The answer to North Carolina's green energy challenge is blowing in the wind-swept mesas of Texas. With the first deadlines fast approaching for North Carolina's renewable energy targets, power companies in this state are snapping up green certificates from out-of-state wind farms. The certificates don't buy electricity, but pay for credits needed to meet state targets.

One of the nation's largest electricity utilities announced its first foray into wind generation Tuesday with the acquisition of Austin-based Tierra Energy. Duke Energy Corp. said it has purchased more than 1,000 megawatts of wind projects being developed by Tierra, a small wind-energy outfit that employs six people in Austin. Duke acquired the company from Energy Investors Funds, which will retain two small natural-gas plants Tierra had owned. Tierra has no wind generation projects completed.