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Now there are a couple of things going on here, one is we scatter
a lot of light in our atmosphere so that you're not getting the
ultraviolet light down on the ground that you get up in space.
The other thing that's happening is you've got nitrogen
and oxygen and water molecules and other pollutants absorbing
in our atmosphere, so that's what these gaps are
in the solar spectrum.
In space it is roughly 1367 watts per square meter.
On the ground it is roughly, in most, in just, on average about
1000 watts per square meter.
So you've got more sunlight, but you're going to see shortly that
you have less of an ability to actually use that sunlight
for productive electricity.
Now, that was sort of an introduction to the physics
of the solar cell, and now I want to go to a little bit more
general kind of background for you.
The first solar cell was done in Bell Labs.
We are very, very sorry that Bell Labs no longer does
basic research of that stock.
Things like the transistor and the solar cell came out
of that lab.
These were the fellows that did it, Pearson, Chapman, and
Fuller, and this was the very first solar powered satellite.
Sputnik was battery powered.
It died within six hours.
They were afraid when they were building this, it was a combined
effort by the Navy research lab and the Army to actually
do this first satellite.
They were afraid to use the solar cells as their primary
power source.
So they put in a battery to run the--really all it was running
was the communications beep beep beep beep, right, and of course
Sputnik didn't last very long.
It turned out that the battery didn't last very long, either.
When they put Vanguard 1 up, it beeped for about six days
and then it died, but they had a back up.
They had the silicon solar cells and the thing, it annoyed
the heck out of people as a matter of fact, beeped on
for six years on the satellite.
Since that day, by the way, has been the power system of choice
for satellites in space.
There have been a few nuclear powered satellites, which mostly
the Russians did, but there are, all of our communications
satellites today are powered by solar cells.
These cells were crystalline silicon cells made
by Hoffman Electronics, which no longer exists, it actually
got folded into Hughs which is now folded into Boeing.
They were about 6% efficient, meaning they turned roughly
6% of the energy of the sunlight hitting
the cell into usable electricity.
There are really four things that should be said
about solar today.
And the truth is it's real, people are out there, businesses
exist, they sell a product, they're being installed.
It will, I believe, firmly believe, play a role in
the future of the world, and for good reason.
We need to invest both in research and development
but also in policy.
We need to put the incentives in place that make this
a viable option.
By that I don't necessarily mean that we need to offer up
tax payer money to incentivicize people to go out
and buy a solar array.
What I mean is that if you take the cost of your electricity
from your utility and factor in the environmental cost
of that electricity, now you've got competition.
Coal, most of our power in this country is from coal-fired
power plants.
If we now are seriously concerned about the amount
of carbon dioxide that is being released, we will need to do
something about that.
That will cost money.
If you levelize the playing field, then I think your
renewable energy alternatives will play on a level basis
with the utility-based electric costs.
It is true we need to shorten the time between pulling it out
of the laboratory and putting it into manufacturing.
And for the last eight years as probably everyone in this
audience knows, there's been a real dearth of research funding
in all arenas.
If you look at where the industry sits today,
and I'm going to come back to this chart in the end because
I'm going to go through it in a little more detail,
you find that what you've been looking at mostly, and in fact
85% of the photovoltaics that is supplied to the market today
is in crystalline silicon.
They had a problem with that.
They couldn't find the silicon they need, and we'll come back
to that momentarily.
What you see, I don't like the word disruptive,
but other people use it.
If you see different approaches for thin film cells
and concentrators and possibly organics, although there are
a number of issues with organic solar cells, and much thinner
wafers and much more efficient silicon, you're looking
at somewhere, in the evolutionary process,
somewhere between 5 and 15 years.
And then I'm involved, particularly in here at NASA,
I do quantum dots as an alternative for photovoltaics,
and there are multiple avenues of approach that we can take
that will play a role in future photovoltaic devices.
Well, we need to close the gaps.
We said before we need to go beyond our research and bring it
to the consumer.
We need to raise our cells, if we can, from where they stand
today to closer to their theoretical maximum,
and we need prototypes.
We need advances in the manufacturing processes that are
there, and we need to remember that we don't use a single cell
by itself, it's in a module.
This is a little about Hoffman Electronics I was talking
about earlier.
The total amount of power they shipped out of
Hoffman Electronics in 1958 was 40 watts.
What are we gonna do in terms of an energy question?
Well, if you look at 2007 we are using, worldwide,
about 14 terawatts of primary energy.
If one takes even a rather modest growth in that,
remembering that some of our developing countries like India
and China will be moving into a more energy consumption kind of
environment, we see growths that we will need
in the energy needs.
So we've got to almost double the energy production
in the world in order to meet those needs.
Well, how would you do it?
Well, you're going to need all of it basically
to solve the problem.
Coal will play a role.
We have a lot of coal.
There's a lot of coal in the world, okay.
It will play a role.
The question, of course, is that you really don't want
the carbon dioxide that you get from burning the coal,
so what are you going to do with it?
And that remains a burning research issue.
Nuclear will grow.
We will have to have it.
We will have to have it to meet our needs.
And last but not least I hope, renewable should grow
significantly over time.