* Q4 net income C$62 mln vs C$79 mln
* Q4 comparable C$0.40/shr vs C$0.37/shr expected
* Cash flow rises 26 pct
CALGARY, Alberta, Feb 24 (Reuters) - TransAlta Corp (TA.TO) said on Thursday its fourth-quarter net income fell 22 percent as the power producer wrote down the value of some of its generating stations.
The company, which runs coal, gas and renewable power facilities in Canada the United States, Mexico and Australia, posted net income of C$62 million ($63.2 million), or 28 Canadian cents a share, down from C$79 million, or 37 Canadian cents, in the fourth quarter of 2009.
Comparable earnings, which exclude most one-time items, rose 4.8 percent to C$88 million, or 40 Canadian cents a share, from C$84 million, or 40 Canadian cents, on improved reliability of its power plants and a better performance from its trading business.
Analysts, on average, had forecast comparable earnings of 37 Canadian cents a share, according to Thomson Reuters I/B/E/S.
Revenue rose 6.2 percent to C$811 million.
Cash flow, a measure of the company's ability to fund new projects, rose 26 percent to C$309 million from C$246 million in the year-earlier quarter.
TransAlta's availability, or the amount of its power-generating capacity that was running, averaged 91.4 percent in the quarter, up from 87 percent.
The company wrote down the value of some of its coal and gas-fired plants by C$54 million in the quarter and reported a C$28 million gain from its hedging program.
TransAlta shares were up 2 Canadian cents at C$20.61 by late morning on the Toronto Stock Exchange. The shares have fallen 14 percent over the past 12 months versus a 20 percent rise by the exchange's benchmark index over that period.
$1=$1.02 Canadian Reporting by Scott Haggett; editing by Rob Wilson