July 24 (Reuters) - The amount of electricity produced

by wind farms in the U.S. fell to a 33-month low on Monday,

forcing power generators to crank up natural-gas fired plants to

keep air conditioners humming during a hot summer day.

Over the past few years, much of the money energy firms have

invested in new generation has gone into renewable power sources

like wind and solar. But when the wind stops blowing and the sun

does not shine, gas is still needed to keep the lights on.

Wind power in the Lower 48 states produced about 335,753

megawatt hours (MWh) on July 22, the lowest since Oct. 4, 2021,

according to preliminary data from the U.S. Energy Information

Administration (EIA).

When the wind does not blow, power companies usually burn

more gas because it is the only big source of power they can

turn to quickly to provide more energy to maintain reliability.

And with power demand expected to keep growing as technology

firms build more data centers and consumers use more electricity

to power cars and heat homes and businesses, reliability is

becoming increasingly important following some deadly blackouts

like the February freeze in 2021 that left millions in Texas

without power, heat and water for days.

Wind farms were on track to produce an average of just 4% of

power generation this week, down from 7% last week, 12% so far

in 2024 and 10% in 2023. Gas-fired power plants were producing

an average of 48% of generation this week, up from 46% last

week, 40% so far in 2024 and 41% in 2023.

It is not unusual for wind power to decline during the

summer months, but this has been a particularly bad month for

wind.

Six of the 10 lowest days for wind power so far this year

have occurred in July. That compares with just two of the 10

lowest days during the same period in 2023.

Wind produced about 11% of the nation's power in 2023 and is

on track to produce about 11% in 2024 and 2025, according

projections from the EIA.

But the amount of wind power produced in 2023 fell from a

record high of 434.0 billion kilowatt-hours in 2022 to 425.0

billion kWh in 2023, the first annual decline in wind power

produced since 1998. To be sure, EIA projects wind power will

rise to 447.5 billion kWh in 2024.

Gas, for comparison, was on track to produce 1,719.4 billion

kWh in 2024, which would top the record 1,695.3 billion kWh

generated in 2023, which represented about 42% of the nation's

total power generation.