Smart meter deployment in city gas distribution (CGD) utilities in India is at a nascent stage. Most CGD utilities record their gas offtake using diaphragm meters, which are predominantly based on mechanical measurement techniques. These meters pose challenges such as inaccurate measurement and require manual intervention, thereby resulting in errors in billing practices. However, several utilities are now opening up to the idea of smart meter deployment.
In order to address the aforementioned issues, mechanical meters can be retrofitted with an electronic interface. Another option is to undertake electronic measurement based on emerging technologies. Smart meters are capable of re-ranging/auto-calibration, stand-alone communication, signal conditioning and self-diagnosis.
Smart metering has emerged as a vital tool to bring about significant cost savings for gas suppliers and consumers. While providing customers with energy usage information via an in-home display that can be utilised to increase energy efficiency, smart meters also enable customers to do away with the need for physical meter readings.
Benefits offered by smart meters
These meters offer improved readability, reliability and accuracy, and are also less prone to the effects of temperature and humidity as compared to analog devices. Moreover, since smart meters can be replaced with different types of devices, using these meters enables inventory reduction.
Types of smart gas meters
Hybrid smart flow gas meters
Although hybrid gas meters still use mechanical elements for measurement, the compensation of errors is easier as these are electronically computed (along with gears). However, these meters are impacted by degradation effects owing to shrinkage of diaphragm material, and wear and tear of the gear train. Consequently, these meters require recalibration every five to seven years.
Electronic gas meters
Electronic ultrasonic meters are smaller in size and lighter than hybrid gas meters. These meters have a wide dynamic range and take electronic measurements. Lasting for a longer time period, these meters have a natural interface with electronic systems.
Meanwhile, electronic thermal gas meters which are noiseless and wear-free, have a very low starting flow. Electronic charge flow meters are also highly accurate and small in size.
Initiatives taken by CGD players
Several firms in the gas sector have taken initiatives for the implementation of smart meters in the country in the past two years. Some CGD players that have undertaken advanced metering solutions are as follows:
Mahanagar Gas Limited (MGL): MGL utilises ultrasonic flow meters, mass flow meters, turbine meters, rotary positive displacement (RPD) meters and diaphragm meters. The company has been able to successfully install automated meter reading (AMR) systems across 1,425 domestic premises on a pilot basis. The system enables meter readers to capture readings using hand-held equipment by physically entering the vicinity/area rather than each individual home. AMR systems have an additional functionality of detecting meter tampering instances. Currently, MGL is in the process of reviewing a cost-effective solution for the implementation of AMR systems for commercial consumers.
MGL also plans to test another technology for obtaining meter readings automatically through the implementation of the photo-based global positioning system (GPS)-enabled smart phone initiative for households. Under this initiative, an AMR tool and a GPS-based android mobile phone will be installed, thereby enabling meter readers to update customer data and take a picture of the meter, thus capturing an accurate reading. The data is then uploaded onto the MGL server for bill generation. The system is effective as it saves time and paperwork, thereby eliminating the need for visiting MGL offices to update customer meter readings.
Gujarat State Petroleum Corporation (GSPC): At present, GSPC utilises metering options such as RPD meters, domestic diaphragm meters and commercial diaphragm meters. Domestic diaphragm meters have an operating pressure of 15 megabar (mbar) to 38 mbar and the flow range is up to 2.5 cubic metres per hour. For commercial diaphragm meters, the maximum flow rate across the models varies from 10 standard cubic metres per hour (scmh) to 40 scmh whereas the maximum working pressure is 0.5 bars. Both meters have provision for retrofitting of meter interface units to enable AMR implementation at a later stage.
Indraprastha Gas Limited (IGL): As a part of its energy conservation initiative, IGL installed flow meters and rota meters. Rota meters have been installed in drain lines to monitor gas losses in reciprocating compressors, whereas flow meters have been installed at suction points of retail outlets for improved gas reconciliation.
Gas Authority of India Limited (GAIL): GAIL has implemented metering options such as turbine gas meters, RPD meters and diaphragm gas meters. Diaphragm gas meters are compliant with AGA 7/T4S standards for domestic and commercial users and can measure low volumes accurately. Meanwhile, turbine gas meters and RPD meters, along with flow computer/electronic volume correctors, are used for industrial consumers. For the compressed natural gas (CNG) segment, GAIL has installed mass flow meters in accordance with the International Organization of Legal Metrology’s standards.
Central UP Gas Limited (CUGL): CUGL USM, process gas chromatographs and a computerised workstation to check gas flows and quality at the Fazalganj and Chakeri CNG stations in Kanpur and the Rohella CNG station in Bareilly. While ultrasonic flow meters help in the accurate estimation of gas flow, process gas chromatographs determine the composition and compute the gross heating value of gas.
In order to track the quantity of gas sold, CUGL has adopted advanced metering systems. GSM-based metering facilities have been installed for industrial users, mainly for ensuring high efficiency. Meanwhile, mechanical meter reading facilities are being used for the domestic and commercial segments. CNG sales are monitored via Coriolis flow meters.
CUGL has also implemented diaphragm and RPD flow meters in the commercial, domestic and industrial segments. The quantity of gas being sold to the company’s customers is being measured through RPD volumetric flow meters, which are equipped with electronic volume correctors. International standards for flow measurement such as AGA 7 and AGA 8 are used for this purpose. These mechanisms are required as gas is sold to consumers at different pressure and flow rate levels.
The slow adoption of smart meters can mainly be attributed to the fact that gas usage does not permit shifting consumption demand from peak hours to off-peak hours. Further, there are several technological issues that restrict their adoption on a large scale.
The successful implementation of smart meters in the gas segment will largely depend on factors such as market demand, metering infrastructure, client selection timelines and national safety regulations.
In light of the advantages offered by smart metering systems, some progress has been made with regard to their implementation at the pilot level in select utilities. Nonetheless, Indian gas utilities are yet to adopt these systems on a larger scale. Major infrastructural development and addressing capacity building issues are required before large-scale adoption of these metering projects can be undertaken.