Domestic Gas Infrastructure

Graduate Report 2012-2013
Urban Infrastructure Planning and Management (CE-634)
Domestic Gas Infrastructure
Submitted By
Malvika Jiashal
(P12UP004)
Faculty Adviser
Dr. Krupesh A. Chauhan
Post Graduate Section in Urban Planning
Civil Engineering Department,

Contents
1. Introduction
2. Natural Gas
2.1. Forms of Natural Gas
2.2. Uses of Natural Gas
3. India: Oil And Gas & Infrastructure
3.1.History
3.2.Current Scenario
4. Gujarat: Present Status
5. City Gas Distribution
5.1. Infrastructure: City Gas Distribution Network
5.2. Various Stations Involved in the Network
5.3. How Gas is reached at Home?
5.4. Challenges in City Gas Distribution Network
6. Summary
References

1. Introduction
Natural gas is a vital component of the world's supply of energy. It is one of the cleanest,
safest, and most useful of all energy sources.
This graduate report is an attempt to give a brief view on Oil and gas Infrastructure of
India and Gujarat state. It also includes the details of Domestic gas infrastructure in urban
area.
2. Natural Gas
Natural Gas is colourless, shapeless, and odourless 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.
Table No.1: Typical Composition of Natural Gas
2.1. Forms of Natural Gas
a. Liquefied Natural Gas (LNG) – Natural Gas which has been liquefied at –
(Minus) 160 degree Centigrade. Natural Gas is liquefied to facilitate
transportation in large volumes in cryogenic tankers across sea.
b. Degasified Liquefied Natural Gas (RLNG) – LNG Re-gasified before
transporting it to consumers through Pipelines.

c. Compressed Natural gas, CNG - Natural Gas compressed to a pressure of 200-
250 kg/cm2 used as fuel for transportation. CNG decreases vehicular pollution on
the virtue of being cleaner fuel than liquid fuels.
d. Piped Natural gas, PNG - Natural Gas distributed through a pipeline network
that has safety valves to maintain the pressure, assuring safe, uninterrupted supply
to the domestic sector for cooking and heating / cooling applications.
2.2. Uses of Natural Gas
Following table the shows the uses of natural gas in various sectors:
Table No.2: Uses of Natural gas
Sector NATURAL GAS IS USED
POWER GENERATION
As fuel for base load power plants
In combined cycle/co-generation power plants
Fertilizer Industry As feed stock in the production of ammonia and urea
Industrial
As an under boiler fuel for raising steam
As fuel in furnaces and heating applications
Domestic and commercial
For heating of spaces and water
For cooking
Automotive As a non-polluting fuel
Petrochemicals
As the raw material from which a variety of chemical products
e.g. methanol, are derived

3. India: Oil and Gas & Infrastructure
India today has a vast network of underground pipelines being used for
transportation and distribution of natural gas. Big power plants, fertilizer plants & other
industrial enterprises are the main consumers of natural gas as on today. However, with
the increase in its popularity, it is now being used in the domestic sector as well as a fuel
in the automotive sector in the big metropolitan cities.
3.1. History
Indian oil and gas (O&G) sector marked its emergence way back in the late
19th century, when the oil was first struck at Digboi in Assam in 1889. Since then, the
sector has not seen back and has emerged as one of the core sectors for the country's
economy..
The country's exploration and production sector is majorly dominated by public
sector corporations wherein Oil and Natural Gas Corporation (ONGC) accounts for the
highest market share. Administrative structure of Natural gas sector is shown in the
following figure.
Fig: Natural gas sector Structure-India

3.2. Current Scenario
India is world's fifth-largest energy consumer in the world; oil accounts for 30 per
cent of the total energy consumption. Buoyant economic growth is the main factor driving
the country's energy requirements. India's gas demand is approximately 11.2 per cent of
the total Asia Pacific regional demand. Several industries are increasing the usage of
natural gas in operations; this has boosted natural gas demand in India.
Gas consumption in India has grown at an annual rate of 10 percent from 2001 to
2011 despite insufficient pipeline infrastructure. Natural gas mainly serves as a substitute
for coal in electricity generation and with 45 percent of total use, the power sector is
currently the largest user of natural gas in India, according to a country specific energy
analysis from the US Energy Information Administration (EIA).
In 2011, India consumed 2.3 billion cubic feet of gas and projections from the
Indian Oil Ministry, see this figure increasing as demand is set to more than double in the
next five years. Of the country's 211GW of installed capacity, about 9 percent comes
from natural gas-fired plants. Coal retains the greatest share of the country's electricity
mix, accounting for some 57 percent of total installed capacity. India suffers from
widespread power outages however as both natural gas and coal-fired plants often shut
down due to insufficient fuel supply.
While the country was self-sufficient in natural gas until 2004, it currently does
not have sufficient natural gas infrastructure on the natural level to meet domestic
demand. As a result, LNG imports account for approximately 25 percent of total gas
demand. India began importing natural gas from Qatar in 2004 and was the world's sixth
largest LNG importer in 2011 according to data from PFC Energy. Indian companies use
both spot and long-term supply contracts to acquire natural gas

Fig: India Natural Gas Production and Consumption-2001-2011
Overall gas demand is also constrained due to insufficient pipeline infrastructure
as the country's current pipeline network primarily services the northwest region.
However, Reliance Gas Transport Infrastructure, owned by Reliance Industries has
brought the East-West gas pipeline online in 2009, which links the D6 gas field to the
north and west regions of the country. Other smaller companies such as Petronet LNG
and Gujarat State Petroleum Corporation (GSPC) are also considering building their own
pipelines. Gas Authority of India Limited (GAIL) has announced plans for an extension
to the Hazira- Bijapur- Jagdishpur pipeline and a line from the D6 field to parts of
southern India.
India also has plans to import natural gas from Turkmenistan via the proposed
Turkmenistan-Afghanistan-Pakistan-India pipeline. While, the countries have made some
progress moving forward, including agreement on a route, unified transit tariffs and
India's signing of supply and purchase agreements with Turkmenistan, significant
geopolitical and technical challenges to the project remain
4. Gujarat: Present Status
Gujarat, which accounts for more than one-third of the total natural gas consumed in
the country, Ministry of Petroleum & Natural Gas show that the total number of CNG
stations in the country was 724 as of November-end. Of these, Gujarat had 258 CNG

stations, the highest in the country. The number of CNG outlets in New Delhi stood at 239,
followed by Maharashtra with 164 CNG stations. Gujarat is the leader not only in CNG
stations, but also in PNG (Piped Natural Gas) connections and consumption.
Table No 3: Existing supply sources in the state
Sr. No. Supplier Source
Volume of supply
(in MMSCMD)
1 ONGC
Onshore fields located near Ahmadabad
region & Ankleshwar / Surat region and
offshore (JV) fields in the Arabian Sea
(Western Offshore – including PMT
supplies)
20.00
2 GSPC/ Niko Resources Hazira gas field 00.60
3 Cairn CB-OS2 field in the Cambay basin 00.80
4
Petronet LNG Limited
(PLL)
LNG from RasGas, Qatar 08.00
5 Shell, Hazira LNG spot cargoes 00.00
6 RIL KG D6 Gas 26.00
Total 55.40
Source: CRISIL Analysis
4.1. GPSC: Gujarat State Petroleum Company
Gujarat State Petroleum Company (GSPC) supplying gas to more than 3, 00,000
domestic customers, 1443 industrial customers and 1068 commercial customers. Through its
network of 120 CNG stations across Gujarat, GSPC Gas is fuelling more than 65,000 CNG
vehicles every day. Today, GSPC Gas has achieved remarkable sale of 4 MMSCMD of Gas,
which make it India's largest City Gas Distribution Company. The CSR initiative of GSPC
Group in Hazira has now turned out to be India's Largest City Gas Distribution Company.
From fuelling the kitchens of common people to energizing micro, small and medium
industries and from uninterrupted supply in hotels and hospitals to refuelling thousands of
CNG vehicles day and night, GSPC Gas is working 24 hours and 365 days for providing high
quality service with best HSE practice.

CGD activity was started at Hazira (Surat) as a corporate social responsibility
initiative from Gujarat State Petroleum Company GSPC Group in 2002-03. An SPV was
conceptualized in 2005 and with one CNG station and few thousand of domestic connections;
GSPC Gas implemented its first CGD network in Hazira (Surat) in the year 2005. Currently
GSPC Gas is operating in more than 21 major town & city and more than 221 villages in the
state of Gujarat.
5. City gas Distribution
The four major sectors identified for the city gas distribution in India are:
a) Transport Sector
b) Domestic Sector
c) Commercial Sector
d) Industrial Sector
Domestic, Commercial and Industrial Sectors use Piped Natural Gas (PNG) where as the
Transport Sector use Compressed Natural Gas.
5.1. Infrastructure: City Gas Distribution Network
To take the gas to such end users who are located within the boundaries of a main
city, there’s a need to build up city gas distribution pipeline networks. Such networks have
already been developed in the cities of Delhi, Mumbai, Vadodara, Surat, Agra/Firozabad,
Kanpur and many more such networks are being planned in the near future. Looking at the
available infrastructure and layout in typical Indian cities, it becomes a difficult task to
build up such a city gas distribution networks in the absence of separate corridors for the
competing utilities. Depending upon the pressures, flow and economic criteria, these
networks can either be constructed using steel pipelines, polyethylene (PE) pipes or a
hybrid system of both PE & steel pipelines
i. The primary network: of steel pipelines provides the core backbone connecting
CGS to various DRS. The pressure levels for primary network are between 26 bar (g)
to 19 bar(g). While most of the industrial customers are not required to be supplied at
this pressure level, only a select few units have specific requirement for medium

pressure delivery would be connected to through this network. The design of the
primary network is based on the demand forecast to be catered.
ii. Secondary network system: consisting of MDPE pipelines operates at pressure level
between 4 bar (g) to 1 bar (g). MDPE pipeline network is planned for cluster of
industrial, commercial or domestic units at low pressure. The secondary network is
normally developed with MDPE pipes.
Using the domestic / small commercial quantity and large commercial
quantity values, and additional information, including location of customers, pressure
requirements at major customers, availability of existing supply, and geographic
features, optimum method of supply is determined and the network is designed and
constructed accordingly.
The supply facilities include the following:-
i. High pressure Steel pipeline main
ii. Medium pressure Steel pipelines
iii. Low pressure MDPE mains
iv. Low pressure MDPE services
v. CGS/ DRS / Hot Taps
vi. Service Connections
5.2. Various Stations Involved in The Network
The various stations involved in the network are:
a) City Gate Station (CGS)
b) Pressure Reduction Station (PRS)
c) District Regulating Station (DRS
a. City Gate Station (CGS)
CGS for the network is normally located at Tap off point of the main transmission
line or else connected by a spur line to the main transmission line. The CGS has an inlet
supply mains from the transmission pipeline, a pressure reduction system, a filtering unit,
gas chromatograph and metering, odorant injection system and associated piping along
with various monitoring and control systems.

The gas transported at city gate station is at a high pressure. The pressure reduction
facility comprises pressure regulator runs with standby units, each having an active /
monitor regulator, each fitted with `slam-shut’ protection facilities. In addition, provision
can be made for natural gas pre-heaters, as per the design requirements.
It is recommended that a CGS be located in a fenced off secure area. To supply the
remainder of the distribution system from the 26 bar maximum transmission pressure
system, `DRS’ is required. The DRS will be similar in design to the City Gate with
different capacity, except no allowance is normally required for gas heating.
b. Industrial Pressure Reduction Station (IPRS)
IPRS for the network is located in major Industries. It has a pressure reduction
system, a filtering unit, Turbine metering system, valves etc. Based on the consumption
profile of the user, customized arrangements are designed with metering arrangement. The
IPRS has slam shut valves, pressure regulating valves, creep relief valve and vent,
isolation valves, non-return valves and pressure gauges
c. District Regulating Station (DRS
DRS for the network is located at strategic locations which are sometimes also
known as field regulating stations to meet various demand centres for Domestic/ Industrial
segment. It too has a pressure reduction system, a filtering unit, Turbine metering system,
valves etc. Based on the consumption profile of cluster of users, customized arrangements
are designed with online metering arrangement. The DRS too has a slam shut valves,
pressure regulating valves, creep relief valve and vent, isolation valves and no-return
valves.
Basically there are three sections that describe the purpose and different
component of stations located at a pressure levels interface
a) The City Gate : interface between High Pressure and Medium Pressure;
b) The Pressure Reducing Station: interface between Medium Pressure and Low
Pressure.
c) The Service Connection: interface between network and end-user pressure

5.3. How gas is reached at home?
Natural Gas is transported and supplied to consumer by extensive pipeline network
or cylinder type. The backbone of distribution network is the main steel pipeline that
brings natural Gas from source to the city. Along the steel network, CNG stations are
located at a pressure (200-250bar) for vehicles. The pressure in the main steel pipe line is
19 to 26 bar.
The pressure of gas is reduced to 4 bar through “District regulator station (DRS)
located at various points on steel pipe line network. The medium density polyethylene
pipeline (MDPE) network takes off distributing natural Gas. The pressure should be 4
bar to 110 mbar at service regulator. Further pressure reduction is done from 110mbar to
21mbar at metre regulator. The pressure regulator maintains the specified pressure. The
metering device installed in the customer records the unit of gases consumed
Gas Supply System:
a. The Service Regulator: This reduces the gas pressure from 4 BAR to 110 m BAR
and ensures the flow of gas at constant pressure at all time.
b. Buried Polyethylene Pipes: The pipes are installed at a safe and secure depth. It
provides low-pressure gas (110 m BAR) to individual buildings.
Figure: Gas Supply System

c. The Riser Pipe (GI pipe): This is an external connection on the building to each
apartment. Each Riser Pipe (GI pipe) has a Riser Isolation Valve.
d. The Meter Control Valve: Fitted in the entrance of your house / flat, this valve is
between the riser pipe and your meter.
e. The Meter Regulator: Installed before the meter, the meter regulator reduces the gas
pressure from 110 mBAR to 21 mBAR.
f. The Appliance Valve: This valve switches on/off the gas to burning appliance.
5.4. Challenges in City Gas Distribution Network
City gas distribution network has different routes of varying lengths and sizes crossing
various hurdles and catering to different end users. The challenges start from the very
beginning of the project when the network is to be laid and continues when the network
comes into operation. As more and more number of branches and consumers are added to the
network, the complexity goes on increasing.
The various challenges in city gas distribution network can be categorized under two broad
heads as below –
a) Setting up the Network
b) Operation & Maintenance of the Network
a. Setting up The Network
No separate corridors or ROW is available in the city area for laying of gas pipelines. The
pipeline is to be laid along the road side or under the pathways in whatever space is available
along with the other utilities like telecom cables, water pipes etc. Due to city congestion and
traffic not enough working space is available for pipeline construction activities. Large
numbers of metalled and unmetalled road crossings along with drains etc are to be made to
take pipeline to the various end users. Each end user means a separate branch line for the
user. As the pipeline is laid in the limited space available in parallel crossing the other
utilities, additional precautions and care is required so that the other or utilities do not get
damaged. Where steel pipelines are used, providing effective cathodic protection for the city
pipeline network is also a challenging task. As safety cannot be compromised, all the
standard codes in design and construction have to follow and compliance has to be strictly

ensured. The dynamic nature of city gas distribution, with frequent addition of new
consumers also requires continuous up gradation and expansion of pipeline network.
b. Operation and Maintenance
Once the network has been set up and gas is charged in the pipeline network, it is not only
required ensure continuous availability of gas to the consumers but also to maintain the health
of the pipeline system. The safety of the system and the surrounding areas is of paramount
importance in city area. A small leakage or an accident / fire in gas pipeline may result into a
big catastrophe. A quick vigil is required to be maintained by the O&M personnel to face the
following challenges in the city gas distribution.
1. Safety and Emergency preparedness.
2. Customer related operations like
a. Proper metering and billing.
b. Changing pressure and flow requirements of consumers.
c. Shutdown, overdraw, non-payment by the consumers.
d. Consumer education and training.
3. Liasoning with District Authorities and other utility departments
Figure: Existing CNG Station in Surat

6. Summary
Time has come when Natural Gas as an industrial, domestic and automotive fuel is
gaining popularity in India. The Natural gas supply scenario in India has changed
dramatically over a period of time. Natural Gas has emerged as most preferred fuel all over
the world. It is growing in fastest pace and India consumption is 9% to 25% at 2025
This is reflected in the fact that India today operates the largest fleet of CNG buses in
the world. With recent gas finds and import of gas, the gas shall be available in abundance in
the years to come. Keeping in tune, the City Gas network in the existing cities are expanding
and also City Gas Pipeline Networks are being set up to cover more cities not only for
industrial supply but also for the domestic as well as automotive sector. This possesses
greater challenges for the personnel involved in setting up, operating and maintaining the
City Gas Distribution Pipeline Networks.
References:
1. “Energy Statistics” 2012 (Nineteenth Issue), issued by Ministry Of Statistics And
Programme Implementation Government Of India, New Delhi.
2. Nitin Zamre,” City Gas Distribution Projects” November 2009), issued by CRISIL
Infrastructure Advisory.
3. “Basic Statistics on Indian Petroleum & Natural Gas” (2011-2012), issued By
Ministry Of Petroleum & Natural Gas Government of India New Delhi (Economic
Division).
4. Ayush Gupta, “Preparedness to Handle Emergency in City Gas Distribution
Networks, published in 4th Pipeline Technology Conference 2009.

Domestic Gas Infrastructure

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