Setting aside the day to day practicalities of off grid living (always watching energy use, no electric heat or cooking, the possibility of running out), the ma

Setting aside the day to day practicalities of off grid living (always watching energy use, no electric heat or cooking, the possibility of running out), the main issue is that this is the middle of the city. A block of apartments might be 6 storeys tall - a 50m2 flat would therefore only have 8.3m2 of rooftop - there's simply not nearly enough rooftop area to generate the power the building needs. Solar wouldn't even be particularly useful for peak compensation, as generally the UK peaks fall on winter evenings, while solar only makes useful power in summer. A better solution would be just the batteries. If these buildings had enough battery storage to compensate for usage during the few peak usage hours per day, the effect of new buildings on the grid would be negligible (as the grid is basically underutilised for most of the day). Then the solar could be built much more cost effectively in a field out of the city.