This collaboration between GridLab and Telos Energy was motivated by the need to answer a critical question: Do current rules for interconnecting power plants to the grid reflect how those plants contribute towards resource adequacy and help keep the lights on during periods of short supply?

To be eligible for inclusion in capacity markets and resource adequacy programs, a power plant must have full transmission deliverability status. This entails a “deliverability study” that assesses whether the output from the power plant can be allowed onto the transmission system without curtailment. If a power plant “passes” this test, it can obtain deliverability status and be compensated for providing capacity. Power plants that are not deliverable cannot secure “firm” transmission rights and are labeled “energy-only.” Energy-only plants are generally unable to participate in capacity markets or resource adequacy programs, and their contributions to the power system are artificially limited in resource adequacy studies (loss of load expectation models) that determine the quantity of resources needed to keep the lights on, and also determine capacity value or accreditation of other resources..

Consequently, the technical assumptions made during a power plant’s interconnection process goes beyond the compensation of an individual power plant and directly dictate the quantity of new resources that the entire region needs, it’s resource mix, and market costs.

Despite the significant financial and reliability impact of these assumptions, there has been little research into whether they align with how power plants perform during real-world grid emergencies, such as extreme weather events. Using PJM as a case study, this study tests those assumptions, quantifying how these grid-connection rules affect the total amount of power a region is required to buy; whether transmission congestion limits the ability of resources to deliver during risky periods; and how we accredit power plants for their contributions to resource adequacy.