San Francisco Chronicle: The Sahara gets twice as much sunshine annually as most of Europe. The European Union wants to get 20 percent of its electricity from renewable sources within a decade. So why not build solar power plants across North Africa and ship the electricity north via power lines under the Mediterranean? Over the past year, more than 30 European companies have joined the Desertec Industrial Initiative, a consortium that seeks a $560 billion investment in North African solar and wind …