Windpower rallied most evenings with peak-time performance
Sunny with a good chance of wind . . . Colorado-Wyoming hourly & daily electric power supply . . . August 1-15, 2021
Colorado-Wyoming hourly & daily electric power supply
August 1-15, 2021
Coors Field in Denver CO at sunset. Time when stadium lights turn on August evenings is near the end or after the daily electric consumption peak in Colorado & Wyoming. Photo by Owen Lystrup on Unsplash.
solar electric mostly steady 8 AM - 4 PM
wind electric better overnights, late afternoons & evenings . . . mostly calm mid’-days
consumers’ daily electric consumption highs 4 - 7 PM
Hourly electric generating data by energy source for only Colorado or Wyoming are not available for public viewing as of the date of this report. See Appendix for details.
U.S. Energy Information Administration hourly electric generating data is the source for charts and tables in this report. Generated power in the Colorado and Wyoming combined area is assumed to approximately equal consumers’ aggregated consumption. Exchanges by utilities and Balancing Authorities with neighboring U.S. States and regions are not included in the results shown here.
Generators fueled by natural gas and coal produced nearly three-fourths of the electricity in Colorado and Wyoming combined in the first half of August 2021. <Figs. 1 and 2>
Fig. 1: Electric generation percent of total by energy source for Colorado and Wyoming: August 1-15, 2021. Linecurrents.live chart, U.S. Energy Information Administration (EIA) data. Tap/click to enlarge.
Fig. 2: Electric generation megaWatt-hours (MWhr) by energy source for Colorado and Wyoming: August 1-15, 2021. Linecurrents.live chart, U.S. EIA data.
A daily pattern of maximum electric generation from all energy sources in late afternoon and early evening was consistent through the August 1-15, 2021 period. <Fig. 3>
EIA data contains unexplained deviations:
August 11 - 10 AM
- spike: WACM hydroelectric
August 13 - 7 PM
- drop: WACM hydroelectric
Fig. 3: Hourly electric generation from all energy sources for Colorado and Wyoming: August 1-15, 2021. Linecurrents.live chart, U.S. EIA data.
Colorado & Wyoming
Hourly Generation
Maximum & Minimum
August 1-15, 2021
Generation |
MWhr |
Date |
|---|---|---|
____________ |
_______ |
_________ |
maximum |
14,145 |
Aug 09 |
|
|
5-6 PM |
minimum |
7,344 |
Aug 01 |
|
|
1-2 AM |
Windpower climbed during evening peak demand frequently
Late-afternoon and early evening windpower increases to support aggregated consumer’s daily peak consumption demands 10 of 15 days: August 2, 3, 5, 6, 7, 8, 9, 11, 14 and 15.
Mid-day declines in windpower supply were common August 1-15. <Fig. 4>
Fig. 4: Hourly wind electric generation - Colorado and Wyoming: August 1-15, 2021. Linecurrents.live chart, U.S. EIA data.
Daily wind electric energy totals were not consistent. The highest daily total was 6-times greater than the lowest. <Fig. 5>
Fig. 5: Daily wind electric generation - Colorado and Wyoming: August 1-15, 2021. Linecurrents.live chart, U.S. EIA data.
Colorado & Wyoming
Daily Windpower
Maximum & Minimum
August 1-15, 2021
Windpower |
MWhr |
Date |
|---|---|---|
_____________ |
_________ |
________ |
maximum |
62,805 |
Aug 14 |
minimum |
10,221 |
Aug 01 |
average |
37,281 |
|
Solid solar electric daily pattern
Solar electric generation performed similar to July 2021. Declines in late afternoon result in little or no solar electric supplied during daily 4-7 PM peak electric consumption periods. <Fig. 6>
Fig. 6: Hourly solar electric generation - Colorado and Wyoming: August 1-15, 2021. Linecurrents.live chart, U.S. EIA data.
Solar energy supplied more than 5,000 megaWatt-hours daily for all but 3 days. <Fig. 7>
Fig. 7: Daily solar electric generation - Colorado and Wyoming: August 1-15, 2021. Linecurrents.live chart, U.S. EIA data.
Colorado & Wyoming
Daily Solar Energy
Maximum & Minimum
August 1-15, 2021
Solar |
MWhr |
Date |
|---|---|---|
____________ |
________ |
_________ |
maximum |
6,874 |
Aug 05 |
minimum |
4,740 |
Aug 15 |
average |
5,997 |
|
Hourly windpower vs. consumer demand
Example: windpower greatest when needed least
August 4 is an example of more wind electric generation overnight, and less during daylight hours. <Fig. 8>
Fig. 8: Hourly wind, solar and total electric generation - Colorado and Wyoming: August 4, 2021. Linecurrents.live chart, U.S. EIA data.
Example: windpower nearly matches demand
August 7 is an example of wind electric generation 24-hour pattern nearly synchronized with aggregated consumers’ consumption demand. <Fig. 9>
Fig. 9: Hourly wind, solar and total electric generation - Colorado and Wyoming: August 7, 2021. Linecurrents.live chart, U.S. EIA data.
APPENDIX
Electric power generated in Colorado and most of Wyoming supplies the consumption demand of electric consumers in these States. Some electric capacity is exchanged with Balancing Authorities and electric utilities in adjoining States.
Electric generating sources include:
wind turbines
- solar PV panels
- natural gas combustion powerplants
- coal combustion powerplants
- hydroelectric dams
- pumped hydroelectric storage
- other, such as biogas methane
Charts in this report created from hourly data supplied to the U.S. Energy Information Administration (EIA) by two Balancing Authorities which monitor electric power supply and demand in Colorado and Wyoming:
Western Area Power Administration
Rocky Mountain Region (WACM)
Loveland CO
Public Service Company of Colorado
(PSCO)(Xcel Energy)
Denver CO
Colorado and Wyoming electric supply are combined in this report. The WACM Balancing Authority includes most of Colorado and Wyoming. WACM hourly electricity generation data supplied to EIA by Western Area Power Administration does separate Colorado and Wyoming. Therefore, charts below show results for both States
The role of Balancing Authorities is described at Colorado and Wyoming hourly electric power - June 1-15, 2021. A map of WACM and PSCO Balancing Authority territories is also available at the same site.
Consistent solar, erratic wind for CO-WY 2nd half July 2021 electric power supply
Coal and natural gas combustion generated the most electric power.
Colorado-Wyoming hourly & daily electric power supply
July 16-31, 2021
Western Area Power Administration photo
consumers’ consumption demand peaked late-afternoon & early evening peak
windpower lowest 6 - 9 AM
solar electric consistent most days
hot days not always cause of higher electric demand
Hourly electric generating data by energy source for Colorado or Wyoming individually are not available for public viewing as of the date of this report. See Appendix for details.
U.S. Energy Information Administration hourly electric generating data is the source for charts and tables in this report. Generated power in the Colorado and Wyoming combined area is assumed to approximately equal consumption. Exchanges by utilities and Balancing Authorities with neighboring U.S. States and regions are not included in the results shown here.
Generators fueled by natural gas and coal produced nearly three-fourths of the electricity in Colorado and Wyoming combined for the second half of July 2021. <Figs. 1 and 2>
Fig. 1: Electric generation percent of total by fuel type for Colorado and Wyoming: July 16-31, 2021. Linecurrents.live chart, U.S. Energy Information Administration (EIA) data. Tap/click to enlarge.
Fig. 2: Electric generation MegawattHours (MWhr) from all sources for Colorado and Wyoming: July 16-31, 2021
Late afternoon & early evening are daily peak electric demand periods
A daily pattern of maximum electric generation from all energy sources in late afternoon and early evening was consistent through the July 16-31, 2021 period. <Fig. 3>
Fig. 3: Hourly electric generation from all energy sources for Colorado and Wyoming: July 16-31, 2021. Linecurrents.live chart, U.S. EIA data.
Colorado and Wyoming
Hourly Generation
Maximum & Minimum
July 16 - 31, 2021
Generation |
MWhr |
Date |
|---|---|---|
____________ |
_______ |
_________ |
maximum |
14,556 |
Jul 20 |
|
|
5-6 PM |
minimum |
8,022 |
Jul 27 |
|
|
4-5 AM |
Windpower: no daily high/low cycle
Windpower hourly mimimums occurred 7-8 AM most days, a few hours after the daily mimimum demand. <Fig. 4>
Only one windpower maximum occurred mid-’day: July 24. Maximums in the 5-7 PM hours on the 16th and 25th helped supply the evening peak demand.
Fig. 4: Hourly wind electric generation - Colorado and Wyoming: July 16-31, 2021. Linecurrents.live chart, U.S. EIA data.
Wind-generated power supplied the Colorado - Wyoming electric grid each day July 16-31, 2021. Production was less than 30,000 MegaWatthours (MWhrs) on July 18 and 19. <Fig. 5>
Fig. 5: Daily wind electric generation - Colorado and Wyoming: July 16-31, 2021. Linecurrents.live chart, U.S. EIA data.
Colorado and Wyoming
Windpower
Maximum & Minimum
July 16 - 31, 2021
Windpower |
MWhr |
Date |
|---|---|---|
_____________ |
_________ |
________ |
maximum |
66,635 |
Jul 20 |
minimum |
22,592 |
Jul 18 |
average |
41,260 |
|
Solar electric: consistent
Solar electric generation performed steadily for most of the second half of July 2021. <Fig. 6>
Fig. 6: Hourly solar electric generation - Colorado and Wyoming: July 16-31, 2021. Linecurrents.live chart, U.S. EIA data.
Total daily output was below 5,000 MWhr only on July 24 and 31. <Fig. 7>
Fig. 7: Daily solar electric generation - Colorado and Wyoming: July 16-31, 2021. Linecurrents.live chart, U.S. EIA data.
Colorado-Wyoming
Solar Energy
Maximum & Minimum
July 16-31, 2021
Solar |
MWhr |
Date |
|---|---|---|
____________ |
________ |
_________ |
maximum |
7,283 |
Jul 18 |
minimum |
4,389 |
Jul 24 |
average |
6,156 |
|
Solar, wind and consumption demand peak times compared
Example: windpower supported daily demand peak
July 20 is an example of solar electric generation declining as consumers’ demand reached daily maximum. Wind electric generation climbed in synchronism with consumption demand. <Fig. 8>
Fig. 8: Hourly wind, solar and total electric generation - Colorado and Wyoming: July 20, 2021. Linecurrents.live chart, U.S. EIA data.
Example: windpower belated recovery
July 27 is an example of wind electric generation remaining flat during the first half of the late-day peak consumption demand period. <Fig. 9>
Fig. 9: Hourly wind, solar and total electric generation - Colorado and Wyoming: July 27, 2021. Linecurrents.live chart, U.S. EIA data.
Higher temperatures not reliable predictor of electric demand
Electric demand and consumption did not always track Denver CO maximum daily temperatures. <Fig. 10 and 11>
Denver weather history is selected to represent Colorado and Wyoming conditions, as it is the largest concentration of electric power consumption in the two-state region.
Fig. 10: Daily maximum demand and Denver daily maximum temperatures. July 16-31, 2021. Linecurrents.live chart, U.S. EIA data.
Fig. 11: Daily total electric energy and Denver daily maximum temperatures. July 16-31, 2021. Linecurrents.live chart, U.S. EIA data.
APPENDIX
Electric power generated in Colorado and most of Wyoming supplies the consumption demand of electric consumers in these States. Some electric capacity is exchanged with Balancing Authorities and electric utilities in adjoining States.
Electric generating sources include:
wind turbines
- solar PV panels
- natural gas combustion powerplants
- coal combustion powerplants
- hydroelectric dams
- pumped hydroelectric storage
- other, such as biogas methane
Charts in this report created from hourly data supplied to the U.S. Energy Information Administration (EIA) by two Balancing Authorities which monitor electric power supply and demand in Colorado and Wyoming:
Western Area Power Administration
Rocky Mountain Region (WACM)
Loveland CO
Public Service Company of Colorado
(PSCO)(Xcel Energy)
Denver CO
Colorado and Wyoming electric supply are combined in this report. The WACM Balancing Authority includes most of Colorado and Wyoming. WACM hourly electricity generation data supplied to EIA by Western Area Power Administration does separate Colorado and Wyoming. Therefore, charts below show results for both States
The role of Balancing Authorities is described at Colorado and Wyoming hourly electric power - June 1-15, 2021. A map of WACM and PSCO Balancing Authority territories is also available at the same site.
Solar electric output tapers-off during daily maximum electric demand
Colorado-Wyoming pattern seen in June 2021 continued in July - late afternoon rise in electric demand while solar energy dropped.
Colorado-Wyoming daily electric power supply
July 1-15, 2021
electric generation highest in late-afternoon & early evening to supply consumers’ consumption demand
windpower produced no daily pattern
solar daily electric declined during evening peak consumption periods
hot days caused electric generation to increase in response to higher electric consumption
Electric power generated in Colorado and most of Wyoming supplies the consumption demand of electric consumers in these States. Some electric capacity is exchanged with Balancing Authorities and electric utilities in adjoining States.
Electric generating sources include:
wind turbines
solar panels
combustion natural gas and coal power plants
hydroelectric dams and pumped hydro storage
other, such as biogas methane
- - -
Hourly electric generating data by energy source for Colorado-alone are not available for public viewing as of the date of this report. See Appendix for details.
Daily peak electric demand consistent at 3 - 7 PM
Fig. 1: Hourly electric generation from all sources for Colorado and Wyoming: July 1-15, 2021. Linecurrents.live chart, U.S. Energy Information Administration (EIA) data. Tap/click to enlarge.
A daily pattern of maximum electric generation in late afternoon and early evening was consistent through the July 1 - 15, 2021 period. <Fig. 1>
Variable windpower with no daily high/low cycle
Fig. 2: Hourly wind electric generation - Colorado and Wyoming: July 1-15, 2021. Linecurrents.live chart, U.S. EIA data.
Daily maximum windpower output periods did not follow a pattern. Some days show little wind electric production until the late-afternoon and early evening peak demand period. <Fig. 2>
Daily wind-generated electric power was present each day July 1-15, 2021, but production was low on July 4, 5, 7, 11 and 15. <Fig. 3>
Fig. 3: Daily wind electric generation - Colorado and Wyoming: July 1-15, 2021. Linecurrents.live chart, U.S. EIA data.
Colorado and Wyoming
Windpower Stats
July 1 - 15, 2021
Windpower |
MWhr |
Date |
|---|---|---|
_____________ |
_________ |
________ |
maximum |
56,562 |
Jul 08 |
minimum |
16,043 |
Jul 11 |
average |
38,387 |
|
Solar electric supply mostly stable, with two poor days
Fig. 4: Hourly solar electric generation - Colorado and Wyoming: Junly 1-15, 2021. Linecurrents.live chart, U.S. EIA data.
Solar electric generation performed steadily for most of the first half of July 2021. <Fig. 4>
Total daily output reached a maximum of 7,338 MWhr on July 7, and was below 3,500 MWhr only on July 13 and 14. <Fig. 5>
Fig. 5: Daily solar electric generation - Colorado and Wyoming: July 1-15, 2021. Linecurrents.live chart, U.S. EIA data.
Colorado-Wyoming
Solar Energy Stats
July 1-15, 2021
Solar |
MWhr |
Date |
|---|---|---|
____________ |
________ |
_________ |
maximum |
7,388 |
Jul 07 |
minimum |
2,917 |
Jul 14 |
average |
5,620 |
|
Solar declined during the daily peak electric demand
Wind sometimes picked-up
July 7 is an example of solar electric generation declining as consumers’ demand reached daily maximum. Wind electric generation was minimal for the first half of the consumption peak. <Fig. 6>
Fig. 6: Hourly wind, solar and total electric generation - Colorado and Wyoming: July 7, 2021. Linecurrents.live chart, U.S. EIA data.
Mixed results
Fig. 7: Hourly wind, solar and total electric generation - Colorado and Wyoming: July 10, 2021. Linecurrents.live chart, U.S. EIA data.
July 10 is an example of both wind electric generation remaining flat during the first half of the late-day peak consumption demand period. <Fig. 7>
90+ degree F days caused higher electric demand
Electric consumption mostly tracked Denver CO maximum daily temperatures. July 3, 4, and 6 were exceptions. <Fig. 8 and 9>
Two days were hotter than most, causing electric demand and consumption to increase in the Colorado-Wyoming region:
99ºF - July 8
95ºF - July 9
Fig. 8: Daily maximum demand - Colorado and Wyoming. Denver daily maximum temperatures. July 1-15, 2021. Linecurrents.live chart, U.S. EIA data.
Fig. 9: Daily total megaWatthours - Colorado and Wyoming. Denver daily maximum temperatures. July 1-15, 2021. Linecurrents.live chart, U.S. EIA data.
APPENDIX
Charts in this report created from hourly data supplied to the U.S. Energy Information Administration (EIA) by two Balancing Authorities which monitor electric power supply and demand in Colorado and Wyoming:
Western Area Power Administration (WACM)
Rocky Mountain Region, Loveland CO
Public Service Company of Colorado (PSCO)
Denver CO (Xcel Energy)
Colorado and Wyoming electric supply are combined in this report. The WACM Balancing Authority includes most of Colorado and Wyoming. WACM hourly electricity generation data supplied to EIA by Western Area Power Administration does separate Colorado and Wyoming. Therefore, charts below show results for both States
The role of Balancing Authorities is described at Colorado and Wyoming hourly electric power - June 1-15, 2021. A map of WACM and PSCO Balancing Authority territories is also available at the same site.
Top photo by Manny Becerra on Unsplash.com
Predictable solar, unpredictable wind: Colo & Wyo hourly electric supply - June 16-30, 2021
A look at the impact of high summer temperatures on regional electric demand, and wind + solar electric generation’s performance during hot days.
Photo: Western Area Power Administration
Charts below depict hourly data supplied to the U.S. Energy Information Administration (EIA) by two Balancing Authorities which monitor electric power supply and demand in Colorado and Wyoming:
Western Area Power Administration (WACM)
Rocky Mountain Region, Loveland CO
Public Service Company of Colorado (PSCO)
Denver CO (Xcel Energy)
Colorado and Wyoming electric supply are combined in this report. The WACM Balancing Authority includes most of Colorado and Wyoming. WACM hourly electricity generation data supplied to EIA by Western Area Power Administration does separate Colorado and Wyoming. Therefore, charts below show results for both States
The role of Balancing Authorities is described at Colorado and Wyoming hourly electric power - June 1-15, 2021. A map of WACM and PSCO Balancing Authority territories is also available at the same site.
Daily electric consumption peaked 3 - 6 PM
Figure 1 (below) shows hourly totals of electric megaWatthours generated from all energy sources to supply the consumption demand of electric consumers in Colorado and most of Wyoming. These energy sources are:
wind turbines
solar panels
combustion natural gas and coal power plants
hydroelectric dams
other, such as biogas methane
A daily pattern of maximum electric generation in late afternoon and early evening is consistent through the June 16-30, 2021 period.
Figure 1: Hourly electric generation from all sources for Colorado and Wyoming: June 16-30, 2021. Linecurrents.live chart, U.S. Energy Information Administration (EIA) data.
Windpower - no daily pattern
Daily wind-generated electric power was present each day July 16 - 31, 2021. Maximum output periods were not consistent. Windpower increased during the morning rise in consumer electric consumption demand on 4 days, and increased 7 days during the late-afternoon peak. <Fig. 2 below>
Fig. 2: Hourly wind electric generation - Colorado and Wyoming: June 16-30, 2021. Linecurrents.live chart, U.S. EIA data.
. . .
June 20 is an example of wind electric generation increasing during the late-afternoon and early-evening high demand period. Solar electric generation declined in the middle of the late afternoon peak demand period. <Fig. 3 below>
Fig. 3: Hourly wind, solar and total electric generation - Colorado and Wyoming: June 20, 2021. Linecurrents.live chart, U.S. EIA data.
. . .
June 27 is an example of wind electric generation decreasing during the late-afternoon and early-evening maximum consumption demand period. <Fig. 4 below>
Fig. 4: Hourly wind, solar and total electric generation - Colorado and Wyoming: June 27, 2021. Linecurrents.live chart, U.S. EIA data.
Solar electric performs best in the morning
Solar electric consistently increased during the morning rise in consumer demand each day. Afternoon solar electric was variable. Late afternoon solar declines coincide with the start of the daily maximum consumption demand period. <Fig. 5 below>
Fig. 5: Hourly solar electric generation - Colorado and Wyoming: June 16-30, 2021. Linecurrents.live chart, U.S. EIA data.
High daily temperatures boosted electricity demand
Summer heat caused electric power generated to increase in response to higher consumer consumption. Charts below compare Denver CO maximum daily temperature to regional daily maximum electric demand and total daily electric energy consumption.
June 20, 21, 26 and 27 were days of lower electric demand and consumption. Solar electric generation was also lower (Fig. 5) on these days, suggesting partial cloudcover may have accompanied cooler temperatures in the region.
Fig. 6: Daily maximum demand - Colorado and Wyoming. Denver daily maximum temperatures. June 16-30, 2021. Linecurrents.live chart, U.S. EIA data.
. . .
Fig. 7: Daily total megaWatthours - Colorado and Wyoming. Denver daily maximum temperatures. June 16-30, 2021. Linecurrents.live chart, U.S. EIA data.
Colorado & Wyoming hourly electric power - June 1-15, 2021
Reliable sunny mornings started the daily solar electric generating cycle. . . . Erratic wind conditions did not produce a consistent daily wind electric pattern.
Map: Colorado and Wyoming utility-scale windpower sites, electric transmission lines, and Balancing Authorities.(1), (2)
Reliable sunny mornings started the daily solar electric generating cycle.
Erratic wind conditions did not produce a consistent daily wind electric pattern.
Two Balancing Authorities monitor Colorado’s electric power supply, as shown in the map above:
Western Area Power Administration - Loveland Area Office (WACM)
Public Service Company of Colorado (Xcel Energy - PSCO)
The U.S. Energy Information Administration (EIA) explains the role of Balancing Authorities:
A balancing authority ensures, in real time, that power system demand and supply are finely balanced. This balance is needed to maintain the safe and reliable operation of the power system. If demand and supply fall out of balance, local or even wide-area blackouts can result.
Balancing authorities maintain appropriate operating conditions for the electric system by ensuring that a sufficient supply of electricity is available to serve expected demand, which includes managing transfers of electricity with other balancing authorities. Balancing authorities are responsible for maintaining operating conditions under mandatory reliability standards issued by the North American Electric Reliability Corporation(3) and approved by the U.S. Federal Energy Regulatory Commission(4) and, in Canada, by Canadian regulators.
EIA collects the data for the Hourly Electric Grid Monitor(5) from its Form EIA-930, Hourly and Daily Balancing Authority Operations Report, which includes hourly electricity demand, forecast demand, net generation, and interchange data. The data are provided by the 65 electricity balancing authorities that operate the electric grid in the Lower 48 states and maintain real-time balance between electricity demand and supply on the grid.
Hourly electricity generation data supplied to EIA by Western Area Power Administration does separate Colorado and Wyoming. Therefore, charts below show results for both States.
Electric energy generated to supply consumer demand follows a daily pattern
Figure 1 (below) shows hourly totals of electric megaWatthours generated from all energy sources for Colorado and most of Wyoming. These electric energy sources are:
wind turbines
solar panels
combustion natural gas and coal power plants
hydroelectric dams
other, such as biogas methane
Figure 1: Hourly electric generation from all sources for Colorado and Wyoming: June 1-15, 2021. Linecurrents.live chart. (Data glitch: June 2 at 3 PM)
A daily pattern of least electric generation before dawn and maximum generation during late afternoon and early evening was consistent for the first half of June 2021 in Colorado and Wyoming.
Hourly total electric generation approximately equals total consumer demand. Colorado electric utilities have little battery capacity to store variable mid'-day solar or overnight windpower for use during peak consumption hours.
Keeping electric generating supply in balance with consumer demand is required to keep the U.S. electric grid spinning at 60 Hertz (Hz, cycles per second). Excess generation causes this alternating current (AC) frequency to increase, a condition called overfrequency. Not enough generation causes a frequency reduction: underfrequency.
Since wind and solar electric supplies are variable, combustion power plants compensate for changes in solar/wind output and consumers’ demand by increasing or decreasing the fuel supply.
Windpower supply - some days good, some not
Daily wind-generated electric power was inconsistent July 1 - 15, 2021. Six days show morning increases beginning 2 - 3 hours after consumer demand climbed. Evening performance was better, as windpower output increased before or during evening consumption peaks in all but 3 days. <Fig. 2 below>
Fig. 2: Hourly wind electric generation - Colorado and Wyoming: June 1-15, 2021. Linecurrents.live chart.
Windpower increased in late afternoon . . . or not
An example of beneficial wind conditions was June 12, as electric power generated by Colorado and Wyoming wind turbines increased in the evening concurrently with the total electricity generated to supply to consumers’ demand. Solar electric generation dropped in the middle of the late afternoon peak demand period. <Fig. 3 below>
Fig. 3: Hourly wind, solar and total electric generation - Colorado and Wyoming: June 12, 2021. Linecurrents.live chart.
. . .
Wind conditions were not favorable for electric generation on June 11, when wind turbine output decreased as consumer demand increased. <Fig. 4 below>
Fig. 4: Hourly wind, solar and total electric generation - Colorado and Wyoming: June 11, 2021. Linecurrents.live chart.
Solar electric daily pattern: sunny, with a few afternoon clouds
Solar electric increased concurrently with the total electric generating supplied to consumers in early morning hours. Late-morning and afternoon declines reduced solar electric ability to support the late-afternoon peak demand in 7 days. <Fig. 5 below>
Fig. 5: Hourly solar electric generation - Colorado and Wyoming: June 1-15, 2021. Linecurrents.live chart. (Data glitch: June 2 at 3 PM)
REFERENCES
Western Interconnection Balancing Authorities - January 5, 2017 map, Western Electricity Coordinating Council
U.S. Energy Information Administration Energy Atlas Electricity Energy Infrastructure and Resources
U.S. Energy Information Administration EIA launches redesigned Hourly Electric Grid Monitor with new data and functionality
Western U.S. Electric Energy Snapshot: Feb 1 - 15, 2021
Hourly solar, wind, hydroelectric, natural gas, coal and nuclear electric energy supplied to the Western grid .
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.
U.S. 2018 Electricity Sales Set New Record
Hotter summer, colder winter added to electric power consumption . . .
Up 4% over 2017
Power consumption increase caused by:
- warmer summers
- population growthResidential and commercial power consumption increase in 2018, industrial declined
The following consists of excerpts from U.S EIA publications. See list of sources at end of this report.
U.S. net electricity generation increased by 4% in 2018, reaching a record high of 4,178 million megaWatthours (MWh), according to the Department of Energy - Energy Information Administration’s Electric Power Monthly - December 2018. Last year was the first time total utility-scale generation surpassed the pre-recession peak of 4,157 million MWh set in 2007.
Annual electric energy, United States, 1950 - 2018. U.S. Energy Information Administration graph with Linecurrents edits. <tap-click to enlarge>
Weather is the primary driver of year-to-year fluctuations in electricity demand.
The increased demand for electricity in 2018 - including record demand in the commercial and residential sectors - is largely attributable to cold winters and a hot summer.
Hotter summers trend
Population-weighted cooling degree days, an indicator of warm weather and air conditioning demand, reached a record high in 2018.
Cooling-degree days, United States, 2000 - 2018. U.S. Energy Information Administration graph with Linecurrents edits. <tap-click to enlarge>
Electric A/C cooling
About 87% of U.S. households cool their homes in the summer with air conditioning,
Indoor cooling/air-conditioning types by U.S. region. U.S. EIA map/chart with Linecurrents edits. <tap-click to enlarge>
Electric indoor space heating
Heating degree days, the indicator of cold weather and space heating demand, were also higher in 2018 than in recent years. Thirty-five percent of U.S. homes use electricity as their primary heating source during the winter.
Heating-degree days, United States, 2000 - 2018. U.S. Energy Information Administration graph with Linecurrents edits. <tap-click to enlarge>
Residential, commercial & industrial electric power consumption
The hot summer and relatively cold winter months of 2018 contributed to increased retail electricity sales to the residential sector, up 6% from the previous year.
Electricity use in commercial buildings is also affected by the weather but to a lesser degree; electricity sales to the commercial sector last year increased 2% from 2017.
Electricity use in the industrial sector has been relatively unchanged in recent years, with 2018 electricity sales to this sector 3% lower than in 2017.
Economic and population growth are the primary drivers of rising electricity demand, with the number of households growing 0.7% per year and commercial floorspace increasing 1.0% per year from 2018 through 2050 in EIA’s Annual Energy Outlook 2019 Reference case. Electricity sales to the residential and commercial sectors are expected to grow more slowly, at 0.4% and 0.5%, respectively, as improvements in technology and energy efficiency standards moderate electricity consumption growth.
Electric energy sales by consumer scetor, United States, 1950 - 2018. U.S. Energy Information Administration graph with Linecurrents edits. <tap-click too enlarge>
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Sources - more info:
Record U.S. electricity generation in 2018 driven by record residential, commercial sales . . . U. S. Energy Information Administration - March 6, 2019
Air conditioning and other appliances increase residential electricity use in the summer . . . U. S. Energy Information Administration - May 22, 2017
Electric Power Monthly - December 2018 . . . U. S. Energy Information Administration - Release date: February 27, 2019
2019 Planned U.S. Utility-Scale Variable-Renewable & Combustion Electric Power Generation Additions & Retirements
3X more GigaWatts windpower, solar-PV and natural gas generation to be added than coal, nuclear and natural gas power generation shutdowns. See why . . .
Energy Information Administration - U.S. Department of Energy
Two nuclear powerplants to shut.
Coal-fired closure trend continues.
Natural gas turbine additions outweigh retirements.
Variable wind and solar PV to add capacity.
2019 Monthly U.S. Electric Power Generating Capacity Additions & Retirements — GigaWatts (GW)
U.S. Energy Information Administration chart
1 GigaWatt(GW) = 1,000 MegaWatts(MW) = 1,000,000 KiloWatts(KW)
2019 Comparison - U.S. Electric Power Generating Capacity Additions & Retirements
U.S. Energy Information Administration chart
Capacity additions planned for 2019 is triple planned retirements -- 24 GW adds compared to 8 GW retires. However, "capacity" rating is output when conditions are perfect.
Variable renewable electric energy sources are unable to generate electric energy continuously. No sun -- no solar PV electricity. No wind -- same result.
Combustion and nuclear electric generators may supply electricity continuously at or near rated maximum output, except during maintenance periods.
Therefore, variable renewable electric energy generating "new capacity" must be greater to replace retired combustion or nuclear generating capacity to achieve the same annual "energy" output.
Example
Solar-PV utility-scale Colorado. "Capacity Factor"= 25% annual (100% = full rated output 24/7/365 continuous, which is impossible for solar-PV).
Combustion powerplant (coal or natural gas) capacity factor up to 100% annual.
For each 1 MW of combustion electric power generating capacity retired, 4 MW of new solar-PV is required to generate the same electric energy annual output.
Carbon Dioxide Emissions from U.S. Electric Utilities Declined 28% from 2005 to 2017
Non-carbon electric generating power sources reached 38% of total U.S. power supply . . .
Donald Von Raesfeld natural gas-fired powerplant. Silcon Valley Power - City of Santa Clara, CA. Photo provided by American Public Power Association at Unsplash.
CO2 emissions from other consumer categories - - transportation, buildings and industry - - decreased only 5% since 2005.
Natural gas generation surpassed coal as the largest source of electricity generation in 2016.
Non-carbon electric generating power sources reached 38% of total U.S. power supply in 2017.
Energy Information Administration
U.S. Department of Energy
October 29, 2018
_______________________
“U.S. electric power sector carbon dioxide emissions (CO2) have declined 28% since 2005 because of slower electricity demand growth and changes in the mix of fuels used to generate electricity. EIA has calculated that CO2 emissions from the electric power sector totaled 1,744 million metric tons (MMmt) in 2017, the lowest level since 1987.”
- - - - - - - - -
U.S. Electric Power
Total CO2 Emissions
2000 - 2017
U.S. Energy Information Administration graph, Linecurrents notations.
U.S. Electric Power
CO2 Emissions
Reductions Per Year
2006 - 2017
U.S Energy Information Administration graph.
Notes - above graph:
Fuel switching from coal to natural gas shown in “blue.”
Renewable power generation additions shown in “green.”
“Up” in the positive direction indicates CO2 emissions reductions.
Units are million metric tons of CO2.
Electric power industry created most CO2 reductions
“In the United States, most of the changes in energy-related CO2 emissions have been in the power sector. Since 2005, as power sector CO2 emissions fell by 28%, CO2 emissions from all other energy sectors fell by only 5%. . . .
“U.S. electricity demand has decreased in 6 of the past 10 years (note: through 2017), as industrial demand has declined and residential and commercial demand has remained relatively flat. . . .”
- - - - - - - - -
U.S Electric KiloWatthours Generated
& Carbon Dioxide Emissions
2005 & 2017
U.S. Energy Information Administration graph.
Notes - above graph:
Left side
Compares KiloWatthour (KWhr) generated in 2005 and 2017. Total KWhr for these years were nearly equal.
Solar PV (yellow) and windpower (green) KWhr increased from near zero in 2005 to about 300 billion KWhr in 2017.
Petroleum (diesel fuel - black) CO2 KWhr decreased from 2005 to 2017 due to displacement by natural gas.
Natural gas-fired combustion (tan) KWhr increased from 2005 to 2017.
Coal combustion (brown) KWhr decreased from 2005 to 2017.
Hydroelectric (blue) KWhr were nearly equal in 2005 and 2017.
Non-carbon (red, blue, green, yellow) KWhr annual generation increased from 28% in 2005 to 38% in 2017. Non-carbon sources are solar PV, windpower, hydroelectric, and nuclear.
Right side
Compares 2005 and 2017 combustion electric power generation CO2 emissions in million metric tons.
Petroleum (diesel fuel - black) CO2 emissions decreased from 2005 to 2017 due to displacement by natural gas.
Natural gas (tan) CO2 emissions increased from 2005 to 2017, as natural gas displaced coal and petroleum for electric power combustion generation.
Coal (brown) CO2 emissions decreased from 2005 to 2017 due to displacement by natural gas.
Coal CO2 emissions reduction exceeded natural gas emissions increase from 2005 to 2017.
Electric power supply “carbon intensity” declines
“The power sector has become less carbon intensive as natural gas-fired generation displaced coal-fired and petroleum-fired generation and as the noncarbon sources of electricity generation - especially renewables such as wind and solar - have grown. The substitution of natural gas for other fossil fuels has largely been market driven, as ample supplies of lower-priced natural gas and the relative ease of adding natural gas-fired capacity have allowed it to pick up share in electric power generation in many markets. In 2016, natural gas generation surpassed coal as the largest source of electricity generation.”
- - - - - - - - -
Combustion Fuel &
Non-Carbon Energy Sources
U.S. Electric Electric Power
1990 - 2017
U.S. Energy Information Administration graph, Linecurrents labels.
Non-carbon renewable electricity sources cut U.S. power supply CO2 emissions 10%
“Increases in electricity generation from noncarbon power sources since 2005 also had an effect on emissions from power generation. This growth has been driven largely by state policies and federal tax incentives that encouraged adoption of renewables. In 2005, noncarbon (note: including nuclear) sources accounted for 28% of the U.S. electricity mix. By 2017, that share had grown to 38%. Almost all of this growth was in renewables, including wind and solar, as shares for other noncarbon sources such as nuclear and hydroelectricity remained relatively flat.”
- (end of EIA direct quotation) -
CO2 combustion emissions by fuel type compared
Declining coal combustion is responsible for most of the U.S. CO2 emissions reduction since 2000. Coal combustion emissions dropped from about 2.1 billion metric tons in 2000 to 1.2 billion in 2017.
Petroleum consumption caused about 2.2 billion metric tons and 46% of U.S. CO2 emissions in 2017.
- - - - - - - - -
U.S. CO2 Emissions
2000 - 2017
Annual by Fuel Type
U.S. Energy Information Administration graph.
Consumption category and fuel type CO2 combustion emissions compared
EIA reviewed annual coal, natural gas and petroleum CO2 emissions of five consumption categories: electric power, industrial, commercial, residential and transportation.
Shown in the graph below, electric power’s coal and natural gas combustion (brown) contributed to CO2 emissions. Industrial (yellow) combustion of all three fuels shown caused CO2 emissions. Transportation was responsible for the greatest share of petroleum CO2 emissions.
- - - - - - - - -
U.S. CO2 Emissions
Annual by Fuel Type
and Consumption Category
U.S. Energy Information Administration graph, Linecurrents markers.
More Information
U.S. Energy-Related Carbon Dioxide Emissions, 2017
U.S. Energy Information Administration - September 2018 - PDF download