Beginning in October, the city of Austin, Texas, moved to 100 percent clean and renewable energy, produced at wind farms in west Texas and purchased from a publicly owned utility company.

The city now is subscribing to approximately 400 million kilowatt-hours of renewable energy, according to an announcement by the city, and officials believe Austin has become the largest U.S. city that’s consuming 100 percent renewables.

Austin Energy is acquiring the renewable energy for the city under the utility company’s voluntary green-pricing program. The renewable energy is approximately 5.7 cents per kilowatt-hour, and 2.5 cents more than the standard charge for residential customers. Austin will be locked into the green rate for 10 years, the city said.

“These subscriptions provide stability in electric costs for city of Austin operations and also take a leadership step forward in climate responsibility,” said Mayor Lee Leffingwell, who co-sponsored the 2007 Climate Protection Plan. “We are setting an important standard for U.S. cities. We hope other American communities will join us soon.”

But the program will come at a price: Projections estimate it will cost Austin city government about $6.9 million more annually, The Austin Chronicle reported late last month. The Austin American-Statesman newspaper put the cost even higher, at $8.5 million in added charges during the first year for the 12,000-person municipal government.

By transitioning to 100 percent renewable energy, the city will comply with one goal of the Austin Climate Protection Program, adopted four years ago by the City Council to reduce pollution. Prior to October, the city government was consuming a mix that included 20 percent renewables, according to The Austin Chronicle.

The city’s public utility, Austin Energy, services nearly 1 million people in Austin, Travis County and part of Williamson County.