Wind and solar energy droughts

In Solar News

Wind and solar energy droughts across the Continental United States

Researchers at Pacific Northwest National Laboratory (PNNL) have recently cautioned that certain regions in the United States may face “energy droughts” lasting nearly a week, as outlined in their newly published paper.

These “compound energy droughts” occur when renewable energy generation comes to a halt—specifically, during periods when both the sun isn’t shining and the wind isn’t blowing. The paper, titled “Standardized Benchmark of Historical Compound Wind and Solar Energy Droughts across the Continental United States,” emphasizes the potential impact of these occurrences on an unprepared grid.

Cameron Bracken, the lead author and an Earth scientist at PNNL, points out the substantial consequences of energy droughts on a grid heavily dependent on solar and wind power in a fully decarbonized scenario. The researchers stress the importance of grid operators anticipating these energy droughts, allowing them to adjust by drawing energy from different sources. Knowing when and where these events occur and understanding their duration can inform grid-level battery planning to store sufficient electricity and offset potential losses.

While previous studies focused on state and regional scales, PNNL’s research stands out for its nationwide perspective. Using four decades of hourly weather data for the continental U.S., the team pinpointed geographical areas with existing solar and wind energy plants. By analyzing wind speeds, solar energy intensity, and historical energy demand data, the researchers identified instances of stagnant air and cloudy conditions leading to lower energy generation—a compound energy drought.

The study unveils that energy droughts can manifest across the continental United States in any season, with varying frequency and duration. For instance, California experiences extended periods of cloudy and windless conditions lasting several days, while Texas encounters similar conditions but for shorter durations. States like Utah, Colorado, and Kansas frequently face energy droughts on both short and extended timescales. The Pacific Northwest and Northeast exhibit more frequent short-term energy droughts.

Acknowledging that the absence of wind and solar power generation in specific areas doesn’t imply a complete halt, as alternative sources like hydropower or fossil fuels may compensate. However, with the ongoing energy transition, PNNL underscores the importance of assessing whether energy droughts coincide with periods of high electricity demand surpassing supply.

Bracken notes that wind and solar droughts tend to align with peak demand events more often than expected by chance. Although he suggests potential meteorological factors, such as inversions suppressing wind and increasing temperatures, as contributing to this correlation, further investigation is needed.

Looking ahead, PNNL researchers plan to explore the impact of climate change on the frequency and duration of energy droughts by examining future weather and demand data. Their future work aims to model energy droughts through the end of the century.

In conclusion, the study highlights the crucial role of solar storage batteries in mitigating the impact of energy droughts. As the world transitions towards renewable energy, the ability to store excess energy during peak production times becomes paramount. Solar storage batteries ensure a continuous and reliable energy supply, reducing the vulnerability of grids to the challenges posed by compound energy droughts. Looking ahead, PNNL researchers plan to explore the impact of climate change on the frequency and duration of energy droughts, emphasizing the need for resilient energy storage solutions to support a sustainable and dependable energy future.