Electrical Standards into DC

Since there are several electrical standards: by frequency 50/60Hz, by low voltage (residential / commercial) use: 120-220-240-277-380-480V. and we could unify between European/American/Asian use changing all to DC 12Volts, which is used by cars. DC Green technologies are now present in power sources (solar panels) and most loads could be served in DC (led illumination, TVs and all electronic appliances) using USB connectors instead of power plugs. All small motors (synchronic and induction) could be replace for DC motors to use for blenders, fridge, air conditioning, ...), panels could be transformed to fuse panels as we have on cars.

The intention is that almost everyone could have a solar panel source to provide most energy to electric loads so that traffic illumination and control, residential and commercial could be reduced to minimum possible and also industrial could be reduced.

Look up the electricity wars where Edison and Westinghouse were electrocuting animals to defend which was better: AC or DC. Edison went as far as using 6900 volts on an elephant. They would routinely send entourages out on publicity campaigns to kill hundreds of dogs, cats, horses...you name it, they fried it...all in the war over AC vs DC.

You need the higher voltage to reduce losses (I**2 x t). It is much easier to change voltage with AC, not to mention the switching and fault current issues.
AC it is and I can't ever see us going backward. Certainly there is a place for DC in low power and electronics and maybe intra-facility nanogrids, but just the copper savings alone dictate higher voltages for any reasonable load.
Ignoring production and transmission, we can and have sort of come into a sort of standards. 12VDC is very common. 5VDC is also quite common.. i.e. USB.

As for your goal, the mini and individual grid model does work very well for large grids as it is digital and there is no requirement for current sync like we have with AC.

My issue is that you don't simply plug into a PV array. You will need a buffer in the form of a battery. This is the direction Tesla, the company, has taken with their home battery system. I feel that will be the future. You can still convert to whatever voltage you'd like, but 12V may be too low based in the wattage required to break ice in a blender.