UPDATE 1-RWE, consortium to build solar plant in Spain

* Plant is one of biggest solar thermal projects worldwide

* Technology comes from Solar Millennium

* Solar Millennium already present in Spanish solar industry

(adds details, share price)

FRANKFURT, July 10 (Reuters) - RWE Innogy (RWEG.DE) and a consortium will build a solar power plant called Andasol 3 in southern Spain, developed by Solar Millennium AG (S2MG.DE), the parties said in a statement on Friday.

It said that Stadwerke Munich, plant builder MAN Ferrostaal, RheinEnergie of Cologne and Eerlangen-based Solar Millennium would form a consortium with RWE Innogy for the unit.

The 50 megawatts (MW) plant is already under construction and will be opened and operated by the project partners in 2011.

"The parabolic trough technology sets new standards for solar power production," said RWE Innogy chief executive Fritz Vahrenholt.

"It is suitable to large-scale applications and thanks to giant thermal salt storages can keep producing after sunset an electricity which is both reliable and absorbable by the transmission grids."

The utility companies for Munich and Cologne said their participation in the project will help them meet their own targets to increasingly tap renewable energies to feed their power distribution businesses.

Solar Millennium already helped develop the Andasol 1 unit of the same size, Europe's first such plant, which was inaugurated in July, while unit 2 is under construction.

Once up and running, the three units together could supply 170 gigawatt hours (GWh) per year, enough for 500,000 consumers, the statement said.

The Munich utility takes a 48.9 percent stake in project company Marquesado Solar S.L. while RWE Innogy and RheinEnergie in a joint unit led by RWE will hold 25.1 percent.

The remaining 26 percent will be held by an entity formed jointly by MAN Ferrostaal and Solar Millennium.

RWE shares were 0.08 percent down at 53.05 euros at 0933 GMT while the blue chipe DAX index .GDAXI was 0.17 percent off.

(Reporting by Vera Eckert)