Reliability Assessments
Each year, NERC is responsible for independently assessing and reporting on the overall reliability, adequacy, and associated risks that could impact the upcoming summer and winter seasons as well as the long-term, 10-year period. As emerging risks and potential impacts to reliability are identified, special assessments are conducted that provide similar technical framework and insights about the range and specific aspects of these to guide steps that may be warranted. Unbiased judgment of industry’s plans for maintaining electric reliability in the future are founded on solid engineering through collaborative and consensus-based assessments.
By identifying and quantifying emerging reliability issues, NERC is able to provide risk-informed recommendations and support a learning environment for industry to pursue improved reliability performance. These recommendations, along with the associated technical analysis, provide the basis for actionable enhancements to resource and transmission planning methods, planning and operating guidelines, and NERC Reliability Standards.
The Reliability Assessment group develops the following key ERO reports, which fulfill the statutory requirements of Section 215 in the Energy Policy Act of 2005.
  • Long-Term Reliability Assessments annually assess the adequacy of the Bulk Electric System in the United States and Canada over a 10-year period. The reports project electricity supply and demand, evaluate transmission system adequacy, and discuss key issues and trends that could affect reliability.
  • Summer and Winter Assessments assess the adequacy of electricity supplies in the United States and Canada for the upcoming summer and winter peak demand periods.
  • Special Assessments are conducted on a regional, interregional, or interconnection-wide basis, as needed.
  • Methods and Assumptions documents (provided below) include the methods and assumptions used in the development of the various assessments. This information is modified only as frequently as the assessment areas change or enhance processes for assessing reliability.

Additionally, the Reliability Assessments program coordinates forecast reliability data between planning areas, the seven Regional Entities, and governmental organizations through the Electricity Supply & Demand Database.

For more information, please send any questions or comments to
NERC WRA 2019_2020.pdf2019/2020 Winter Assessment11/21/2019
NERC_LTRA_2019.pdf2019 Long Term Reliability Assessment12/19/2019
NERC_SRA_2020.pdf2020 Summer Assessment6/2/2020
expand Header : Long-Term Reliability Assessments ‎(26)
expand Header : Methods and Assumptions ‎(5)
expand Header : Short-Term Reliability Assessments ‎(1)
expand Header : Special Assessments ‎(16)
expand Header : Special Assessments on Environmental Regulations ‎(12)
expand Header : Summer Assessments ‎(17)
expand Header : Variable Generation Assessments ‎(11)
expand Header : Winter Assessments ‎(16)