UPDATE 2-GDF Suez Q1 profit rises on emerging markets, gas

* Q1 EBITDA rises 5.7 pct to 5.8 bln euros, sales up 10.5 pct

* Keeps forecasts including International Power acquisition

* GDF Suez shares closed down 2.7 pct

PARIS, April 23 (Reuters) - French utility GDF Suez posted a 5.7 percent rise in first-quarter core earnings, thanks to growing demand at its natural gas business and contract wins in fast-growing emerging markets through British unit International Power.

Japan's nuclear disaster last year has meant several governments have turned their backs on nuclear power, helping boost demand for natural gas.

Nuclear energy took up 10 percent of GDF Suez's total 2011 energy production capacity while natural gas represented 55 percent.

At its annual shareholder meeting on Monday, GDF Suez confirmed it would detail its nuclear strategy review by mid-year, in line with what it said in November after Belgium proposed raising its nuclear tax and exiting nuclear power by 2025.

Belgium is looking into what energy forms could replace nuclear energy before deciding on the fate of seven nuclear reactors at two plants, owned by GDF Suez's Electrabel.

"We have not been contacted yet by the Belgian government but it will happen soon, by the end of this month," vice-chairman Jean-Francois Cirelli told shareholders.

GDF Suez said first-quarter core profit, or earnings before interest, tax, depreciation and amortisation (EBITDA), rose to 5.8 billion euros ($7.7 billion) on revenue up 10.5 percent to 28.2 billion.

The group still expects 2012 net recurring income to grow to 3.7-4.2 billion euros from 3.5 billion last year, provided it completes the acquisition of the 30 percent stake it does not own in International Power, which it expects to contribute 200 million euros.

"The first-quarter results are a strong step in the right direction, further confirming the outlook we gave for 2012," finance director Isabelle Kocher said.

GDF Suez's earnings follow those of International Power, benefiting from its strong presence in emerging markets, and French group Suez Environnement, which saw Europe's economic slowdown weigh on waste volumes.

GDF Suez recently improved its bid for the remainder of International Power, leaving it better placed to win contracts in the Middle East and Asia-Pacific. To fund the acquisition, GDF Suez boosted its asset sale plan by 3 billion euros to 13 billion by 2013.

Also on Monday, the companies announced the expansion of capacity at three of their Tihama power sites in Saudi Arabia, adding 532 megawatts (MW) and 2,210 gigajoules per hour (GJ/h) of steam in a deal from Saudi Aramco for about $430 million.

International Power owns a 60 percent stake in the Tihama project, which should have total capacity of 1,595 MW and 8,112 GJ/h of steam after its expected completion in 2015.

GDF Suez benefited from a rise in sales of liquid natural gas, mainly to Asia, saying volumes more than doubled to 16 terawatt hours (TWh).

Data earlier this month showed Japan, the world's top LNG buyer, imported a record 83.2 million tonnes in 2011/12 largely due to an increase in gas-fired power generation after the Fukushima nuclear crisis.

GDF Suez has forecast natural gas consumption should increase 3.5 percent annually in Asia's developing economies, and in China in particular. Europe's economic crisis has widened the gap between the region's more mature and competitive energy markets and emerging markets.

Shareholders voted in favour of extending the age limit of GDF Suez chairman and chief executive Gerard Mestrallet to 67 from 65, allowing him to stay until 2016. Mestrallet has been at the helm since 2008.

Shares in GDF Suez, 36 percent owned by France, closed 2.7 percent lower, almost in line with France's main CAC-40 index but underperforming a 1.8 percent drop in a European utilities index.