The basic problem is energy storage. If your not talking gigawatt-days then it's not feasible and most storage currently is megawatt-hours... i.e. because you

The basic problem is energy storage. If your not talking gigawatt-days then it's not feasible and most storage currently is megawatt-hours... i.e. because you need to store energy made during the day to use at night, to make solar power realistic you need a way to store huge amounts energy. BTW: The England power grid is about 30 GW. So 1 GW-day is just shy of an hour of demand.