As Solar Capacity Grows, Duck Curves are Getting Deeper in California
Overview
Source: U.S. Energy Information Administration (EIA)
Published: June 21, 2023
Focus: Impact of increasing solar capacity on net load demand in California
Introduction to the Duck Curve
Duck Curve Definition: A graph showing the drop in net load (electricity demand minus renewable generation) during midday and steep increase in the evening, resembling a duck's shape.
Origin: Named for the pattern observed when solar generation is highest at midday.
Solar Capacity Growth in California
More Solar Online: Increased solar capacity observed by the California Independent System Operator (CAISO).
Impact on Net Load: Decrease in net load during midday when solar output peaks.
Challenges: Grid operators face difficulties as the midday net load dips lower.
Power Demand Patterns
Demand Fluctuations:
Lowest during the night
Increases in the morning, stays elevated during the day
Spikes in the evening as residential consumption increases
Drops again late at night
Challenges Posed by Duck Curves
Grid Stress:
Rapid ramp-up in demand post-sunset requires quick response from conventional power plants.
Increased difficulty in matching supply and demand due to these fluctuations.
Economic Impacts:
Reduced operation times for dispatchable power plants result in decreased energy revenues.
Potential for plant retirements without replacements affects grid stability.
Opportunities from Duck Curves
Energy Storage Solutions:
Storing solar energy generated during the day to use at night flattens the curve.
Battery storage is rapidly expanding in California.
From 0.2 GW in 2018 to 4.9 GW by April 2023.
Plans to add 4.5 GW more by end of year.
Broader Implications
Not Limited to California: Duck curves are emerging nationally and internationally where solar generation is rising.