Cost is both a long term and short term issue, but in the long run the more space you need to generate power the higher the cost is going to be. Renewability is nice but isn't a real issue for any of our current sources of power. The problem with cleanness as a guide is that the two most clean methods we have right now for power (wind and sun) are grossly inefficient and you'd have to pretty much blanket the country with them to generate the power we need.
Cost is both a long term and short term issue, but in the long run the more space you need to generate power the higher the cost is going to be. Renewability is nice but isn't a real issue for any of our current sources of power. The problem with cleanness as a guide is that the two most clean methods we have right now for power (wind and sun) are grossly inefficient and you'd have to pretty much blanket the country with them to generate the power we need. Ok that's a better answer. As you mentioned cost is not that simple either because there are long term costs. Renewability is an issue if there is a negative effect to any of our current methods or if the supply of any of our menthods is beginning to be an issue. We all know that we have plenty of coal and uranium.
Believe it or not public opinion actually counts for something and people want clean renewable energy. Most of us don't buy that nuclear energy is clean.
People misuse the term inefficient when they describe wind power. It is not inefficient, it is intermittant which is a totally different thing.
Texas, N Dakota and Nebraska could easily provide all the wind power this country uses which is 3 quads per year.