
UNSW researchers set record in solar energy efficiency - prostoalex
http://newsroom.unsw.edu.au/news/science-technology/unsw-researchers-set-world-record-solar-energy-efficiency
======
acqq
Much better source, which means, the journalist who actually checks and
provides the sources and doesn't just retype the press release of UNSW is
here:

[http://www.semiconductor-
today.com/news_items/2014/DEC/unsw_...](http://www.semiconductor-
today.com/news_items/2014/DEC/unsw_121214.shtml)

"This exceeds the record solar photovoltaic module efficiency of 36.7%
reported in July by Fraunhofer Institute for Solar Energy Systems ISE of
Freiburg, Germany, using four-junction solar cells of concentrated
photovoltaic (CPV) solar system maker Soitec of Bernin, France. The 40%
efficiency is the latest achievement by UNSW solar researchers spanning four
decades, including the first photovoltaic system with over 20% efficiency in
1989."

"The new results are based on the use of focused sunlight, and are
particularly relevant to photovoltaic power towers being developed in
Australia" (note the comment from adwn here about that!)

The general and technical background of his field was delivered by the UNSW's
leading researcher here:

[https://www.youtube.com/watch?v=FomSzmIezVQ](https://www.youtube.com/watch?v=FomSzmIezVQ)

~~~
abandonliberty
Life imitating art.
[https://www.google.com/search?espv=2&q=helios+one](https://www.google.com/search?espv=2&q=helios+one)

~~~
istjohn
Actually HELIOS One was based on
[http://en.wikipedia.org/wiki/The_Solar_Project](http://en.wikipedia.org/wiki/The_Solar_Project)
.

------
adwn
From the original press release ([http://newsroom.unsw.edu.au/news/science-
technology/unsw-res...](http://newsroom.unsw.edu.au/news/science-
technology/unsw-researchers-set-world-record-solar-energy-efficiency)):

 _" The new results are based on the use of focused sunlight [...]"_

So it has the usual drawbacks of focused photovoltaics: you need tracking in
two dimensions, scaffolding, and active cooling of the PV cells.

~~~
ChuckMcM
Exactly, and what does '40%' conversion mean in this case? Are you collecting
twice as much light and focussing it on half the number of cells? Or is there
a silicon junction that can convert 40% of the light energy that is incident
on it?

~~~
adwn
> _Or is there a silicon junction that can convert 40% of the light energy
> that is incident on it?_

This. The main benefit of concentrated solar power is that the area of the
photovoltaic cells can be a lot smaller than the area of the collector (on the
order of 100-1000 times). This in turn allows having expensive, but highly
efficient PV cells, so you can convert 40% of the insolation on a given area
to electricity, instead of only 20%.

A side-benefit is that you can actually use the waste heat from cooling the
cells. The ETH Zürich is doing research on this, I think.

------
kosmic_k
We've gotten above 40% before...
[http://upload.wikimedia.org/wikipedia/commons/a/a5/PVeff%28r...](http://upload.wikimedia.org/wikipedia/commons/a/a5/PVeff%28rev141208%29.jpg)

~~~
raverbashing
"We used commercial solar cells, but in a new way, so these efficiency
improvements are readily accessible to the solar industry,"

~~~
kosmic_k
Thank you, I knew I had to have overlooked some aspect.

------
VeejayRampay
Slowly but surely we're getting there. I look forward to an inevitable time in
the future where the yield will be great and we'll know how to deal with the
panels (how to recycle them, etc). It'll be grand.

~~~
higherpurpose
This is why I've always dismissed and gotten annoyed by comments from fossil
or nuclear lovers who were saying for years that "solar is just not there". Of
course solar wasn't there where there wasn't even a tiny fraction of
investment into it as there is for fossils or nuclear. Put tens of billions of
dollars into researching solar, and let's see what we get then.

~~~
alexhill
In recent decades renewable have enjoyed much more investment than nuclear.
People love renewables, so governments love renewables, so industry builds
renewables.

However, they aren't going to displace coal any time soon, which is what we
need to do to avoid the catastrophe we're heading for.

Transmission, storage and integration are all problems that will certainly be
solved, with time and many billions spent on research and new infrastructure.
Nuclear gives us drop-in zero-carbon replacements for coal plants _today_ ,
without major changes to existing grids.

If we're going to avoid disaster, 0% fossil fuels must take priority over 100%
renewables. I hope and pray that the green movement embraces nuclear as a
brother in arms soon.

~~~
bebop
The green movement will not embrace nuclear for two reasons: One is that
nuclear produces highly toxic waste with a very long half life. And two, we
have already seen that we are not good at making our sites safe and resilient
to disaster, nor containing waste post disasters.

It is really to bad because without these facts nuclear would have solved our
energy problems long ago.

------
larrydag
Instead of electrical or equivalent power efficiency numbers I would like to
see benchmarks in terms of $ per KwH after installation. Or in other terms
what would be the current sunk cost to get to 40% efficiency.

I mean no disrespect to the scientists and engineers that are working on solar
efficiency. They are doing amazing work. I think journalists are seizing
headlines for sensational value (i.e. ad revenue) and not doing worthy
research.

~~~
Retric
There is no way to actually calculate that based on lab results. So, it would
just end up as a question of who was willing to fudge the numbers more.

------
ck2
I can't quite grasp this - 40% to what?

Availability of photons?

What is 20% vs 40%? Same size cell putting out twice the power for the same
sunlight? Okay, but what makes the 20% ?

~~~
dagw
40% of the total electromagnetic radiation that reaches the cell is converted
to electricity.

~~~
pingec
What happens with the other 60%? Turns into heat and/or is reflected?

~~~
CapitalistCartr
Yup, same as solar energy hitting any surface. It becomes heat.

~~~
melling
...or is reflected off...

------
whyaduck
I don't understand exactly what the purpose of the bandpass filter is. Why
does it improve efficiency by only allowing transmission of frequencies that
can actually be converted to electricity by the photovoltaics? Wouldn't that
light already be falling on the cells? My best guess is that by using the
bandpass filter, the temperature of the panels is lower than it would be
without them.

~~~
yourapostasy
There was an interesting discussion about this exact topic on /r/science [1].
Layperson me's (likely mis-)translation of what they were talking about in
that thread: the optical bandpass filter might not be a filter in front of all
the cells, but the actual cells themselves; or the optical bandpass filter
might be on the backs of the cells, reflecting what wavelengths would normally
heat up the cells onto a solar thermal collection mechanism.

The concentrated PV+solar thermal designs can get pretty intense: the high
concentration designs use liquid metal to carry away a 1600°C heat difference.
[2] If the UNSW team has hit upon a way to avoid most of that heat from
hitting the cells themselves and redirect it straight into the thermal
collection system, instead of trying to absorb the heat away from the cells
through thermal conduction, then that is a big win.

[1]
[http://www.reddit.com/r/science/comments/2okaxt/researchers_...](http://www.reddit.com/r/science/comments/2okaxt/researchers_convert_sunlight_to_electricity_with/)

[2]
[http://www.greenrhinoenergy.com/solar/technologies/pv_concen...](http://www.greenrhinoenergy.com/solar/technologies/pv_concentration.php)

------
pauly
Solar panels (stock image). Find the rest of our content somewhere after this
pointless image. It's not even an ad...

------
ars
This article is rather lacking in details.

------
baldfat
Is this an end of the year cause to show what scientist are doing with grants?

This month we have had so many "Breakthrough" Scientific articles that
basically don't match up.

We had super conductor that wasn't 0 Celsius for room temperature. That would
be a game changer.

This is focused light requiring active cooling and X and Y axis control.

Graphene article that actually shows that the title wasn't true since we are
still at the beginning of the graphene stages without much real world impact.

We also had the carbon filters for use around the world that also is far from
being practical or usable yet contrary to its title.

