Table 4.08.C. Usage Factors for Utility Scale Storage Generators

  Battery Pumped Storage
Year/Month Time Adjusted Capacity Usage Factor Time Adjusted Capacity Usage Factor
Annual Data
2013 126.7 0.7% 22,389.3 9.8%
2014 155.1 1.7% 22,477.9 10.2%
2015 206.8 3.6% 22,568.9 10.2%
2016 423.0 3.8% 22,752.7 11.2%
2017 632.8 6.8% 22,791.7 11.4%
2018 713.6 5.2% 22,815.4 10.8%
Year 2016
January 364.9 3.8% 22,683.7 9.2%
February 370.9 3.6% 22,705.7 8.0%
March 391.7 3.9% 22,705.7 8.4%
April 398.7 4.0% 22,705.7 8.6%
May 408.7 3.9% 22,778.7 10.9%
June 419.1 4.0% 22,778.7 15.6%
July 439.1 3.9% 22,778.7 15.9%
August 439.1 4.0% 22,778.7 16.4%
September 440.1 3.7% 22,778.7 13.3%
October 442.1 3.7% 22,778.7 10.1%
November 480.1 3.5% 22,778.7 8.6%
December 480.1 3.3% 22,778.7 9.6%
Year 2017
January 562.8 6.9% 22,753.4 10.2%
February 573.8 7.4% 22,753.4 8.0%
March 581.8 8.3% 22,753.4 8.5%
April 611.8 7.6% 22,753.4 9.5%
May 627.7 6.8% 22,810.4 11.7%
June 641.2 6.8% 22,810.4 14.2%
July 643.2 6.2% 22,810.4 16.9%
August 645.4 6.8% 22,810.4 16.2%
September 678.2 6.1% 22,810.4 12.9%
October 679.4 6.6% 22,810.4 10.2%
November 681.4 6.8% 22,810.4 9.0%
December 663.4 6.2% 22,810.4 9.1%
Year 2018
January 643.7 5.2% 22,785.2 9.8%
February 663.5 5.1% 22,785.2 9.6%
March 667.1 5.2% 22,785.2 7.9%
April 681.1 5.0% 22,785.2 8.2%
May 690.6 5.2% 22,830.2 11.0%
June 696.1 4.9% 22,830.2 13.2%
July 742.1 5.6% 22,830.2 15.5%
August 740.1 5.6% 22,830.2 16.1%
September 746.4 5.6% 22,830.2 12.2%
October 748.9 5.0% 22,830.2 9.4%
November 768.9 5.3% 22,830.2 8.2%
December 770.7 5.1% 22,830.2 7.7%

Values are final.
Time adjusted capacity for month rows is the summer capacity of generators in operation for the entire month; units that began operation during the month or that retired during the month are excluded. Time adjusted capacity for year rows is a time weighted average of the month rows.
Usage factors are a comparison of gross generation with available capacity. See the technical note for an explanation of how usage factors are calculated.
Sources: U.S. Energy Information Administration, Form EIA-923, Power Plant Operations Report; U.S. Energy Information Administration, Form EIA-860, 'Annual Electric Generator Report' and Form EIA-860M, 'Monthly Update to the Annual Electric Generator Report.'