Wind Speeds Elevated Across the US in Q2 2011

3TIER’s Analysis Shows Influence of Climate on Wind Power

3TIER®, a global leader in renewable energy risk analysis, today released a wind performance map for the second quarter of 2011. The map illustrates that wind speeds were above their seasonal averages for a majority of the continental United States.

3TIER’s second quarter map indicates departures from long-term mean wind speeds that range from -20% to +20% and provides an indication of how wind projects should have performed relative to their long-term production average based on their location. This type of analysis enables financiers and owners to perform portfolio analysis across regions and quickly view the effects of weather anomalies on both existing and proposed investments.

Looking at wind speeds during the second quarter of 2011, the pattern is 5 – 10% above normal for nearly the entire US. Especially strong positive wind anomalies centered over the southern Mississippi Valley and the southern Rocky Mountains. Some areas within these regions exceeded 25% above normal wind speeds when averaged over all of April, May, and June.

The only areas that experienced wind speed conditions below average were North Dakota along the Canadian border, isolated areas of California, and along the Carolina coast down through Florida. These areas saw minor negative anomalies of about 5% with the exception of Florida where wind speeds were up to 15% below normal.

Climate conditions across North America during the second quarter of 2011 were influenced by a weakening of the La Niña event that occurred this past winter in the tropical Pacific Ocean, leading to neutral El Niño/Southern Oscillation (ENSO) conditions by the end of the quarter. This quarter was also affected by a gradual transition in the Arctic Oscillation (AO) and North Atlantic Oscillation (NAO) from a positive state at the start of the quarter to a negative state at the end.

However, the dominant feature of the second quarter across the US was a stronger pressure gradient and thus much higher than normal winds over the south-central part of the country. The unusually strong pressure gradient resulted from three anomalous patterns that developed during the quarter: an upper-level trough over the northwestern United States, associated low surface pressure in the northern Great Plains, and high surface pressure over the Southeast.

The wind performance map was created by comparing output from 3TIER’s continually updated meteorological dataset with wind conditions averaged over the period 1969-2008 from the same dataset. Wind speed values were computed using a numerical weather prediction (NWP) model run at a 15 km resolution and adjusted using available observations. The underlying datasets for 3TIER’s wind performance maps provide clients with operational intelligence for every location within a region and are available in nearly all regions worldwide.

To learn more about 3TIER’s wind performance analysis, please visit www.3tier.com.

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