During May, the North American Electric Reliability Council (NERC) released the 2015 Summer Reliability Assessment. This annual assessment provides an independent forecast on the adequacy of generation resources and transmission systems required to meet projected summer peak demands in North America. While the report provides a total assessment of North America, it also analyzes each region that makes up the North American electricity grid.
The executive summary pointed to four key findings, 1. There are sufficient generation and demand-side resources in place to meet summer peak demand. 2. Coal-fired generating plant retirements combined with additional natural gas electricity generation and intermittent electricity resources (read renewables) are changing the generating resource mix. 3. The California drought is not expected to impact the Bulk Power System and 4. The shifting natural gas infrastructure and outages in New England are not expected to impact summer reliability there.
More important to Midwest power users is the impact of item two above. With the April 2015 implementation of the Mercury and Air Toxic Standard (MATS) causing the actual/impending retirement of many coalbased generating facilities in the Midwest, the interplay between natural gas pricing and delivery and electricity becomes very important. While the retirements are not expected to cause the planning reserve margins for PJM and the Midwest System Operator (MISO) to decline below the NERC Reference level, there is less resource capacity in total in the Midwest as compared to recent summers.
In the report is an analysis that focuses on operational risks to the bulk power system. NERC tested each region/Independent System Operator (ISO) under two scenarios, normal and severe load. The severe load scenario provides an insight into low probability conditions that could pose a threat to system stability.
The conclusion from these tests was that while severe load conditions in PJM would cause an operational concern, these problems could be mitigated by Demand Response, additional power purchases, voltage reduction and public appeal before actually shedding load. The same severe load tests in MISO showed that Demand Response would be needed in an extreme scenario and it was determined that there are enough demand response resources to manage such a scenario.
