IEEE Power & Energy Magazine - November/December 2014 - 79

By Richard Levitan, Sara Wilmer, and Richard Carlson

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U

november/december 2014

Uncertainties sUrroUnding the continUed
operation of older coal generation units, the increased penetration of renewable resources, and the aging or retirement of certain nuclear units have exposed vulnerabilities in the natural
gas supply chain. the increased availability and low price of
natural gas for electric generation in many parts of the United
states compounds them by increasing the economic pressure
on various non-gas-fired base-load generation plants. our
growing dependence on natural gas as a primary fuel for electricity generation offers environmental and efficiency benefits,
but it also presents operational challenges for independent system operators (isos) and regional transmission organizations
(rtos) that depend on the natural gas pipeline and storage network to facilitate reliability objectives. during the peak heating
season, pipeline congestion can result in interruptions of gas
deliveries to those gas-fired generators lacking primary firm
entitlements. scheduling restrictions associated with the provision of nonfirm transportation for gas-fired generators stress
the capability of the electric system to meet demand and maintain operating reserves, as rtos must quickly replace output
from more efficient natural gas-fueled combined-cycle plants
and quick-start peakers to maintain electric reliability. in this
article, we address the gas-electric interdependencies across
the eastern interconnection that are the subject of a multitarget
research project sponsored by the U.s. department of energy
(doe) with the participation of PJM interconnection, Midcontinent independent system operator (Miso), new York
independent system operator (nYiso), iso new england
(iso-ne), tVa, and the independent electricity system operator of ontario (ieso), collectively known as the participating
planning authorities (PPas).
constraints on natural gas deliverability have been
observed sporadically for several years. From 3 to 7 January
2014 and then again in the last week of that month, frigid
arctic air masses blanketed much of the eastern United
states. Meteorologists have referred to such frigid arctic
air masses as examples of the "polar vortex," a name that
has since stuck in planning circles, making it overnight into
the lexicon of gas-electric interdependencies. of critical
importance, this study is all about seeing how the natural
gas supply chain flexes when stressed. the polar vortex and
subsequent vortex-like events highlighted the gas-electric
interdependencies that electric planners and system operators assess in safeguarding the reliability of the electric grid.
since the early 2000s, there has been heightened regulatory interest on the part of the doe, the Federal energy
Digital Object Identifier 10.1109/MPE.2014.2347632
Date of publication: 20 October 2014

ieee power & energy magazine

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Table of Contents for the Digital Edition of IEEE Power & Energy Magazine - November/December 2014
