Natural Gas Transportation Network Research Articles

Decarbonizing the Spanish transportation sector by 2050: Design and techno-economic assessment of the hydrogen generation and supply chain

The transport sector is difficult to decarbonize due to its high reliance on fossil fuels, accounting for 37% of global end-use sectors emissions in 2021. Therefore, this work proposes an energy model to replace the Spanish vehicle fleet by hydrogen-fueled vehicles by 2050. Thus, six regions are defined according to their proximity to regasification plants, where hydrogen generation hubs are implemented. Likewise, renewables deployment is subject to their land availability. Hydrogen is transported through an overhauled primary natural gas transport network, while two distribution methods are compared for levelized cost of hydrogen minimization: gaseous pipeline vs liquid hydrogen supply in trucks. Hence, a capacity of 443.1 GW of renewables, 214 GW of electrolyzers and 3.45 TWh of hydrogen storage is required nationwide. Additionally, gaseous hydrogen distribution is on average 17% cheaper than liquid hydrogen delivery. Finally, all the regions present lower prices per km traveled than gasoline or diesel.

A Goal Programming Approach for Optimizing Natural Gas Transportation Network

Natural gas (NG) is widely transported through the high-pressure pipeline network. For maintaining the high pressure in the gas pipeline network, compressor stations are installed at fixed intervals along with the pipeline. The compression procedures involve huge amounts of energy and investment. So designing any pipeline network in NG transportation also needs to include conflicting goals of various criteria with the priority like maximization of demand satisfaction and minimization of compression energy and investment cost. In this paper, a goal programming approach dependent upon lexicographic methodology is proposed for solving the multi-criteria problem in NG transportation where each criterion is incorporated on a priority basis to achieve targeted goals. The relevance of the proposed model is explained via an example. Maximization in demand satisfaction is a prime objective and remaining targeted goals are attained on a priority basis. The deviation variable in the proposed model is solved in GAMS by using the CPLEX solver. These deviation variables provide flexibility to the decision-maker to change their priorities according to the social, environmental, and economical constraints.

A hybrid approach for high precision prediction of gas flows

About 23% of the German energy demand is supplied by natural gas. Additionally, for about the same amount Germany serves as a transit country. Thereby, the German network represents a central hub in the European natural gas transport network. The transport infrastructure is operated by transmissions system operators (TSOs). The number one priority of the TSOs is to ensure the security of supply. However, the TSOs have only very limited knowledge about the intentions and planned actions of the shippers (traders). Open Grid Europe (OGE), one of Germany’s largest TSO, operates a high-pressure transport network of about 12,000 km length. With the introduction of peak-load gas power stations, it is of great importance to predict in- and out-flow of the network to ensure the necessary flexibility and security of supply for the German Energy Transition (“Energiewende”). In this paper, we introduce a novel hybrid forecast method applied to gas flows at the boundary nodes of a transport network. This method employs an optimized feature selection and minimization. We use a combination of a FAR, LSTM and mathematical programming to achieve robust high-quality forecasts on real-world data for different types of network nodes.

Planning natural gas networks and storage in emerging countries – an application to Brazil

Some emerging countries, such as Brazil, have large remaining natural gas resources but relatively poor infrastructure to monetize it. When most of the natural gas extraction derives from associated gas, this results in high reinjection rates in production fields combined with fuel imports also to deal with an increasingly variable demand. This study test the hypothesis that modeling the natural gas transportation network expansion with Underground gas Storage (UGS) is crucial, as UGS can reduce transportation costs by better fitting natural gas supply and demand. Without UGS chances are that network expansion will be based in oversized pipelines, or pipelines often challenged by peaking demands. Therefore, this study emulated a real natural gas transport network in a thermo-hydraulic model, aiming at diagnosing its bottlenecks mainly caused by demand intermittency, and pointing out infrastructure solutions. Findings indicated the design of UGS associated with new pipelines as a problem-solver for network bottlenecks, under a least-cost approach. This option reduced idleness and lowered gas transmission costs by 60%. In addition, it increased the network operation reliability and created a virtuous cycle, where a better planning reduces the gas tariffs and spur infrastructure expansion by raising the fuel competitiveness.

Research on Green Energy Internet Planning Model

This paper intends to take power system planning as the main module, while considering the requirements and constraints of natural gas network and transportation network construction and use the energy hub model to analyse the energy transmission and transformation relationship between different networks, to realize the power system, natural gas network, and transportation. Integrated energy system planning for the network. To verify the effectiveness of the proposed PMIES planning method, an improved Garver test system is used for simulation. The system includes a 7-node natural gas network system and a 6-node electric test system. We optimized and analysed the simulated system for model research.

Research on Implementation Methods of Power Grid Technology Supporting Energy Internet Construction

The energy Internet is a complex multi-grid flow system, which is based on the power system, the Internet and other cutting-edge information technologies, with distributed renewable energy as the main primary energy and closely coupled with natural gas network, transportation network and other systems. The power grid technology has to develop to support the energy Internet construction. This paper discusses the changes and challenges in the asset environment, asset types, asset scope and asset risk under the energy Internet. Then the corresponding implementation methods of power grid technology to supporting energy Internet construction are put forward. The research results can provide reference for power grid companies to implement power technical innovation.

Polyethylene/Clay/Graphite Nanocomposites as Potential Materials for Preparation of Reinforced Conductive Natural Gas Transfer Pipes

A series of high-density polyethylene/Cloisite 20A/graphite nanocomposites were prepared via melt blending for the production of polymeric pipes for natural gas transfer. The microstructural, mechanical, thermal, electrical and barrier properties of prepared nanocomposites were investigated. An intercalated morphology was observed for prepared nanocomposites. Improved mechanical properties e.g. over 148 % increase in Young’s modulus were observed by incorporating the nanoparticles into the polyethylene matrix. The thermal analysis showed that the melting point of polyethylene was slightly increased by incorporating both fillers, i.e. Cloisite 20A and graphite in it, and the crystallinity was depended on the type of filler. The results showed that the MFI values decreased by incorporating the fillers into the polyethylene matrix and further decreases were observed by increasing the contents of the filler. It was also found that a considerable amount of electrical conductivity is created in graphite loaded nanocomposites. The natural gas permeability investigations revealed of more than 51 % decrease in the permeability by incorporating 5 wt.% of Cloisite 20A to the polyethylene. It was concluded that the prepared nanocomposites due to their enhanced mechanical, thermal and barrier properties along with the conductive nature are excellent materials to be used in the production of polymeric pipes in natural gas distribution and transportation networks.

Network optimisation for transporting liquefied natural gas from stations to end customers

This paper presents an approach to optimise the liquefied natural gas (LNG) transportation network. As the Chinese government put forward the coal to gas heating convention project in its Jing-Jin-Yi area, demands of LNG increased dramatically in 2017, rising an emergent need for optimisation of current LNG transportation network. A number of tanker trucks with limited capacity, parking at truck centres are available for LNG transportation. Each truck loads LNG at refuelling stations, transports LNG to customers, and returns to the truck centre after the delivery. According to the size of orders, the problem is divided into two sub-problems: a big order problem (BOP) to deal with integral trucks of LNG demands, and a small order problem to fulfil fractional demands. Trucks can be sent from multiple truck centres; and trucks need to move the LNG in gas stations – pickup locations – to a series of customers – delivery locations. We formulate the BOP with integer programming, and provide a decomposition approach. For small order problem, a network representation and a mathematical model are presented. A tailored object-coding genetic algorithm is developed to solve the small order problem. Four purposely designed experiments are conducted to test its performance.

Simulation of the operation of a natural gas transport system based on a criterion of minimum operating cost

In this article, a simulation model of a natural gas transport network based on the minimization of its operating costs was developed. For this, a system of equations that determine these costs and the conditions that characterize it are established, to later be transformed into a system that can easily be solved by common linear programming methods. A system of equations and matrices resulting from a transport network of few elements is presented as an example. The model is applied in the simulation of the future operation of the Colombian natural gas transport network to project the cost of its operation, section flows, its associated tariffs, and shortage level. Finally, the conclusions derive possible use applications of this model for the analysis of natural gas transport networks and other energy systems.

Operation of natural gas and electricity networks with line pack

This paper addresses the coordinated operation of the electricity and natural gas networks considering the line pack flexibility in the natural gas pipelines. The problem is formulated as a mixed integer linear programming problem. The objective is to minimize the operation cost of the electricity and natural gas networks considering the price of the natural gas supply. Benders decomposition is used to solve the formulated problem. The master problem minimizes the startup and shutdown costs as well as the operation cost of the thermal units other than the gas-fired generation units in the electricity network. The first subproblem validates the feasibility of the decisions made in the master problem in the electricity network. And if there is any violation, feasibility Benders cut is generated and added to the master problem. The second subproblem ensures the feasibility of the decisions of the master problem in the natural gas transportation network considering the line pack constraints. The last subproblem ensures the optimality of the natural gas network operation problem considering the demand of the gas-fired generation units and line pack. The nonlinear line pack and flow constraints in the feasibility and optimality subproblems of natural gas transportation network are linearized using Newton-Raphson technique. The presented case study shows the effectiveness of the proposed approach. It is shown that leveraging the stored gas in the natural gas pipelines would further reduce the total operation cost.

ОПТИМІЗАЦІЯ ГАЗОПОСТАЧАННЯ В УМОВАХ СВІТОВОЇ ЕКСПАНСІЇ СКРАПЛЕНОГО ПРИРОДНОГО ГАЗУ

Питання диверсифікації та оптимізації газопостачання до України є надзвичайно актуальним у процесі досягнення енергетичної незалежності. Сьогодні ще не існує світового ринку природного газу, проте проведений аналіз дозволяє говорити про існування процесу цінової дивергенції регіональних ринків природного газу. Розглянуто оптимізаційні моделі газопостачання в Україні з урахуванням наявності потужних газосховищ, розвинутої мережі транспортування природного газу, власних джерел газовидобування та можливості придбання природного газу в країнах ЄС.Показано, що диверсифікація газопостачання приводить до значного зменшення витрат на транспортування. У даному випадку значення цільової функції знаходили за умови однакової ціни газопостачання з усіх наявних джерел порівняно з варіантом газопостачання з одного джерела на кордоні з РФ. Наявність газосховищ дозволяє врахувати в оптимізаційній моделі сезонну флуктуацію цін. Так, газосховища виступають як споживачі влітку і як джерела газопостачання в опалювальний сезон. Наявність в оптимізаційній моделі газосховищ істотно зменшує інтегральну цільову функцію, що включає вартість придбання, збереження і транспортування природного газу. Потужність газосховищ використовується не повністю, отже, вони можуть бути задіяні в оптимізації газопостачання до країн Східної Європи.Методами економетричного аналізу проведено дослідження впливу підвищення цін на природний газ та обсяги його споживання. Здійснено оцінку коефіцієнта еластичності лінійної та логарифмічної моделей. На основі даного показника оцінено споживання газу в разі подальшого зростання цін на нього для населення. Проаналізовано можливості використання газосховищ для стабілізації газопостачання до країн Східної Європи.

Approximating Nonlinear Relationships for Optimal Operation of Natural Gas Transport Networks

The compressor fuel cost minimization problem (FCMP) for natural gas pipelines is a relevant problem because of the substantial energy consumption of compressor stations transporting the large global demand for natural gas. The common method for modeling the FCMP is to assume key modeling parameters such as the friction factor, compressibility factor, isentropic exponent, and compressor efficiency to be constants, and their nonlinear relationships to the system operating conditions are ignored. Previous work has avoided the complexity associated with the nonlinear relationships inherent in the FCMP to avoid unreasonably long solution times for practical transportation systems. In this paper, a mixed-integer linear programming (MILP) based method is introduced to generate piecewise-linear functions that approximate the previously ignored nonlinear relationships. The MILP determines the optimal break-points and orientation of the linear segments so that approximation error is minimized. A novel FCMP model that includes the piecewise-linear approximations is applied in a case study on three simple gas networks. The case study shows that the novel FCMP model captures the nonlinear relationships with a high degree of accuracy and only marginally increases solution time compared to the common simplified FCMP model. The common simplified model is found to produce solutions with high error and infeasibility when applied on a rigorous simulation.

Model and Discretization Error Adaptivity Within Stationary Gas Transport Optimization

The minimization of operation costs for natural gas transport networks is studied. Based on a recently developed model hierarchy ranging from detailed models of instationary partial differential equations with temperature dependence to highly simplified algebraic equations, modeling and discretization error estimates are presented to control the overall error in an optimization method for stationary and isothermal gas flows. The error control is realized by switching to more detailed models or finer discretizations if necessary to guarantee that a prescribed model and discretization error tolerance is satisfied in the end. We prove convergence of the adaptively controlled optimization method and illustrate the new approach with numerical examples.

Methane emissions from the Algerian natural gas pipelines transportation: Exploring process to reduce environmental consequences

The global environmental community recognizes global warming as one of the major serious threats to the planet. The emissions of methane from natural gas transportation pipeline are an important factor for global warming. While being transported by pipeline, natural gas is often emitted to the atmosphere, either for depressurization (venting emissions) or leak through the pipeline (fugitive emission). Emissions of methane are of particular concern since the methane represents the major component of natural gas and a powerful greenhouse gas. The present study investigates the feasibility of gas venting mitigation, from the Algerian natural gas transportation network with pipeline pump-down technique, prior pipeline maintenance activities. First, we calculate the amount of methane released during venting operation from GZ3 40″ pipeline based on the weighted average pipe diameter and pressure in the pipeline section being repaired. We then estimate quantity of cost value of the gas recovered. We, thereafter, suggest a mobile compressor for saving this gas. The results obtained showed that using pump-down technique with portable compressor solution instead of venting mainly saves 54.873 million m3 of gas with gain net cost saving about 11.628 million USD. Avoiding the release of gas to the atmosphere during venting operations will be crucial to mitigating greenhouse gas emissions. For the developing countries, including Algeria, mitigating these emissions can provide green investments for the joint implementation Kyoto Protocol flexibility mechanism. This will contribute to sustainable development and additional economic benefits through carbon credit revenues and technology transfer from industrialized countries.

Considerations on determining the explosion risk and the areas with explosion hazard in a natural gas compressor station

Compressor stations are important components within natural gas transportation networks. The current paper analyses some of the safety aspects involved in the operation of such facilities – on the one hand related to the explosion risk for employees working in compressor stations and on the other hand related to determining to the areas with increased explosion hazard in such a station, in order to help reducing work-related accidents and the occurrence of professional illnesses. The explosion risk is determined based on a method devised by the National Institute for Research and Development for Environmental Protection Bucharest, while the explosion hazard areas are determined and displayed with the help of the software package AutoCAD Plant 3D.

A linear-rate analog approach for the analysis of natural gas transportation networks

Modeling natural gas transportation networks poses a number of challenges due to the significant non-linearities associated to the governing equations. Pressure (nodal or p-) formulations and flow (nodal-loop or q-) formulations are the most commonly deployed approaches used to formulate gas flow network models. They treat nodal pressures and pipe branch flow rates as primary unknowns, respectively, and the Newton-Raphson method is the typical choice used to solve the resulting system of pipe network equations. The major disadvantage of Newton-Raphson methods is their tendency to hopelessly diverge when good initializations for the unknown pressure and flow variables are not available. In order to overcome this drawback, a linear-pressure analog approach, applicable to the p-formulation, was recently proposed to formulate an initial-guess-free solution protocol. However, solving the q-formulation rather than the p-formulation would be an alternate, practical, and desirable way to study gas flow in pipeline networks because the system of equations is predominantly linear—with the exception of the loop equations. Linear Theory and Hardy Cross methods have been used in the past solve such q-formulation. Unfortunately, these methods are not initial-guess-free and have been shown to become potentially unstable and thus inefficient because their convergence is also strongly associated with the availability of good initial guesses. This work proposes a linear-rate analog method capable of effectively solving the q-formulation. Through case studies, the proposed linear-rate analog method is shown to be a robust and initial-guess-free solution scheme to effectively model horizontal and inclined natural gas pipeline networks.

Electricity-Natural Gas Operation Planning With Hourly Demand Response for Deployment of Flexible Ramp

This paper proposes an integrated stochastic day-ahead scheduling model to dispatch hourly generation and load resources and deploy flexible ramping for managing the variability of renewable energy system. A comprehensive framework for the natural gas transportation network is considered to address the dispatchability of a fleet of fuel-constrained natural gas-fired units. System uncertainties include the day-ahead load and renewable generation forecast errors. Illustrative examples demonstrate that the real-time natural gas delivery can directly impact the hourly dispatch, flexible ramp deployment, and power system operation cost. Meanwhile, the demand side participation can mitigate the dependency of electricity on natural gas by providing a viable option for flexible ramp when the natural gas system is constrained.

Adding flexibility in a natural gas transportation network using interruptible transportation services

Abstract We present a modeling framework for analyzing if the use of interruptible transportation services can improve capacity utilization in a natural gas transportation network. The network consists of two decision makers: the transmission system operator (TSO) and a shipper of natural gas. The TSO is responsible for the routing of gas in the network and allocates capacity to the shipper to ensure that the security of supply in the network is within given bounds. The TSO can offer two different types of transportation services: firm and interruptible. Only firm services have a security of supply measure, while the interruptible services can freely be interrupted whenever the available capacity in the transportation network is not sufficiently large. We apply our modeling framework on a case study with realistic data from the Norwegian Continental Shelf. The results indicate substantial increased throughput and profits with the introduction of interruptible services.

Environmental impact assessment methodological framework for liquefied natural gas terminal and transport network planning

The recent discovery of significant offshore natural gas reserves in the Aphrodite field, south of the island of Cyprus in the Mediterranean Sea, changes the energy landscape in the greater Mediterranean-Middle East-Caucasian Region. In this paper, different alternative locations for the construction and operation of a liquefied natural gas (LNG) terminal station in Cyprus were evaluated, explicitly considering also their connection to the power generation station of Mari and the country׳s gateway.The problem of determining the optimal location for an LNG terminal in Cyprus has been approached using multiple methodological components, which consider environmental and transportation issues, both technocratic in nature, as well as more subjective and based on expert opinion. The first step was a REGIME multi-criteria decision analysis used to prioritize alternative LNG terminal locations. Then, multiple modes (railroad and pipeline) of transportation connections were evaluated and geometric alignments were proposed, considering a multitude of restrictions. Finally an environmental impact assessment based on a structured questionnaire and an expert panel was conducted to validate and assess the impact of the alternative options (combination of location and transportation mode and route). During the evaluation process parameters such as safety, existing infrastructure, and access were also considered.

System for Real Time Managing the Natural Gas Transport Network

Managing a natural gas transport system is a complex process that requires controlling a huge amount of data regarding the instantaneous available transport capacity, the reserved capacity, the gas source capacity, the hourly consumption profiles and the network problems. Managing this system must be realised in such a way that it satisfies all the requirements and is materialised in an operation manoeuvres set for a specific period of time. The paper presents the concept of a real time managing system based on the informatics model of the network in GIS, a numerical simulator, a database and a SCADA interface. This system is now implemented at SNTGN Transgaz SA.