We’ve always thought that Arizona should be the place to lead the world in solar energy, given the enormous amount of sun they enjoy. The good news is that it’s beginning to happen. It turns out that it’s actually almost too hot in AZ for tradition PV installations – they lose their efficiency if the gets too hot. So Arizona turned to a different type of solar power using 3200 mirrors to direct the desert light at a special tank holding oil that in turn boils water and generates electricity through traditional steam turbines.
What is different about this plant is that the oil is also used to heat salt, which stores the heat and can be used to boil water for up to 6 hours after the sun goes down. This allows the plant to meet needs of customers for most of the time they aren’t sleeping.
The Solana plant was built by a Spanish company and cost $2 billion. It is guaranteed to be profitable, as the local power utility will be buying its output for 30 years.