Found two articles about Fed Ex's latest activities to go green. FedEx Ground to Install US's Largest Rooftop Solar Power Array at New Jersey Distribution Center : TreeHugger FedEx Converts 92 Delivery Trucks to Diesel Hybrids with Lithium-Ion Batteries : TreeHugger
A closer look might show that this is due to solar becoming profitable more so than any other reason.....and there is nothing wrong with that.
They've been doing it for awhile(completed in 2005 in Oakland airport): http://www.renewableenergyworld.com/rea/news/article/2005/08/cas-largest-corporate-solar-project-completed-35351