Assessment of Reliability and Operational Issues for Integration of Renewable Generation

California has led the nation in the development of renewable resources. The California Renewables Portfolio Standard was passed by the California legislature in September 2002, mandating that energy production from renewable resources account for 20 percent of annual energy production by 2017. In May 2003, the California Energy Commission, California Public Utilities Commission, and the California Power and Conservation Financing Authority called for the acceleration of that timetable by setting the goal of 20 percent by 2010 with adoption of the Energy Action Plan.

Renewable resources offer the benefits of price stability, resource diversity, reduced dependence on fossil fuels, and reduction in environmental impacts. These benefits are important for California consumers. Prudent facilitation of a substantial increase in renewables requires proactive identification, analysis, and development of options to address potential operational and resource integration issues that might otherwise hinder and delay achievement of statewide policy goals for renewable development.

This study is based on a review of experiences and best practices of other regions that have integrated large amounts of renewables, input from grid operators and stakeholders in California, and analysis of the impact of renewables integration on key operating metrics. The study identified nine specific operational and reliability issues that must be addressed to ensure successful integration of an expanded renewables portfolio. These issues are:

1. Load Following
2. Minimum Loads
3. Reserves and Ramping
4. Load and Generation Forecast Variability
5. Storage
6. Frequency and Voltage Requirements
7. Resource Deliverability
8. Transmission Import Capability
9. Planning and Modeling