Metering plays a vital role in the city gas distribution (CGD) industry to ensure the accurate measurement of gas that is billed for revenue collection and for the proper reconciliation of accounts. Meters are used to measure the volume of gas consumed by domestic customers, industrial and commercial customers, and at compressed natural gas (CNG) stations.
The primary reason for giving a greater thrust to accurate metering and billing is to minimise the gap between the amount of gas purchased by suppliers and that sold to consumers. One of the major concerns of a CGD entity is related to the loss of unaccounted gas (LUAG). Today, most of the companies in the upstream, midstream and downstream segments are facing issues of LUAG.
The quantum of leakage from a pipeline is directly proportional to the volume of gas carried by the pipeline. Further, factors contributing to LUAG are multiple leakages from medium density polyethylene (MDPE) pipes, damage to pipes by rats, pressure regulator seal tampering, gas theft using flexible tubes, bypassed meters and meter regulator skid (MRS), stolen gas being supplied to nearby industries, damage to domestic meters by pouring sand, and tampering of meter index and rotary positive displacement (RPD) meters, among others. Further, in most cases, domestic customers are billed on the basis of estimated gas consumption leading to a huge gap in the actual supply of gas and the billed volume. Also, there are instances in which the actual gas consumption is less than the billed volume requiring a reversal of the balance amount in a subsequent bill.
Globally too, a number of cases of gas meter tampering and the illegal use of natural gas have been recorded. A case in point is the theft of 23,000 million cubic feet worth of gas annually from Sui Southern Gas Company Limited in Karachi. In monetary terms, the gas stolen was worth Rs 7.25 million per annum. Another such case was recorded in Lahore where a 6.3 km long illegal pipeline was detected using sourced information and a pipeline detector. The CGD operator in the area, Sui Northern Gas Pipeline Limited, took action against 400 industrial units and nine CNG stations. Similarly, the CGD operator in Dhaka, Titas Gas Transmission and Distribution Company Limited, also recorded a case of gas meter tampering where an approximately 250 km long illegal pipeline was detected. The company detected a number of pilferage rackets and nearly 0.3 million illegal gas connections.
Measures for reducing LUAG
Measures that can be taken to control LUAG include installing MRS cages, electronic locks and tamper-proof seals, penalising customers, permanent disconnection, regular surprise checks, regular consumption pattern monitoring, installing MRS outside customer premises and installing automated meter reading (AMR) systems.
AMR systems can be deployed to control LUAG in the case of both domestic and commercial customers. The different types of AMR systems available are walk-by meters, drive-by meters, fixed meters, optical character reading meters, AMR with photos and AMR with prepaid meters. Of these, AMR with prepaid meters are the most preferred.
Some of the other measures that can be undertaken to control gas losses include improved caging with high security locks on MRS devices installed for industrial and commercial customers, welding hinges on MRS doors, blocking and sealing vent points and sealing the meter index.
Given the importance being given to CGD development by the government and industry players, there is a need to work towards addressing operational challenges. The areas that require attention are leakages in MDPE pipelines, illegal connections (that will require increased monitoring by the workforce), proper functioning of RPD meters, low turndown ratio of turbine meters, and accuracy of diaphragm meters (which is as low as 3-6 per cent at present). Besides, issues such as poor collection efficiency, inaccurate billing and irregular billing cycles need to be urgently addressed.
Based on a presentation by Sushil Kumar, Head, Metering Cell, Indraprastha Gas Limited, at a recent India Infrastructure conference