My instinctive response: if the parking lot is too large to generate power that will be consumed at the source, it is yet another reason to consider parking lots as inefficient land use.
My second response: if society considers the electric automobile as an acceptable substitute for efficient land use and transportation infrastructure, perhaps we should be mandating this form of in situ power generation for automobiles so that people who make more environmentally sustainable decisions and those who cannot afford an automobile do not end up subsidizing power for those who choose to drive.
EDIT, just to be clear: I commented on electric cars since they are a way to consume power at the source.
True, that’s a good point, I had forgotten about the idea that they could be used to charge a new electric fleet which would require a lot more electricity than the supermarket alone. In that case it makes sense, the supermarket becomes the petrol pump (which it was to an extent anyway). Surely then it’s just a case of time, when the market economics make sense and supermarkets can make money out of it they will do it anyway.
My second response: if society considers the electric automobile as an acceptable substitute for efficient land use and transportation infrastructure, perhaps we should be mandating this form of in situ power generation for automobiles so that people who make more environmentally sustainable decisions and those who cannot afford an automobile do not end up subsidizing power for those who choose to drive.
EDIT, just to be clear: I commented on electric cars since they are a way to consume power at the source.