We started discussing the history of photovoltaics in the last video.
And I was using this Facebook timeline kind of a format
to describe or to summarize this very long history of PV.
And we had reached the year 1954 on this timeline.
And we saw that these three scientists from Bell
Labs, they have invented this silicon-based solar cell, which achieved
efficiency of 6%, approximately 6%.
And the New York Times proclaimed this invention on their front pages,
said it's a new beginning of it's a beginning of a new era.
But still it takes a few decades until people start
to use solar cells as a mean of electricity production.
And the reason for that, that even though this
solar cell had an efficiency of 6%, which is not
that shabby, the cost of producing electricity using this solar cell or even
the cost of using the solar cell was $300 for producing 1 watt of electricity.
And this, this might see, to, to make
this number relevant, we must compare or contrast it
with the cost of producing that same watt of
energy using a conventional, say a coal powered plant,
which was $.50 a watt.
So, solar energy was 600 times more expensive, in terms
of install costs, to produce that same watt of energy.
And this was, you know, a very high barrier, so there
no, there was no, even though, you know, the people this
was, the efficiency of the cell was 6%, it was not
being used to to make, you know, electricity on a large scale.
In fact,
the first saving grace for, for you know, so
it will not being used for electricity, main-stream electricity generation.
So the first saving grace, or you know the first application
for this Bell Labs invention of solar cells, came for space application.
So there was a space a war which was, you know, going
on between the US and Russia in the 60s and the 70s.
And the
first usage of these solar cells was in fact
to power this these satellites and that was also, you
know, after a very long debate people were debating whether
to use nuclear plants or whether to use solar cells.
In fact solar cells end up ended up winning that race.
And this is first satellite which was using
solar cells, the Vanguard satellite, which was launched by US and
this is another satellite, the Explorer satellite which was again um,
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launched by Explorer 6 which was launch around the same time.
And, if you look at any of the modern satellites, they used a
very large area, so they use this very large area of solar cells.
But of course this is not a very
aerodynamic design for launch, so when the satellite
is launched, these these panels are folded onto
each other, so this is a foldable array.
And, when the, when your satellite reaches orbit, these,
these, foldable panels expand and they make these, arrays
of, solar cells which are used to power, which
supply most of the power of these, current day satellites.
And so this was, this was the first you
know, the first real application of these solar cells.
Around 1970s was
the time when these solar cells, they came from
space to Earth. And there was a major, I mean, the, the
main driving force was that people started to use poorer gear,
grade of or cheaper silicone to make the solar cells and that
brought the cost down from approximately $100 per
watt to $20 per watt, and that made it you know,
feasible for use of the solar cells. At least, the first on earth.
And the first applications which were
developed were for powering these powering these
Navy Coast Guard kind of towers.
Which were you know, they which
were separated from, the conventional power plants.
It was not feasible to power this by, you know, taking and routing a transmission
line all the way to these remote sources. So the first application is really
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these remote locations. So on these Coast Guard
stations or on these railway tracks. Powering the signals on
railway tracks and so on. And then on 1977
was the year when the total production of these solar panels they, you
know, exceeded 500 watt. And in 1982 was
the first mega-watt scale solar power plant, which was
[INAUDIBLE],
in fact the first plant was located in
in California, and it used two access tracking.
It used a dual access tracking.
And it had an installed capacity of 1 megawatt of peak power.
And at the same time, you know, the efficiency of these cells kept on rising.
And in in 1985 there was a silicon,
single crystal based solar cell demonstrated by Martin
Green and his team at University of South Wales in in
Australia and they demonstrated this cell with an efficiency of more than 20%.
And you know we have come a long way since then.
Today these utility scale apart drawing, which are, you know huge
in terms of in terms of the area they occupy and these are
pretty common and to just give you some stats and you know how far we have come
from that from that first silicon based solar cell
in 1954. Some stats for 2012 are given over here.
So, the total install capacity, it's it's,
just, this is, these numbers are just for USA, so the total
install capacity in the USA is over 7 Gigawatts as of 2012.
The capacity which was installed just in 2012 was just over 3 gigawatts.
It was around 3.3 gigawatt.
At the same time the price of solar power has come down.
So if you look at just the panel, just the panel
today, it costs less than a dollar, dollar per watt, one dollar
per watt, that's the cost of the panel.
The total, the total installed cost of the model, it has to include all of the items,
such as the cost of installing, and the
cost of making the tracking system, and so on.
But still, you know, if you compare it,
and it really is depending upon the application.
If somebody has to install it on a
residential, on your home, on a residential application,
the install cost is much higher, as compared to a utilities
scale sort of plant, where the install cost is much lower.
So, you know, the total install cost in utilities scale also is approaching,
it's approaching close to $2, $2 per watt.
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So we have come far.
We have come a long way from that original number of $300 per watt
just for the panel to, now the panel costing less than a dollar per watt.