Nearly a decade ago, Duke Energy placed several weather towers along the Gulf Coast to measure winds coming off the Gulf of Mexico. Duke's engineers were soon struck by one particular characteristic of the sea breezes: They blow like clockwork.

This realization helped spur the development of a rapidly growing energy source that is beginning to challenge, or at least cut into, the dominance of West Texas wind farms, which account for more than 70 percent of the state's wind energy. While the generating capacity along the coast is still a fraction of that in West Texas, and wind speeds are far lower, Gulf wind is becoming more important to the state's energy mix because it blows more reliably and when the power grid needs it most, during high demand periods in the morning and afternoon.

The well-timed supplies can help ease price spikes in wholesale markets on hot summer days and lower customer bills.

"The nice part about the Gulf Coast wind generation is that it tends to be very consistent and it happens at peak," said Chris Coleman, the senior meteorologist for the Electric Reliability Council of Texas, which oversees 90 percent of the state's power grid. "West Texas tends to be very erratic."

Since Duke, headquartered in Charlotte, N.C., developed its first wind farm in 2012, wind generation capacity along the Gulf Coast has increased sixfold, from 500 megawatts to 3,000, about 15 percent of the state's total wind generating capacity of nearly 20,000 megawatts. (One megawatt can power 200 average homes on a hot Texas day.) Today, nine wind farms stretch from north of Corpus Christi to Brownsville, and at least four more projects are planned.

The developments are benefiting the Gulf economy, particularly in rural stretches where jobs and industry are scarce. Duke alone has invested more than $1 billion to build five South Texas wind farms dubbed Los Vientos.

In Willacy County, where the unemployment is above 10 percent, more than double the state average, Duke Energy's two wind farms have become the largest private investment in this ranching and farming community of about 20,000. Construction on the first two wind farms generated 300 jobs in the area, created new income streams for farmers and ranchers, who lease their land, and generated much needed revenue for local governments and schools.

The Willacy County development pays about $650,000 a year in taxes to the county. Lyford Consolidated Independent School District, which serves Lyford and unincorporated areas of Willacy and two other counties, receives the largest tax benefit from the wind farm, about $31.5 million over 15 years.

"One of the biggest positive impacts has been education," said Robert Pena, president of Texas Energy Consultants, a Hidalgo County firm that helped Duke scout wind farm locations. "With these additional wind farms, and facilities on farm lands, it's boosted the economy."

Back to Gallery Sea change: Gulf Coast wind farms become vital to Texas... 9 1 of 9 Photo: JOHN DAVENPORT, SAN ANTONIO EXPRESS-NEWS 2 of 9 Photo: JOHN DAVENPORT, SAN ANTONIO EXPRESS-NEWS 3 of 9 Photo: JOHN DAVENPORT, SAN ANTONIO EXPRESS-NEWS 4 of 9 Photo: JOHN DAVENPORT, SAN ANTONIO EXPRESS-NEWS 5 of 9 Photo: JOHN DAVENPORT, SAN ANTONIO EXPRESS-NEWS 6 of 9 Photo: JOHN DAVENPORT, SAN ANTONIO EXPRESS-NEWS 7 of 9 Photo: GLORIA FERNIZ, SAN ANTONIO EXPRESS-NEWS 8 of 9 Photo: EDDIE SEAL, BLOOMBERG NEWS 9 of 9 Photo: GLORIA FERNIZ, SAN ANTONIO EXPRESS-NEWS

















The center of the state's - as well as the nation's - wind energy production is West Texas, where wind turbines tower over desolate reaches of the Texas Panhandle, extending into the distance in some places as far as the eye can see. The region accounts for 73 percent of the wind power flowing into the grid overseen by ERCOT; in 2016, Texas accounted for 25 percent of the nations' wind power. At times, the winds that blow across the state's flatlands produce so much power that they drive the price of electricity in wholesale markets to zero.

The problem, however, is that the winds are strongest overnight, when electricity demand is low, and weakest in summer, when demand is at its highest, making West Texas wind power, even in abundance, inconvenient. Along the coast, however, generators can count on steady winds at least twice a day because of temperature differences between the Gulf and land.

The ocean retains heat longer than land, so in the early morning, cooler air onshore rushes to replace the heat rising from water. By late afternoon, hot air is rising from the land, and cooler air flows from the Gulf to replace it. Both effects mean reliable winds for power producers.

The growth of the Gulf Coast's wind energy has been aided by advances in turbine and blade technologies, allowing producers to generate electricity at lower wind speeds, said Andrew Dickson, managing director for business development for Duke's renewable projects. Taller turbines and wider rotator have increased the average power that a wind project can produce, making projects profitable in areas where before they wouldn't have generated enough power, Dickson said.

Beyond reliable sea breezes, South Texas' other appeal is its proximity to cities and industries that are hungry for power. Unlike West Texas, which is far from the most populous parts of the state, Gulf Coast wind farms are near Houston, its suburbs and industrial complexes. In addition, more transmission is available to move the energy to wholesale markets, where prices are higher than in West Texas.

"You want the ability to essentially plug into the energy grid," said Paul Copleman, spokesman for Avangrid Renewables, which has three wind farms on the coast south of Corpus Christi, "and the Gulf Coast has that in more abundance."

Mark Goodwin, CEO of Apex Energy, has been intrigued by the Gulf Coast's wind power potential since 2009, when the company was founded. Developing wind farms in South Texas had its challenges: Space was limited and the area lacked the familiarity with wind projects that make them easier to build in West Texas. Competitors were perplexed by Goodwin's interest in the region.

But the predictable winds, higher wholesale electricity prices and the promise of supplying the growing power demand from refineries, chemical plants and other industrial customers along the Gulf, encouraged Goodwin. The company expects to build three more wind farms along the coast - one is already under construction and two are in the planning stages.

"There is no way that this won't be a sought-after energy resource," he said.