UPDATE 1-U.S. approves world's biggest solar power project

* First phases of project to produce power in 2013, 2014

* Project expected to get Energy Dept loan guarantee

* Rows of mirrors 192 meters long will collect sun's rays (recasts, adds project price, start-up date)

By Tom Doggett

WASHINGTON, Oct 25 (Reuters) - The world's biggest solar plant that plans to provide power to more than 300,000 homes in southern California was approved by the U.S. Interior Department on Monday.

The $6 billion, 1,000-megawatt project, a joint venture of Solar Millennium AG (S2MG.DE: Quote) and Ferrostaal AG, will be located on federal lands near Blythe, in the southern tip of California.

"The Blythe Solar Power Project is a major milestone in our nation's renewable energy economy and shows that the United States intends to compete and lead in the technologies of the future," said U.S. Interior Secretary Ken Salazar.

The project by the two Germany-based firms fits with the Obama administration's drive to boost renewable energy sources like wind and solar power and create thousands of clean energy jobs in the process.

This the sixth solar power project approved by the department in the last few weeks, which together have the potential to generate 2,800 megawatts of electricity, enough to power 2 million homes.