good thread.
although replacing existing 220/110 60hz power might be more efficient it would be a major investment by the average consumer in replacing all of their existing ac goods into a dc format. not to mention the cost to manufacturers in redesign of their product lines, standardization of voltages distribution of said voltages and overcoming the difficulty of even moderate distance voltage drops. this could be the realization of Edison’s dream of a dc distribution network that was shot down by Westinghouse and Tesla. in a transition to dc there could be benefits to dual service. but for the average consumer fast change would be economically unfeasible. imagine the workforce of electricians required to rewire neighborhoods and individual houses not to mention sky scrapers and industrial facilities, businesses hospitals ect. a major impact.
ac has served us well for power transmission and industrial applications. could you imagine the use of 3 phase motors without ac. I have and looking at just the power requirements of dc vs ac ac wins. lower currents for a given horsepower which means smaller conductors and switch gear which means lower cost.
society for the most part is resistant to change. they must have a worthwhile reason to convert to dc.
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in the interim i believe that a shift from coal fired to fusion source of energy would have great impact on the use of energy as affordable it could become. heating or cooling dwellings electrically rather than gas, charging vehicles for commuting rather than fossil fuel, refrigeration costs go down decreasing food costs. all of these would greatly help out the consumer. with no change to the infrastructure that we currently enjoy.

employing many substation generator facilities throughout our current network gradually would phase out coal fired plants along with dams, wind,solar, nuclear,tidal ect. this would give time for society to embrace the new technology while they feel zero impact on their lives other than a few more bucks in their wallet. it also gives time for exploring explaining the benifits of dc to the world and why it could be the next best thing.

first and foremost we must create the viable equipment necessary to make the change to fusion (working on it) secondly the infrastructure could be modified to include dc but economics seem to dictate how and when that occurs. just because we conceive a better mouse trap does not mean that it will come into wide spread use especially when an old scrappy cat does the job.