The US bulk power system operated reliably in 2020 despite unprecedented challenges ranging from a global pandemic to extreme weather events, according to the North American Electric Reliability Corp.
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NERC determined that the performance trends of generation, transmission, and protection and control systems were "generally positive," especially considering the challenges the grid faced in 2020, according to NERC's new report, the 2021 State of Reliability: An Assessment of 2020 Bulk Power System Performance.
Over the course of the year, the system withstood a global pandemic, cybersecurity threats, extreme weather events and supply chain issues. And all the while, the grid was "transforming at an incredible pace" to accommodate more variable energy sources, such as wind and solar generators, the regulatory authority said.
"While the full impact of the pandemic will not be known for some time, there is no evidence to suggest that the pandemic adversely affected the reliability of the [bulk power system] in 2020," NERC said. "Instead, there is ample evidence to suggest that advance planning by the industry and the consistent execution of these plans was highly successful in addressing the unprecedented reliability operating challenges caused by the pandemic."
Climate impacts worsen
However, due largely to Hurricane Laura, western wildfires and the California heat wave, firm load saw significant interruptions in 2020. Such disasters forced operators to shed load, resulting in more hours of localized load loss than the prior four years combined.
While many system metrics improved or remained stable year over year, the increase in load shedding is one of the most important trends, John Moura, director of NERC's reliability assessment and performance analysis, told reporters during an Aug. 17 webinar. It signifies that grid operators ran out of all other options to maintain the system's reliability, the official said.
"I think it is indicative of some of the trends both in how we have changed our resource mix very rapidly but also how extreme weather is increasingly impacting the system," Moura said.
Severe 2020 weather events, from hurricanes to cold weather, also led to the highest level of AC circuit unavailability in the last five years, NERC said. However, last year's level would have been more consistent with previous years' without those extreme events.
Planning for more frequent extreme weather events is the "reliability challenge of our lifetime," Moura said.
"Weather and the climate is the most important factor of the electric system," Moura said.
Other 2020 trends
Texas and regions of the Western Interconnection face "energy and resource adequacy issues," NERC said. Texas was able to meet peak demand levels during the summer of 2020, partially due to mild weather, but the "underlying resource mix and forecasts of future loads remain a significant resource and energy adequacy concern," NERC said.
NERC and the Federal Energy Regulatory Commission are working on a joint inquiry into how the February 2021 cold snap affected the bulk power system. In its 2021 Long-Term Reliability Assessment, which is slated to be published in December, NERC will evaluate the system's longer-term reliability issues. NERC plans to include an evaluation of the system's impacts in its 2022 State of Reliability report as well.
In its Aug. 17 report, NERC also said that the threat of cyberattacks are causing "significant concern," given the growing "threat landscape" that involves supply chain risks and ransomware from adversaries. But while cyberthreats have grown, more and more companies have voluntarily reported incidents, contributing to more information-sharing within the industry, NERC said. In 2020, the industry did not report a single cyber or physical security event that resulted in a loss of load.
On the transmission front, NERC determined that there has been an "improving trend" in the last five years showing that transmission outages "resulted in less severe reliability impacts." Last year, large weather-related event restoration helped with the resiliency of the bulk power system.
In 2020, the electric grid saw reduced rates of protection system misoperation, which "exacerbate the severity of transmission outages," continuing a positive trend seen over the last few years, NERC said.
Among its recommendations, NERC suggested that the industry develop and use comparative metrics to better evaluate the electricity system's "different dimensions of resilience," including disaster recovery and preparation.
Also, the organization recommended that system planners better examine flexibility impacts, including those on the interconnection level, as generators are retired and critical transmission paths are lost.
To help mitigate security threats, NERC also called on the industry and government to more quickly share detailed information regarding cyber and physical threats. Such an endeavor should include a review of security standards, risk assessments and supply chains.