a gas that is mostly methane through anaerobic digestion. The government aims to install hundreds of thousands of domestic biogas plants but more support is needed to promote this sustainable technology.

1. Prepared by:
Rimsha Khan ®

2. Pakistan and most of the developing countries are in energy
crisis. 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 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
today.

3. Sources in Pakistan:
• Pakistan is world’s fifth major sugarcane producer country
and it produces sugarcane approximately 50 million tons
annually and produces 10 million tons bagasse.
•There are about 80 sugar mills having potential to generate
almost 3000 MW energy through biogas generation.
• The livestock sector of Pakistan is growing annually at the
rate of 4% and approximately 35.625 million KWh electrical
power can be generated from its dung per day.

4. With rapid increase in population and industry, energy
needs are on rise. Biogas energy corridor can work as a good
substitute for nearly 70% of country’s population residing
in rural areas. Almost 2.5 KWh electrical power can be generated
from 1m3 of biogas. Installation of plants to store the biogas
can be additional opportunity. The need of a national policy
is imperative to bring this technology at farmer’s doorstep.
In Pakistan almost 20% of the foreign exchange is spent on
import of fossil fuels. Careful estimates show that by 2050 Pakistan’s
energy needs are expected to increase three times while the
supplies are not very inspiring. It is necessary that any
alternate source of energy must be explored.

5. Biogas is a type of bio-fuel, which primarily consists of
methane and carbon dioxide. It is smokeless, hygienic and
more convenient to use than other solid fuels. Biogas is an
attractive fuel for use in engines since it has no harmful
pollutant that can damage them. The biogenic material
generates biogas and consists of the following gases.
Composition of Biogas:
Gases Percentage
Methane 50-75 %
Carbon dioxide 25-50 %
Nitrogen 0-10 %
Hydrogen 0-01 %
Hydrogen Sulphide 0-03 %
Oxygen 0-02 %

6. Conversion Technologies:
Biomass can be converted into biogas by anaerobic digestion
technology and for this purpose there are different models
of biogas plants.
1- Floating Gas Holder type Plant
2- Fixed Dome Type Biogas Plant
3- Fixed Dome With Expansion Chamber type Biogas Plant
Anaerobic Digestion Technology consists of three stages.
In the first stage complex biomass material is decomposed
by a heterogeneous set of microorganisms to make it water soluble.
The second stage involves dehydrogenation obtaining acetic acid
as the final product. Finally the third phase is the production of
biogas from acetic acid by a set of fermentation reactions
performed by methanogenic bacteria.

7. Starting from the cellulose the overall reaction may be
summarized as,
(C6H10O5)n + nH2O 3nCO2 + 3nCH4 + 19Jmol-1

8. Floating Gas Holder Type Plant:
The digestor chamber is made underground by bricks and
cement and a steel drum called gas holder is placed on the
top of digestor to collect the biogas separately. It helps to
keep the pressure constant. The gas holder rises when the
pressure is increased due to production of gas and allows
the generated gas to let out through the gas supply pipe.
It lowers when
pressure
is decreased to
stop the supply
of the biogas.

9. Fixed Dome Type Biogas Plant:
In fixed dome digester , the gas holder and the digester are
Combined, gas is stored in the upper part of the digester.
Fixed dome digester is usually built below the ground level
and is suitable for cold regions. As the plant does not
involves any steel parts, it can be built with local materials
and hence its
construction
costs are low.

10. Fixed Dome With Expansion Chamber Type Biogas Plant:
It has a curved bottom and hemispherical top which are
joined at their bases with no cylindrical portion in between
An inlet pipe connects mixing tank with the digester.
This type of biogas plant is very cheaper as compared with
the other two types of Biogas plants.

11. Advantages:
 There are significant social, economic and environmental
benefits of biogas technology.
 Biogas is an eco-friendly technology, unlike conventional
gas power plants biogas has no environmental hazards and
handling aspects.
 Biogas plants are low-cost and can be run with very small
budget.
 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.

12. Government Policy:
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.
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.
The Rural Support Program Network (RSPN) envisions setting
up 300,000 domestic biogas plants across Pakistan within
10 years of time.

13. Suggestions:
 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.
 Government should help people to set these plants on small scale
by providing loans and machinery at low price.
 NGOs and foreign investors should be encouraged
to invest in this sector too.

14. Thank you….. 
Rimsha Khan