Frequently Asked Questions

What’s in natural gas?
Natural gas found in the ground contains methane, ethane, propane, pentane, and traces of hexane and heptane. Gas utilities remove almost everything but the methane so the natural gas delivered to your home will burn cleanly.

What is methane?
Methane is a molecule made up of one carbon atom and four hydrogen atoms. Its chemical formula is CH4.

What makes natural gas a clean fuel?
The main products released when natural gas is burned are carbon dioxide and water vapor. Coal and oil are more chemically complex than natural gas, so when burned, they release a variety of potentially harmful chemicals into the air.

How much natural gas is produced in the world?
Natural gas is found in about 50 countries. About 3,193 billion cubic meters of natural gas was taken out of the ground and processed for use in 2010. Here is a breakdown of how much of that was produced by various countries and regions:
  • Europe and Eurasia 32.6%
  • United States 19.3%
  • Asian and Pacific Countries 15.4%
  • Middle East 14.4%
  • Africa 6.5%
  • Canada 5.0%
  • Central and South America 5%
  • Mexico 1.7%

Why is natural gas used to run electric power plants?
In the 1970s and 1980s, most electric power plants were fueled by coal or nuclear power. But due to environmental concerns, by the 1990s, about 60 percent of new electric power plant capacity was fueled by natural gas. Because it is a clean-burning, competitively priced, and efficient fuel, the use of natural gas to generate electricity has increased dramatically during the last decade.

What is “liquefied natural gas?”
When natural gas is cooled to 260 degrees below zero, it changes from a gas into a liquid. Liquid natural gas takes up much less space than natural gas, making it easy to transport and convenient to store. Six hundred cubic feet of natural gas turns into just one cubic foot of liquid gas!
What’s in natural gas?
PNG is mainly methane – CH4 with a small percentage of other higher hydrocarbons. The ratio of carbon to hydrogen is least in methane and hence it burns almost completely making it the cleanest fuel. It is procured from the oil / gas wells and transported through a network of pipelines across the country.

Is the supply of PNG regular ?
Yes, the supply is absolutely regular. The pipeline distribution network is based on an on-line supply system that consists of safety valves and regulators that control and monitor the gas supply and pressure, and assist in identifying system leaks. Thus an un-interrupted supply at a constant pressure is assured.

What changes are required for conversion of an LPG appliance to be PNG friendly ?
PNG works on a cooking appliance just like LPG does. Converting an existing LPG appliance to a PNG friendly one is done by trained IGL technicians, and at no extra cost.

What becomes of the LPG cylinders after the cooking appliance gets converted ?
The LPG connection can be surrendered to the respective oil company and security deposit refund obtained.You are under obligation to discontinue the LPG connection as per the Ministry of Petroleum & Natural Gas directive dated 23.09.09 according to which both LPG & PNG connection can not be availed at the same address (even under different names / relations). If however you do not submit the same within 60 days of completion of PNG connection as per the directive, PNG supply shall be discontinued.

What is a domestic PNG connection ?
A domestic PNG connection includes conversion of one LPG appliance to PNG, laying of associated galvanized iron (GI) pipeline network, along with necessary fittings, pressure regulator and a meter.

What is the cost of getting a PNG connection ?
Cost of PNG connection is dependent on the type of house and installation charges are as applicable at the time of registration. Applicable interest free refundable security deposit is to be deposited for a PNG connection.

What is the system of billing ?
Billing is based on the meter readings taken by the authorised HNGPL staff once in two months for the domestic consumers. The bills are delivered at the customer’s residence. The payment of the bills can be made by using any of the payments modes specified under ‘Payment Modes’ in PNG section.

How are customer queries and complaints attended to ?
We have 24 hour helpline service for attending to your queries / complaints. Our network of control rooms are manned 24 hours by Engineers and trained technicians to address any queries / complaints.

What is CNG ?
CNG stands for compressed natural gas. It is gaseous fuel and is a mixture of hydrocarbons mainly Methane. For use in Automobiles as fuel, it is compressed to a pressure of 200-250 Kg/cm² to enhance the vehicle on-board storage capacity.

Is CNG safe ?
Yes, it is safe. The properties of CNG make it a safe fuel. It is lighter than air, so in case of a leak it just rises up and disperses into the atmosphere. Besides, a high auto-ignition temperature of 540 degrees centigrade as against petrol’s 360 degrees centigrade, makes it a safe fuel. Also, in case of a leak, if CNG’s concentration in the air is less than 5% and more than 15%, the gas will not burn even in the presence of a spark.

What is involved in converting a vehicle to a CNG-friendly one ?
All spark-ignited engines can be converted to CNG, but a specially designed conversion kit is required for the purpose. The kit consists of a cylinder to be fixed in the boot of the car and other equipment to allow gas flow into the engine.

Can a car, fitted with CNG conversion kit, run on Petrol after its CNG gets over ?
Yes, after conversion to CNG the vehicle can run on petrol whenever desired simply by flicking a switch on the dashboard.

What are the dimensions and weight of a CNG cylinder ?
CNG cylinders are manufactured from a special steel alloy and are seamless in construction. Their compact size allows them to easily fit even in a small car. An empty CNG cylinder with a 50 litre-water-carrying capacity weighs 48 kg, with a length of 835 mm and a diameter of 316 mm. The 50 litre capacity cylinder is the one most regularly used; cylinders with 45 litre, 55 litre, 60 litre and 65 litre capacity are used as well.

What is the capacity of a cylinder, and mileage from one fill? How does one get to know the quantity of CNG left in the cylinder ? Under city road conditions and may vary from vehicle to vehicle and driving habits

What is the pressure of CNG in a cylinder? Is refuelling of a cylinder safe, given the pressure ?
CNG cylinders are designed and built in such a way so as to withstand high pressure. The maximum pressure in a CNG cylinder is up to 200 kg/cm2 (g) (about 2840 pounds per square inch (gauge) or psi[g]). CNG cylinders are safe as they are manufactured as per specific requirements and tested before use, in accordance with international specifications and standards and they are duly approved by Chief Controller of Explosives. Moreover, these have been provided with a ‘safety burst disc’ such that in case of inadvertent high-pressure/high temperature at the time of filling or at any other time, this disc is ruptured and pressure released.

How much will be the saving after conversion to CNG ?
The fuel bill on the basis of average running of vehicle is reduced by 50 percent approximately after conversion of CNG at the present price of CNG & Petrol in Delhi.

Does CNG kit require servicing ?
CNG kit is safe and simple. It gives years of trouble free operation. It doesn’t require frequent servicing. Just as for all other fuels, it is advised to have routine services. An authorized person should be consulted for service. As per Gas Cylinder Rules, 1981, the cylinder should under go hydro-stretch testing every 3 years to check pressure tolerance.

Does CNG have any harmful effect on the engine ?
Owing to CNG’s distinct features, it does not contaminate or dilute crankcase oil, giving a new lease of life to the engine. The absence of any lead content in CNG helps avoid lead fouling of plugs, thereby enhancing plug life. One of the important benefits of CNG is that upon entering the engine in the form of a gas (and not as a spray or mist like other fuels), it doesn’t disturb the presence of lubricating oil in the engine, and reduces chances of wear and tear.

Can a diesel vehicle be converted to CNG ?
Yes, a diesel vehicle can be converted to run on CNG, but the conversion cost is higher than the conversion of petrol vehicles and under the current technology it can not run on duel fuel mode

Why are exhaust fumes so small in CNG-run vehicles ?
CNG is an environment friendly fuel. The natural gas is mainly composed of methane and its exhaust emissions consist of water vapours and a small fraction of carbon monoxide. The absence of carbon and other particulates result in negligible amount of harmful elements in exhaust fumes.

How does large-scale CNG usage benefit the country ?
CNG emits less carbon dioxide and other pollutants as compared to liquid fuels. Thus, CNG contributes in lowering air pollution, also helps in improving the Balance of Payments by acting as a substitute for imported liquid fuels, provides more business and job opportunities with the opening up of a new sector, and being competitively priced, it appeases motorists.

What is the capacity of a cylinder, and mileage from one fill? How does one get to know the quantity of CNG left in the cylinder ?
Under city road conditions and may vary from vehicle to vehicle and driving habits

What to do in case of emergency ?
Call HNGPL helpline in case such a situation arises. Do not under any circumstances tamper with any equipment on your own.

What to do if we are not at home for long time ?
In case you are traveling or not going to be using the connection for a long period, turn the main connection valve of your home off. Also, open all windows and doors when you turn the connection on again.

What kind of stoves are best?
Always use stoves and burners bearing an ISI mark only.

Can we clean rubber tubes ?
Yes, you can regularly clean the rubber tubes with a wet cloth. You must also ensure that you do not accidently loosen the connection, or keep hot utensils near the gas pipe. When cleaning the burners, allow some time for the burners to cool down to avoid burning yourself. Then use soap and water to clean. Also, let the burners dry before reusing them.

Can we identify PNG odour ?
Yes, though PNG is naturally odorless, a special substance is added to PNG to give it a distinct odor.

What to do in case leakage ?
Open all doors and windows, cease any cooking and turn off the gas and call HNGPL’s helpline in case you smell leakage.

Why is it important to save energy?
If people use less energy, there is less pressure to increase the available supply of energy, for example by constructing new power plants, or by importing energy from a different country.

What does “life-cycle” mean? What does it have to do with energy use?
Nearly all everyday products have an impact in terms of energy, especially when you consider their energy requirements across the whole life-cycle: production, use and end-of-life. In many cases the use phase is dominating. Plastics, for example, are one of the most resource-efficient materials available. In their use phase, plastics products help to save more energy than is needed to produce them: For example, when you choose a bottle of water packaged in a light weight material such as plastic, remember that lighter packaging requires less energy for transport. Thus, less fuel was used to power the truck that delivered those plastic bottles.

What can I do to save energy?
There are many sources on the web that give you ideas of what you can do to save energy. Here are a few ideas to get you started:
  1. Change your travel behaviour, think more in terms of public transportation, if possible, walk or ride your bicycle instead of taking the car
  2. Reduce your house heat by 1C, keep the windows closed while heating, dress warmly
  3. Choose products that come with lightweight packaging
  4. Turn off lights and appliances when you are not using them, use energy-saving light bulbs
  5. Reuse plastic bags for shopping and storage
  6. Use a microwave instead of a stove to reheat food
  7. Use rechargeable batteries instead of disposable batteries


What effect do materials have on the environment?
In our daily life, we rely on many materials. Wood, metal, glass and plastics all have environmental consequences. Think about the impact of every product you use. For example, the lighter an object, the less fuel is required to transport it. A heavy suitcase in the boot of a car will require the car to consume more fuel during its journey. The same goes for all product packaging. Therefore, buying food wrapped in lightweight materials thus helps the environment.