Episode Transcript
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Speaker 1 (00:04):
Welcome to tech Stuff, a production from I Heart Radio.
Hey there, and welcome to tech Stuff. I'm your host,
Jonathan Strickland. I'm an executive producer with I Heart Radio
and I love all things tech. It is time for
a classic episode. This episode originally published on October two.
(00:25):
It is titled tech Stuff Shines Light on Solar Panels.
So we get down to the technology of solar power
and how it all works. And you know, whether or
not it makes sense. It doesn't make sense for everybody,
as it turns out, But let's listen in on this
classic episode. You know what, it's been a while since
we've done an episode about solar panels. Yeah, since August
(00:48):
two thousand eleven, I believe, in fact, back when Chris
Paulette was on the show. Yep. So we did an
episode back then and we thought we would update it.
So here's the update. We're going to start off with
a little bit of background on how all those solar
panels actually work. Your basic solar panels tend to be
made out of silicon and then dope silicon, dope impure,
(01:09):
purposefully impure silicon. Right, that silicon is dope you so, uh,
And there's another. Oh, I got the hands over the
face this time, guys. Awesome, that's a that's a pure wind. No, okay,
So silicon. The reason why we're using silicon in solar
panels is that, you know, if you remember your illustrations
of atoms, they have the electron shells on the outside
(01:32):
of the atom, and those electron shells can hold a
certain number of electrons depending upon what which energy shell
you're talking about. Now, silicon has some free electrons in
its outermost shell, meaning that not every single space that
can hold an electron has an electron. And when I
say space, I just mean the number of electrons that
can inhabit at outer shell. Since they're they are free,
(01:56):
then silicon can bond with something else, like other silicon atoms.
So if you can have it bond with lots of
silicon atoms, you then create a silicon crystal. If you
then bombard this silicon crystal that has been doped in
various ways, either with ions that have a negative charge
or ions to have a positive charge, you can then
(02:17):
induce electrons to flow. Now, in our article on how
stuff works dot Com about how solar panels work, there's
an healthful analogy there, right, it's about uh kind of
talking about hills, right. It's saying that essentially when when
you create when you create one of these cells with
a with the negative side and a positive side, it's
going to create an electron flow that's downhill, right, Meaning
(02:40):
that like if you were to have a rock and
you pushed it down the hill, it would roll down
the hill, but it wouldn't roll back up the hill.
There there'd be that blocking mechanism to keep it from
going up the hill. Uh. In the case of silicon
based solar cells, the photon is kind of that initial
push that gets the rock rolling. So if the photon
(03:00):
is strong enough to push the rock and get it moving,
everything's cool. You're actually you're gathering energy through solar power.
So the photon hits the silicon crystals that are doped
so that you're it's not just a pure silicon crystal
all the way through. That gives energy to allow electrons
to break clear of what is called the band gap.
(03:22):
That allows the electrons to break free of their bonds
and flow through a pathway. Now they want to get
to the negatively charged electrons, want to get to a
more positively charged environment. But if you have a barrier
there so that they can't just crossover, they you know,
you get this potential energy, but you don't have any
(03:43):
real energy. But if you make a pathway from negative
to positive, then the electrons will travel that pathway to
get to that positive site because that's really where they
want to be. That's that's the awesome place for them.
And if you make them do work along the way,
you get a benefit from it. So like that work
might be lighting a light bulb, or it might be
(04:03):
opening the doors on the enterprise. I've been reading a
lot about star Trek recently. Um anyway, the work could
be whatever you could imagine an electronic circuit, and the
electrons are going to go and do it because it
means they get to be on the positive party on
the other side. It's just like b if you tell
me there's a positive party on the other side, I'm
willing to do a lot of work to get there.
I'm not on a lot of lists anyway. So this
(04:26):
is the basic premise of a solar panel. You have
the photons providing the initial energy. Now, not all photons
are created equally. We have lots of different frequencies of light. Right,
And so some photons have a really low amount of
energy and are only going to be able to excite
certain types of electron. Maybe maybe they can excite an electron.
If they don't have enough energy to equal what that
(04:50):
band gap energy is, then they're not going to have
the push needed to get the electron to break free.
They might in fact flow right past that electron, which
will come in handy later on. Um. But but high energy,
high energy photons can either at a certain point, no
matter how much energy it has, you can't. You're you're
gonna lose a little bit if if it's got more
(05:11):
than it needs, right. Yeah. So for example, the example
I used in the old podcast, if you want to
go back and listen to that, is that let's say
that I'm capable of lifting a hundred ten pounds. I'm
actually able to lift more than that just then, you know,
but for the purposes of this example, pounds of my limit.
If you if you put a hundred pound weight in
front of me, no problem, I can lift it up.
(05:31):
You put to one pound weights in front of me,
I can lift one or the other, but not both
at the same time. However, you know, you sit there,
and you look at that from an energy perspective. I'm
capable of lifting a hundred ten pounds. I lift a
hundred pound weight. That means ten pounds of my lifting
power are going to waste. I can't it's not being utilized.
I'm not capturing it in some useful way. And in
(05:53):
the case of traditional photovoltaics, if Jonathan were that photon
and you put to fifty pound weights in front of him,
he wouldn't be able to lift them both, only one. Yeah,
so we have to that. This is where we're starting
to get into some of the challenges that we face
with solar power. The big one there is efficiency. Maximizing
efficiency in solar panels is no easy task, and in
(06:15):
fact it's something that we've seen. If you were to
look at it from a big picture perspective, it looks
like really minor increases over the last couple of decades,
but in fact, every tiny increase means that you get
quite a bit of return on your investment, simply because
when we're talking about solar panels, were usually talking about
big arrays of solar panels, where a little improvement means
(06:36):
a lot of output in the in the long run,
and they've been so inefficient. Uh, you know, generally about
five of the potential energy of the sun is captured
by them. In fact, according to some sources, your typical
commercial solar cell will get you about nine return. So
(06:57):
of all the potential energy you could be gathered based
upon the photons that hit that panel is what you're
actually capitalizing on. Right, the theoretical maximum for silicon wave
for cells is about fifty percent efficiency, right, we just
don't get there. In fact, the current world world record
in a lab is only forty four point seven percent efficiency,
(07:18):
reached just this year by German and French researchers with
a four junction cell. And more on multijunction cells later
on in the podcast. But that's but that's an elaborator lab,
which means it's not it's not sunlight that you're doing.
You're bombarding that with specific kinds of light to check
on its on its efficiency levels when you get into
the field. Sometimes literally in the field, it's much lower.
(07:42):
In a field. Well, you know, in my mind, there's
there's one field and everything else is just a pathetic
copy field of dreams. What's I'm not sure what I
built it they came, that's all I'm saying. So then yeah,
that so we're talking about really low efficiencies when it
(08:03):
comes to how much energy is hitting it versus how
much you are actually gathering. On top of that, you
have to talk about the actual financial cost of solar cells. Right.
They're traditionally pretty expensive. And I think that you and
I both managed to compile completely different figures because there's
there's a few different ways that people talk about the
cost of solar panels. You've got the pure manufacturing before
(08:25):
they go into use, and then you've got the installation costs,
and then you've got maintenance costs. Yeah, there's there are
a lot of different costs associated with it. I was
going from a report that m I T created about
some improvements that people at m I T had made
to solar panels, and that report they said that solar
panels cost about seventy five cents per what of energy
(08:49):
UH and that in order to be UH to be
competitive against fossil fuels, it need to be closer to
fifty cents per what. Now, that's just one method of
figuring out the expense. And and in fact, the report
did not say, like what which factors they took into account,
whether that also includes installation in there and maintenance as well,
(09:11):
or if that was purely from a manufacturing standpoint, The
point being that creating silicon based solar panels is not cheap.
It's getting less expensive over time. We're seeing improvements definitely.
So some numbers that I was saying, we're talking about
the pure manufacturing is of two thousand nine being over
a dollar per what um as maybe fifty cents per
(09:32):
what So, then you've got a and moving moving towards
to something like thirty six cents per what right, And
we're also going to talk about some alternatives that might
get that even lower. But we're seeing we're seeing the
cost of solar panels drop year over year, and that's
that's because of a lot of different factors. One is
(09:54):
that the materials are getting less expensive, We're getting better
at making them, We're getting better and making them with
cheaper material reels, we're getting better at installing them. I mean,
it's become more business as usual, and so more companies
are more used to installing these for people. Therefore, you know,
we have people with expertise in the field now that
we didn't have five years ago because it was really new,
and the manufacturing processes have become more streamlined over time.
(10:18):
It's just kind of the same with what we saw
with the computer industry and microprocessors initially. When you when
a new microprocessor hits the market, it tends to be
really expensive. And part of that is because the manufacturing
cost to create something brand new that has a brand
new architecture, it's using super sophisticated electronics that you know,
(10:39):
to pay off for that, you have to have a
pretty high price on your product. But as you get
more money, you can invest more in the manufacturing process,
make things more streamlined, you increase efficiency on the back end.
That means that you have lower costs, so then you
can actually lower the cost of the final product. Same
thing we're seeing in the solar panel industry. Yeah, and
I did want to put in that those numbers. If
(10:59):
you have yourself installed any kind of solar panels, you
are saying a dollar per what I wish um. And
that's because for private use installation costs will cost anywhere
from like three to six bucks these days, and per
per what right, And and that's um, that's a huge
improvement over the eight to ten that it was a
few years back, but in fact I remember seeing one
(11:22):
report and it was based out of the UK, which
is already kind of interesting because the UK is not
necessarily the ideal spot to have solar panels. They don't
have as much it's a little bit cloudier in general,
they can get a lot a lot of cloud cover,
just that's the climate in that region of the world.
But the report found that after about seven years of use,
the first seven years, you would essentially be offsetting that
(11:44):
cost of installation. After the seven years, you would essentially
have recaptured those costs, and apart from maintenance fees for
whatever purposes you would need, your energy production at that
point forward would be free. So you would then you know,
be be at a surplus, which is fantastic and the
same thing is generally true throughout the world. Um And
(12:06):
as we see these costs go down, both installation manufacturing,
both all of the cost installation manufacturing and maintenance going down,
then that will mean you don't have to wait as
long for this investment to pay off. Part of this
is depending on the market. Currently there is more supply
than there is demand for photovote takes and that's only
(12:27):
because it has been so expensive, and so I think
that as this price comes down, it's going to be
interesting to see how the market adjusts and whether we're
going to see a flattening a plateau prices or or
what's going to go on. And also, I mean this
also has to do with rare and toxic materials, which
you know, rare earth metals are a big component and
(12:48):
component and China is the chief producer of rare earth metals.
We've talked about that in a previous episode of tech
Stuff as well about you waste right, Yeah, well e
waste yes, that was one of the yeah in particular
was e ways, but rare earth metals. And I think
we have a specific episode just about rare earth metals
because we we wanted to explain what what they were,
(13:09):
why they're important, and why is it that China is
the main producer And the main reason that China is
the main producer is because it's super cheap to get
it from China, because China does not I I'm sure
they have fewer. The problem with rare earth metals is
that they all contain certain radioactive elements and also getting
them out can can release a lot of toxic stuff
(13:33):
and there, and in general, if you're doing that, you
tend to incur lots of expenses, except in China where
they don't care as much. Yeah, if you have fewer
regulations then it's a lot cheaper, but a lot more
dangerous for the people who are doing it and for
the environment, because, as it turns out, there are other
places on Earth that are rich, relatively speaking, in rare
earth metals. But it's the term rare earth metals doesn't
(13:54):
mean that there are very few of them in the earth.
That generally means that there are very few of them
concentrated in a single area, right, Yeah, So the mining
process is very different than you know, striking a vein
of say iron, and then being able to mind it. So,
and of course that's going to play into the other
podcasts that we're going to record next but has already published,
I believe. So if you've listened to our Minecraft episode,
(14:15):
just know that we haven't recorded it yet. Yeah, you've
actually traveled. I don't even know where you are now. Hey, guys,
it's Johnson from just breaking in here to say we're
going to take a quick break, but we'll be right
back so we've got efficiency, we've got cost, we have
(14:38):
the fact that there's these rare materials toxicity those that's
another challenge, h And another one is just the and
we talked about this briefly with the UK. It's just
the how how practical is it? Is it practical depending
upon where you are in the world, because if you
are someplace that does not get a lot of sun exposure,
then you're not going to reap the benefits of solar power. However,
(14:59):
if you live pretty near to say, the Majabi Desert,
you're in a decently good spot right exactly. And you know,
I've that we live in Atlanta, and I've seen homes
in Atlanta that have solar panels. In fact, there's some
that are very close to where I live that have
solar panels installed. Uh. And it's something that I've thought
about too. But it's another one of those things where
I would really need to have a kind of study
(15:20):
done about how much sun does my home really get?
Would I would I be doing? Would I be getting
a good return on my investment, meaning that if it's
going to be one of those things where I'm only
barely offsetting my energy costs, I might be doing more
harm than good by adding solar panels, especially you know
when you figure in maintenance fees and all that kind
of stuff in the in the process. So uh, you
(15:43):
know your mileage will vary depending upon how much sun
you get. So those are the basic challenges. Now what's
great is about solar panels is that we see lots
of different companies and engineers and scientists looking to address
these challenges in different ways. So people are coming at
this problem from all different directions, not just from solar panels,
(16:04):
but from huge collections of solar panels. Yeah, that's speaking
of the Majave Desert. Actually, there is a large solar
thermal farm being built in California right near the Nevada
border called ivan Pa. I didn't look up the pronunciation.
We're going to go with that, um, but so it's
like ian hoe. Yes, um, it's on some four thousand acres,
(16:29):
which is about sixteen square kilometers, which is something like
six square miles for anyone else who doesn't know what
on earth an acre is and heck tears, No, I'm
just kidding. Um. And so solar thermal farms as opposed
to classic solar farms which are just large collections of
these photovolt take plates use mirrors a k. A heliostats
(16:52):
if you want to use the technical science term for it,
um to concentrate sunlight into a tower, which then boils
water to create steam to turn a turbine to create
power or not create power, I'm sorry, generate energy. Yeah.
And this, this particular Ivan Power is using some one
(17:12):
D seventy thousand mirrors in fact, to concentrate the sunlight
onto three large like four a k at seven towers.
And yeah, it's it's pretty impressive. They it's set to
turn on this year. They first tower just went through
a power power cycle test and they green lit it.
(17:36):
They said good to go. So that's exciting. As at September,
we are recording this on October something something there you
go dates numbers only because it was right there on
my screen. N I guess it's online too. That's great. Um.
But yeah, but co location this is this is an
(17:56):
idea that we see in lots of different power strategies
where almost in almost everything we talk about when it
comes to power. In fact, I'll go so far as
to say in every form of power, we're talking about
heat is one of those factors that if you can
harness the heat as well as whatever it is you're
doing to generate the power in the first place, then
(18:17):
you can end up generating more power that way than
you would if you just let that heat dissipate into
the atmosphere. Sure, and these these thermal farms are a
little bit a little bit tricky in that you have
to have a really good location for them. I mean,
it's there aren't that many sixteen square kilometer areas just
kind of hanging out where people are willing to let
(18:39):
you completely disrupt an ecosystem in order to put down
a whole bunch of mirrors and a whole bunch of
really hot water towers, um, in order to generate energy.
Deserts are pretty good candidates, although part of the two
point two billion dollar cost of building this thing out
was a very expensive move of a threatened species of
desert tortoise from this area to to a safe place
(19:02):
where they wouldn't be boiled. Um. Yeah, yeah, I can
see where that would be a concern. I mean, you know,
it's we often will think about things like desert environments
as being practically like but now it's not like, it's
not like tattooing or Mars or Mars. Yeah, now, solar
solar farms on Mars. The solar Mars will not be
(19:23):
hurting for that, although they don't know you don't know
about the Martians. Well, also I don't know about the storms.
So the storms could also really block a lot of
the soul. Now that I think about it, you know,
maybe I shouldn't make such sweeping statements. But you know
there are of course, they're already solar panels on Mars. Yes,
that's thanks thanks to a couple of rovers out there. Um.
But yeah, this, this particular one is is set to
(19:45):
deliver some three seventy seven net mega watts of power
in uh as opposed to the three it's capable of
total You're you're always going to lose some in a
system like this, and which is about the same as
a medium sized also fuel plant. It's kind of sort
of and yeah, the two of the towers are going
to be selling to pgn E and the third is
(20:07):
going to be selling to Southern California Edison. And supposedly
the whole system is going to power some hundred forty homes. Right,
So here we're looking at a system that, while it
does have a huge initial cost, Uh, they are going
to be able to start selling to customers. I don't
know how long it will take them to recapture the
costs of building that place. I mean that's going to
(20:28):
take a while. You're two point two billion dollars. It's
no chump change, right. Yeah, they had their investments from
people like Google, and they were working partially on a
federal government loan. So some of that some of that
is offset, some of it's offset, sure, and then uh,
but on top of that, you're looking at a much
lower environmental impact in the long run compared to the
carbon dioxide emissions you would get from from a fossil
(20:51):
fuel plant. Right, And there has been some research on
The brook Haven National Laboratory released a study saying that
regardless of the technolog of the specific technology being used
in photovoltaics, they generate fewer harmful gas emissions, like some
fewer UM than anything fossil fuel related. So well, and
(21:12):
related to this is the concept of solar trackers. This
is something else that you can find at solar farms
where uh, in this case, I'm talking about your more
traditional solar panels that are using photons to convert it
to electricity, as opposed to this approach where you're using
the solar the solar energy to heat water. But solar
trackers are kind of what they sound like. These are
(21:35):
devices that can track the movement of the Sun. Although
of course we know the Sun's movement is relative to
the Earth and there's spin and all that stuff. At
any rate, we're just gonna go with the movement of
the Sun across the horizon, across the sky, the pathway
across the sky. So you've got these solar panels. Not
all the solar panel panels are going to be angled
at a way where they're going to capture as much
(21:56):
sunlight as possible throughout any particular part of the day.
So what do you do. Well, you could mount the
solar panels on some sort of pivoting system that would
change throughout the day, or you create solar trackers that
are enormous mirrors mounted on some form of of Essentially
(22:16):
you're looking at something that can that can tilt so
that it will direct sunlight back down to the panels. Right,
So the panels are stationary that you don't move throughout
the day. But the trackers, these enormous mirrors that can
move in relation to the way the sun's path takes
it across the sky, can continuously adjust so that the
sunlight is directed back to the solar panels, thus maximizing
(22:38):
the number of hours when you can collect sunlight. Because
that's another one of those challenges that we didn't really mention.
Sometimes the sun's not out, it might be you know, night,
or sometimes it's in a different place. You know, if
you if you cover say the west wall of your
house with solar panels, which is a terrible plan overall,
don't do that, but um, that's the least efficient way
(22:59):
of going about anything. Yeah, you're you're only going to
get the western facing sun. Yeah, and even then, like
at different times of the year, you're not going to
get as coverage exactly. Yeah. The the there will be
sometimes the year where you will get more uh or
you'll get longer hours, not longer hours, but longer time
periods where the hours will stay the same, but you'll
get longer period Yeah. Well, you know, back in my day,
(23:22):
hours used to be sixty three minutes long. But you know,
the kids, Uh no, you get you'll have longer times
when you'll be able to collect sunlight. So these are
just little strategies to try and maximize that as much
as possible, so that even if the solar panel efficiency
is low, if you can maximize the amount of time
(23:44):
that they receive sunlight, you still generate more power. We
have more to say about solar panels after this quick break,
all right, so let's talk a little bit about improving
solar panels um, not just making solar farms more efficient,
(24:07):
but the actual panels themselves now, right, because there's a
lot of interesting materials science and even quantum science that's
going on in this Yeah, you know, we can we
can always confuse that confuse things by adding the word
quantum in there. So, uh, one of them is one
of the things we can do is look at introducing
some sort of film to put upon solar panels so
that it reflects less light. That's one of the problems
(24:29):
with solar panels is that some some photons when they
hit the panel, we'll just bounce right off. Again. Silicon
specifically is very shiny, and so so you're going to
lose more photons than you really want to in this
process of reflection. Right, So one way to increase efficiency
is to make sure those photons don't get away. And
there are different ways of doing this, and one of
(24:49):
them is to copy a certain insect, the moth, the moth, right,
I had heard about this, Yeah, so moth eyes. Now,
let's talk a little bit about moth eyes. If you
were to get microscope and look at a moth's eye,
you know you've borrowed it from the moth. Maybe the
moth has flown off a little eye patch and hook
and it's gone to be a piratical moth. Meanwhile, you're
(25:10):
looking at the moth's eye, you're gonna see there are
these little micro structures, and those micro structures in the
eye are they have a specific purpose. They reflect light
back to the back of the moth's eye so that
the moth can perceive more light. And a lot of
animals have this, but moth eyes in particular are extremely
efficient at doing so. Yeah. And if you've ever seen,
(25:31):
like like a photograph of a cat and the eyes
are glowing at you, that's because of a reflective layer
at the back of the eye, which is which is
reflecting light back into the right. Now. Yeah, no, in
this case, we can really say that there are probably
two big reasons for moths to have this particular micro
structure in their eyes. One is so that they see
more light. They can perceive more light because they're flying
(25:52):
around often at night, and the other is that they
reflect less light so that potential predators can't see them
and gobble them up. So it's a survival mechanism on
two fronts. How we can take advantage of it is
by making a kind of a model of those same
micro structures designs in such a way so that when
(26:14):
light hits it, more of the light gets reflected down
to the surface of the solar panel, the the actual
collection surface, and fewer photons bounce off, and we thus
increase efficiency. Now there's a fellow named Noboru Yamada who
came up with this idea along with a team of scientists.
Uh he is a scientist at Nagoako University of Technology
(26:38):
in Japan. And I'm sure I butchered all of that.
But but other than that, yes, yes, well, okay, fair enough.
Uh So he what he did was he took some
molds made out of a notic porous alumina to create
the micro structures that were similar to those of you
would find in a moth's eyes and uh, put that
(26:59):
into a crylic resin. So if you're wondering what that
actually means, a notic is another, you know, anode. We're
talking about the positively charged electrode in a in a system.
Poorous of course, just means it's got little bit of
holes and holes or spaces within it. And alumina is
actually a type of aluminum oxide, which is an electrical
insulator but also has a high thermal conductivity, so it
(27:22):
conducts heat really well, but it insulates electricity. Um They
found that this film could boost the efficiency of solar
panels by around five percent, so which again sounds really
small until you consider that that a five percent efficiency
rate is the that's the average. Let's say, let's say
that we have it on close to the high end,
(27:44):
so somewhere around, which is pretty high. I mean, especially
if you're talking about commercial solar panels, that's really high.
And then if you were to apply this film and
get that five percent increase, knowing that it's up to
five percent, you're not always going to get a five
percent improvement either, But that's a tent of sittiency at
that point, and when you multiply that across an entire
array of solar panels, Like I said, that equals a
(28:06):
lot more electricity. So while it might be tiny in
comparison to one solar cell, when you're talking about an
array of solar panels, it makes a huge difference. So, uh,
that's one way that we've seen solar panels get some improvements. Now,
this is just a film you would put over a
solar panel. It doesn't replace the panel itself. We have
some other technologies that would actually either improve solar panel
(28:31):
silicon or replace it. So for example, University of New
South Wales, So New South Wales, it's in Australia. Uh
and uh the what now she's shaking her head, have
you versus saying Australia that was a that was a
terrible accent. My Australian accent is amazing. It's almost as
good as my New Zealand accent, which is the same accent.
(28:53):
I can't wait for all of our friends down under
to yell at me, but I won't understand them, so
it's okay. So the University of New South Whales, some engineers,
some scientists decided to take a look at using hydrogen
atoms to try and correct deficiencies in silicon crystals. Now,
the deficiencies in silicon would mean that normally it would
(29:14):
decrease the efficiency of a solar panel, so not you know,
when you're doping silicon, you want it in a very
specific way so that you can maximize its efficiency. But occasionally,
through manufacturing processes or whatever mistakes happen, you'll get a
deficiency and it will decrease that of the efficiency of
that particular solar panel, and as a result, you'll get
(29:35):
less energy out of it than you had anticipated. They
found that by using hydrogen atoms and inserting them into
silicon crystals, the hydrogen atoms would bond with the deficiencies
inside the silicon and negate them and essentially help move
the photons toward the silk the silicon. That would actually
(29:55):
help transfer that into electric electric energy so or electricity
as we sometimes call it. So it was it was
one of those improvements that doesn't necessarily mean we're going
to have mega, super powerful new silicon based solar panel again,
It's going to be a small improvement, right. Instead, what
it means is that we could actually use cheaper silicon,
(30:18):
so By using cheaper silicon, we bring down the price
of the solar panels in general, So yeah, you can.
The problem with using cheaper silicon normally is that you
get more defects and less efficiency, But if you have
the hydrogen to correct those defects, then you can ignore
that effectively and it would be cheaper than using the
higher quality silicon exactly, So lower prices that means higher
(30:39):
adoption rates and uh better used for solar power all around.
Some researchers have also been using layering of different materials
with different band gaps that this is that multi junction
solar cell thing that I was talking about earlier to
improve the efficiency of solar cells overall. And the way
that these work is the top layers will absorb high
(31:00):
energy photons and let low energy photons slip through to
be absorbed by lower layers, which interesting and so originally
this came out of like NASA and Space Tech, but
it's pretty promising simulations is achieved fifty one eight percent
efficiency that would be incredible, which even in a laboratory
is amazing. So the interesting thing here is that and
(31:23):
we talked about this in our older podcast about how
if you go with the the lower energy band gaps,
you can cast that net. But the problem with going
with low energy band gaps is that you get a
very low voltage out of it. So the work you
can do with the electricity you generate is not necessarily
(31:44):
better than what you would if you were just going
for high energy. But by doing this multi tier approach,
you can capture all of it, which is a great idea,
or a lot more of a lot more of it
efficiency in the simulation. But still right, they're they're working
on matching current among the different sub cells because if
one sub cell is is lacking, then it's going to
(32:05):
throw off the entire device within this multijunction cell. So
it's kind of one of those weakest link type Yeah. Yeah,
so so people are people are working on it. Um.
The other thing that I'm really excited about is completely
out there. This is quantum photovoltaics also called quantum dots
our cells quantum dots. This takes me back, yeah, yeah,
(32:25):
and so this is this is using matrix of finally
tuned nanocrystals instead of the typical silicon crystals that you're
that you're used to. And what's cool about these nano
crystals is that they can be tuned to specific segments
of the light spectrum um of of of these band
gaps that we've been talking about, so that cells can
(32:46):
capture more of the available light based on how different
bits of it are tuned. And the really exciting part
of this is that photons can hypothetically excite as many
as seven electrons per per photon. So so yeah, that's
that's where you're getting that crazy boost in efficiency right
right in Researchers at the University of Buffalo found that
(33:10):
they could reach a efficiency and also because you've got
fun quantum physics mucking up this business um, that's how
I call it. Yeah. Recently, an international team discovered that
that these quantum dots can self assemble into nano wires
(33:30):
that will more efficiently carry that current so into their
into their own pathways, like like Jonathan was talking about
earlier with when you create a pathway, you're allowing the
electron flow to happen, right right, Because if you didn't
have that barrier there to block the flow, then the
electrons would just flow automatically from the more negative side
(33:50):
towards the more positive side. You have to create a
barrier and then you have to create a path, and
and all of this takes work on your part, but hypothetically,
this quantum stuff can can do it for you know.
That's that's pretty cool. I've got one other alternative to
silicon based panels, and it may end up not being
an alternative but rather an augmentation. But that's for pov skites.
(34:13):
I have no idea if that's the right way to
say it, but this is a material that apparently the
Earth is just lousy with parov skites. This is incredibly plentiful,
incredibly cheap material that may in fact be a valid
alternative to silicon. You might have heard about this talked about.
I believe these are also called thin film cells. Correct, yes, yes,
So this is a it's a material that's very good
(34:36):
at absorbing light, and it's a semiconductor like silicon. It
could transport electric charge when a photon hits it, just
like silicon um and unlike silicon, which those panels can
be as thin as a round a hundred eighty micrometers thick.
Hundred micrometer is one millionth of a meter um. That
(34:57):
sounds pretty thin, but a but one made of this
other material can be less than one micrometer thick, so
the manufacturing process could be much simpler. It ends up
being you need less of this material than you would
of silicon material. Stuff is already cheaper. The sheets that
you wind up with are more applicable to two different objects.
(35:19):
They can be thin and bendy and and right, which
means that you're not stuck with that one form factor
that you would be with a solar panel, where you
have a more rigid, thicker material, uh, which you depending
upon what you're trying to coat, could be a big deal.
It's sort of this pigmented stuff. And uh, it's, like
(35:40):
I said, very cheap and could eventually lead to solar
panels that cost ten to twenty cents per what. And
I remember we're talking now around between fifty cents and
a dollar per what, depending upon how you define it.
So this would be significantly less expensive and in fact
more than comparable to fossil fuel on a per what basis.
(36:02):
Knowing that this is not really apples to apples, so
but anyway, Uh, they right now are only an efficiency
of around fifteen percent. Uh. Scientists think that they might
be able to get get it to about twenty or
twenty five percent efficiency, so much lower than some of
these other ones we're talking about. But if the cost
(36:23):
is much lower, then it may make sense. If it's
cheaper to to turn these out than silicon ones, even
if the silicon ones are better, it may make more
financial sense to go with this material it's cheaper in
the long run. Kind of kind of idea. Now, right now,
there's an effort to commercialize the product through a company
called Oxford Photovoltaics, which is so far raised more than
(36:45):
four million dollars in capital. And uh, there's also a chance,
because we're still seeing silicon based cellar panels, we're seeing
those prices go down over time, there's a chance that
this won't make a big impact. So because if silicon
ends up being as cheap or only a little more
expensive than this alternative solar panel, people are going to say, well,
(37:07):
why would I sacrifice performance for just a tiny savings.
Plus you're talking about not just people, but entire companies
that would have to create their own manufacturing processes to
build these these panels. It would require a big change
in infrastructure, and it may not be worth that investment
to change the infrastructure. Although for certain purposes. Again, when
(37:29):
you're talking about the rigidity of the final product, you
might wind up, yeah, finding finding benefit and using something
that's a little bit less some Yeah, if you have
around building, for example, and you want to have part
of that building like a column where there's not any
windows facing out to be a solar gathering column. Uh,
and you don't want to place a million tiny panels
(37:51):
on it, right, this might be a way of doing that.
It's also been discussed as a way to augment silicon
based solar pans, where you would use the pigment to
help reduce the reflectivity of the panels, just like we
were talking about with the moth eyes. It would mean
that more photons would be reflected down into the solar panel,
as opposed to bouncing off and going willy nilly to
(38:13):
not do anyone any good, those lazy bums. So those
are those are some other alternatives. Do you have any
others you want to talk about? Before we talk about
some of the crazy fun stuff. That's all I've got.
But before we do that, let's take a quick break
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Go to Hulu Plus dot com Forward slash tech now
and there are a ton of shows on there that
are some of my favorites. The I T crowd is
way up there. So you'll hear lots of I T
crowd references in our episodes if you listen hard enough.
But in order to get the references, you need to
(39:41):
watch the show first, So go check it out. All right,
this isn't that crazy fun. But I did run across
an article about how solar panels are coming to Ikea
that if you're in the UK, that that was where
I got the UK information right, Lauren just shook her
fist for those who are those who were curious, those
who are listening in on say the radio. I shook
(40:02):
my fist in the other solar panel episode and I
announced it too, because so there's some things that just
carry over. It doesn't matter. So Ikea is looking at
carrying solar panels to for customers to purchase solar solar
panel kits, So flat pack Ikea style solar panel can
(40:23):
go in you buy a flat pack of ike I'm
sure they'll have some sort of Swedish name that will
be hilarious and um, you'll you know, in the UK,
you can purchase these and then go and have them
installed at your home. Uh. It sounds like if it's
a successful program that it will roll out to other
(40:44):
parts of the world, the United States included, and it's
you know, they're no stranger to solar power. In fact,
they use solar panels and several of their locations forty
of their US locations have solar panels energy. Yeah, they
essentially are powering their their buildings with solar energy as
much as they possibly can. So, uh, you know, now
(41:05):
they're looking at instead of just using it on a
corporate level, to actually offer it as a product. So
it'll be interesting to see if this ends up being
successful because then we'll see it rolled out to other
whether whether it's really is you know, in grand Ikea style,
cheaper and easier to install. Yeah, because you can as
a customer right now. I mean, if if you're a consumer,
(41:27):
you can go out and buy solar panels and have
them installed in your home. There are hardware stores like
Lows that that sell solar panels. It's not like i
Kea is the first business to come out and say
we're finally making solar panels available to cut customers, but
it's probably the first place that you can get Swedish
meatballs and also solar panels. Yeah, at least from a
reliable source. There is a guy outside of my local
(41:49):
lows who sells what he calls the Swedish meatballs, but
I just don't trust them. Uh So, that was one
of the wacky things I want to talk about. But
the other one is my favorite, which is the robo raven.
Robo raven. Yes, so a pair of University of Maryland
professors sk Gupta and Hugh Bruck came up with along
(42:09):
with their students, the robo raven, which is a robotic bird.
It's a little robot that can fly, and flying takes
up a lot of energy. It takes up a lot
of energy for birds, and it takes up a lot
of energy for robots, as it turns out, And so
they were trying to think of ways to extend a
robot's flying life so that it would be useful. Otherwise,
(42:29):
you know, your typical robotic flying device is going to
have a fairly small range and half batteries are going
to run down fuel source of money. So yeah, it's
it's roaming range is going to be about half of
what you would want just based on the battery life alone.
Because if you have it go all the way out
to its battery life, then you have to go to
retrieve it. You wanted to be able to come back, right,
(42:51):
So they were thinking, well, how could we build something
that could recharge its batteries while it's out in the
field sometimes literally dom and then make its way back home.
And so they decided to use a special material where
they were essentially weaving in solar panels along the wings
of this robo raven. So the idea is that this
(43:13):
little uh, this little device, this can the micro air
vehicle can fly out. It would land when its power
would get low, and it would recharge its battery. And
now they point out that the solar panels are nowhere
near efficient enough to power the bird's flight. Yeah, it
would have to land and recharge batteries and then fly
(43:35):
because I think it would generate something like gather like
three point six watts and it needs thirty wats to fly,
and like it just it cannot, you know, it would
just it would just crash if you were to try
and fly it beyond its battery life. So I thought
that was yes. Now, the robo raven that plays into
the podcast, we did not that long ago about drones. Uh,
(43:58):
in this case, the robo ravens just it's a robotic bird.
It's not designed to be anything specific apart from a
robotic bird. But you could easily see this kind of
technology being used in things like environmental uh monitors, you know,
looking for things like changes in climate, changes in environment,
exploration of areas that might be difficult to get to
(44:19):
on foot or otherwise, or you know, surveillance. You know,
there's that fun version to whether birds are spying on
you and the robots. I don't want that. I don't
want bird shaped robots spying on me. I want that
even less than I want other robots spying on me.
In fact, I'm not sure why I have this strong emotion,
but that sounds like i've I mean, I don't know,
(44:39):
maybe it's watched too much Alfred Hitchcock or something. I
recommend you don't turn around then, I'm just your back
is to the window. Yeah, we have an exciting new
window in the podcast, yes, which I can look out
of and Lauren cannot because of the way we sit.
I refuse to have my back to the window, all right,
So anyway, that's that's kind of our our update on
solar panel technolog g. You know, it's going to constantly
(45:01):
be this quest to eke out as much efficiency as
possible to make solar panels a true competitor when it
comes to generate electricity. Uh. And you also have to
offset the downsides to solar panels. So, for example, if
you were to try and go off the grid and
just use solar panels for your home, you would also
need some sort of energy storage device for those times
(45:25):
when the sun is not out and you would be
able to tap into that. So batteries essentially is what
I'm talking about. So you could have your own on
site generator that runs on something else, but you're talking
about some other fuel. Maybe pair it with a with
a wind generator or something like that, or not a
wind generator, but a wind harvesting wind driven Yeah, that
would if you if you live in a very sunny,
windy place, that would work out well for you. If
(45:47):
you don't, then uh, you know, that would probably probably
be marginally improvement over just solar panels alone. I hope
you guys enjoyed that classic episode of tech Stuff. If
you have any suggestions for future topics we should cover
on the show, let me know. Send me a message
on Twitter. The handle is text stuff HS w and
I'll talk to you again really soon. Text Stuff is
(46:14):
an I heart Radio production. For more podcasts from I
heart Radio, visit the i heart Radio app, Apple Podcasts,
or wherever you listen to your favorite shows.