A consortium of 12 European businesses outlined an ambitious plan Monday to build a massive solar-power facility in North Africa that they said could satisfy 15 percent of Europe's energy needs by 2050. The so-called Desertec project involves, among others, German industrial conglomerate Siemens AG, power companies RWE AG and E.ON AG, reinsurer Munich Re AG, Deutsche Bank AG and Swiss-based electrical engineering firm ABB. The project would be based largely on solar thermal-power plants, which use mirrors to focus the sun's energy to heat a special oil, create steam and power generators. Such power plants are already running in the US, Spain and elsewhere. Power would be transmitted to Europe across a new 3,000-kilometer network.