Sustainability: Solar Tower Technology

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Australian company EnviroMission is planning to build a massive solar tower in La Paz County, Arizona. Chris Davey, EnviroMission’s executive director, talks about his company’s solar tower technology that uses virtually no water to produce utility scale amounts of solar energy.

Ted Simons: Tonight on "Arizona Horizons" continuing focus on sustainability, we take a look at a huge solar tower that an Australian company is planning to build in the Arizona desert. The concept was featured on a discovery channel program about innovative technologies.

AD: Roger Davey will build a solar plant on the scale never seen before.

AD: It is spectacular. The talk of the town. Be right on our side as we are situated right now. About 65 meters across, all about 190 feet in diameter.

AD: He calls it the solar power tower. It will be the world's biggest solar power plant and one of the tallest objects ever built. It will rise 400 feet taller than Taipei 101, the world's tallest building. Around the base a sheet of glass six times the size of New York's central park.

Roger Davey: It's a vast area even from up here, isn't it? And the tower in the center, 600 meets tall. It really is a sight.

AD: Unlike traditional solar plants, Roger's tower is powered by the same principle that keeps this balloon aloft. Rising hot air. The sun's rays beat down on the glass and heat the air trapped underneath.

Roger Davey: Hot air rises so the air runs towards the center of the tower.

Roger Davey: And just like a cold day when you light a fire, smoke goes whoosh up the chimney, runs through to the generators generating electricity. Which I think is almost the holy Grail of renewable energy.

Ted Simons: Joining me now to talk about his cop efforts to build a solar Tower in western Arizona's La Paz county is Chris Davey, the executive director of enviromission. Thanks for joining us.

Chris Davey: Nice to be here.

Ted Simons: We saw a lot of animation, a lot of ideas going on. And we kind of saw how this works. Give me a better indication. This sounds fascinating. How exactly are we going to get power out of that big old silo out there?

Chris Davey: Just quickly, we put a large sheet of plastic out there and when solar energy hits that plastic it heats the air beneath it as it would in a hot house of flowers or a green house. The hot air flows in towards the center where the tall tower is located and that differential in temperature being hot at the bottom and cold at the top causes the hot air to be drawn out.

Ted Simons: That's what we are seeing right now. There's the ground heating, goes up the silo.

Chris Davey: Yeah. Just like if you lit a fire in a fireplace. The hot air rises. We channel the air through turbines which in turn turns the generator, and creates electricity.

Ted Simons: 200 megawatts it says.

Chris Davey: 200 megawatts of electricity which is in excess of 150,000 households. It's a lot of power to be generated.

Ted Simons: That's a lot of hype and that is a tall tower compared to some pretty tall things in the world here. Is this viable?

Chris Davey: Very. Very. The divide tower is being built. It's in excess of 2800 feet. This is planned to be shorter than that now. And given the height to width ratio meaning the diameter of that tower versus the height it's extremely stable. We are talking about seven to eight tons where a sky scraper is 12 to 14 times.

Ted Simons: 120,000?

Chris Davey: In excess.

Ted Simons: How is that power delivered?

Chris Davey: Those large transmission lines you see crossing the country? We essentially plug into those. Once it's there, it can feed the market. It can get to the utility.

Ted Simons: Are there lines where you are planning to build there in La Paz County close enough?

Chris Davey: They run adjacent to the property. We are the substation where you plug the power in just north.

Ted Simons: Compare the power cost of in to current methods, current models.

Chris Davey: OK. If you were to turn around and build a new coal facility or a new nuclear facility today, not one that's already been paid for 10 times over, we are cheaper than nuclear and cheaper than coal to actually generate the power. If you were to build a natural gas facility, that's the only thing right now that, given gas prices being at all-time lows that would be cheaper.

Ted Simons: So how much cost to build, just to build something like that? Forget power costs. Let's talk about construction. How much land is needed? And again, are these things viable?

Chris Davey: Yeah. Well, capital cost of the project, ballpark, around $700 million. We have a financial commitment, 100% commitment for those dollars right now. In terms of land use, it's around about three to 3500 acres which if you would compare that to other solar resources it's about the same for the power you generate.

Ted Simons: That's that three to 3500 facilities is that for one facility? Is getting 120,000 out of this you may want to build a cluster of these things.

Chris Davey: We would love to build more facilities in the same region. Each facility is 200 megawatts. We would plan to build moisture towers in the same region. So the economies of scale will drive prices down even further.

Ted Simons: It looks like there's something of a reflective material down there at the base. Is there a concern regarding that with aviation and other aspects?

Chris Davey: You have got to love animations. Because we are trying absorb all the energy, it will actually look relatively mat from the air. It won't reflect because you are looking to absorb as much energy as possible, unlike a mirror, for instance, which would be looking to reflect. From the air, it will not act as a mirror. It will not look as reflective as it does in that video.

Ted Simons: Are there other aviation concerns? I thought there might have been concerns from the military in California regarding those lines. What was that all about?

Chris Davey: I believe that was a reflective --

Ted Simons: A reflective thing?

Chris Davey: Completely different to what we are talking about. We have actually filed with the FAA as it relates to this project in western Arizona. And have been in constant dialogue with the military as well.

Ted Simons: Water concerns, western Arizona, not a lot of water out there. What does this need? How is it going to get that water?

Christ Davey: We don't use any water at all in power production. So in terms of building this in the west --

Ted Simons: Yes.

Chris Davey: -- makes a hell of a lot more sense than other technologies when you take into consideration 40% of the United States fresh water gets used in power production. We are in the west. We live in the desert. And this is going to use none.

Ted Simons: There is some maintenance going on out there, though. There will be some human beings keeping an eye on things.

Chris Davye: Yes. We are going to employ during construction in the range of about 1500 workers. It's peaking at 1500, drop afterwards. On an ongoing basis it's probably going to be 40 to 50 people out there maintaining the facility, security, scheduling, operation, maintenance.

Ted Simons: Speaking of maintenance, what kind of longevity for something like this?

Chris Davey: In excess of 75 years.

Ted Simons: 75 years.

Chris Davey: If you compare this to traditional power you ask me about the costs earlier. This has a last in excess double that of a traditional power plant and to you three times that of renewable power plants.

Ted Simons: We did talk about the land out there and how much is needed and where this particular project would be. Trust land is involved in this as well. Talk to us about that.

Chris Davey: Yeah, we have actually got a couple of leases in with Arizona state land trust. We are just moving through the final logistics as it relates to that. And plans have site control in the coming months.

Ted Simons: So there is a plan afoot to work and get the State some money out of this as well?

Chris Davey: They will be the biggest beneficiary of this project. The lease that's being negotiated would see them revenue share in the project.

What kind of timetable we looking at here?

Chris Davey: Looking to break ground toward the end of next year, beginning of the year after, be online two years after that.

Ted Simons: What the biggest holdup if it doesn't happen or it gets delayed?

Chris Davey: Given we already have capital to build the project it's permitting phase, just making sure we can move through the various permits within the State in a streamlined process.

Ted Simons: It's interesting stuff. It's good to have you here. Thanks for E. plaining for us and good luck about your project.

Chris Davey: Thank you.

Chris Davey:Executive Director, EnviroMission;

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