I know this sounds good. But have you ever calculated the land required per MW?
Not to mention what it takes to manufacture the Panels.
It depends on the business. Just think of all the wasted space of Costco and Walmart buildings and parking lots. It may not cover all their energy usage. It would reduce it a lot. With the added side benefit of shading customer cars and shading the roofs of their buildings. The same could be said for strip malls and office parks. In the long term. Solar panel installations can pay for themselves. Depending on power prices (and expected increases), solar energy potential and installation and maintenance costs in a region.