Don Bogard, radio-geochemistry, nuclear geochemistry, planetary science: This article is another scientist's opinion on use of fossil fuels and what will be required for a transition when fossil fuels eventually run out or if governments decide to force abandonment of these energy resources that have created the modern world. He makes a very important conclusion: "Any significant change to the US power infrastructure MUST be a measured and long-term endeavor." There are several reasons for the long transition time: a) We don't have the technical ability to build nuclear plants that fast. b) We must establish used nuclear fuel reprocessing, mainly to save the unused 99% of nuclear energy from the ore. Don't put it back in the ground "forever." c) We must establish standard ways of storing the remaining radioactive waste. d) Nuclear power should only be used in countries with stable governments, strong economies, good education systems, well developed industries to perform some of the maintenance operations. e) We must develop additional nuclear power technologies besides the very large Light Water Reactors of the past. Don Bogard understands these needs. Too many outside the nuclear power profession wrongfully claim that the whole world can be owning and operating nuclear plants in fifty or one hundred years. In reality, it will be several centuries, maybe longer. We must have wise energy planning for the whole world NOW. That must include fossil fuels for generating electricity, not abandoning them for wind and solar.