R&D Update - Sodar Project Moving Forward
The WindLogics Sciences Center recently completed its initial evaluation of Sodar wind measurement technology. The ground-based instruments promise to provide useful measurements of winds at turbine hub heights and beyond.
The results revealed shear in tree-covered northern Minnesota beyond the levels that would be predicted by standard shear analyses. In particular, standard values of the wind power law exponents, if used to extrapolate wind speed from met tower heights, would significantly underestimate the nighttime hub-height wind speeds at the test site.
This graph shows the mean diurnal (daily) cycle of winds based on the recently completed two-month Sodar deployment. The wind shear is very large at night (the lines spread apart). At sunrise, the insolation (solar heating) mixes the lower atmosphere, reducing the shear during the day. Note also that the upper levels (above 100 meters) seem to indicate negative shear during the daytime hours. This occurrence is likely from ambient noise generated by the wind in the forest canopy (which reduces measurement quality at the highest measurement levels) rather than an actual effect.
The Sodar units were recently moved to the NextEra Energy wind plant in Mower County, Minnesota to begin a field measurement campaign for a research project that was awarded to the University of Minnesota, WindLogics and Barr Engineering by the Xcel Renewable Development Fund. Bob Conzemius, Senior Atmospheric Scientist, is leading this effort. For more on this project, please read our July 21 issue.
Industry Involvement - UWIG Fall Workshop
Utility Wind Integration Group Fall Technical Workshop Over 100 utility personnel met in Cedar Rapids, Iowa, during the first week in October for an update on utility wind integration developments. Cathy Finley, Senior Atmospheric Scientist, contributed to the workshop with a presentation on ramp event forecasting, focusing on the meteorology behind these sudden changes in conditions and the challenges in forecasting them.
New this year was a utility-scale photovoltaic (PV) variability workshop, examining methods of improving understanding of PV plant variability and its impact on utility planning and operations. As part of this discussion, Mark Ahlstrom led a presentation on solar resource forecasting covering the current state of the art, challenges and opportunities for improvement, and integrating solar into utility operations.
To view both Cathy's and Mark's presentations, please visit Wind Energy Resources.
WindLogics in the News - Power Engineering
The September issue of Power Engineering featured Mark Ahlstrom's perspective on utility wind integration in the magazine's View on Renewables page. In the article, Mark discusses the evolution of thought and progress in renewable energy integration within the utility industry. Please visit Power Engineering online to read the entire article.