* Net profit 12.55 billion crowns, vs forecast 13.23 bln
* Confirms full-year guidance, sees similar 2010
* Shares down 0.8 percent
(Adds quotes, forecast, updates share price)
By Jan Korselt and Jana Mlcochova
PRAGUE, Aug 13 (Reuters) - Czech electricity group CEZ posted a 4 percent fall in second-quarter net profit, missing forecasts after demand for energy fell and as margins were hit, but confirmed guidance for 2009.
Central and eastern Europe's largest listed power company also said on Thursday its performance in 2010 should be similar to this year.
CEZ made an April-June net profit of 12.55 billion crowns ($686 million), below a forecast for 13.23 billion. Revenue rose 1.2 percent to 42.3 billion crowns.
"The recession affected demand for electricity in the Czech Republic, mostly in April and May when the year-on-year drop reached 10 percent," CEZ said. "The June figures, however, returned to the previous level of minus 6-7 percent."
Shares in CEZ, active throughout central and eastern Europe, dipped 0.8 percent to 975 crowns at 0845 GMT, lagging a 2.8 percent jump in the country's main PX index.
"It (results) is slightly negative because you can see the figures at all levels are below market expectations," said Jakub Zidon, an analyst at Ceska Sporitelna. "Primarily it was lower sales (behind the dip)."
CEZ said sales and margins had dropped due to lower spot prices and optimising output to save carbon emissions permits. It said income from the saved permits would be booked at the end of the year.
Utilities in Europe have been hit by a slide in demand and prices as key industrial customers cut energy use as the economic crisis weighs on demand for their products.
CEZ confirmed full-year guidance of a 6 percent rise in net profit before minority shares are deducted of 50.2 billion crowns. It also still saw year earnings before interest, tax, depreciation and amortisation (EBITDA) rising 2 percent.
The company said it expected the economic crisis to affect its performance in the second half but the forecast would be met, and power production in CEZ's own plants would rise to 61.3 TWh from 60.4 TWh last year.
Finance director Martin Novak said similar results could be expected next year. "Electricity prices are similar or lower for 2010 compared with 2009," Novak said. "That should lead us to lower revenue and profits, on the other hand we are very well able to compensate for that by cost savings."
CEZ has sold about three quarters of its 2010 electricity.
Its stock has lost 20 percent of its value over the past year, in line with the Prague market. (Writing by Jan Lopatka; Editing by John Stonestreet and Dan Lalor) ($1 = 18.29 Czech crowns)