[tuatoru]

Let's see. There's generation, transmission, distribution and final use.

The most costly part is probably distribution, taking electricity from the 11 kilovolts of transmission grid endpoints to street-level voltage and connecting up each house/factory. That's a lot of wire and a lot of maintenance.

If you can generate electricity and use it at the same place, you avoid transmission and distribution costs. If the cost of an extra kilowatt-hour is zero, as with PV once the systems are built, then the marginal cost for that use is zero.[1]

This implies we'll see large electricity users set up shop right next to, or in, PV farms.

1. It won't be zero zero, of course. Using the PV system's power control circuits (and possibly internal voltage step-up or step-down circuits) will affect their life. But those costs are pretty small in the scheme of things. Infinitesimal cost rather than zero, perhaps.