Solar energy use is on the rise, and as this technology becomes more integrated into our power grid, the duck curve becomes increasingly relevant. What is the duck curve? Who came up with it? How does the duck curve work?
Here’s everything you need to know about the duck curve and what it means for combined power plants.
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What Is the Duck Curve?
So named because the line graph image resembles a duck’s profile, the duck curve was first implemented in California and is now widely used to gauge and regulate energy availability. Essentially, it’s the method used to gauge the availability of energy over 24-hour periods, and it helps to prevent power shortages by utilizing available energy sources appropriately.
History of the Duck Curve
Developed in 2008 by the National Renewable Energy Laboratory (NREL), the duck curve is the standard for tracking solar energy availability.
Recognizing the potential for a decrease in cost for photovoltaics (PVs), which would spark increased usage of solar cells, the NREL began researching usage patterns with the goal of anticipating the challenges presented by integrating solar energy. They released a report examining the future of solar integration and how to plan for this large-scale adaptation to the electric grid.
The report, along with the graph now known as the duck curve, is an efficient and accurate tool for recognizing those challenges and creating solutions. Now for more than a decade, the duck curve has provided a way for energy providers to anticipate variances and improve reliability.
The earliest version of this chart was adopted and given its name by the California Independent System Operator (CAISO). Because California was early to adopt solar technology, CAISO was able to apply the chart in a real environment. With long periods of moderate weather and low energy use, CAISO could now analyze electricity use and set goals for integration based on the supply of electricity in accordance with the demand.
California was an ideal testing ground for the duck curve for two reasons: early integration of solar energy and periods of low energy use due to moderate temperatures. The duck curve represents a 24-hour day of electricity use. CAISO analyzes the results during springtime when demand for air-conditioning and heat is low.
How Does the Duck Curve Work?
Solar energy is, by definition, dependent on the sun. Photovoltaics (PVs), which convert light into energy, do most of their work when the sun is up.
Most people recognize PVs by the most common example, solar cells. When the sun goes down, the availability of solar energy available to the power grid decreases significantly. The duck curve was created to chart these variances in availability and provide a data history in order to foster continuity of electrical capacity.
The duck curve serves as an evolving source of data, analysis, and tools to apply to the practical deployment of PVs and the most effective use of their contributions. By providing data on the supply of solar energy available, it offers a real-time resource for anticipating and addressing drops in PV output.
The cost of solar technology has dropped dramatically in the last decade, creating a rapid rise in solar energy use. Integrating solar energy highlights the need to address significant dips in solar availability and the potential overcollection of solar energy during peak daylight hours. Additionally, utilities must address the strain on generators to quickly make up for the dip in contribution from PVs when the sun goes down and demand peaks.
Currently, inconsistencies often require limiting PV generation. This isn’t a good long-term solution, as it can limit the environmental and economic benefits of PV applications. Solar energy has shifted from niche technology to a valuable component in our energy landscape, and we’re currently in transition. The duck curve has been a useful tool to keep utilities on track as energy sources and demands evolve.
Duck Curve Solutions
Researchers and utilities are focusing on storage solutions. The duck curve clearly shows potential periods of overproduction, reducing the efficiency and environmental benefits of solar technology. Storage of PV surplus contributions will clear the way for further integration of energy sources, strengthening the utility grid overall.
While storage solutions aim to “flatten” the curve, another solution is to “fatten” the belly by increasing the system’s flexibility, with more frequent power plant cycling and other operational elements. Both solutions are being applied and analyzed throughout the United States.
As utilities and researchers continue to develop programs to help predict solar generation patterns, PV installations are expected to triple by 2030, bringing the duck curve to relevance across the country as a vital tool for maximizing solar energy production.
Combined power plants are putting all this rigorous work into action. As more PVs are deployed, power plants must be able to integrate them smoothly and effectively. The real value of the duck curve is in its contribution to the ability of power plants to bring benefits to consumers.
The Future of Integrated Energy
Over the last decade, the duck curve has shown us a few things about how energy distribution and use will look. Solar energy is no longer just a contender in the future; it’s a major player with some challenges and a potentially big payoff for the economy and the environment. Thanks to the duck curve, combined cycle power plants can set a path for the responsible integration of our energy sources.
The forward-thinking analytics that are the foundation of the duck curve, and over ten years of rigorous use of the data and tools within, promise a bright future for integrating solar energy with our electric grids. PV implementation continues to increase at a record pace, and due to continued focus on the duck curve, combined cycle power plants will be able to successfully merge technologies with the benefit of over ten years of analysis.
Making such a major change to a system as complicated as the power grid is no small undertaking, but the duck curve is evidence that keeping an analytical eye on the potential challenges of emerging technologies pays off when it comes to creating innovative solutions.
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