UW Study Demonstrates Benefits of Pairing Wyoming and California Wind

A new University of Wyoming study further demonstrates that combining the strengths of Wyoming wind with California wind and solar will reduce the intermittency of renewable energy and smooth the power supply -- leading to benefits for utilities and energy consumers alike.

Conducted by UW’s Wind Energy Research Center, the study digs into the details of geographic diversity relative to renewable energy and is based on one year of actual one-minute average wind and solar electrical production data from California and data from four operating meteorological towers in Wyoming. This analysis builds on previous research based on general atmospheric and modeled data. The new study results were previewed June 11 at the Wyoming Infrastructure Authority’s Spring Energy Conference. The complete press release and study may be viewed at http://wyia.org/documents/reports/university-of-wyomings-phase-ii-geographic-diversity-study-for-delivering-wyoming-wind-to-california/.

Analyzing this precise wind data over the course of days and over the course of a year, the UW researchers confirmed that Wyoming and California wind patterns are not only very different, but also very complementary. Based on a yearly average, California wind is strongest at night, while Wyoming wind is strongest during the day and peaks in the afternoon -- coincident with the time when the sun is beginning to set while the electric load is still increasing into the evening hours.

“Although the benefits of geographic diversity to renewable energy have been suggested for some time, only recently have there been attempts to quantify these benefits,” says the study’s author, Jonathan Naughton, a UW professor of mechanical engineering and director of the Wind Energy Research Center. “The renewable energy quality metrics proposed in this study are a start at being able to characterize different combinations of renewable energy sources. The result of applying these metrics to energy produced from Wyoming wind and California renewables provides a quite compelling case for geographic diversity.”

Renewable energy power plants may be considered intermittent because their output depends on varying weather, wind and sun patterns. However, by combining different and complementary renewable resources -- also called diverse resources -- utilities can effectively smooth out the peaks and valleys of renewable energy production to ensure less variable and more predictable renewable energy supplies. This makes the energy grid easier to balance, minimizes ramping events and lowers operating costs.

“This Phase II study is yet another study that quantifies the benefits California ratepayers can achieve by integrating Wyoming’s world-class wind energy into the California Independent System Operator System (CAISO),” says Danny Curtin, director of the California Conference of Carpenters.

The study reflects that a less variable, more predictable grid will provide other benefits for California, including a decrease in water use; a decrease in greenhouse gas emissions; a decreased requirement for more costly energy storage; and reflects significant value of utilizing Wyoming wind vs. the addition of even more solar resources to the CAISO System. For example, the study looks at a scenario for adding incremental renewables to an existing portfolio and, when comparing Wyoming wind to more same-profile California solar, Wyoming wind would yield a 50 percent higher capacity factor; a 41 percent lower relative variability; and increase by 86 percent the amount of time in which power is producing at 25 percent or greater.

The study also proposes new ways to measure the performance of renewable energy plants, collectively called renewable energy quality metrics. Just like stock market investors have metrics and information to help guide their investment decisions, the study suggests that utilities need a more robust set of metrics to guide their renewable project investment decisions -- and to choose resources that not only work well and are cost-effective on their own, but also, and more important, that work well and are cost-effective when combined on the grid.

“Capacity factor alone does not fully describe a renewable resource or … the combination of renewable resources,” the report notes. How these quality metrics would benefit California’s electrical grid are outlined in a separate companion report by Jim Detmers, former COO of the California Independent System Operator Corporation.

The new UW study and the Detmers report are the latest in a string of reports that demonstrate the economic advantages of Wyoming wind for California, including a 2011 analysis that showed California consumers could save $600 million annually; UW’s Phase I Geographic Diversity Study in 2013 that showed cost savings by boosting resource diversity; and a 2014 analysis that showed up to $1 billion in annual savings to California by tapping Wyoming wind resources.

“As California moves toward mandating the use of more renewable energy, the families and individuals paying those monthly electricity bills would agree that the best and most beneficial types of renewable energy sources are the ones that should be used,” says Loyd Drain, executive director of the Wyoming Infrastructure Authority. “Collectively, the findings within these studies are consistent and clear. Incorporating diverse, cost-effective Wyoming wind into California’s power grid will help California best protect their consumers and enhance their economy. Wyoming energy can help California citizens save literally billions of dollars over time on their electric bills, freeing up such money that can be spent on other goods and services to further benefit California’s economy.”