Regarding the location of generation plant, given that thermal generation using a steam cycle (coal, gas, nuclear, oil, bio-mass, waste incineration etc) accounts for the vast majority of electricity generation and is likely to for decades to come the plant should be as close to consumers as possible.  These thermal plants waste two thirds of the heat output up the chimneys and cooling towers (only(!) half for CCGTs).  This waste heat should be reused in district heat and power systems thus increasing the efficiency from ~30% to more like ~80% requiring the plant to be local.

There are pollution issues with large scale combustion close to population centres but `technology' can go a long way to clean the kinds of pollutants that local populations is concerned with.  City centre nuclear plant is unlikely to be popular neither is nuclear district heating though it is used in Russia.