Slowing wind production blamed on, well, wind
August 12, 2015 | By
Jaclyn Brandt
Wind production is dropping across the west coast, but it's not for a lack of trying by the industry. Wind speeds have been slowing down in the region, leading to the reduced generation.
According to the Energy Information Administration (EIA), average wind speeds in the region dropped in early 2015, and wind plants in California, Oregon, and Washington saw a decrease in generation due to the drop. In the first five months of 2015, wind plant utilization rates were well below the previous five-year average. "Capacity factors for wind turbines are largely determined by wind resources," EIA explained. "Because the output from a turbine varies nonlinearly with wind speed, small decreases in wind speeds can result in much larger changes in output and, in turn, capacity factors." In January of 2015, wind speeds remained 20 to 45 percent below normal on areas of the west coast, but it was especially bad in California, Oregon, and Washington, where those levels dropped to 50 percent below normal during the month of January. "In order to accurately compare performance over time, these calculations were based on the output of wind plants in operation before 2010, which excludes all of the new wind capacity added since then," EIA explained. "At the end of 2009, these three states had a total of 6.3 gigawatts (GW) of wind capacity. By the end of 2014, their capacity had increased by an additional 5.3 GW. Wind generation in the three states increased from 12,882 gigawatthours (GWh) in 2009 to 28,614 GWh in 2014." The wind industry in California has caught up due to wind turbine performance improvement, but Oregon and Washington have not. EIA found that the further north the turbines are located, the lower their average performance. Although it improved from January levels, turbine performance in Washington in March, April, and May remained 25 percent below average levels. As 2015 has progressed, California wind turbine performance appears to have recovered to near-normal levels, but turbine performance in Oregon and Washington remains below average 2010-14 levels. In general, performance this past spring tended to be lower the farther north the turbines are located, with Washington turbine performance more than 25% below average levels in March, April, and May. "Wind plant generation variability occurs over different time scales, from subhourly to seasonally and even annually, reflecting variations in wind speeds," EIA added. "Unexpected drops in output may require grid operators to schedule other sources of power on short notice. Furthermore, because the federal tax credit for utility-scale wind energy is based on generation volumes, lower wind speeds mean reduced tax credits." However, Oregon, and Washington are different from California in that their climates change on a monthly basis, while California's stays more uniform. "In the summer, ocean-cooled air in California interacts with the warmer mountains nearby to create a relatively reliable and well-timed land-sea breeze air circulation pattern," EIA said. "California's wind resources and generator output tends to peak during the summer at a time when electricity demand in the state is also relatively high." For more: © 2015 FierceMarkets, a division of Questex, LLC. All rights reserved. http://www.fierceenergy.com/story/slowing-wind-production-blamed-well-wind/2015-08-12 |