Cascading of fluctuations in interdependent energy infrastructures: Gas-grid coupling

Abstract

The revolution of hydraulic fracturing 1 has dramatically increased the supply and lowered the cost of natural gas in the United States driving an expansion of natural gas-fired generation capacity in many electrical grids 2. Unrelated to the natural gas expansion, lower capital costs 3 and renewable portfolio 4 standards are driving an expansion of intermittent renewable generation capacity such as wind and photovoltaic generation. These two changes may potentially combine to create new threats to the reliability of these interdependent energy infrastructures. Natural gas-fired generators are often used to balance the fluctuating output of wind generation. However, the time-varying output of these generators results in time-varying natural gas burn rates that impact the pressure in interstate transmission pipelines. Fluctuating pressure impacts the reliability of natural gas deliveries to those same generators and the safety of pipeline operations. We adopt a partial differential equation model of natural gas pipelines and use this model to explore the effect of intermittent wind generation on the fluctuations of pressure in natural gas pipelines. The mean square pressure fluctuations are found to grow linearly in time with points of maximum deviation occurring at the locations of flow reversals.

Optimal model switching for gas flow in pipe networks

“…With each edge e j ∈ E of such a network, we associate a pipe model from the hierarchy in Section 2.1 and a given pipe length L j > 0. Furthermore, depending on the role of each node in the network, we impose appropriate coupling conditions for the gas density and flow at the boundary of pipes corresponding to edges being incident to that , see [13]. To this end, we define for v ∈ V and e j ∈ δv…”

“…This yields α k 1 = 1 and α l 0 =ᾱ. The compression ratio of centrifugal and turbo compressors mostly lies within the rangeᾱ ∈ [1,2], withᾱ ≈ 1.3 being a typical value, see [13], [39,Chapter 4] and [12,Chapter 5.1]. For realistic long distance gas networks, compressors are set along the pipes in a distance of around 100-300 km, see [12,Chapter 5.3].…”

Operational Risk Assessment of Electric-Gas Integrated Energy Systems Considering N-1 Accidents

“…The research on integrated energy system risk assessment is in its infancy, and the research results of this research direction are currently mainly focused on the reliability assessment of integrated energy systems. In [13], the influence of electricity-gas coupling on the operation status of the integrated energy system was studied, but the impact of gas supply risks on the security of the entire system has not been fully considered. In [14], the impact of the shortage for natural gas supply on the operation of the integrated energy system was analyzed, and the impact of intermittent new energy power injection on the feasible region of the natural gas system was also evaluated.…”

An SNA-DEA Prioritization Framework to Identify Critical Nodes of Gas Networks: The Case of the US Interstate Gas Infrastructure

“…As conventional reliability modeling is unable to deal with the complex and dynamic characteristics of large gas pipeline systems, in the last years, scholars have proposed several techniques and methodological approaches based on the implementation of the network theory to assess the performance of gas infrastructure networks in terms of vulnerability, resilience, and security. Such approaches include methods based on the implementation of network theory, allowing study of the network topological properties [4], material flows [5], and functional properties of the system [6]; and hybrid or systemic methods that integrate different methodologies, i.e., stochastic analysis of processes, graph theory, and thermal-hydraulic simulation to account for the complexity, uncertainty, and physical constraints of gas networks [7].…”