Metering plays a crucial role in the city gas distribution (CGD) industry. It ensures the accurate measurement of gas consumption, which is billed for revenue collection. This helps in the proper reconciliation of accounts. Meters are used to measure the volume of gas consumed by domestic, industrial and commercial consumers. These are also installed at compressed natural gas stations. However, the existing metering technologies and equipment are prone to human errors and wear and tear. Incorrect meter readings lead to leakages, which creates a gap between the gas supplied and consumed.
One of the major concerns of a CGD utility is the loss of unaccounted gas (LUAG). Today, most companies in the upstream, midstream and downstream segments are facing LUAG issues. Therefore, greater emphasis is being laid on the deployment of new technologies and smart metering solutions to improve the metering and billing efficiency and operational performance of utilities.
Measures for reducing LUAG
The natural gas industry is gradually making a shift from conventional metering to smart metering solutions. In order to check their LUAG, CGD operators are testing advanced technology solutions, smart metering devices and innovative equipment. These include automated meter reading (AMR) systems, optical corrective reading devices, thermal meters, ultrasonic meters and prepaid meters.
AMR systems can be deployed to control LUAG for both domestic and commercial customers. These devices are retrofitted in meters that transmit gas consumption data to the operator’s central database through radio frequency. This automatic collection of data ensures accurate measurements, thus eliminating the need for manual meter reading for billing purposes. These AMR devices can also be used for walk-by and drive-by data collection, wherein representatives of the CGD entity are equipped with a hand-held unit and a smartphone. The meter reader walks or drives through a guided route and meter data automatically gets collected through a wireless network. The collected data can then easily be sent to the central control room through a smartphone over a secured internet connection. Further, the data collected through these AMR devices can be directly interfaced with the central database, wherein data for a 24-hour consumption profile is communicated via SMS-based metering.
In addition, optical corrective reading devices are being installed on meters. These are capable of reading numbers and converting them into electronic data, which is transmitted to the control room using a wireless network. It also raises an alarm in case of tampering. Besides, new types of equipment such as thermal meters, ultrasonic meters and prepaid meters are being deployed to curb LUAG. Prepaid meters allow users to purchase gas as and when needed. They can be recharged regularly, depending on the consumption. Further, prepaid meters enable real-time tracking of consumption and send recharge reminders once credit drops to the programmed threshold level. Prepaid meters are ideal for non-resident Indians, who use their gas connections for just a few months and do not wish to pay recurring bills for their gas meters year round. Also, upgraded meters such as ultrasonic meters and thermal meters are being tested in India on a pilot basis. Ultrasonic meters are non-invasive. They have two transducers that can be clamped onto a pipeline to measure the velocity of flow using ultrasonic waves without coming in contact with the fluid.
Further, operators can upgrade their billing systems through information technology solutions. Billing software such as SAP can be interfaced with AMR meters and data analytics. Other measures that can be taken to control LUAG include installation of meter regulator skid cages, electronic locks and tamperproof seals; blocking and sealing of vent points; meter index sealing; imposition of penalties; permanent disconnection; surprise checks; and regular monitoring of consumption pattern.
The China experience
In many cities across China, tiered pricing has been adopted for residential gas consumers in order to balance regional supply and demand, and encourage users to conserve energy, thereby reducing emissions. With these complex billing strategies in place and frequent price adjustments, gas companies need to ensure accurate metering. To meet this requirement, many gas companies introduced smart gas meters based on conventional technologies including prepaid integrated circuit card meters and wireless remote reading meters. While in the former gas companies cannot monitor the gas consumption behaviour of users, the latter requires advanced wiring, resulting in high deployment costs.
As a result, several businesses have introduced short-range wireless meters to enable centralised meter reading using unlicensed frequency bands. This is also known as the small wireless method. However, this solution has a number of issues, including unstable data transmission, the inability to guarantee data security, high power consumption by meters and poor wireless network coverage. Problems in smart meter reading applications used in gas companies arise mainly because different smart gas meter vendors use different communication methods for their devices, with propriety communication protocols and different back-end software. For large-scale deployment, interoperability becomes highly complex.
In February 2018, the Goldcard Smart Group and Huawei teamed up to develop a smart gas solution based on Huawei’s NB-IoT connection technology, internet of things (IoT) platforms and Goldcard Smart Gas software. NB-IoT is a powerful, secure and inexpensive long-range wireless communication technology that can solve smart metering issues and guarantee wide coverage, low power use and a large number of connections.
The IoT smart gas solution is based on a cloud, pipe and device architecture. It uses smart IoT meters to accurately measure gas consumption and securely transmit meter readings and device data into the cloud over new IoT networks such as NB-IoT. The cloud application system uses distributed computing and big data analytics to connect a large number of meters, provide real-time billing, and enable efficient data analysis and decision-making. The system interconnects the cloud control centre and meters based on service rules, facilitating functions such as remote valve shut-off alarms. It allows transfer of data between devices and service personnel. This data can be passed on to customers on social media.
The way forward
Given the government’s focus on CGD development, there is a need to improve the operational efficiency of utilities through better metering and enhanced billing techniques. Although several innovations have been made in metering solutions, the sector continues to face challenges such as leakages in MDPE pipelines, illegal connections, faulty RPD meters, low turndown ratio of turbine meters and inaccuracy of diaphragm meters. Besides, consumers are reluctant to retrofit new devices or replace existing ones. The high cost of meters also acts as a deterrent to their wider deployment.