AT&T announced Thursday that it's buying a giant amount of wind power from farms in Texas and Oklahoma.

The Dallas-based telecom is purchasing 520 megawatts of wind power from two farms that will be operated by subsidiaries of Florida-based NextEra Energy Resources. On the high end, that's roughly equivalent to taking 350,595 passenger vehicles off the road or providing electricity for a quarter-million homes a year.

Some of the wind power will be generated by a farm in Caddo County, Okla., about 70 miles southwest of Oklahoma City, and some will be generated by a Texas wind farm across Webb and Duval counties near Laredo.

The purchase puts AT&T in the company of Google, T-Mobile and many other corporations that have stepped up their renewable energy use as a way to promote sustainability and in some cases, reduce costs. AT&T has joined the Corporate Renewable Energy Buyers' Principles, a coalition of large companies advocating for renewable energy. The group is led by the World Wildlife Fund, a global conservation organization.

Scott Mair, president of AT&T operations, said the wind power will help offset AT&T's energy use. He said the company's cell sites, routing and switching equipment and other infrastructure are very power-intensive, but AT&T has worked hard to shrink its carbon footprint.

"We'll stay on that path and continue to do everything we can in being good corporate citizens for sustainability," he said.

Chad Singleton, principal analyst for North America power & renewables at Wood MacKenzie, said AT&T's announcement isn't surprising. It's a savvy publicity move and it makes economic sense. The cost of wind-generated electricity has dropped significantly, in part because of federal tax credits, and that's made it more attractive for companies, he said.

In a recent earnings call, NextEra Energy CEO James Robo said wind had become the company's cheapest form of energy to generate at 1.2 to 1.8 cents per kilowatt hour at high-wind sites. He said costs of operating an existing coal or nuclear generating facility range from 3.5 to 5.0 cents per kilowatt hour.

One of AT&T's wireless competitors, T-Mobile, recently announced it is funding its second wind farm project and has pledged to use 100 percent renewable energy by 2021. In a news release, T-Mobile CEO John Legere said the move benefits the environment and the company's finances. He said T-Mobile's energy costs will drop by around $100 million over the next 15 years.

Amazon has a wind farm in Texas that's between Abilene and Lubbock in Scurry County. The company hired Chicago-based Lincoln Clean Energy to build and operate it. Amazon will purchase about 90 percent of the power generated by the wind farm to offset the energy used by its data centers.

Apple funded construction of a wind farm in Oregon in a step toward its goal to power all of the company's global facilities with renewable energy.