Grocery Store Skylights

The paragraph below is found in the article written by Christopher Anderson (See the link below)

I’ll likely recommend a skylight retrofit project that may increase sales, reduce energy spend, and cut emissions.  Natural light is free and has long been known to be the best form of light available.  Numerous studies have shown improvements in employee morale, productivity, and even increased retail sales, all attributable to natural light.  Though either initially not considered or deemed not viable, I've changed some minds through my even conservative analysis.  If skylights were retrofitted at a third of Ahold USA stores, we'd likely save more than 13,000 metric tons of CO2 per year with a five year net present value nearing $30 million.