The Achilles heel of renewable energy has been its challenge with intermittency. Other problems include its use of natural resources such as water for cooling. What if you could design a utility-scale solar power plant that was persistent, not intermittent, and also used zero water?
Turns out you can. Unlike photovoltaic technology and other solar technologies, two Solar Towers proposed by EnviroMission Limited, the U.S. subsidiary of Australia-based EnviroMission, would be 100 percent reliable (non-intermittent), and waterless—two benefits the developer of the Solar Towers call a “game changer.”
What appear to be an innovative step forward in the solar industry, the Solar Towers combine solar and wind power to generate a substantial amount of energy—200 megawatts at each location. The technology used in the Solar Towers is known as “solar updraft” and consists of a single tall tower that uses both the sun’s rays and a chimney-like effect to heat air that’s collected in a greenhouse collector zone. The temperature of the air inside reaches 150 degrees Fahrenheit and is then pushed out in drafts of hot air that generates power through wind turbines built near the structure. And the sun doesn’t have to be shining for the Solar Towers to generate power.
“Because we use direct and indirect heat, the Solar Tower produces the same amount of energy when it’s cloudy than it does when the sun is shining,” said Chris Davey, president of EnviroMission. “Other solar technologies such as PV rely solely on direct heat and are, therefore, intermittent. The Solar Tower technology is not intermittent. We can guarantee that power to the utility company.”
In addition to the reliable nature of the power profile, the other big benefit of solar updraft technology is that it’s waterless. Unlike other energy sources, including traditional PV solar projects, the Solar Towers do not need water for cooling. In a perpetually dry state such as Arizona—and an increasingly dry world—waterless energy isn’t just a good idea; it’s a necessity.
Together, the two Solar Towers—which will be about as wide as a two-car garage but more than a half-mile tall—will cover 11,000 acres of desert land, which is significantly more than the average utility solar installation. But, according to Davey, the environmental study was found to be culturally benign and in no need of environmental mitigation.
“There’s already a substation five miles from the project as well, so we can get power out to the customer without having to build transmission lines,” said Davey.
According to Davey, EnviroMission Limited is currently in the delivery phase of the proposed project after filing with the Arizona Power Plant and Transmission Line Siting Committee.
“At the risk of sounding too promotional, the Solar Tower technology is the holy grail of solar,” said Davey. “It’s truly sustainable where other solar technologies and renewable simply aren’t. As water prices begin to rise to where they should be, the ability to generate power without using water is going to be essential.”
Pictured: Not only are Enviromission's Solar Towers waterless, but they provide a home to both Morlocks and the Eloi. Image courtesy of Enviromission.