Weather or not? Welfare impacts of natural gas pipeline expansion in the northeastern U.S.

With the rapid development of new natural gas resources in the United States has come a number of proposals for new natural gas transmission infrastructure. We use a unique and fine-grained data set on natural gas spot pricing and gas transmission operations to model how a local pipeline expansion connecting a Marcellus Shale producing area to the main Transco pipeline system would affect flow patterns and zonal gas pricing across the Transco. Our modeling approach is based on arbitrage cost models for constrained energy networks, accounting for the effects of zonal gas transmission rates as mandated by the U.S. Federal Energy Regulatory Commission. Application of our model to a data set of daily gas market outcomes and operating conditions on the Transco between 2012 and mid 2014 suggests that the modeled pipeline expansion would increase overall economic welfare in the spot market for Transco deliveries by $1.7 billion and have positive net social benefits of about $0.4 billion. However, more than 80% of this estimated welfare gain occurs in one season (winter 2014) featuring high gas demand due to colder weather. Thus, the spot market efficiency gains associated with pipeline projects in the Marcellus region may be limited by the frequency of extreme cold weather conditions. To examine the sensitivity of our estimates of welfare gains to different weather conditions, we calculate the expected benefits of the pipeline expansion in terms of historical temperatures from 1992 to 2011, and find that Atlantic Sunrise would have increased welfare by approximately $1.8 billion over a two and half year period, on average.