The ease of introduction of FF power into existing grids will vary from state to state. Governmental red tape and political opposition from vested interests will provide obstacles in some states. In California and possibly many other states the process may not be so difficult.
During one of our many energy crises, California lawmakers passed legislation permitting private entities and individuals to generate electricity and requiring the power companies to buy it at the rate that it would cost the power companies to generate it themselves. The results have been multifold. Power companies have not built any major generating stations since the Diablo Canyon nuclear facility almost thirty years ago, even though the population of the state has increased by thirty percent since then. The law has allowed a competition among sources of electricity which has resulted in about forty percent of our power coming from these private entities, which generally burn natural gas. I have not heard of any significant bureaucratic hurdles to their proliferation.
This legal framework and the history of power generation in this state would indicate that FF power might find a ready entry point here and perhaps in a number of other states. The low projected cost of generation (did I hear .2 cent/kwh?) would be a powerful selling point.