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  • Tonight, I want to share with you a vision.

  • A vision to bring renewable solar energy into each one of your homes,

  • and to make Arizona an exporter of the same,

  • clean solar energy to the rest of the nation.

  • (Cheering and Applause)

  • So let’s start out by talking about solar.

  • So when I think aboutsolar”,

  • a picture kind of like this comes to mind.

  • The sun is shining, it’s a blue sky, maybe one cloud in the sky...

  • there’s even a sunflower.

  • It’s just a beautiful picture of renewable energy

  • and how clean that can be.

  • So let me show you another picture.

  • This is a map of the United States,

  • with Tucson and Phoenix kind of in that white circle right there.

  • And what you can see is that were in the very center

  • of the best solar resource in the country.

  • Right in the middle of that red-orange zone.

  • So let’s put these two things together.

  • Weve got clean, solar power, and weve got the best solar resource.

  • So how come we don’t see solar

  • just sprouting up everywhere, all over the state?

  • Well, there are a couple of things that solar has to overcome.

  • In fact, there are three big hurdles.

  • The first one, is it has to be cheap.

  • Right now, installed solar is about 50 % to 66 % subsidized

  • by the government for every installation.

  • If youre going to compete with coal and nuclear,

  • somehow you have to get beyond needing that subsidy.

  • Second, it’s got to be reliable.

  • When you build a coal or nuclear plant,

  • it lasts for 20 or 30 years,

  • in order to pay off the capital cost of building it.

  • Now, a solar plant is going to have to last just as long,

  • but it would be out in the desert, dealing with monsoons,

  • dealing with the hot Tucson summers for 20 years.

  • And that’s a real challenge.

  • Third, it has to be scalable.

  • If you take a look at this circle right here,

  • that’s about the area you would have to cover in Arizona

  • to power the whole US.

  • And if you think about solar panels right now,

  • that’s going to be a lot of solar panels.

  • So whatever solution you use, it has to be something

  • you can scale to real quantity,

  • really be able to make it mass produced

  • and make a real effect on the way we use power in this country.

  • So that brings me to the very basic problem of solar power:

  • that the sun is actually a very diffuse source of energy.

  • So let me give you an example.

  • If I were to go to a solar power plant

  • and stand right in the center of the solar power plant

  • for eight hours, twelve hours, the whole day,

  • at the end of the day I’ll probably have a sunburn, I might peel

  • that might be the worst thing that happens.

  • If I were to go to the center of a coal or nuclear plant,

  • say , (Laughter)

  • I would last maybe a second before being incinerated,

  • and the difference there is that in those plants,

  • the energy is concentrated,

  • and it’s much easier to convert into electricity

  • when your energy source is concentrated.

  • So some of you may have already come up with a solution in your heads.

  • I’m sure many of you have done this before in the backyard.

  • The solution therefore is to concentrate the sun.

  • And I’m sure many of you have had that experience concentrating the sun

  • on dry leaves, unsuspecting insects?

  • (Laughter)

  • And with this concentrated energy,

  • it’s now much more easily converted into electricity.

  • So this is the kind of experiment you can do in your backyard.

  • But Roger Angel and the researchers at the University of Arizona

  • took this to the next level.

  • So they took a 10–footdiameter mirror, or segments of a mirror,

  • and focused that much sunlight on a single point.

  • And instead of focusing on a dry leaf or an insect,

  • they chose a quarterinchthick plate of steel.

  • And this was the result.

  • Within about 10 seconds, there was a quartersize hole in a plate of steel.

  • So that’s the power of concentrated energy.

  • So now that weve solved the problem of concentration,

  • now the problem is to convert that concentrated energy into electricity.

  • And were actually fortunate in the solar world

  • to have photovoltaic cells that are capable

  • of transforming sunlight directly into electricity

  • without any moving parts

  • and [are] highly reliable.

  • So youve probably seen these before:

  • this is a picture of some being installed on a roadway in Oregon

  • youve seen them on rooftops,

  • youve seen them on parking garages,

  • things like that.

  • And now this is a great technology, but it’s fairly expensive right now.

  • And the reason that two thirds of the price

  • is in the solar cells is because sunlight is diffuse.

  • You have to cover a huge area with these expensive semiconductors,

  • which ends up making it pricey.

  • So let’s take the concept of concentration

  • and let’s take the photovoltaic cells,

  • and put them together.

  • Let’s imagine that you can concentrate the sun

  • 1,000 times onto one of these cells.

  • You would immediately need only one thousandth the area of cell,

  • cutting the cost dramatically.

  • Now youre right to say that these cells maybe can’t take a thousand times,

  • maybe we want to use more efficient cells

  • because were concentrating the light, etc, etc,

  • but at the end of the day, we see a 95 % reduction

  • in the cost of the cells with concentrating.

  • And that’s better than any of the sales I saw last Friday for Black Friday.

  • (Laughter)

  • So now that weve solved the PV problem,

  • the only thing left to do is to take these cells and this concentration,

  • put it in the ground and point it at the sun.

  • And follow the sun throughout the day to really maximize the energy we get.

  • So the other thing they looked at at the University

  • was how do we do that in an inexpensive way.

  • How do we do that cheaply, reliably, in a way that we can scale.

  • And they came up with the design that youre also probably familiar with.

  • Something that moves,

  • something that can potentially track the sun,

  • something that’s really pretty inexpensive.

  • So the Ferris wheel, in fact, moves around,

  • carries pieces around the outside,

  • and can actually be disassembled in a day,

  • put on a truck and taken to the next carnival.

  • What a great solution.

  • So it’s actually a steel space frame,

  • and steel is cheap, steel is abundant,

  • and now we can support these concentrating mirrors

  • and do all of these solar things cheaply and effectively.

  • So let’s put all of these things together.

  • Weve got the concentration, weve got the photovoltaics,

  • and weve got the space frame structure to hold it.

  • And let’s look at what the prototype looks like.

  • So some of you may recognize thisif youre familiar with the university

  • as being the pool behind Bear Down Gym,

  • that is actually no longer in use

  • but is now the Steward Observatory Solar Lab.

  • And this contraption actually

  • can carry eight different mirrors to concentrate the light,

  • and you can see where those will start to go,

  • and you can see a little bit of where the sun is being concentrated right now

  • on that spot making power.

  • So let me zoom in just a little bit,

  • and this is an example of four mirrors

  • focusing 2,000 Watts of sun energy on a ball lens

  • to distribute that over the photovoltaic cells.

  • And to give you an idea of scale,

  • this right now produces 500 Watts of electricity.

  • If you were to do that with solar panels that you have on your roof,

  • it would take about 4 ft by 4 ftabout two panels.

  • This much space. Pretty good area.

  • We were able to do that

  • with enough cells that can fit in the palms of your hands.

  • We use three square inches of solar material

  • at 1000x concentration to make that same amount of power.

  • And that’s where we think the real cost savings will come.

  • So looking forward,

  • this is what the final artist’s rendition

  • of one in a desert environment will look like.

  • It’s got eight parabolic mirrors, concentrating light at 1000x

  • onto individual photovoltaic receivers, at each of the focuses.

  • So to give you an idea of scale again,

  • if these were to supply even 1% of the power in the US,

  • it would take 500,000 of these units to do that.

  • Now it’s certainly not insurmountable, but it is certainly a challenge.

  • And if I can leave you with one final thought tonight,

  • I want you to imagine a future:

  • a future that’s free of smoke stacks,

  • it’s free of piles of coal outside our power plant,

  • it’s even free of coal power plants.

  • And replace that with fields of solar generators

  • that are using the power of the sun to make electricity,

  • and not only enough to provide energy for Arizona,

  • but enough to power the rest of the nation.

  • Thank you very much.

  • (Applause)

Tonight, I want to share with you a vision.

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B1 solar energy power sun concentrated solar power

【TEDx】TEDxTucson - Dave Follette - Solar Energy At The Gigawatt Scale

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