Above: The Magenn Air Rotor System (MARS) is one of the leading high-altitude designs for capturing wind power.

Scientist Compiles Data on High-Altitude Wind as Renewable Energy Source

Cristina Archer, Geological and Environmental Sciences, has collaborated with Ken Caldeira of the Carnegie Institution’s Department of Global Ecology to compile the first-ever global survey of wind energy at high altitudes.

Archer is a world expert in wind power and has done considerable research on mapping the wind resource near the ground. Also a meteorologist, Archer is interested in large-scale flows in the atmosphere. She is the author of a paper on jet streams and how they are slowly shifting toward the earth’s poles. Archer said, “Linking wind power and jet streams was a natural evolution in my research. Ken Caldeira, who was my former supervisor at the Department of Global Ecology, had looked at high-altitude winds in the past and was interested in moving forward with this idea, so we agreed to collaborate on the research.”

The two researchers used 28 years of public data from the National Center for Environmental Prediction and the Department of Energy to assess the potential for wind power. They transformed the data in such a way that they could extract information regarding wind-power density at each level in the atmosphere.

In an article on Archer’s research in the online journal ScienceDaily on June 16, 2009, jet streams were described as “meandering belts of fast winds at altitudes between 20,000 and 50,000 feet that shift seasonally, but otherwise are persistent features in the atmosphere.” Jet streams have great potential for energy production because they are large (usually a few hundred miles wide and almost three miles thick), persistent, and can reach speeds between 57 and 300 miles per hour.

Since the release of their findings, Archer has done a dozen interviews with a variety of journalists and media representatives. “What was surprising,” said Archer, “was that almost everybody asked the same question: How long before this new technology becomes commercially available? And the answer is still unknown, but no fewer than 10 years.”

Cristina Archer

Before the release of this data, Archer guesses that other researchers and innovators of devices to use wind energy in the upper atmosphere used sounding balloon data and “gridded reanalyses,” all of which is at fixed pressure levels, not fixed altitudes.

Archer said that before their analysis, scientists did not know what the wind resource was at constant altitude levels and how reliable such winds are. “This is useful,” she said, “because the high-altitude companies need to know how long their tethers need to be to reach the high winds. Also, there is a general understanding that high-altitude winds are steady and strong all the time, which is actually not the case, unfortunately. Even at high altitudes, winds can die down or be too weak to be harnessed at times.”

Archer is organizing the first high-altitude wind power conference here in Butte County, hosted in part at the This Way to Sustainability conference and in part at the Regional Energy Advancement Program center in Oroville in November. At these two venues, many of the start-ups in high-altitude wind power will present their ideas and show videos of their prototypes.

There are potential positive economic implications for Northern California, as it is a good location for harnessing high-altitude wind power, said Archer. “Having Butte County as a center for high-altitude wind power would attract high-tech jobs and cutting-edge research.”

Archer received her MS in civil and environmental engineering in 1995 from the Politecnico di Milano in Milan, Italy, and a second MS in meteorology from San Jose State University in 1998. She then started her PhD in civil and environmental engineering at Stanford University, where her thesis work focused on the Santa Cruz Eddy, a vortex that forms over the Monterey Bay, as well as on wind-power resource assessment for the United States and the world.

Archer will present “The Role of Wind Power in a Clean and Renewable Future” on Wednesday, Sept. 30, at 7:30 pm as part of the Museum Without Walls Lecture Series. The series runs from Sept. 23 through Oct. 21 Wednesday nights at the Chico Area Recreation District Center, 545 Vallombrosa Ave., Chico.

—Kathleen McPartland, Public Affairs and Publications