US electricity demand and consumption vary seasonally, typically peaking in the Summer and to a lesser extent in the winter. Demand and consumption are typically lower in the Spring and Fall when the weather is milder. Fossil and nuclear generating units are frequently taken offline during the Spring and Fall for maintenance and necessary repairs. Solar generation operates throughout the year during the hours when sunshine is available, though its capacity factor varies hourly, daily and seasonally as a factor of solar intensity, weather conditions, sun angle and time of day. 

Solar generation provides the output it can, all of which is consumed by the grid. The remaining grid demand and consumption is provided by the balance of the generation fleet, including other renewable generation, nuclear, coal and natural gas generation. Nuclear generation typically operates at constant output, functioning as baseload generation. Coal generation is also used as baseload generation and as intermediate load generation with its output adjusted slowly as load increases toward the daily peak and then declines after the peak. Natural gas generation is used both as intermediate load generation and to adjust to rapidly changing demand during the day.

The images below are based on US electricity consumption during the month of May 2026. EIA Electric Power Monthly does not include data for May 2026 as of June 21^st. However, we will assume that the generation percentages shown under the first image below are accurate, though EIA lists Total Solar as an estimate in the linked table. Total utility scale generation during peak months is approximately one third higher than in the lowest demand months. However, total solar generation during the peak generation months is more than twice generation during the lowest capacity factor months.

The month of May is typically a month of relatively low grid demand and consumption, approximately 75% of peak monthly consumption. However, May is a month of relatively high solar capacity factor, approximately 90% of peak generation. Therefore, May is a month in which solar generation is closer to peak generation than the grid is to peak demand. For example, in May 2024, total solar generation met approximately 8.9% of grid consumption, while coal met approximately 13.1%; and, in May 2025, total solar generation met approximately 11.3% of grid consumption, while coal met approximately 14%. However, for the year 2024, total solar met approximately 7% of grid consumption while coal met approximately 15%. For the year 2025, total solar met approximately 8.8% of grid consumption while coal met approximately 16.7%.

EIA total solar generation data for the first three months of 2026 shows 20 – 25% increased total solar generation while grid consumption shows minimal growth. However, solar generation is unlikely to exceed coal generation through the year as total electricity consumption increases toward the summer peak. Also, the rate of growth of total solar generation is likely to slow as projects funded with significant subsidies are completed and new installations must proceed without subsidies.

 

Evolved Chimp

 

Solar generated 12.8 percent of the nation's electricity. Coal generated 12.2 percent.

 

 

Clean energy might be cleaner, but intermittent clean energy generation certainly is not cheaper when the full costs of providing and supporting it are included.