Difficult to produce
I would bet a large doughnut on the fact that from an energy perspective it will never be viable. For something like this to actually have an impact there has to be the possibility that you get more energy out than went into making the thing in the first place. This is where so much of the PV solar industry falls down. The embedded CO2 in the panels is horrendous and you really have to question if we would be better off just burning the coal, oil, gas or whatever to make more electricity or petrol in the first place.
It does however give the greens a warm fuzzy feeling and the PVs bandits a license to print money, ripping bill payers off in the process. But his is a Government scheme so it must be okay.