These are cool! They are huge, they float, and they include steam, balloons, and your choice of ocean going or deserts with optional canals. They would be better if they included a giant watch spring to rewind them every day. Real life steam punk! I might have called them solar turn tables.
Solar collectors need to point at the sun. So there is a lot of mechanism to rotate them through out the day. These clever guys decided to mount a huge number of mirrors on a turntable and rotate the whole thing. This can work by arranging the mirrors in strips, each strip runs in a line toward the sun. This is easy to understand by watching this little video.
They are building one in the desert; it’s not too big. The unit costs goes down the larger you make them; particularly the power plant. You can get a sense of it’s scale because, I assume, those are your typical big trunks scattered around the site.
They have two additional tricks. The rim of the turntable floats in a channel. Then a membrane is stretched over it and air pressure under it supports the mirrors and the pipes.