I wrote an article just today about Google's green energy strategy that addressed some of the items in this thread. The Electric industry has been a hotbed of competing approaches since its inception. Hopefully no animals will be injured by this skirmish over renewables. Google has written a nice overview of why they are motivated to purchase Green Power, so the answers to "why a business would buy green power" are there for anyone to read.
I want to focus this response on where change is needed most in order to enable and empower electricity buyers and sellers to take control over their own destiny and, in the process, bring change to the way the "evolving system" is operated for reliability and economic goals.
"Freedom to choose" could be the tag line for the changes we see occurring all around the electric industry today. Buyers want to have control over the type of fuels used to produce the energy they consume. Sellers of electricity want to build profitable businesses that can compete, and win. And there are many other parties with their own self-interest goals and objectives that would like to influence how power is produced and consumed. A new set of policies and regulations are needed that factor in the needs of buyers, sellers and other interested parties to produce a consensus approach that the majority of interested parties can live with.
Factors such as fuel mix, base load, and integration of various technologies, each with their own set of constraints and dependencies, are operational matters that need to be managed. But these are not the most significant challenges for today's electric system - these can be handled with proper engineering and operations. What is needed most is an open, transparent and fair forum to create guiding principles and agree on standards for business practices that a rough consensus of interested parties can agree to which can become regulations that help drive the industry down a more productive and collegial path.