The article explains that the trees are only glowing because they are being illuminated by ultraviolet light - the energy comes from the UV.
I would imagine that this would be much less efficient than normal lighting and constant exposure to UV probably wouldn't do the trees or people any good at all.
usually plants/animals that glow provide their own UV light via a luciferase/luciferin system. Still takes energy.
At that point, you might as well just engineer a luciferase system (three well known ones: renilla, firefly, bacterial) that emits blue light and throw in a chain of flourescent proteins (gfp, rfp) that shunts an appropriate amount of color down the chain. Then, you could use a promoter system to force expression only on the bottom side of the leaf, and only during the nighttime.
Very possible within the realm of current science, the only question is how well would the tree tolerate it. And considering it takes years for a tree to get that big, that's a long time to wait to find out.
I would imagine that this would be much less efficient than normal lighting and constant exposure to UV probably wouldn't do the trees or people any good at all.