Western U.S. Electric Energy Snapshot: Feb 1 - 15, 2021
The Western Interconnection is one of three U.S. grids which operate independently of each other. A network of electric transmission lines connect power/energy generating stations and utility substations across the U.S. West.
Capacity to transfer electric power/energy between the Eastern, Western and Texas grids is small compared to total generating capacity in each grid.
The boundaries or seams between electric grids do not match state borders, as shown by dashed lines in the map above.
The map indicates natural energy resources which may be converted to electric energy. Map excerpted from Interconnections Seam Study - National Renewable Energy Laboratory (NREL) - Golden, Colorado.
Combustion and hydroelectric energy sources compensate for varying solar and wind
Figure 1 - Linecurrents chart, U.S. Energy Information Administration (EIA) Hourly Electric Grid Monitor data. Tap/click to enlarge.
A history of electric energy generated hourly from all Western Interconnection sources for February 1 - 15, 2021 is charted in Figure 1. Times are Mountain Standard, with Pacific Time Zone results adjusted by one hour.
Electric energy suppliers controlled the fuel supply of coal and natural gas combustion electric generators, and water releases for hydroelectric energy, to meet varying consumer electric energy consumption demand systemwide. Natural gas, coal, hydroelectric and nuclear energy sources are not affected by changing wind or sunshine. Variable wind and solar sources are not controllable.
NOTES
Tap/click images to enlarge.
EIA 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.
The daily cycle
The solar energy daily cycle, and consumer electric energy consumption patterns, caused each energy source output to vary through 24-hour periods,. Figure 2 illustrates this pattern for February 1 -15, 2021.
Wind-turbine electric energy production did not follow a consistent daily cycle.
Figure 2 - Linecurrents chart, U.S. Energy Information Administration (EIA) data.
Solar energy contributed little to supplying daily peak demand periods
Figure 3 illustrates MegaWatthours generated hourly by each energy source for February 4 - 5, 2021.
Figure 3 - Linecurrents chart, U.S. Energy Information Administration (EIA) data.
- - - - -
Figure 4 - Linecurrents chart, U.S. Energy Information Administration (EIA) data. Peak demand periods for February 4 are highlighted.
Western Interconnection systemwide consumer electric consumption demand for the period February 1 - 15, 2021 was highest during two periods daily:
7 - 11 AM
4 - 10 PM
Solar electric energy production ramped-up about half-way into morning peak periods, but was unavailable for the evening peak. February 4 -5 solar energy results, illustrated in Figure 4, were typical of the entire February 1 - 15 period.
- - - - -
A wind energy generation daily cycle pattern was evident February 9 - 13, 2021. Maximum hourly output during these days occurred during the Western Interconnection systemwide evening peak demand period. All other days in the February 1 -15 period had no wind energy daily cycle. February 8 - 15 wind energy results are illustrated in Figure 5.
Figure 5- Linecurrents chart, U.S. Energy Information Administration (EIA) data. Evening peak Western Interconnection systemwide demand periods are highlighted. Arrows indicated wind energy maximum daily output coincident with daily systemwide peak demand.
Totals - all energy sources
Natural gas fuel for combustion generation supplied the most electric energy during the February 1 - 15, 2021 period.
Figure 6 - Linecurrents chart, U.S. Energy Information Administration (EIA) data.
Combustion energy sources -- natural gas and coal -- generated about 49% of total electric power supply. Thermal energy -- natural gas, coal and nuclear -- generated about 57% of total.
Figure 7 - Linecurrents chart, U.S. Energy Information Administration (EIA) data.
Maximums and minimums
All results below are MegaWatthours per Hour.
Total all energy sources
Feb 01 -15, 2021
17,994,453 MWhrs
|
MWhr/hr |
Date |
|---|---|---|
-------- |
------- |
-------- |
maximum |
93,759 |
Feb 11 |
mimimum |
64,418 |
Feb 01 |
_____
Coal |
MWhr/hr |
Date |
|---|---|---|
------- |
-------- |
-------- |
maximum |
19,012 |
Feb 11 |
mimimum |
9,758 |
Feb 04 |
_____
Nat Gas |
MWhr/hr |
Date |
|---|---|---|
------- |
-------- |
-------- |
maximum |
32,780 |
Feb 09 |
mimimum |
12,698 |
Feb 07 |
_____
Hydro |
MWhr/hr |
Date |
|---|---|---|
------- |
-------- |
-------- |
maximum |
13,2731 |
Feb 15 |
mimimum |
12,698 |
Feb 07 |
_____
Wind |
MWhr/hr |
Date |
|---|---|---|
------- |
-------- |
-------- |
maximum |
14,643 |
Feb 03 |
mimimum |
2,780 |
Feb 14 |
_____
Solar |
MWhr/hr |
Date |
|---|---|---|
------- |
-------- |
-------- |
maximum |
15,874 |
Feb 03 |
mimimum |
7,063 |
Feb 01 |
_____
Nuclear electric generation supplied about 7,200 MWhr/hr in the first three days of February, and near 6,300 MWhr/hr thereafter.