The Core

Agrivoltaics also, another dual use of land that doesn't make the space requirement sound as daunting.

Interesting data about rooftop PV potential in the U.S. form NREL:

"The total national technical potential of rooftop PV is 1,118 gigawatts (GW) of installed capacity and 1,432 terawatt-hours (TWh) of annual energy generation. This equates to 39% of total national electric-sector sales..."

https://www.nrel.gov/docs/fy16osti/65298.pdf

"First, we use light detection and ranging (lidar) data, geographic information system (GIS) methods, and PV-generation modeling to calculate the suitability of rooftops for hosting PV in 128 cities nationwide—representing approximately 23% of U.S. buildings—and we provide PV-generation results for a subset of these cities. Second, we extend the insights from this analysis of areas covered by lidar data to the entire continental United
States. We develop two statistical models—one for small buildings and one for medium and large buildings—that estimate the total amount of roof area suitable for hosting PV systems, and we simulate the productivity of PV modules on the roof area to arrive at the nationwide technical potential for PV."

"this analysis assumed a module efficiency of 16% to represent a mixture of various technology types."

>>Agrivoltaic farming

As one who has driven a tractor with implement behind it, driving under a roof to plant things sounds ... difficult. How are the panel towers built to accommodate for turning radius/ height concerns? 

>parking lots

Oy!  Parking lots sounds good for the southern US,  but might not work for snow country up north.  I can just see some plow guy wiping out $200 thousand in solar cells at the Walmart.

We lost a panel to a probably pine-cone strike. To be fair... the sugar pine is the biggest pine in the world and has the biggest cone, weighing up to 3 pounds when full of sap/sugar and, in our case, falling 70 to 120 feet before impacting. They commonly break car windshields too, which if you've ever tried or seen someone try to break one with a hammer, you know how much impact that takes.

But it does have us thinking of taking out the offending sugar pine, which also drops sap everywhere, concerns us for when it strikes a human, and blocks our internet. If we had known what we were getting into, our house would sit 30 feet over from it's current location.

>> plow guy

As a plow guy... unlikely. The parking lot panels I have seen are on solid steel pillars that put the panels above the lot, making a covered parking area. The would more likely obviate the need for plowing at all.