Pressure Fluctuations in Natural Gas Networks caused by Gas-Electric Coupling

TL;DR

This paper presents a new method to assess pressure fluctuation risks in natural gas networks caused by gas-electric coupling, especially due to variable gas consumption from wind balancing in power generation.

Contribution

It introduces a model combining forecasted and fluctuating gas consumption to analyze pressure fluctuations, highlighting the impact of renewable energy integration on gas network stability.

Findings

Pressure fluctuations grow diffusively over time due to consumption variability.

The diffusion rate depends on the steady distribution of gas flow.

Application to the Transco pipeline demonstrates the method's relevance.

Abstract

The development of hydraulic fracturing technology 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 several electrical inter-connections. Gas-fired generators have the capability to ramp quickly and are often utilized by grid operators to balance intermittency caused by wind generation. The time-varying output of these generators results in time-varying natural gas consumption rates that impact the pressure and line-pack of the gas network. As gas system operators assume nearly constant gas consumption when estimating pipeline transfer capacity and for planning operations, such fluctuations are a source of risk to their system. Here, we develop a new method to assess this risk. We consider a model of gas networks with consumption modeled through two components: forecasted consumption and small spatio-temporarily varying consumption due to the gas-fired generators being used to balance wind. While the forecasted consumption is globally balanced over longer time scales, the fluctuating consumption causes pressure fluctuations in the gas system to grow diffusively in time with a diffusion rate sensitive to the steady but spatially-inhomogeneous forecasted distribution of mass flow. To motivate our approach, we analyze the effect of fluctuating gas consumption on a model of the Transco gas pipeline that extends from the Gulf of Mexico to the Northeast of the United States.