If you are going to build a solar dish using photovoltaic cells to power a 40,000 homes, would you use a utility grid or battery bank?
40,000 homes is a utility grid but how do you plan to power the homes at night? Electrical production in general has very limited storage capacity. Usually it is easier to simply turn off non baseline facilities and generate sufficient power with some spinning reserve. Many solar thermal facilities have built into them some heat storage capacity that allows operation at night. Neither photovoltaics nor parabolic dish/stirling engine electrical production has any built in energy storage. If you intend to supply power at night you will need additional production or some storage capacity.
Solar dishes are not used to drive photovoltaic cells. You collect the solar radiation direct on the photocells. And usually feed that power to a battery bank for storage until needed. Solar dishes concentrate the solar energy to be used either to warm water ( for heating ) or to boil water, for electricity production, which again is usually stored in battery banks. For large scale ( 40,000 homes is large ) it might make sense to store the energy as GPE in a high level lake ( called pumped storage ) or as molten salt and you would then need a grid to distribute the energy to those who need it. Note that the grid itself does not store any energy, so the choice you are given , grid , or battery bank, doesn't make sense. They do not do the same job.
