
The perovskite lightbulb moment for solar power - AndrewDucker
http://www.theguardian.com/technology/2014/mar/02/perovskite-lightbulb-moment-abundant-solar-power-britain
======
InclinedPlane
The biggest roadblock to widespread adoption of solar as a baseload power
source is the storage problem. Photovoltaics stop producing power when the sun
goes down, that's not just inconvenient it's unworkable with the way power is
used today. Until we can economically shift the output curve of solar power
plants to match demand rather than supply it will always fill no more than a
niche. Today the only way to do this is to work in concert with hydropower,
but that is a very limited solution.

Also, it's not strictly necessary to solve the problem on a large scale, even
at a small consumer-grade scale it could be helpful. If every house had a
battery pack or supercap bank or what-have-you and it allowed for smoothing
out power demand or perhaps enabled charging electric vehicles overnight, then
it could have a huge impact on energy usage patterns. Even with the PV ->
battery -> battery losses it would still be a substantial net win.

~~~
Gravityloss
That's only a problem that's much farther down the road, say when solar
penetration goes above 10% or 20%.

In the mean time you could just throttle hydro plants and natural gas plants
to account for both usage variations as well as wind and solar production
variations.

Too bad coal is very very cheap right now.

~~~
InclinedPlane
It's a problem _preventing_ solar penetration beyond a niche market. It also,
as you point out, prevents solar from actually displacing existing power plant
_capacity_. That means that solar power comes at an extraneous cost, since it
doesn't obviate the need of building even a single non-solar power plant.
Those are big problems and it's not as though we're magically going to start
building lots and lots of solar power capacity without solving those problems.
The sooner their tackled the faster those technologies will be on the
amortization/improvement train and their costs will fall.

Solar and wind are today just sideshows in power production, if you want them
to be otherwise the smart move is to invest in storage technologies.

~~~
mikeyouse
I agree with your sentiment, but solar prices have plummeted and clever new
financing arrangements from Solar City et al. have made them much more
accessible, in the US at least.

[http://www.urbanphotovoltaic.com/Portals/0/solutions/photovo...](http://www.urbanphotovoltaic.com/Portals/0/solutions/photovoltaic/GlobalSolarInstallation-92-12%20Download.JPG)

We're slowing getting there, ~100GW of capacity installed in 2012, up from
~40GW in 2010.

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danmaz74
An older but more detailed article about this:
[http://cen.acs.org/articles/92/i8/Tapping-Solar-Power-
Perovs...](http://cen.acs.org/articles/92/i8/Tapping-Solar-Power-
Perovskites.html)

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ars
Is this going to be another one of those products that are cheap in small
quantities, but are simply not available in large quantities?

The reason we keep going back to silicon is the planet (the crust) is
basically made out of it. It's available in any quantity.

~~~
Turing_Machine
"methylammonium trihalogen plumbates"

Methylammonium ions can be had from methylamine, which is dirt-cheap (made
from methanol and ammonia, usually).

Halogens are fluorine, chlorine, bromine, iodine. All common and cheap.

Plumbates are lead and oxygen. Again, common and cheap.

So, no, there shouldn't be any supply problem.

Disposal might need some watching due to the lead, but I doubt this would
involve anywhere near the volume that's used in (e.g.) lead-acid car
batteries.

~~~
ars
Chlorine is available in quantity, but fluorine, bromine, and iodine are not.
Bromine and iodine are actually quite rare - there's more uranium than either
of those.

Lead is also somewhat rare.

> All common and cheap.

Exactly what I'm talking about. In the small quantities we use currently -
common and cheap. In the quantities needed to make energy? Not common at all.

> So, no, there shouldn't be any supply problem.

Actually, if that's what it's made of there will be huge supply problems.

Based on all this I suspect this is the last we will hear of this technology.
It works in the lab, but is not practical at scale.

Although maybe those elements are just used at ppm levels, and the bulk of
this is silicon, then this could work.

> but I doubt this would involve anywhere near the volume that's used in
> (e.g.) lead-acid car batteries.

To provide energy at country level scales? It would use WAY more. I once
calculated that there is not enough lead on the planet to make enough
batteries to store enough energy for overnight use. (In the context of
batteries to buffer the diurnal nature of solar energy.)

~~~
Turing_Machine
> Chlorine is available in quantity, but fluorine, bromine, and iodine are
> not.

All of these are available in quantity. Bromine is available in tank-car lots.
Iodine is available in tonne lots.

"Lead is also somewhat rare."

"Somewhat rare", perhaps, but it only sells for about $1/pound, and 8 million
tonnes are produced annually.

"Actually, if that's what it's made of there will be huge supply problems."

Actually, you're totally wrong. Sorry.

"I once calculated that there is not enough lead on the planet to make enough
batteries to store enough energy for overnight use."

Batteries use multiple heavy plates of solid lead. This is a micrometer scale
thin film on a substrate. There's a difference.

~~~
Turing_Machine
Assume the film is entirely lead (likely the limiting component -- as others
have noted there is no shortage of bromine, chlorine, and iodine in the ocean)
and 10 micrometers thick.

Lead has a density of 11,340 kg/m^3.

A ten micrometer thickness means that each m^2 of material will use about 0.11
kg of lead.

While the earth receives something like 1,000 watts/m^2 in full sun, other
factors (e.g., night, clouds, different sun angles) mean that the mean is
closer to 250 watts/m^2.

This stuff is expected to reach 20% efficiency, so each m^2 of collector will
produce a mean output of 50 or so watts.

Human civilization as a whole produces about 15 terawatts of power, so
replacing it would require about 300 billion square meters of collector.

At 0.11 kg/m^2, that would require about 33 billion kg of lead.

World production of lead is about 8 billion kg per year.

So, unless I messed up the arithmetic (please correct if so) total replacement
of _all existing power sources_ would require only about 4 years of lead
output. Given that that will never happen (and even if it did, the time scale
would be much longer than 4 years), it is safe to say that the availability of
lead is _not_ a limiting factor for this technology.

~~~
ars
Your arithmetic is correct except for lead production figures and optimism on
iodine. You are including recycling, so real production is about half of what
you wrote.

The trouble is that at current rates of consumption the world will run out in
42 years (according to wikipedia). So this project would use 20% of all the
remaining lead in the world. (Well not really, the film is not 100% lead, but
it's still quite a lot.)

I call that "not enough". Although it might be worth it anyway. But what do
you do when energy use goes up?

And despite people saying there is bromine and iodine in the ocean, there is
no practical way to get it _out_ of the ocean in quantity. There is
_everything_ in the ocean - in huge quantities! For example 1/10 as much gold
as has ever been mined by humans exists in the ocean - but no one can get it
out in quantity.

World production of iodine is about 1/200 of lead production and we already
see that we barely have enough lead.

And world _existence_ of iodine is 1/100 of lead. And considering we need a
significant percentage of the lead in the world, there is no way there is
enough iodine.

But we are ignoring the substrate. It won't be so thin, so we'll need a lot of
it. I wonder how much of it is for mechanical strength (i.e. replaceable) and
how much is essential.

Maybe this could work - using a thin film is very promising, but I'm skeptical
this could be scaled.

~~~
pjc50
I still don't understand where you're going with this. Just because it's not
capable of entirely providing our current power consumption doesn't mean it's
a bad idea for deployment. After all, our current majority power source is a
finite resource that's going to run out, and similar resourcing issues apply
to uranium.

You're probably going to reccomend Thorium, but the barriers to
commercialisation there are more serious.

Personally I suspect we'll end up with 30% solar, 30% wind, 40% other (tidal,
nuclear, geothermal, biomass etc).

~~~
ars
> I still don't understand where you're going with this.

This is a useful technology _only_ because it is inexpensive. If it were more
expensive it would not have value.

Because it relies on rare elements it can not be used in scale because as soon
as you do the price goes up, it is no longer inexpensive, and no longer
useful.

This feedback loop has killed every solar technology I've read about except
silicon.

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CamperBob2
EU regulators, the people who brought us lead-free solder, are going to love
the "plumbate" part. It might as well be plutonium.

~~~
thrownaway2424
You're not one of those RoHS deniers are you? I hate to break it to you, but
EVERYTHING made in the last ten years is made with lead-free solder and ta-da:
it all works perfectly well.

~~~
aidenn0
Yes, they've figured it out now. There was an ugly transition period though.

~~~
analog31
Agreed, but I'd add that the transition period coincided with the switch to
water based flux processes, and the headlong rush to China. All of those
things involved their own sets of birthing pains.

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aaron695
These sorts of comments always set off alarm bells for me -

"If we could capture approximately 1% of the X on Y"

I think in a lot of countries the labour costs are the major factor in the
price.

If this is true then what we really need is longevity and efficiency rather
than cheaper panels.

~~~
dredmorbius
It's a useful statistic, particularly as it places a minimum bound on the land
area requirements. In fact most renewables (solar, wind, biomass, wave, tidal
power) can be translated into land-use requirements: so many kW/m^2 or
MW/hectare. Useful conversion: 1 kW/m^2 is about the average insolation at
Earth's surface, which translates to 10 MW/hectare, or 1 GW/km^2.

Knowing that 1% of the incident sunlight on Britain would provide the nation's
energy requirements, and that solar cell efficiency is 20%, means that Britain
could be energy self-sufficient with 5% of its land-area covered with PV
cells. The land area of the UK is about 229 million km^2, so roughly 11.5
million km^2. Knowing what the material requirements per m^2 for perovskite
solar cells would give us a first-order bounds check on how viable the
technology might be for this application.

The challenges for solar are not just cost (of which installation and
infrastructure costs are a significant component), but substrate abundance
and, unmentioned by this article, storage.

Still, it seems an interesting development.

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higherpurpose
This is why I never understood the argument "but solar is so expensive right
now", when it was still very early days for solar investment. If you start
pouring the billions of dollars nuclear gets into solar panel research, and
bring it to a high enough scale, you eventually start getting not just a real
alternative, but potentially a much better alternative to any other energy
source.

Once we "fix" the cost of solar panels, then we need to figure out how to
store solar energy cheaply and easily, too, and then it can be a source of
energy that's not just for day time and sunny seasons, too.

------
af3
RIP organic photovoltaics.

~~~
chm
Not so fast.

We're working on it.

~~~
af3
We too ;)

