Regarding land use, just yesterday I was pondering about what technology it would take to create survivable off shore solar. Some loose grid of floating collectors happily bouncing on the waves like a flock of resting seabirds, perhaps cleverly reeling in and out link and anchor lines to match the geometry of the waves? Or just the right amount of springyness, dynamically tuned to the wave situation?

Then it occurred to me that even nature hasn't really solved ocean surface plants, what could be a more clear indicator that it's a really hard problem...

We have plenty of calm freshwater sites for solar, so there will be no need for ocean solar.

Land isn't cheap, but there's a lot of land that can have a solar panel on top of it without causing problems. A good place to start is every building roof.

Land is, in fact, cheap in very many places. If one were making fuel with the solar energy you wouldn't put the solar in places where land was expensive, since the fuel would be highly transportable.

> I don't even want to think about...

I'd call that an argument from laziness.

> Last time I checked, land wasn't cheap and they weren't making any more of it.

Land that is remote, not fertile and that doesn't harbor any natural resources is actually rather cheap. Moreover, "they" are making more land in certain coastal areas where land is expensive.

(I assume you mean GW not MW, because MW is very little for a proper power plant). Solar panels produce about 200Wp/sqm. In Germany they average to about 12% of peak production over a year, so say 22W/sqm averaged. 6GW continuous is then about 51k football fields[1]. I assume that the US has lots of land that is much sunnier than Germany, so you can probably get away with fewer football fields.

[1] https://www.wolframalpha.com/input?i=%286GW%2F%2820W+per+squ...

The correct unit to use is parking lots. If you base this unit on the current area used for parking in the USA, you can even use centi-parkinglots ;-)

Yes, you didn't think about how much surface area, since if you did you'd realize it wasn't a big problem.

SF Reservoir has 12 football fields worth of solar panels and generates 4.5 megawatts.

It generates zero megawatts far more often than 4.5 megawatts. 4.5 is peak on the best days. 0 is assured for several hours every day.

Thanks for added details. I was wondering if this project was efficient considering the amount of "fog" in this area.

When algee biofuels were first proposed someone calculated that Arizona could produce all the fuel we use on currently unused land.

The limit is our ability to scale algee, but the lab results also show that the numbers are right.

yeah and there's crop failure coming decades in advance compared to IPCC's predictions, so better not using crop space.

Some of that crop failure is due to heat, which could be mitigated by using solar panels to provide shade. That doesn't work for all crops, some of which require direct sun, but it works for more than I expected.

No crops require 100% direct sun.

Maize and wheat yield is reduced a bit, without, but the year-round revenue from solar panels easily exceeds the difference.