In 2013, the California Independent System Operator (CAISO) conducted an analysis to understand how increasing penetrations of renewable resources would impact grid conditions. The result was the iconic “duck curve” chart, which predicted that as variable generation grows so too will the trough of load served by conventional supply in midday. ScottMadden analyzes if actual results align with the original forecast in the new report: Revisiting the Duck Curve: An Exploration of Its Existence, Impact, and Migration Potential.

ScottMadden finds the duck curve is real and growing faster than expected. In addition, the analysis reveals some interesting, unexpected, and important nuances. In particular, the duck curve is:

• Producing net loads lower than forecast
• Increasing ramps throughout the year
• Most severe on the weekends
• Occurring in multiple seasons, not just spring months
• Driven by utility-scale solar in California, not distributed resources

“One of the most important implications is the duck curve may migrate to other parts of the U.S.,” said Greg Litra, partner and energy, clean tech, and sustainability research lead. “Growing numbers of utility-scale solar installations could mean that ‘the duck’ could migrate to states like Arizona, Georgia, Nevada, North Carolina, and Texas in the not-too-distant future.”

Overall, understanding the root cause and comprehensive impact of the duck curve is essential before developing strategies to address operational impacts. Solutions for a seasonal, weekend, utility-scale solar issue may well be different than solutions for an every day, distributed resource issue.

Additional Contributing Author: Paul Quinlan