
Energy Breakthrough could Store Solar Power for Decades - sdan
https://www.bloomberg.com/news/articles/2019-11-04/moth-poulsen-s-energy-trapping-molecule-could-solve-solar-storage
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pjc50
Real paper, I think (from the linked principal researcher):
[https://research.chalmers.se/publication/511209/file/511209_...](https://research.chalmers.se/publication/511209/file/511209_Fulltext.pdf)

The claims are reduced somewhat:

> The system features several attractive properties, such as a long energy
> storage half-life (40 h) at room temperature,

> Concerning the energy storage efficiency, 0.88% of the solar energy could
> theoretically be stored in a neat sample (S5, ESI†). The highest efficiency
> that can be expected for a 5104M solution is 0.02%, and for a 2104M
> solution is 0.01%

> However, the reaction rate was still too low to be used for macroscopic heat
> release purposes

This isn't a commercialisable solution. What this is, is fundamental research.
Which often looks completely terrible because it's a first attempt at
something. Once the relevant quantum effects are more understood, better
candidate chemicals can be developed.

~~~
jimrandomh
Paper: "a long energy storage half-life (40 h) at room temperature" Headline:
"Energy Breakthrough could Store Solar Power for Decades"

This is too egregious a misrepresentation by Bloomberg to let slide. Flagged,
and I encourage others to do the same.

~~~
xster
I also generally have trouble taking anything from Bloomberg seriously after
the chip story.

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dredmorbius
Oddly enough, there's a chemical with proved hundred-million-year-plus storage
capability for solar power, of the general form CnH2n+2:

[https://en.wikipedia.org/wiki/Hydrocarbon](https://en.wikipedia.org/wiki/Hydrocarbon)

Though in recent decades sourced from naturally-occurring reserves, a practice
which raises both suffiency and unintended consequence concerns, these are
also produced within the biosphere (though at levels insufficient to present
or projected future levels of human consumption), and may be synthesized by
artificial means from surplus electricity generation, or possibly, other forms
of energy.

[https://en.wikipedia.org/wiki/Synthetic_fuel](https://en.wikipedia.org/wiki/Synthetic_fuel)

~~~
marcosdumay
Those require a large deal of work to be reformed into an usable form after
storage. Even an year is enough to damage them to the point that they are
unfit for many mainstream applications.

~~~
dredmorbius
If directly synthesized in to desired forms, absent an antifungicidal
treatment, storage for months to decades is well within reason. Particularly
for direct thermal use.

The problem with the really old stuff is that the synthesis process was a bit
slipshod and the Designer(s) failed to anticipate the strict quality controls
required of present consumers.

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lr
Articles like this remind me of this house, which was built in Iowa City, IA
by a Physics professor (he was my professor for several classes). At the time
this house was being built, ISU had an "active solar" research facility, i.e.,
using all kinds of mechanical means to turn solar energy into heat for homes.
Once this house was built, ISU shut down the "active solar" research because,
as this house showed, passive solar was just so, so much cheaper and
efficient:
[https://lhodges.public.iastate.edu/house.htm](https://lhodges.public.iastate.edu/house.htm)

~~~
jackhack
It's actually remarkable how much heat a simple "soda can solar panel" or
"downspout solar panel" can inject into a room. Add a photovoltaic panel to
run a 12v brushless 100CFM fan to stir the air and inject the hot air into the
room, and you have a "free" source of 120F air to heat a few hundred square
feet. Add a south-facing window shining sunlight onto a dark grey slate tile
floor (which acts like heat sink) and the floor will release that heat well
into the night. So with two very simple passive elements, one can, to a large
degree, supplement a traditional heat source (heat pump, gas furnace, etc.).
I've seen this approach work with vacation cabins in the mountains, and RVs, a
well as the traditional house-on-the-cul-de-sac.

These heat collectors are cheap and simple to make (<$500), and should be
quite reliable, giving a +50 degree F delta with almost zero maintenance and
no utility consumption. The only moving part is the inexpensive and reliable
fan.

* [https://www.pinterest.com/jayhike/soda-can-solar-heater/](https://www.pinterest.com/jayhike/soda-can-solar-heater/) and [https://lifehacker.com/build-your-own-soda-can-solar-heater-...](https://lifehacker.com/build-your-own-soda-can-solar-heater-5574597)

~~~
timbit42
You might enjoy this:
[http://www.iedu.com/Solar/Panels/index.html](http://www.iedu.com/Solar/Panels/index.html)

~~~
jackhack
Ah, a high-efficiency version of the simple soda can version. Yes, it's of
great interest to me. Thank you!

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jjtheblunt
Titles with "could" seem strongly correlated with clickbait.

~~~
sneilan1
Sociologists discover titles with “could” could be correlated with clickbait.

FTFY :-)

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daddylonglegs
I think the domestic applications are partly covered by phase change
materials: waxes selected for a melting point at the desired temperature. So,
for example, you can embed a 23C phase change material in the plaster of a
room - giving the room a high apparent thermal mass at the temperature you
want it to stay at. A phase change material formulated to melt at 60C can make
a hot water tank much "bigger" for coupling with a solar thermal system. These
days houses can and should be built with enough insulation that they need very
little heating (in most climes).

On the other hand there probably are valuable industrial applications for this
sort of material, particularly now that we really want high efficiency. There
might even be uses in neighbourhood or utility scale power project.

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neonate
[http://archive.is/Ayuyv](http://archive.is/Ayuyv)

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gwbas1c
> A big unknown is whether the system can produce electricity.

So what! In the winter, demand for energy goes up for heating. With current
solar technology, it's impossible for someone to stockpile energy from rooftop
solar for winter heating. (Net metering is a numbers game.)

If this works, and I could somehow put panels on my roof or exterior walls
that allow me to stockpile energy throughout the year to use for winter
heating, it would be "the solution" for me.

Edit: I should add, anyone who sells a "magic thing" that charges up
throughout the year, and then provides free heat through the winter, will be
extremely rich.

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gene-h
Disappointingly this article doesn't provide a link to the research. I think
this paper might be it[0], but I am not sure. So in the paper they develop a
material that has an estimated storage efficiency of 3.8%(this might be solar
conversion efficiency) and energy density of 0.48 MJ/kg. This material is
what's called a photochromic meaning it changes color when exposed to
sunlight. This is just like those glasses which darken when you go outside.
Well it turns out that many photochromic molecules accomplish this by changing
or reconfiguring their molecular structure, with azobenzene being the classic
example of this[1].

Now as you may know color changing glasses eventually change back to their
original color, this is because the color changed state is at a little bit
higher energy than the clear state. There might be a bit of a hill it has to
overcome before it can go all the way downhill to the lower energy state, but
eventually random thermal motion will push it over. So because the color
changed state is at higher energy it can release energy as it falls down.

So the interesting thing they show here is that their molecule has a half life
or rate at which it converts back to its original form of 10 months, which is
a pretty long time. The energy density is also pretty good too, 0.48 MJ/kg is
about the energy density of alkaline batteries. And while 3.8% energy
conversion efficiency seems pretty bad it's pretty good for photochromic
materials of which efficiencies less than 1% are typical. Of course they want
to put this in windows and since you can't make the whole window out of this
material the energy density of the material+window plastic ends up being
~2.7-3.8 kJ/kg. Of course there's another problem here too. The material they
develop is yellow in its uncharged state only converting to clear when exposed
to sufficient sunlight, which may not be very attractive to consumers.

[0][https://research.chalmers.se/publication/510123/file/510123_...](https://research.chalmers.se/publication/510123/file/510123_Fulltext.pdf)

[1][https://en.wikipedia.org/wiki/Azobenzene](https://en.wikipedia.org/wiki/Azobenzene)

[2][https://en.wikipedia.org/wiki/Energy_density](https://en.wikipedia.org/wiki/Energy_density)

~~~
DoctorOetker
table 1 of the paper you reference [0], also lists "N5d" with a half-life of
18 years

I am confused with the different efficiency metrics, one kind of metric hovers
around the single digit percentages, but Table 1 lists Φ/photo conversion [%]
between 46% and 77% ...

This is substance 2l in the referenced paper at

[https://doi.org/10.1002/chem.201802932](https://doi.org/10.1002/chem.201802932)

~~~
gene-h
The single digit efficiency metric is probably overall conversion efficiency
of sunlight. The two efficiencies are probably quantum yield, or the
efficiency at converting one wavelength of light. We have two because the
molecule's tristable. Converting from state 0 to 1 has one efficiency while
converting from state 1 to 2 has another. State 0 and 1 also absorb different
wavelengths of light. Because sunlight's a mix of different wavelengths not
just the two our molecule's active at, the efficiency at sunlight conversion
will be different than the quantum efficiency.

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nmeofthestate
As soon as I read that eco-something could be used to "coat windows, or even
clothing", I just assume it's bollocks.

~~~
jackhack
nothing like having a molecular coating on one's clothing storing large
amounts of energy, and releasing it as heat. What could go wrong?

However, this type of storage might have promise as a power source for an
external combustion engine like the Sterling?
[https://en.wikipedia.org/wiki/External_combustion_engine](https://en.wikipedia.org/wiki/External_combustion_engine)

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iamaelephant
Bloomberg. Proceed with extreme caution.

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tempguy9999
Could any physicist speculate on the viability of using the Wigner energy for
energy storage.

Questions are, energy density, ease of 'injecting' the energy, how controlled
can the release be, anything else.

