NERC (North American Electric Reliability Corporation) "a not-for-profit international regulatory authority whose mission is to assure the reliability of the bulk power system in North America." 

2014–2015 Winter Reliability Assessment (November 2014)

• "The U.S. capacity from gas-fired generation increased by almost 5 GW since last year; however, only 252 miles of new pipeline (4.5 Bcf) were added in 2012—the lowest pipeline addition since 1997. More than half of new pipeline projects that entered commercial service in 2012 and 2013 were in the Northeast, but most of that capacity was added outside of New England’s constrained areas, where there is an increasing reliance on gas-fired generation. Announcements for new pipeline capacity from 2014 through 2016 show infrastructure enhancements to pipelines in the Northeast, but these projects do not alleviate the constraints across the New England interface. Therefore, from a natural gas availability perspective, similar conditions as last year can be expected. For New England, this includes the potential for natural gas interruption to gas-fired generators and a reliance on backup fuel (generally oil) to meet peak demand.”
• "… The [Bulk Power System’s] effectiveness at responding to unusually high stress depends on how prolonged and extreme the weather is, the region it is affecting, and what the resource mix is. For example, New England (and other areas with significant amounts of natural gas) may be vulnerable to extreme cold weather, particularly if many of the natural gas power plants have interruptible (or non-Firm) natural gas transportation services. During the 2013–2014 winter, ISO-NE lost more than 8,000 MW of gas-fired generation during its peak hour (Figure 3). A majority of the generators that were unavailable were forced out of service due to a lack of fuel, which stemmed from the non-Firm fuel delivery arrangements. While significant progress has been and is being made to address these concerns, the risk extends through the upcoming winter period, as a significant amount of additional pipeline capacity has not been constructed in the past year.”

• "State and federal environmental regulations combined with low natural gas prices have prompted a number of coal and nuclear generation retirements, resulting in greater reliance on gas-fired generation. This may pose a reliability challenge, given that most generators in the Northeast do not have firm capacity on pipelines for a number of reasons, such as economics. New England and some other Eastern Interconnection regions witnessed a number of cold snaps that increased energy consumption last winter. In addition, many generators could not access fuel supplies or had operational issues because of extreme weather conditions or after prolonged operations at peak capacity. New England has performed gas studies and other plans to address the issue in New England."

• "Thorough harmonized efforts between electric and gas sectors are needed in order to meet future infrastructure needs to supply and transport fuel. System planners in certain areas (i.e., those with high levels of natural-gas-fired resources) should examine system reliability needs to determine if more Firm fuel transportation or units with dual-fuel capability are needed. Additionally, fuel availability and deliverability should be specifically considered and integrated into resource adequacy and other planning assessments. This calls for a new approach to assess reliability given the potential energy limitations of natural-gas-fired generation without firm fuel commitments.”

• "Although the ISO-NE’s load curve has changed during the spring and fall due to the effect of behind-the-meter solar generation, this will not be a factor in 2014–2015 winter except during off-peak hours. The demand forecast has not changed significantly since last winter. New England did experience periods of extremely low temperatures and, if it experiences similar periods of low temperatures this winter, could expect the winter peak load to be higher than last year. ISO-NE has seen a significant decrease in its winter peak load since the region’s record peak load in January of 2004 due to the effects of the recession and energy-efficiency measures fostered by the six New England states."
• "Eight generators will have retired by the end of 2014, which accounts for a loss of 1,827 MW since the 2013–2014 winter assessment. Seven of these are fossil-fired generators, and one is a nuclear power plant. ISO-NE anticipates that the retirement of these non-gas-fired generators will further aggravate the existing natural gas pipeline constraints. New generation, totaling 10 MW (40.2 MW nameplate) of renewable energy is forecast to be available during the 2014–2015 winter assessment."
• "ISO-NE anticipates the potential for various amounts of single-fuel, gas-only power plants to be temporarily unavailable during cold or extreme winter weather conditions or during force majeure conditions on the regional gas grid. New England projects that up to 4,254 MW of natural-gas-fired capacity will most likely be at risk for this winter period. It is accounted for within the Existing-Other category. New England could experience higher rates of gas-fired generator outages if large gas infrastructure contingencies or non-gas-fired electrical contingencies occur. The ISO-NE long- and short-term outage coordination efforts evaluate and account for gas-fired generation at risk, and ISO-NE would balance the mitigation of these scenarios with real-time supplemental commitment and use of emergency procedures, as needed.”

Polar Vortex Review, (September 2014)