I still don't understand how exactly I ended up at the Tucson's power plant with all my coworkers. From what I've pieced together, one of my coworkers, Mike, met one of his neighbors at a home owner's meeting. Turns out this guy is only in town for a couple of months while he set up the new solar power plant installation. Bing bang boom. Mike has convinced him to give our entire department a private tour.
Since the power plant is no longer along my commute, I was completely unaware that they were even building anything new. To sum it up, they've basically built a 400 meter field of mirrors which they can angle to reflect sunlight at a length of tube overhead. Water runs through the tube and is heated to super saturated steam which then powers the turbine.
Our tour started with a little lecture in the construction trailer on how all this works. Then, we moved onto the fun part: walking around under the mirrors. Since the installation wasn't up and running yet, all the mirrors were facing the ground, to protect them. It made for some great pictures.
The great thing about this new solar installation is that it uses water. Other installations of this type tend to use oil and need some sort of heat exchanger, which lose efficiency. This system uses water, the same water that is already being turned into steam in the gas portion of the power plant. It means that when it's daylight and the solar power is running, less gas is needed to power the city. The new solar portion reduces the energy needed in an existing system, which is apparently a very big deal to those in the know.
The water pipes run a hundred feet in the air above the mirrors. These specially-coated tube can be serviced by a little trolley suspended below them. That is a job I would not want to have.
So, next time you're driving along I-10 and you look over at the power plant, you can say you know what that ridiculous tower and mirrors are.