What are the reasons why we do not use current technology to move towards alternative energy sources (i.e. nuclear energy source instead of coal)?

The previous posts are entirely accurate in that there is a great deal of cost associated with pioneering new technologies and that there is a relatively low cost in using oil and burning fossil fuels.  I am going to take this in a different direction, though, and focus a bit on why the United States is so dependent on oil. This might sound conspiratorial, but I think that there might be some level of validity present.  According to statistics produced, 42% of all oil production is domestic.  This is a sizable chunk and this particular segment possesses enough political and economic capital to ensure that their voices are heard in government.  They utilize the ability to petition the government quite effectively.  The remaining comes from abroad, and in particular what lies in the Middle East, in particular Saudi Arabia.  In my mind, the relationship between the United States government and the oil producing nations, such as the Saudi Arabian government helps to make certain that our dependence on oil will not be precluded by investment in new technologies.  At this time, the Saudis provide about 13% of our total oil supply.  Yet, the amount of oil reserves sitting in the Saudi Kingdom and adjacent to it totals about 255 billion barrels of oil.  The amount of oil in the United States is nowhere near that amount, and even if it were, it lacks the institutional capacity to produce this much.  This means, that the United States, with its dependence on oil, has to look to the Saudis in order to provide it.  There is a reason that the Saudis price their oil in US dollars, the only nation to enjoy that benefit.  Additionally, the relationship between the US and Saudis has enjoyed complete stability, even though an overwhelming of the hijackers from September 11 came from Saudi Arabia.  In the end, the dependency on oil is what guides our interests in the region.  The fear is that if there is an investment in other resources outside of oil, then this oil can be taken by another producing nation such as China.  In order to prevent this level of growth and to ensure that there is a steady supply to feed the US dependence on oil, there cannot be a full fledged investment in alternative resources.  There is a wonderful movie that articulates this phenomenally well called "Syriana."  The relationship between the US and Saudi government and how there might exist a collusion based relationship between the oil business and government policies is brilliantly articulated.  This might also help explain why we do not use current technology to move towards alternative energy sources.