Science: Are there any unbreakable laws of physics that we would have to break thus making the proposition impossible? (i.e. things like conservation of energy or the speed of light). I can't think of any, so my answer to that is no. If anyone disagrees, please raise those objections early.



Engineering: This is where I would like to focus this thread. Is it practical? What are the engineering, economic, or legal obstacles to PV scalability?



Social: Just because we can do something doesn't mean we should. I would like to leave social questions, including renewability or the cleanliness of PV, out of this discussion if possible. I also note that it would not make sense to abandon wind or any of our existing investment in electric generation even if 100% PV is possible. I mostly fear that the discussion in this thread may become too unfocused if we include social issues. PF already has a thread YOU!: Fix the US Energy Crisis for unfocused energy discussion.

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To make this thread interesting, let's dump the suggestion to place all that capacity only in Arizona.The sun shines in all places in the lower 48 states, but because of weather, and because of latitude, PV panels are most effective per ##m^2## in some regions. However as Jim pointed out in #3, the cost of panels is only $0.86 out of a total installed cost of $5/kw. If we had to add 50% or even 100% more ##m^2/watt## to compensate for location, it wouldn't have a big effect on costs. Therefore, the benefits in locating all the generation in a sunny region are tiny compared to the massive costs of transmitting that power to the entire 48. Please let's scratch that part of the idea and focus on the potential of PV distributed over the entire country, close to the loads.The interesting part of the question is scalability. Could the use of PV solar plus storage be scaled all the way up to the ultimate extreme of 100% of our electric capcity? The question must be asked on three levels.42% of the USA population lives in multifamily housing with 5 or more units with very few ##m^2## of rooftop per tenant. Also as a guess, half of the single family homes have shade trees or orientation, or blocking hills or mountains that make PV unsuitable for them. Therefore, a discussion of PV solar scalability necessarily includesconsumer-owned rooftop PV and utility-owned central PV generation.Given all the above, the existing bulk power transmission grid would remain largely unchanged in form and in public need by conversion to PV. We don't need to include that in the discussion at all. Local power distribution at the neighborhood level however, faces some major challenges.