RIIA Analyzes Impact of Increased Use of Renewables

Evolutions in the use of various energy resources for generating electricity are moving toward more renewables (solar and wind), bringing about less use of coal-fired generators. How do increased renewables impact the reliability of the MISO grid? Is there a complexity inflection point as increased renewables are integrated into the system? These questions and many others are at the heart of a four-year technically rigorous analysis by MISO, informed by stakeholder discussions, known as the Renewable Integration Impact Assessment (RIIA).

“The report looks at the types, causes, magnitude and potential solutions for the challenges faced by increasing wind and solar integration in order to proactively address them,” according to MISO’s Jordan Bakke, senior manager, Policy Studies. “Managing the system with increased renewables penetration increases the variety and magnitude of the bulk electric system needs and risks. We all need to know what the challenges are, what is most difficult and what is needed to design a transition plan,” he added.

The report examines the impacts of increased solar and wind resources in the MISO footprint at 10% incremental steps up to 50%. MISO already sees growing renewables driving localized reliability risks and these risks likely will become footprint-wide once the system reaches more than 30% renewable penetration. “RIIA provides examples of integration challenges and examines potential solutions,” according to Aditya Jayam Prabhakar, principal engineer, Policy Studies at MISO. “How we prepare for those changes requires short-term and long-term solutions,” he added.

Three major technical areas were analyzed to understand the challenges of increasing renewable energy: resource adequacy, energy adequacy and operating reliability. This adds up to ensure there are sufficient resources to reliably serve demand in all operating hours and the ability to withstand unanticipated system disturbances. Everyone responsible for system reliability has an obligation to work collaboratively to address the challenges of grid reliability and MISO calls this the “Reliability Imperative.”

MISO is preparing now to adapt the existing planning, markets and operations’ constructs. This will meet the needs of the grid for now, with certain caveats. New and changing risks require coordinated and collaborative new practices to emerge. MISO sees that risk patterns for the grid are shifting and new risks are emerging with the increased penetration of renewables:

  • New Stability Risk requires multiple transmission technologies, operating and marketing tools to incentivize the availability of grid services
  • Shifting Periods of Grid Stress requires flexibility and innovation in transmission planning processes
  • Shifting Periods of Energy Shortage Risk requires new unit commitment tools, revised resource adequacy mechanisms
  • Shifting Flexibility Risk requires market products to incentivize flexible resources
  • Insufficient Transmission requires proactive regional transmission planning

“Transformational change is needed to enable efficient and reliable operations into the future, and MISO is committed to being the most reliable, value-creating RTO” Bakke observed.