MARTA is installing a 1MW PV solar array at its bus garage at the intersection of Laredo Dr and E. Ponce de Leon in Decatur (Avondale Estates) on top of a structural canopy built over the bus parking lot. The canopy will actually accommodate 2 MW of cells with half to be for future expansion. If you are in the area, you might take a look as the canopy is complete and the PV array is being installed at this time.
This required the primary transformer to be replaced. It has a 20 kV primary and a 480 V secondary at 1 MVA. It had to be replaced in order to operate efficiently when reverse fed. The primary metering now has two meters, one inbound and one outbound. The secondary has terminations going to the main building and to the PV array. When solation exceeds consumption, the outbound meter measures energy returned to the grid. Consumption is paid at the retail rate and generation is paid at the wholesale rate; since, this is how co-generation works in Georgia. Lighting underneath the canopy is via LED fixtures. No energy storage is included. The system was built with $11M of federal funds. I am not at liberty to discuss the economics. :-) T
