April 13, 2011
3TIER®, a global leader in renewable energy information services, today released a wind performance map for the first quarter of 2011. The map illustrates that wind speeds were above their seasonal averages for large areas across the western US. The rest of the country experienced slightly below average wind speeds, including a majority of Texas, the Midwest, and the East.
3TIER’s first quarter map illustrates 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 first quarter of 2011, the pattern is 0 - 20% above normal in the western half of the country and 0 - 5% below normal in the eastern half. However, the first quarter map does not illustrate the significant wind speed variability that occurred month to month throughout the beginning of 2011.
Of the three months, January was a clear outlier, with well below normal wind speeds across the entire country except in the higher elevations of the Intermountain West and in isolated areas of southern California and Arizona. This was caused by two large-scale atmospheric circulation patterns: a weak La Niña and a strongly positive Pacific/North America (PNA) pattern.
In contrast, February and March saw increased wind speeds across the entire western US – keeping with the 3-month average pattern. However, over February and March the eastern US also experienced above normal wind speeds, but few high enough to cancel out the substantially below average wind speeds that occurred in January.
February showed considerably elevated wind speeds nearly everywhere in the US. This was due to the severe winter storms that dominated the month, which were caused by a PNA pattern shift from positive to negative and the strong La Niña originally predicted for January. In March, climate conditions were characterized by a weakening of La Niña, a less positive PNA pattern, and a transition from a weak positive to a weak negative North Atlantic Oscillation. Strong frontal systems also moved across the southern US, producing severe weather and contributing to the elevated wind speeds in that region.
In October 2010, 3TIER released a forecast for the first quarter of 2011 predicting a high probability of elevated wind speeds across nearly all of the US. This type of forecast allows operators and energy marketers to do integrated resource planning as well as purchase and sell energy and capacity. As a whole, conditions over the quarter were consistent with 3TIER’s forecast, which was based on the connection of winter La Niña conditions and above normal wind speeds, particularly in the western US.
In January, a weaker La Niña than forecasted and an unexpected positive shift in the PNA pattern distorted the overall first quarter forecast. However, conditions in February and March closely matched 3TIER’s prediction with widespread elevated wind speeds. Nevertheless, these positive anomalies were not reflected in the overall first quarter map because they were not strong enough to overcome the low wind speeds of January.
The wind performance maps were 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 contact 3TIER http://www.3tier.com.
Founded in 1999, Seattle-based 3TIER is one of the largest independent providers of wind, solar, and hydro energy assessment and power forecasting worldwide. People around the world turn to 3TIER when they want the best scientific information to make decisions about renewable energy projects — from the prospecting stage to operations. For more information, visit www.3tier.com.
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