North America's electric reliability organization has released its long-term reliability study, recommending that U.S. regulators recognize coal and nuclear generation's reliability and resilience attributes.
The Federal Energy Regulatory Commission recently was given a 30-day extension of its deadline for considering a U.S. Department of Energy proposal aimed at shoring up financially struggling nuclear and coal-fired generating units. The North American Electric Reliability Corp. released its "2017 Long-Term Reliability Assessment" on Dec. 14, calling on FERC to recognize the reliability and resilience attributes of coal and nuclear generation as well as to back new market rules that support "essential" reliability services of generating electric resources.
John Moura, NERC's director of reliability assessment and system analysis, explained in a webinar that the reliability services and "on-site" fuel assurance offered by coal and nuclear power plants helps maintain a highly reliable and resilient bulk power system as generation mixes rapidly shift towards natural gas and renewables.
"We don't have the authority, or really the view, as to how the market should address that [resilience need], but we know, and our view is, that they need to address it," said Moura.
While reserve margins are expected to remain adequate through 2022 across the continental U.S.; most of Canada; and Baja, Mexico, NERC said recent retirements of conventional generation in Texas and the cancellation of the expansion of the V.C. Summer nuclear plant in South Carolina will lead to reserve margins dropping below their recommended levels for Texas and the southeast U.S. starting in 2018 and 2020, respectively.
The growing reliance on natural gas-fired generation and intermittent renewables "can actually increase the amount of reserve margin targets that you need to maintain the same level of reliability," said Moura. "As more conventional resources are retired, … our measuring stick to determine whether resources are adequate … is evolving."
NERC also said all new generation resources should be capable of voltage and frequency support and encouraged transmission planners and operators to identify and study expected reliability issues resulting from disruptions in the flow of natural gas supplies. NERC also cautioned policymakers about the long lead times in building transmission, generation and gas infrastructure, especially for new right-of-way projects.
NERC expressed concern over the grid's growing reliance on natural gas-fired generation, especially in markets that lack fuel assurance incentives and requirements, such as mandates for dual-fuel capabilities, liquefied natural gas contracts and firm gas supplies on pipelines to meet wintertime peak demand.
"Areas can have and can rely on large amounts of natural gas as long as they have fuel assurance mechanisms," Moura said. For instance, between 2012 and 2015, most of Florida experienced only one day with a gas-fired outage due to fuel disruptions. In contrast, the ReliabilityFirst Corp. region, centered around the Midwest and Pennsylvania, suffered 533 days of gas generator outages during that same period, including losing nearly 12,000 MW of natural gas-fired generation during the 2014 polar vortex.
While natural gas-fired generation has increased to 442 GW from 280 GW in 2009, with an additional 44.6 GW planned in the coming decade, NERC expects solar to grow by a projected 37 GW by 2022, 20 GW of which would be distributed generation.
Mandated renewable generation mix and target date by U.S. state.
That growth of distributed energy resources raises visibility concerns for system planners, the report said. "It's more than just knowing how much is behind the meter and how much is being installed," explained Moura. He said grid operators need to collect more specific information, including where DER resources are located, their technology and manufacturer to determine capabilities, protection settings and voltage ranges that the resources can operate in.
Regional reliability entities in areas with high levels of DER penetration, such as Ontario and California, recommend that other markets start collecting this information now, Moura said. "The forward curve on DER, it doesn't stop," he said. "It really is a call of action to start that data collection now so that by the time you get into an area where you're concerned, you've got the lay of the land."