Totally not viable for a grid-scale installation.

Main issue is that voltage transformation in DC comes with massive losses, and so does power transfer at 100-200V.

AC allows you to easily and efficiently scale voltage up and down. Transmission lines are typically at 10.000-500.000V, allowing them to move massive amounts of energy with low amperage. As energy losses are dictated by amperage, keeping it low means your grid is very efficient.

Also, while there's a growing requirement for various kinds of AC to DC converters to charge various batteries and use electronic devices, switching grid to DC will come with a giant reverse problem, as everything with a motor would need to convert from DC to AC. There are plenty of electric motors out there, some of them very sensitive to the imperfect output of most converters.

So, yeah, as much as I love the simplicity and low-scale efficiency of DC, it just won't work too well when scaled.