A proposal to build the world's biggest solar-thermal power plant in the Southern California desert got the go-ahead Monday from the Obama administration, which used the announcement to bolster its message that renewable energy creates jobs. The $6 billion project is being developed by Solar Trust of America, a joint venture between Germany's Solar Millennium AG and privately held Ferrostaal AG on 7,025 acres of federally owned land near Blythe, Calif. The approval clears the way for the developers to seek federal grants and loan guarantees.The Obama administration has been criticized over the past year for hurting job creation by...