Kauai Island Utility Cooperative: The Impact of Extensive Photovoltaic Penetration

This case study focuses on the challenge faced by Kauai Island Utility Cooperative to maximize the contribution of low-cost solar and other valuable renewable resources while maintaining grid reliability and frequency control.

Case Study

Kauai Island Utility Cooperative: The Impact of Extensive Photovoltaic Penetration (Lovas 2015)
The experience of Kauai Island Utility Cooperative from this rapid growth of solar power on Kauai Island provides a rich source of reference material on the impact of extensive distributed energy resource penetration that may help guide others.

Topics Covered

The topics addressed in this case study are:

  • System details
  • Renewable portfolio summary
  • Categories of consumer-owned renewables agreements
  • Administrative, technical, and financial challenges of high renewable penetration
  • Lessons learned.

Key Takeaways

Monitor Deployments

Monitor the progress of interconnection applications through the use of process checklists to accomplish safe and coordinated interconnection, as well as to ensure administrative oversight of the process. Establish a database of the installed systems as soon as possible, so that engineers can track system details individually and in the aggregate. Knowing the capacity of each system will enable the utility to better support capacity planning and estimate on-site solar contribution to system energy requirements.

Managing Variability

When clouds pass over a photovoltaic system, it decreases output significantly—as much as 90%, depending on the severity of the cloud cover. This change can occur in less than one minute and can occur many times throughout the day. The case study outlines Kauai Island Utility Cooperative's portfolio approach to manage variability through a combination of batteries and conventional generating units, with droop control.


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