Non-combustion electric sources nearly 40% of total electric power generated in late September 2021

Electric Power Supply Review
Hourly & Daily
September 22 - 28, 2021

 

United States regions of greatest windpower

 

Quick summary

windpower

  • 10.21% of total electric energy generated in the period

  • strongest in late evening and early A.M. hours most days

  • high-to-low daily totals differed by 37.8%


solar electric

  • 2.92% of total electric energy generated in the period

  • high-to-low daily totals differed by 22.4%


all non-combustion

  • wind, solar, nuclear and hydroelectric combined supplied 39.7% of total electric power generated

 

Note: see APPENDIX for discussion of Time Zones, Data Source, and Transmission Access

 
 
 

U.S. hourly electric power supply
September 22-28, 2021

Natural gas and coal combustion contributed the largest share of electric generation for the September 22-28, 2021 period.

Non-combustion energy sources — wind, solar, nuclear and hydroelectric — combined supplied 39.75% of total electric power generated in the United States contiguous 48 States during the period.

Hourly electric generation from combustion and non-combustion energy sources. U.S. Energy Information Administration (EIA) Hourly Grid Monitor chart created from Linecurrents.live custom query. Times are Eastern zone.

Total electric generation from combustion and non-combustion energy sources. Linecurrents.live chart, U.S. EIA data.

 
 

Solar electric

The largest U.S. solar electric sources are Texas (Central time zone) and California (Pacific time zone). Daily solar production maximums in the chart are shifted 1 to 2 hours due to chart times are Eastern zone.

  • highest hourly maximum
    329,318
    Sept 25

  • lowest hourly maximum
    255,647
    Sept 21

  • minimum is less than maximum
    22.4%

Hourly electric generation from solar energy sources. U.S. EIA Hourly Grid Monitor chart created from Linecurrents.live custom query. Times are Eastern zone.

 
 

Windpower

U.S. windpower generation produced late-evening or early-overnight highs in each of the seven days.

  • highest hourly maximum
    1,278,491
    Sept 26

  • lowest hourly maximum
    795,310
    Sept 22

  • minimum is less than maximum
    37.8%

 

Hourly electric generation from wind energy sources. U.S. EIA Hourly Grid Monitor chart created from Linecurrents.live custom query. Times are Eastern zone.

 
 

Combined wind and solar electric

Wind and solar electric energy daily production were complementary. Solar electric production increased mid-mornings when windpower declined, and wind increased most evenings as solar declined.

The second chart in this section shows hourly wind and solar electric production combined. The resulting total is the top edge of the green area.

Hourly electric generation from solar and wind energy sources. U.S. EIA Hourly Grid Monitor chart created from Linecurrents.live custom query. Times are Eastern zone.

Hourly electric generation from solar and wind energy sources. U.S. EIA Hourly Grid Monitor chart created from Linecurrents.live custom query. Times are Eastern zone.

 
 

Regional windpower

West and central United States regions defined by U.S. Energy Information Administration (EIA). Texas, California, Midwest and Central, are regions of greatest U.S. windpower production. Map adapted from U.S. EIA Hourly Electric Grid Monitor . . . colors and region labels added by Linecurrents.live.

Hourly windpower for the September 22-28, 2021 period is shown in regional charts. All chart times are Eastern Zone.

Maximum windpower time of of day varied by region:

  • Northwest > no regular pattern

  • California > midnight + /- a few hours

  • Texas > midnight + /- a few hours, except Sept 23

  • Central > midnight + /- a few hours, except Sept 23 and 24

  • Midwest > no regular pattern

 
 

The next section examines the hourly impact of removing all combustion electric supply from the U.S. contiguous 48 States’ three electric transmission grids, and increasing wind and solar electric generating capacity by a factor of seven. Results assume that new wind and solar electric plants are at existing sites, and perform the same as older units. Other new sites, such as off-shore windpower, may produce daily or seasonal production patterns which differ from existing sites.

 

Daily electric supply if combustion sources are eliminated and wind/solar increased 7X

The following analysis illustrates scale-up for existing U.S. wind and solar electric generating capacity, and elimination of combustion generation sources. Nuclear and hydroelectric capacity now in service are not changed.

Total actual U.S. hourly generated electric energy supply is represented in the following charts by a gray line:

  • includes all electric generating sources: wind, solar, hydroelectric, nuclear, natural gas, coal, petroleum and other.

  • is an estimate of actual U.S. electric consumers’ hourly consumption.

  • does not include electric energy imports or exports via electric transmission lines with Canada and Mexico.

Color-shaded areas represent hourly wind and solar increased by a factor of 7 from actual. Actual wind and solar hourly electric supply are shown as dashed lines.

Arrows indicate times when excess wind or solar collected and collected in batteries or other systems storage systems may be released during electric supply shortages. If no excess supply is present, or hourly electric generation is adequate to supply consumption demand without storage, no arrows are shown.

 

Daily summary:
7 X wind & solar electric adequacy to replace combustion generation

  • Sept 22 - no

  • Sept 23 - yes

  • Sept 24 - yes

  • Sept 25 - yes

  • Sept 26 - yes

  • Sept 27 - yes

  • Sept 28 - yes

 
 

Appendix

time zones

Hourly charts in this report are based on Eastern time. Compared to local time at generator sites, hourly MWhr results are shifted to later in the day if the generator is not in the Eastern time zone:

1 hour: Central time zone - Midwest, Great Plains, Texas
2 hours: Mountain time zone
3 hours: Pacific time zone - Northwest, California

data source

U.S. Energy Information Administration (EIA) Hourly Electric Grid Monitor is the source for data for this report. EIA provides this disclaimer:

Disclaimer: The information submitted by reporting entities is preliminary data and is made available "as-is" by EIA. Neither EIA nor reporting entities are responsible for reliance on the data for any specific use.

transmission access

Factors which may affect future electric power transfers among U.S. regions

  1. inadequacy of existing transmission grid to move large amounts of electric power between regions

  2. new transmission line construction right-of-way acquisition and State/local jurisdiction issues

  3. States, Balancing Authorities and regions priorities for use of potential excess variable wind/solar electric energy:

    a) export to other BA’s or regions
    b) store and consume with no export
    c) consume electric energy when produced by electrification of transport, water and indoor space heating, and other fuel-switching to electric energy

  4. hydroelectric supply reduction due to drought

  5. nuclear electric supply reduction due to plant closures

  6. other

grid, solar energy, trends, windpowerAllyn SvobodaEIA, Energy Information Administration, U.S. renewable energy, solar energy, windpower, wind energy