T he consumption of natural gas is on the rise and projected to keep rising for years to come.  In China (and elsewhere), demand has steadily surpassed supply.  In the U.S., thanks to the shale gas boom, natural gas overtook coal to become the leading source of electricity generation in 2016, while pipeline and liquefied natural gas exports are expected to increase through the mid-century.

As the capacity to transport natural gas becomes increasingly important, so do investments in infrastructure.  Several questions arise: is the existing pipeline infrastructure sufficient to satisfy the increasing demand for natural gas in the future?  What is the plausible range of magnitude of future investments in pipeline capacity?  How are these investments regionally distributed?  Are there conditions under which the pipelines are underutilized?

Development of natural gas infrastructure is strongly influenced by domestic and international socioeconomic conditions.  For instance, economic growth patterns in the U.S. could shift the demand centers for natural gas, which in turn could shift investment patterns; or changes in environmental policies in Mexico and Canada could affect U.S. pipeline and liquid natural gas exports and thus U.S. energy security.  Such interactions underscore the need for an integrated approach to study future development, one that captures complex factors within the broader economy, from regional to national to global processes and conditions.

Previous studies on natural gas infrastructure development have largely ignored the broader economy.  Thus, in our newly published study we developed an integrated framework to explore five socioeconomic scenarios of the future that vary across domestic and international natural gas demand patterns. Although our focus centered on the U.S., the methodology and scenarios we developed can be applied to other geographical contexts.

In short, we coupled two models: a global multi-sector Human-Earth system model with state-level detail (GCAM, the Global Change Assessment Model), and a natural gas sector infrastructure investment model (NANGAM, developed my MODL) with updated data on the newest pipelines in North America.  This new modeling perspective not only incorporates the constraints imposed by global markets and sectors of the economy but also those constraints imposed by existing infrastructure access.

Our findings show that existing pipeline infrastructure in the U.S. is insufficient to satisfy the increasing demand for natural gas, and investments in pipeline capacity will be required. However, the geographic distribution of investments within the U.S. is varied and depends on the capacity of existing infrastructure as well as the magnitude of increase in demand.

Further, our findings also illustrate the risks of under-utilization of pipeline capacity, especially under a scenario characterized by long-term systemic transitions toward a low-carbon economy.  For example, although the Middle Atlantic region emerges as a supply hub in all our scenarios, an economy-wide transition toward low-carbon technologies results in a reduction of flows from that hub by almost a third compared to a reference scenario that is agnostic to technology.

Our study provides a framework to assess natural gas pipeline infrastructure development under future socioeconomic scenarios.  This framework, coupled with our results, can provide scientific decision-making support to agencies like FERC.

While our study highlights the value of integrated approaches to facilitate informed decision-making, it also opens several avenues for future research.  For example, feedback loops between the two models we coupled could benefit from further development, and a broader suite of socioeconomic scenarios could be examined.