This is one of the best discussions I have seen on energy in quite some time. However, there are still a few points that have not yet been introduced, so I will try to add to the flavor while remaining on topic.
@watthead - I am with you on the need for clean, cheap, energy and agree with John that you need to add reliability to that goal statement. One reason is that it is not true that one kilowatt-hour is like another and has equal value. The customer really does care whether or not the light burns with the prescribed intensity when he throws the switch. Those of us who operate motors and semiconductors REALLY care about the quality of the current that flows when we demand it.
Anyone who has ever been at a tailgater or has experienced the aftermath of a hurricane can understand the extreme jealousy that can be stimulated when your neighbor's lights and refrigerator works while yours do not. That emotional response explains why there are some times when you are willing to pay far more for power than you are at other times.
There are "early adopter" markets available for useful energy sources. Think about the rich folk that like beautiful views from the top of a mountain where the nearest distribution line is several miles away. How do you provide that mountain retreat with reliable power for the Sub Zero refrigerators and big screen TV's? That customer is willing to pay a pretty penny if you can demonstrate a reliable power source that will not destroy his expensive toys and will make sure they do not conk out in the middle of the big game. What about off shore oil rigs, mining or lumber towns, 100 meter yachts, or seaside resorts on distant islands? If you really have a power source that works, why not sell it to those customers and learn enough in the process to bring the price down - if that is possible.
Here is my rub with your argument about how to make something "cheap". Some basic analysis makes some of us scoff at the notion that it is worth much time or money to try to develop certain types of politically approved "renewable" power technologies. The wind will NEVER blow when you want it to (I have been a competitive sailor, so I am pretty well aware of wind limitations and variability) and the sun sets with depressing regularity (even here in the mid Atlantic regions, I go for whole weeks during the winter when I never see the sun - I am at work before it rises and depart after it sets.)
I am also pretty well versed in the most advanced battery technologies; I have owned a number of laptops, cell phones, and handhelds, plus I know more about submarine batteries than I am allowed to share. The amount of stored energy is tiny compared to the demand that would be placed on batteries to fill in the gaps in a wind or solar powered grid.
You do not understand the history of atomic fission. Light water reactors DID NOT come from weapons programs. They were developed to solve a very challenging POWER problem - how do you supply reliable power to ships that have no access to oxygen and can not discharge waste products because they are SEALED environments. It turned out that the only technology available was something using fission, and at the time, the only fission power source that could be squeezed into the available space was a steam plant. At the time, the only available Brayton cycle gas turbines were lasting about a hundred hours each while hanging under the wings of some demonstration aircraft.
If there had not been a war on when Fermi, Hahn, Meitner, Szilard, and others figured out fission, we would have had small atomic power plants without ever having gone in the weapons direction. CP-1 showed just how simple it would be to construct heat sources using fission. Please do not try to tell me that Europeans, Americans, Asians and Africans of the 1930s and 1940s were unaware of the high costs, pollution and economic unfairness caused by society's growing dependence on burning coal, oil and gas. Early fission researchers were very excited about the possibility of clean, affordable energy using the concentrated nature of the brand new phenomenon that they had discovered.
The cost structure of the commercial nuclear power industry has a lot more to do with the fact that the government selected developers had goals in mind that conflict with those of ordinary people, like continuing to protect fossil fuel dominance. The technical potential, however, of fission is that it can provide reliable, emission free, affordable power in a variety of ways - including the LFTR that Charles Barton describes. (I personally like atomic gas turbines with high temperature pebble bed reactors, but recognize that there are an almost infinite number of ways to use standard heat engines to produce useful power from fission.)