Operating pressure modulation: a solution for reducing methane emissions.

In the face of the climate emergency and the increasing awareness of the effects of methane emissions in the atmosphere, we can no longer stand still. Perhaps we have already been so for too long. 

According to the Global Methane Tracker 2022 report published by the International Energy Agency (IEA), In fact, as new monitoring and measurement systems, also based on satellite technology, are introduced, more and more data are becoming available, and thanks to these we can confirm that the energy sector produces 70% more methane emissions than it officially declares.

The report continues: “If globally all the leaks that occurred in 2021 in the fossil fuel energy sector had been captured and put on the market an additional 180 billion cubic meters of gas would have come onto the market, for example: An amount similar to all the gas used in the European energy sector.” In this respect, a significant part of the losses is related to overpressure conditions in gas plants and networks. By starting to manage networks with a logic based on dynamic pressure regulation, these losses could be drastically reduced. These figures are certainly alarming.

The challege presented by the United Nations

At the 2021 United Nations Climate Change Conference (COP 26 in Glasgow), starting with the impetus given by the Italian G20 Presidency, the importance of methane emissions, which is the second most important greenhouse gas after carbon dioxide CO₂, was recognised. It is interesting to note that a significant part of the losses is related to overpressure conditions in the plants, in the sense of maintaining high pressures to ensure adequate service quality. Adopting dynamic pressure regulation means exponentially decreasing the volumes of gas lost and subjecting the networks to less stress, thus also reducing the frequency of failures. The concept of dynamic regulation is closely linked to a true data-driven approach: using data collected from field devices as input for an intelligent system capable of processing and returning appropriate corrective actions to the field. This is in regards the monitoring capability on the one hand and control capability on the other hand: Dynamic regulation. At the same time, regulations are becoming increasingly stringent in terms of safety and operational efficiency therefore more must be done with fewer resources. The GIANT Project is AUTOMA's answer to the challenges that natural gas distribution companies face every day. A project aimed at finding a solution based on a real data-driven digital system that was created with the objective of developing an efficient, totally smart and automated network through intelligent remote monitoring and dynamic regulation to reduce methane emissions.

The GIANT Project for Intelligent Management of Operating Pressures

GIANT is an integrated digital platform for managing operating pressures in gas distribution networks, based on the remote monitoring of the actual situation in the field and the possibility of using these data to take appropriate corrective action. The system is based on technologies already field-proven during our 35 years in the business, such as remote monitoring and control. It integrates Edge Computing features that allow faster responses and make the system more robust and reliable. Instead, the management of big data is entrusted to Artificial Intelligence capabilities, which can find a pattern to classify information, make decisions or predict the future course of events. Finally: the cybersecurity aspect is fundamental to the protection and enhancement of these data.

The technologies that make up the GIANT system

GOLIAH4P (G4P)

The G4P is a very compact device that can be used both as a data logger and as an RTU. Typically it is used for upstream and downstream pressure measurements in GRs or distribution line termination points (as per UNI/TR 11631). When installed in network termination points, it provides a complete picture of actual operating conditions - pressure at the end users' homes - and this information can be used to set pressure regulators at gas reduction stations. Here, then, is the concept of a digital system to manage the operation of the distribution network based on the data collected from the field.

GOLIAH2P (G2P)

G2P consists of an integrated compact RTU for remote monitoring and control in gas reduction stations and city-gates. The I/Os can be digital and analogue and can be expanded according to the specific application. In addition to the typical functionality of an RTU, it is also used in conjunction with GOLEM technologies to make remote control of reduction units possible.

GOLEM – System

GOLEM is a patented technology for making any pressure reducer remotely controllable and this is a key concept. GOLEM technology turns any existing pressure regulator into an element that can be remotely controlled. In this way, we can remotely control the gas pressure based on a desired value, whether it is a measurement from the termination point or a local measurement in the GR, and we can avoid overpressure. In detail, it is a mechanically coupled servomechanism that attaches to the pressure reducer's adjustment screw and makes it controllable. Therefore, this adaptation technology makes it ideal for retrofit operations.

GOLEM – Safety and range

GOLEM system is also complemented by intrinsic mechanical safety mechanisms in addition to the possibility of manual actions. Finally, the system can also regulate on a flow basis. This is essential in situations where it is necessary, for example, to limit the flow, which could damage the fiscal meters or to keep the flow constant, as required in the injection units of biogas plants.

Artificial Intelligence integrated into the GIANT project

Data-science technologies, including those based on artificial intelligence, offer great opportunities for service managers. Artificial Intelligence, built into GIANT is a solution that optimises network pressure, ensuring more efficient management with fewer losses and less waste of resources. This is regarding the advanced algorithm based on predictive models which, by analysing process data (flow rates, pressures, etc.) at each execution cycle estimates the demand required by the utilities. Based on the estimate made, the system corrects the network management parameters, if necessary, and updates itself periodically in real-time, making system management more efficient. All this makes it possible to keep the network pressure at a minimum at times when user demand is lowest, and to raise it - without ever exceeding it - at times when demand is at its highest. This results in optimal compensation that limits leakage and ensures efficient system management at the same time.

GIANT solution simple network

To summarise: GIANT solution consists of dataloggers for measurements in grid termination points (G4P), RTUs for measurements in GRs (G4P, G2P), a central software system for the advanced analysis of these measurements (AI) and a system capable of remotely modifying the operating pressure, GOLEM. The case shown above is that of a simple network, such as an antenna network consisting of a termination point and a GR.

GIANT solution complex network

In contrast, we see below a more complex network situation, reflecting distribution situations on a meshed network, where several GRs interact and contribute to the measurements taken at different points in the network termination points. The complexity of the situation in question cannot be managed without resorting to a system with artificial intelligence capabilities.

Our plans for the future

G4P evolution

Besides artificial intelligence, also the data loggers in the network termination points play a key role within this architecture. In fact, let us recall that the operating mode of a data logger involves spontaneous communication, generally on a daily basis, during which the data recorded during the observation period are transmitted. This information, which is fundamental for the AI system's self-learning, is not sufficient for the optimal management of the data-driven system. In this regard, we have identified a couple of operational alternatives: a photovoltaic panel provides the datalogger with the energy it needs to operate as an RTU, i.e., communication that can take place continuously. Alternatively, the data logger is a device that not only collects data and transmits them, but also has processing capabilities and a local intelligence capable of waking it up and putting it in communication with the central system in the presence of abnormal operating conditions (evolved management of off-thresholds, where the threshold value is dynamically imposed by the central intelligence).

GOLEM evolution

As far as GOLEM is concerned, we are working on a couple of fundamental evolutions for this technology. The main feature of the GOLEM is that it is applicable to any existing controller. In addition to this adaptability on the controller side, we are also making it controllable from any RTU in the field. To do this, we are introducing on-board intelligence that can be controlled locally via an RS485-type serial interface. The second evolution concerns the mechanical coupling mode, which we are modifying in such a way as to make the entire system certifiable in ATEX zero zone.

Conclusions

We have seen the advantages of applying a true dynamic regulation system to reduce all those situations in which overpressure is used to operate the gas distribution network. And the reduction of operating pressure reduces gas emissions due to leaks, with obvious economic and environmental benefits. This solution also allows gas network operators to benefit from operational and safety advantages: 

• More monitoring, more control, faster responses result in greater pipeline safety;
• Digitisation means fewer personnel in the field, which in turn translates into reduced operational costs;
• Finally, big data and analytics lead to predictive maintenance capabilities, which again translates into reduced operating costs.

In addition to these benefits, AUTOMA's solution is in line with EU and EU Green Deal regulations and associated incentive mechanisms.