The opinions expressed here are those of the author, a columnist for Reuters.

By Gavin Maguire

LITTLETON, Colorado, Oct 31 (Reuters) - Wind farms have generated a record share of U.S. electricity production so far in 2024, and are the second largest source of clean power behind nuclear plants in the U.S. generation system.

Shortages of parts, jumps in labour costs and drawn-out development timelines have slowed the pace of wind farm construction in the last couple of years.

But recent drops in development costs plus lucrative tax credits set to become available in 2025 have rekindled wind project growth in 2024.

That should further elevate wind power's status in the U.S. generation mix, and establish wind farms as a key pillar of the U.S. energy system over the coming years.

Below are some of the key trends and data points that can help track the ongoing development of this critical power source.

GROWING FOOTPRINT

Current installed wind generation capacity in the U.S. is roughly 152 gigawatts (GW), according to the U.S. Energy Information Administration (EIA).

That capacity is up 46% from 2019, and is 135% more than 10 years ago.

For the past decade, U.S. annual wind capacity growth has averaged 9%, which is slightly more than Europe over the same period, but slower than the global average of 13% a year, according to Ember.

The U.S. growth pace is also far slower than the 19% a year expansion posted by China, the world's top wind producer.

Still, the U.S. ranks second in terms of overall wind capacity behind China's roughly 441 GW, and ahead of Germany (69 GW), India (45 GW) and Spain (31 GW) on the top 5 list.

CHANGING POWER MIX

The steady climbs in U.S. wind generation capacity has resulted in a major swing in the country's generation mix.

Wind power accounted for an average of 15% of capacity additions to the U.S. power system from 2000 to 2010, and 27% of capacity additions since 2010, according to EIA data.

Combined solar and wind capacity accounted for around 60% of U.S. power capacity additions since 2010, underscoring the drive towards clean energy in the U.S. over that time.

As of 2023, wind power accounted for 12% of U.S. electricity generation capacity, compared with 11% for solar, 8% for nuclear, 7% for hydro, 16% for coal and 43% for natural gas, Ember data shows.

STATE & SYSTEM SPAN

Texas is by far the largest wind power generating state, accounting for 28% of total installed capacity in 2023, according to EIA.

Texas' nearly 42 GW of wind capacity compares with 13 GW in Iowa, 12.6 GW in Oklahoma, 9 GW in Kansas and 8 GW in Illinois, which are the top 5 states by wind capacity.

In terms of wind power's share of the power generated in each state, Iowa has the largest wind share of nearly 60%.

South Dakota (55%), Kansas (46%), Oklahoma (42%) and New Mexico (38%) round out the top five. Texas generates 22% of its state power from wind.

At the system level, the Southwest Power Pool - which covers 14 states stretching from Oklahoma to North Dakota - generates around 37% of its power from wind farms.

The Electric Reliability Council of Texas (ERCOT) system has the next largest wind share of 24%, followed by the Midcontinent Independent System Operator (MISO) system, with 14%.

TALLER, WIDER & CHEAPER

The size and scale of wind generation systems have grown alongside capacity.

The average nameplate capacity of U.S. wind turbines in 2015 was 2 megawatts (MW), according to data from the American Clean Power Association (ACPA) and the Lawrence Berkeley National Laboratory (LBNL).

That average capacity jumped to 3.4 MW by 2023, fuelled by increases in the average size and height of the rotors and hubs which power each turbine.

The average diameter of a turbine rotor - which holds the blades and rotates to generate power - has increased 31% from an average of 102.4 meters (336 feet) in 2015 to 134 meters (440 feet) by 2023.

The average height of a turbine hub - the main turbine drivetrain - has also increased, from around 83 meters (272 feet) in 2015 to 103 meters (337 feet) in 2023.

Wind turbine systems have become cheaper.

The average global price of a turbine sold by Vestas VWS.CO - one of Europe's largest turbine manufacturers - has dropped from around $1,700 per kilowatt hour (kWh) during 2010 through 2014 to around $1,050 per kWh since 2018, according to LBNL.

That's resulted in a more than 35% drop in the capacity-weighted average cost of a wind project, from around $2,600 per kWh from 2010 through 2014, to around $1,650 since 2018.

Lower turbine and generation costs have in turn helped lower the so-called levelized cost of wind power production, which allows comparisons of generation costs by power source once projects are completed.

In 2023, a typical power purchase agreement available to energy project developers had wind power costs at around $26 per megawatt hour (MWh), according to LBNL.

That compared with $37 per MWh for a utility-scale photovoltaic solar farm, and around $28 for a combined cycle natural gas plant, and means that wind currently ranks as one of the most economical forms of power in the country.

And with more wind project construction underway, and strong competition among turbine makers serving to keep wind system prices under pressure, additional cuts to generation costs are likely.

(Reporting by Gavin Maguire; Editing by Marguerita Choy)

((gavin.maguire@thomsonreuters.com; +720 295 6101;))