EEVblog 1466 - Stanford Solar Power at Nightime BUSTED

[EEVblog]

Stanford University researchers have made a solar panel that works at nighttime!
It will reduce or eliminate the need for battery storage!
You can probably guess how it works... Let's BUST this impractical boondoggle wide open.

The research paper: https://aip.scitation.org/doi/pdf/10.1063/5.0085205

[golden_labels]

1467

[wilfred]

Is it in fact orders of magnitude higher than previous demonstrations. It seems to me it might be true. My reading of the paper suggests they are claiming 50mW/m² and they later go on to claim "Our approach can provide night-time standby lighting and power in off-grid and mini-grid applications, where PV cell installations are gaining popularity." and also "Our design can also power sensors in remote locations, reducing the size or eliminating the requirement for battery storage."

They're pretty modest claims. If you're just relying on the published paper.

Do they ever suggest more?

[wilfred]

1467

Don't forget some numbers were skipped so using one twice is just a way to slide things back to a correct count.

[Kleinstein]

Part of this may be the journalists refelctions on an 8 days old publication they did not really understand.

It is not really usefull energy, more like an oddity from the understanding of solarcells. When pointing to the cold and really dark sky, the PV cell should show a reverse voltage, as there is less NIR radiation than in equilibrium. However just some starts and a faint reflection of moon light may compensate for this and reverse the voltage back to normal.

[nctnico]

Is it in fact orders of magnitude higher than previous demonstrations. It seems to me it might be true. My reading of the paper suggests they are claiming 50mW/m² and they later go on to claim "Our approach can provide night-time standby lighting and power in off-grid and mini-grid applications, where PV cell installations are gaining popularity." and also "Our design can also power sensors in remote locations, reducing the size or eliminating the requirement for battery storage."

They're pretty modest claims. If you're just relying on the published paper.

Yep. It basically is adding a peltier generator (TEG) and using the solar panel as a heat source or heat sink. You'll need a crystal clear sky at night as well to achieve maximum cooling from space.

Do they ever suggest more?

They seem to claim it is usefull but realistically I doubt it is ever going to be cost effective.

@Dave: you got so worked up you lost count on your videos 

[bsfeechannel]

What is being debunked, the news or the article?

The article says explicitly that their invention can be useful for places where there's no electricity whatsoever and where the presence of battery banks would be impractical. Whether those places exist is a matter of debate, of course, but where is the bunk?

[AndyC_772]

At 50mW/m² you'd hardly be talking about a battery bank to deliver equivalent energy overnight.

[StillTrying]

Reminds me of this crackers one.

https://www.eevblog.com/forum/chat/harnesing-cold-outer-space-on-the-ground-through-a-transparent-ir-wavelength/

[SiliconWizard]

Ha! Finally. THIS is what's gonna get us "there".

[SiliconWizard]

At 50mW/m² you'd hardly be talking about a battery bank to deliver equivalent energy overnight.

What if we cover the entire globe though?

[bsfeechannel]

At 50mW/m² you'd hardly be talking about a battery bank to deliver equivalent energy overnight.

Yes. You can find batteries virtually anywhere around the globe. Even in remote and economically challenged regions.

So I find this kind of application very difficult for this technology.

But if you have zero watts and you can't have batteries for some reason, would you reject 50 mW/m²?

[AndyC_772]

If I can have the equipment to generate 50mW/m² each night, I can have the equipment to store a tiny fraction of the power that conventional solar cells generate during the day, store it, and release it overnight. A supercapacitor, if not a battery. Or a wind-up generator. Maybe a well-fed hamster.

[bsfeechannel]

If I can have the equipment to generate 50mW/m² each night, I can have the equipment to store a tiny fraction of the power that conventional solar cells generate during the day, store it, and release it overnight. A supercapacitor, if not a battery. Or a wind-up generator. Maybe a well-fed hamster.

OK. There's no immediate application for their technology. So, meh.

But the paper is not dishonest. It says that you'll harvest 50 mW/m², and apparently it is what you'll get. It is not a scam, pseudoscience or the like. So why is it busted?  So that we can laugh at their expenses?

[ssander]

Did Stanford watch this news conference from Anthony Albanese?

https://youtu.be/vyS9uqRLbB8

 

[jonovid]

more political fake science & green communist propaganda.
yes it works but at 0.1% 
piezoelectric running shoes will get you more output!
the truth is that oil and gas are the backbone of western civilisation.
not just the obvious heating and transportation.
but also everything from plastics to preservatives, from cleaners to cosmetics.

[bdunham7]

But the paper is not dishonest.

ABSTRACT
A large fraction of the world’s population lacks access to the electric grid. Standard photovoltaic (PV) cells can provide a renewable off-grid
source of electricity but only produce power from daytime solar irradiance and do not produce power at night. While there have been several
theoretical proposals and experimental demonstrations of energy harvesting from the radiative cooling of a PV cell at night, the achieved
power density is very low. Here, we construct a device, which incorporates a thermoelectric generator that harvests electricity from the temperature difference between the PV cell and the ambient surrounding. We achieve 50 mW/m2 nighttime power generation with a clear night
sky, with an open-circuit voltage of 100 mV, which is orders of magnitude higher as compared with previous demonstrations. During the
daytime, the thermoelectric generator also provides additional power on top of the electric power generated directly from the PV cells. Our
system can be used as a continuous renewable power source for both day- and nighttime in off-grid locations.

It is entirely possible to string together a lie from a series of entirely true statements.  If you ignore the numbers, the abstract makes it seem as if they've had a breakthrough.  If you understand the numbers, you readily understand that they have not, at least not in any practical sense.  Implying that this line of research has any real hope of being a widespread practical source of energy is a crock of crap, no matter where it comes from.  Recycling old calculators and attaching one calculator panel to each solar installation (not panel) would probably have a greater effect.  But recycling calculator panels will not....can you guess the punch line.....attract VC dollars.

[rs20]

Your video is really an indictment of the pointlessly vehement cheerleading that social media and popular science media do for the tiniest and most irrelevant research articles. The paper is a harmless "we glued A to B and it kinda worked" effort.

Developing a mean to extract energy from existing PV cells at night would alleviate the daytime limitation of PV power generation and reduce or eliminate the need for battery storage in electrical power systems.

Seems like the paper itself is doing plenty of pointless cheerleading all on its own; and social media and popular science only amplified that. Neither the author of the paper nor journalism come out of this as innocent bystanders, they're all bending the truth beyond recognition by stating true-but-utterly irrelevant statements like that quote above and by bdunham7 in the previous post. It's actually really sad to see this marketing nonsense leaking into the papers themselves, normally the scientists have some sliver of morality and it's only the university's press releases that stretch the truth.

[Circlotron]

I'm waiting for the first night time solar roadway.

[EEVblog]

Stanford University researchers have made a solar panel that works at nighttime!
It will reduce or eliminate the need for battery storage!
You can probably guess how it works... Let's BUST this impractical boondoggle wide open.

The research paper: https://aip.scitation.org/doi/pdf/10.1063/5.0085205

Dave,

Your video is really an indictment of the pointlessly vehement cheerleading that social media and popular science media do for the tiniest and most irrelevant research articles. The paper is a harmless "we glued A to B and it kinda worked" effort - not earth shattering, not false, just sort of unremarkable.

Why amplify it and feed into the mayhem? You've only "busted" some college student's balls. The liars here are the Twitterites and IFLSciencers, not the researchers. You're better than this.

Perhaps you missed the parts where it was publicised everywhere?
And as RS20 pointed out, the authors are the ones who talked this up like it was going to " reduce or eliminate the need for battery storage in electrical power systems.". That's 100% grade A delusional 

[EEVblog]

If I can have the equipment to generate 50mW/m² each night, I can have the equipment to store a tiny fraction of the power that conventional solar cells generate during the day, store it, and release it overnight. A supercapacitor, if not a battery. Or a wind-up generator. Maybe a well-fed hamster.

OK. There's no immediate application for their technology. So, meh.

But the paper is not dishonest. It says that you'll harvest 50 mW/m², and apparently it is what you'll get. It is not a scam, pseudoscience or the like. So why is it busted?  So that we can laugh at their expenses?

Read the above quote from the paper. They literally say it could eliminate the need for battery storage in electrical power systems.

[EEVblog]

At 50mW/m² you'd hardly be talking about a battery bank to deliver equivalent energy overnight.

Yes. You can find batteries virtually anywhere around the globe. Even in remote and economically challenged regions.

So I find this kind of application very difficult for this technology.

But if you have zero watts and you can't have batteries for some reason, would you reject 50 mW/m²?

Like I said in the video, there may be some small niche for it. But at a huge material and cost expense. Vastly cheaper and simpler to charge a single 18650 cell durign the day and you'll get the equivalent energy to a whole 5kW solar array filled with this energy harvesting.

[EEVblog]

What is being debunked, the news or the article?

The article says explicitly that their invention can be useful for places where there's no electricity whatsoever and where the presence of battery banks would be impractical. Whether those places exist is a matter of debate, of course, but where is the bunk?

Did you even watch the video?
I spent maybe a third of it showing all the hyped up media reports.
And then I showed some delusional claims in the paper itself.

As for the "where the presence of battery banks would be impractical", use super capacitors or some other form of storage to store real meaningful amounts of power during the day. Not 50 bloody mW.
Seriously, adding huge amounts of heatsinking and TEG and associated circuitry which ALSO require storage itself in the form of capacitors, to get the equivlent of a single 18650 cell of energy per day is so far from being practical it's a joke.

If it was just the paper on it's own without any delusion claims or replacing battery storage or other stuff and simply presenting the research and then no meadia hype, fine. But that's not what happened, so it gets busted.
And it's busted in the same way that solar roadways, batterieser, fontus etc etc are busted. All of them "worked" and could have a small niche application.
Did this one have to raise a million bucks on Kickstarter to be worthy of being busted?

[golden_labels]

Truth is very different from facts. The most effective lies are crafted from facts only.

The researchers seem to be dishonest in the abstract and intro, but I suspect I see the cause. It is at the opposite side of the publication:

This work was supported by the U.S. Department of Energy No. DE-FG-07ER46426 and by the Strategic Energy Alliance program at Stanford University.

Seems to me like they applied some “lube”, so the project would easily go through and receive support. Doing science is a constant fight for funding and not getting discarded, so I can’t easily blame them.

As for the media, I do not even see a reason I should comment on that cesspool.

[tszaboo]