From the UNIVERSITY OF EXETER
Butterflies heat up the field of solar research
The humble butterfly could hold the key to unlocking new techniques to make solar energy cheaper and more efficient, pioneering new research has shown.
A team of experts from the University of Exeter has examined new techniques for generating photovoltaic (PV) energy – or ways in which to convert light into power.
They showed that by mimicking the v-shaped posture adopted by Cabbage White butterflies to heat up their flight muscles before take-off, the amount of power produced by solar panels can increase by almost 50 per cent.
Crucially, by replicating this ‘wing-like’ structure, the power-to-weight ratio of the overall solar energy structure is increased 17-fold, making it vastly more efficient.
The research by the team from both the Environment and Sustainability Institute (ESI) and the Centre for Ecology and Conservation, based at the University of Exeter’s Penryn Campus in Cornwall, is published in the leading scientific journal, Scientific Reports.
Professor Tapas Mallick, lead author of the research said: “Biomimicry in engineering is not new. However, this truly multidisciplinary research shows pathways to develop low cost solar power that have not been done before.”
The Cabbage White butterflies are known to take flight before other butterflies on cloudy days – which limit how quickly the insects can use the energy from the sun to heat their flight muscles.
This ability is thought to be due to the v-shaped posturing, known as reflectance basking, they adopt on such days to maximise the concentration of solar energy onto their thorax, which allows for flight.
Furthermore, specific sub-structures of the butterflies’ wings allow the light from the sun to be reflected most efficiently, ensuring that the flight muscles are warmed to an optimal temperature as quickly as possible.
The team of scientists therefore investigated how to replicate the wings to develop a new, lightweight reflective material that could be used in solar energy production.
The team found that the optimal angle by which the butterfly should hold its wings to increase temperature to its body was around 17 degrees, which increased the temperature by 7.3 degrees Centigrade compared to when held flat.
They also showed that by replicating the simple mono-layer of scale cells found in the butterfly wings in solar energy producers, the could vastly improve the power-to-weight rations of future solar concentrators, making them significantly lighter and so more efficient.
Professor Richard ffrench-Constant, who conducts world-leading research into butterfly mimicry at the University of Exeter, said: “This proves that the lowly Cabbage White is not just a pest of your cabbages but actually an insect that is an expert at harvesting solar energy.”
The paper, White butterflies as solar photovoltaic concentrators, by Katie Shanks, Dr Senthilarasu Sundaram, Professor Richard ffrench-Constant and Professor Tapas Mallick from the University of Exeter, is available online.
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Brilliant, actually. I’ll have to try to read the article and understand the geometry of this.
It looks like this is in the category of “concentrated photovoltaics” which is most often done with lenses.
https://en.wikipedia.org/wiki/Concentrated_photovoltaics
Specifically, this is in the “low concentration” end of this approach. Typically it doesn’t require active cooling or (necessarily) active tracking. If they can get to 50%, that is a 15% improvement over most other low concentration approaches which (according to this article) are around 35%. The thing that the blurb above does not tell us is just how much extra area is required — butterfly wings are many times the size of the body being warmed. How big do the “wings” of a solar cell have to be to make 50% more electricity and bump a cell that is nominally 17% efficient to maybe 25% as far as cell area is concerned? Do they have to “flap” to remain optimized on the sun?
These things matter a lot when one directly compares cost-benefit (see the short section on “grid parity”, which is where solar of any sort “breaks even” with other ways of putting power onto the grid). The problem is that solar cells are so cheap that most concentration methods, which require both tracking and active cooling, push the cost over that of a flat unconcentrated array. If this lets one increase the efficiency of a solar cell by an average of 50% without cooling or tracking and using the moral equivalent of 50 cents worth of cheap foil on plastic in a static wing, one could build a very simple panel where (say) solar cells are only 1/3 of the area but make 1/2 of the electricity the whole panel would make if covered with solar cells. It costs you more area, but the higher cost efficiency otherwise might make this very competitive.
rgb
Well what I want to know is for air mass 2 solar (60 degrees from zenith) at the earth surface, and their new butterfly wing solar panel, what is the optimum electrical power density (DC) out of the panel assuming the solar irradiance is 1,000 Wm^-2 ??
No trickery. Simply assuming the sun approximately 30 degrees above the horizon, and the butterfly solar panel optimum pointing axis pointed straight at the sun, so that the incident irradiance on its projected area is 1,000 Wm^-2.
Current production panels can get between 210 and 240 Wm^-2 DC electrical power density. No losses for any AC inversion inefficiencies.
I’m presuming from their report that they can get between 315 and 360 Wm^-2 .
As for ” concentrated photovoltaics ” I don’t think you will find too many operational systems that use “lenses”.
The most efficient systems actually use ” non-imaging ” optics, and the higher the concentration, the more likely that is.
But that does not preclude using ” lenses ” as part of the non imaging optical system.
I actually have several patents; well I don’t, but the “customer” does, with my name on them, that do use a combination of a thin Fresnel lens, and other optical elements to concentrate but do not form an image.
Imaging optics placing additional and unnecessary restrictions on the optical design. All you really are trying to do is catch photons in a bucket. You don’t really give a hoot where they land in the bucket; just that they enter the entrance aperture of the bucket, from some prescribed solid angle of space.
I’ll look forward to seeing the first installation of butterfly solar panels in my local area, which happens to be a quite hot market for roof solar panel installations, on already committed surfaces.
g
And rgb, they say a 50% improvement, over existing; they don’t claim a 50% conversion efficiency.
I took the current commercial state of the art as 21-24% for solar to DC. I don’t penalize the solar panel for the extrania of putting the juice on the grid.
g
In Norway it does not matter. Even if they had 110!!!% efficiency. In winter we, south Norway, have about 4 hours of sun if there are no clouds. I have 2 * 140W panels at my cabin and they do not work nov-dec-jan-feb. Then I have to charge my batteries with my Honda generator. Sola power is not always available and cheap. And will not work. But if you live close to equator it might work during day. But it will still be expensive. The leftist here in Norway wants to put solar panels on all government buildings. We have ample and cheap hydro, but they are eager to have less available and very expensive solar. The logic is very difficult to grasp?
Sadly Robert it doesn’t change the useless nature of solar panels without the ability to store GW of energy for night time use.
Not really. Panel like this need a larger surface. Any lense structure will have the same effect.
No real argument, but I think their assertion would be that it won’t require either heat dissipation or dynamic orientation, which most lens-augmented cells require, as well as the assertion that it is cheaper to build two white “wings” for a cell that don’t ned to be reoriented to work than to put a lens over it.
I already commented on the area problem but too late to catch your post, sorry. I agree with you — at some additional area (which might be a fairly small area!) it isn’t worth it to put two white “butterfly wings” onto each cell in a passive collector panel, even for a 50% boost in the cell output. Because of fixed costs building panels and additional costs for area to deploy and LARGE costs associated with tracking or cooling, there is a fairly narrow window where this will be useful.
Still interesting, though.
rgb
Solar energy might be more popular if, instead of littering the countryside with ugly solar farms, we used them as an art form as can be seen in Singapore. They positively enhance the built environment
http://edition.cnn.com/2012/06/08/world/asia/singapore-supertrees-gardens-bay/
Tonyb
Tony,
Nice. Thanks for this link. From the article: “The man-made mechanical forest consists of 18 supertrees that act as vertical gardens, generating solar power, acting as air venting ducts for nearby conservatories, and collecting rainwater.” and “The large canopies also operate as temperature moderators, absorbing and dispersing heat, as well as providing shelter from the hot temperatures of Singapore’s climate to visitors walking beneath.”
Regards
Hey, Tony, I looked at your “supertrees” in Singapore. While they are indeed lovely, it looks like from each tree you might harvest a peck of watts, or perhaps a bushel of watts … but not modern amounts of watts. This is “greenwashing” at its finest. Putting solar on those trees is just a sop to the carbophobes, a meaningless feel-good gesture.
w.
To put this in context, a single monocrystalline panel, made in the US, framed and ready to go on a roof, with 270W output costs around $270 and is a bit over 5×3 (feet) or around 1.5 m^2. If one could make the same panel using only half as many solar cells but with 3/4 of the power — say 200 W — for a bit over half of $270 (say, $170) — that’s a huge increase without much penalty in terms of area. If it takes TWO panels of this size to reach 200W, though (a 4x the area with half the area in cells) then the advantage starts to fade as the fixed costs of making and shipping two panels with no cells at all are certainly not zero, and in some contexts the available e.g. rooftop area is limited or else one has to add the expense of more land for a commercial array.
So it isn’t as brilliant or advantageous as all that UNLESS they can get to 50% more efficiency for nearly any kind of cell and only use 2-3 x as much are. I’m guessing if it requires 4x the area or more, it is a dead loss compared to just filling the same panel with unconcentrated cells.
rgb
Ha ha, wonder if it will work during the ice age? 🙂
Well, since we are still in an ice age (in an interglacial thereof) I guess the answer is yes. Unless the additional CO_2 has altered the climate enough to eliminate the current 100,000 year glaciation cycle. A fair number of people think this is probably the case. I’m open minded, but it certainly seems reasonable that it has, and if so, good for it! Glaciation sucks.
rgb
Any fixed flat panel installation, would normally be pointed in altitude at or near the midpoint between the minimum and the maximum sun altitude angle at local noon throughout the year. It’s not quite that simple as the air mass losses change with sun altitude, and other factors. But the solar PV industry knows how to determine that optimum install angle, rather than just slapping the panels flat on the tilted roof at whatever the roof angle is.
For the daylight hour tracking from horizon to horizon, it is best with flat panels to not use 3-D concentrators in fixed installations.
But it is ok to use 2-D trough ” optics ” to increase the capture over the annual local noon sun altitude range.
The trough concentration can be up to 1/ sin ((solar altitude range)/2).
You can do more than that, if you want to complicate the installation to allow for altitude angle periodic adjustment (say weekly or monthly, or continuous if you want). But the altitude range at noon is around 47 deg over the year. So 23.5 deg. would be the capture viewing angle required.
So 2.5 X is the maximum trough angle concentration, and you really don’t want to use all of that because it implies some flux incident on the solar cells at grazing incidence, and you really don’ want to go past the Brewster angle of incidence on the cell.
I’m not going to do the calculation, but I suspect a 1.5 X concentration is ok but 2X is pushing it. Well you might do the 2x and accept the lower efficiency if area reduction is more important than maximum possible concentration.
I’m not going to hold my breath on this.
Remember a while back some 4-H club kid spread a bunch of tiny cells like leaves on a tree and random angles, and everybody went gaga over it. Well yes, he could just stick his phony potted plant in the window and forget it, but efficient, it was not.
g
I wonder how practical is the underside construction for a large number of panels, the stability in strong winds and the snow accumulation in the areas with large winter’s snowfalls.
Talking of winters, last night it was recorded the lowest ever the CET’s July temperature of only +1 (one) degree C (the CET instrumental records of one kind or another go back to 1659)
It certainly doesn’t work at night, Jay.
Willis
I am not a fan of solar farms but those that matter are. Consequently if we have to have the things I would rather they were attractive pieces of work in their own right and situated in the urban environment performing a number of useful functions.in the manner that Danny has usefully highlighted
tonyb
climatereason July 31, 2015 at 11:47 pm
Thanks, Tony, always good to hear from you. Like you, I prefer anything in the urban environment to be a piece of art. South Korea is a master in this, even the canvases covering the sides of buildings being remodeled have lovely designs on them, and their bridges are most certainly, as you said, “attractive pieces of work”.
However, my point was different. It is that the amount of energy generated by such a tree is trivially small, so small that putting solar panels on the trees is just a feel-good exercise.
And I have no use for feel-good actions, I dislike them immensely because they fool us into thinking we’ve actually accomplished something. It’s like when the girls were kidnapped in Nigeria, everyone started using the hashtag #saveourgirls, and walked away feeling good because they’d “done something”.
But that very illusion of doing something is hugely counterproductive, because when someone thinks they’ve already taken action on a particular subject, they often don’t do anything else. They’ve fooled themselves into believing that they have already taken action, and that dissuades them from taking actions that actually might do something … and now, a year later, the girls have been sold into slavery or forced marriage. Yeah, that #saveourgirls was so effective …
So while I agree that the trees are beautiful and functional for other reasons, putting solar panels on them is an empty feel-good gesture. The Singaporeans get to say “We’re doing our part to be green”, when they have done nothing of the kind, and Singapore is still drawing gigawatts of fossil power …
Heck, reflecting on it, maybe I was wrong, maybe that’s a good thing! … maybe we could put up a dozen magic trees like Singapore did and say OK, that problem’s solved, guess there’s no need to cut back on fossil fuels …
All the best,
w.
rg, I suspect installation costs would increase as well.
How come butterflys & man can’t use mirrors @ 17 degree angles to concentrate at least a portion of the 333W/m2 back radiation from the sky and use it to do thermodynamic Work & as unlimited power source?
Because for a heat engine to work, your heat engine need more than just a “hot” end, you need a cold end as well. And since the 333 W/m2 implies a radiation temperature of just about freezing, you’ll need a block of dry ice to cool the cool end of your heat engine.
Simple, really.
Oh, and the reason that you can’t use a photocell to capture the downwelling IR? Thermal IR doesn’t contain enough energy to knock an electron out of its orbit, so there is no known photocell that can harvest it.
w.
[Comment deleted. commenter using fake identity, deleted per WUWT policy –mod]
Willis says “Oh, and the reason that you can’t use a photocell to capture the downwelling IR? Thermal IR doesn’t contain enough energy to knock an electron out of its orbit, so there is no known photocell that can harvest it.”
Well, actually a “reverse solar cell’ was patented over a year ago and generates power by LOSS of IR/thermal energy to the ~-18C sky that’s chock full of ‘heat-trapping’ greenhouse gases to COOL one end of the Carnot atmospheric heat engine, i.e. the Maxwell/Clausius/Carnot/Feynman gravito-thermal greenhouse effect.
http://hockeyschtick.blogspot.com/2014/03/new-renewable-energy-device-generates.html
Second related physics Q: If I point a solar cooker with 17 degree angles on 4 sides to concentrate at least some portion of the diffuse GHG 333W/m2 back radiation at a wide focal point, does the temperature of the focal point:
a) increase
b) decrease
c) no change
Joel D. Jackson July 31, 2015 at 1:19 pm
Sorry, amigo, but that is near-visible infrared, not the thermal infrared that hockeyschtick and I were discussing.
Unfortunately, it appears that your desire to prove me wrong overcame your reading skills …
w.
hockeyschtick July 31, 2015 at 1:32 pm Edit
Sorry, but what does that have to do with my comment about a photocell?
Also, you seem to make a point that the atmosphere is cooler than the surface, and yet warmer than the background radiation in outer space … but what is the point of your point?
w.
To hockeyschtick, you can make ice at night using a solar cooker, even if ambient temp never descends to freezing:
https://flutrackers.com/forum/forum/personal-family-professional-emergency-preparedness/water/19439-making-ice-in-the-solar-cooker
One has to point the cooker away from trees, buildings, clouds, etc. whose “back radiation” will keep the water warmer and prevent freezing. Unfortunately, even the “back radiation” from the clear night sky will keep the apparatus from achieving temps much lower than freezing. If only the cooker could “see” outer space directly, one could reach lower temps (I have no idea how low; at some point heating from conduction and convection would overwhelm the cooling effect of radiation.
PS Willis…
….
Just to help you out with your apparent lack of understanding about the adsorption of photon energy, you need to consider two items.
..
First of all, photons with RF energy levels can be adsorbed by wire of the appropriate length. These things are more commonly known as “antennas” Yes, Willis, there are devices out there that can actually convert photons with wavelengths longer than infrared into electrical energy.
…
Secondly please read the following: https://en.wikipedia.org/wiki/Shockley%E2%80%93Queisser_limit#Photon_upconversion
“…photons with RF energy levels can be adsorbed by wire of the appropriate length”
Adsorbed or absorbed?
Willis says, “Sorry, but what does that have to do with my comment about a photocell? Also, you seem to make a point that the atmosphere is cooler than the surface, and yet warmer than the background radiation in outer space … but what is the point of your point?”
The points are
1. Heat Energy transfer (not radiation which is indeed BI-directional) is one-way-only from hot to cold
2. The CO2+H2O ‘hole’ in the OLR spectra is at a “corresponding” true blackbody temperature of ~217K, which is colder than the annual average “BB” temperature of the 288K surface, 255K equilibrium temperature with the Sun, and minimum temperature of the rest of the atmosphere 0-100km including the ~220K tropopause. The ~15um line-radiation radiation from a true blackbody at an emitting temperature of 193K for CO, or ~217K for CO2 (+H2O overlap) cannot be thermalized/increase the frequency of/increase energy of/increase temperature of a blackbody warmer than 217K. The reason why is that all of the lower frequency/energy/temperature microstates of the higher frequency/energy/temperature blackbody are already completely saturated and contribute insufficient quantum Energy to raise the microstates in the higher temperature blackbody.\
The answer to the question about solar cookers pointed at the clear sky is that the temperature of the focal point decreases, and that is why solar coolers have been used as refrigerators in the 3rd world.
http://hockeyschtick.blogspot.com/search?q=solar+cookers
A pure N2 atmosphere Boltzmann distribution without any GHGs would in be warmer than our current atmosphere containing ~0.04% GHG IR passive radiators, which increase both convection and radiative surface area/IR loss to space:
http://hockeyschtick.blogspot.com/2014/11/why-greenhouse-gases-dont-affect.html
Feynman concurs with the pure N2/O2 atmosphere gravito-thermal GHE:
http://hockeyschtick.blogspot.com/2015/07/feynman-explains-how-gravitational.html
Willis, I really look forward to meeting you tomorrow in Ontario, CA to discuss these matters further 🙂
“Furthermore, specific sub-structures of the butterflies’ wings allow the light from the sun to be reflected most efficiently, ensuring that the flight muscles are warmed to an optimal temperature as quickly as possible.”
Butterflies do.
I would think you would want to read the paper to know if it was actually brilliant.
Moths fly at night. Their whole “look at the Cabbage White” spiel is fallacious.
Clever obfuscation, there…
Not once did I read that all they’re doing is moving the output of a PV panel closer to its theoretical maximum.
‘Course maybe that’s just my inner cynic talking…
LeeHarvey – A technological improvement is still a technological improvement, no? Granted, I doubt this will make them commercially viable any time soon, but surely we should be pleased by this…?
If I had some cheese, I could make a ham and cheese sandwich… if I had some ham. CO2 is not a pollutant.
If the PV panel were a theoretically perfect absorber in the first place, then there’d be no reflected energy to absorb. All of the pie in the sky projections of the future of solar power are effectively based on the collection being perfect, and they still fall short of meeting real world energy demand.
Moving toward the ‘good’ end of the economic spectrum doesn’t mean that it hasn’t left the ‘bad’ zone.
Well Mark, if it isn’t commercially viable, it isn’t a technological improvement. Technology makes apparently lunatic ideas commercially viable.
g
Paul Westhaver – never said it was a pollutant. For the record, I’m very much with Watts et al when it comes to climate change.
eorge e. smith – What? Of course you can have a technological improvement that’s not commercially viable. Lots of inventions and the like start out as unprofitable ones, but over time improvements are made that change this. Economic viability has exactly zero bearing on whether it’s been technologically improved or not – you’re comparing apples to oranges.
For what it’s worth, I hope that solar panels do eventually become commercially viable (without massive taxpayer subsidies, I mean), if only because more marketplace competition and spin-off applications & developments will be good things in and of themselves. But I fully agree that they’re a long way from that stage.
Mark,
I wasn’t directly restricting my comment to your neutral statement. I was making a run of the mill generic comment that applies to all “renewables”… that none make any sense in light of CO2 not being a pollutant so we are in agreement. I guess I was too cryptic. Cheers
“all they’re doing is moving the output of a PV panel closer to its theoretical maximum.” all?
“Fresh Eyes” should be used to look at pretty much everything! 50% increase is impressive. Now to look at how to get more reflectivity off the moon and viola`!
Dan, “50% increase is impressive” , But they should have said, “over 75% increase, but only during the night time hours.
Can some explain why these butterfly’s have white ‘reflective’ wings instead of dark ‘absorbing wings if they are trying to heat some flight muscles?
The flight muscles are in the thorax, the main body of the butterfly. The wings are just stiff boards. So the white wings are reflecting light on to the thorax, which seems rather light itself. The orientation of the hairs or their structure may help to absorb heat – Polar bear fur is said to bring light down to the skin where useful warming takes place.
The wings get pumped up after the butterfly emerges from the chrysalis, then they harden. They don’t have any muscles or circulation in them to benefit from warming.
What is the scale?
This geometry is similar the anechoic room surface topography. The size of the surface elements need to be in this orientation at the scale of light wavelengths.
So to the naked eye the surface could be smooth but to the appropriate wavelength it is inverted wedge shaped.
My guess would be that this could be achieved at the crystal lattice level.
ie why is glass transparent and metals not?
But… all this is for not. Solar power is just not practical compared with nuclear, nat gas, hydro, or coal. Remember CO2 is not a pollutant.
Metals are electrically conductive. That precludes extensive propagation of electric fields in them.
Indium Tin Oxide is electrically conductive and transparent in thin films; but then so is gold, if you make it thin enough.
Don’t try replacing your house wiring with indium tin oxide wiring.
g
Good, so this must mean they will now allow the free market to decide what type of energy to use…
like
Surely the wings are partly curved convexly and not a flat ‘V’. Either of these shapes would seem to me to reflect vertically incident light across to the other wing and then back out. I suppose it means that each ‘beam’ of sunlight is captured partly by one wing and then reflected to the other to capture part of the reflected beam. I don’t see how this heats the thorax, though unless via the vascular system in the wings. If the wings were presented concavely (parabolically) perhaps the rod of heat above the thorax at the focus would heat it(?)
There’s nothing at all special about being parabolic, unless you are a point source on axis.
Judging by the number of Cabbage Whites I’ve seen in recent nights, it’s all academic.
Oh, and don’t call me Surely.
Article: http://www.nature.com/articles/srep12267
Pretty clever, but the one good thing about solar panels is that they don’t have any moving parts.
The other thing to keep in mind is that solar panels today are about $ 0.70/W. A 270 watt panel costs $190 and take up 17 sq ft. So, $11 per square foot. About the same price as high end tile flooring – just to put it into terms everyone is comfortable with.
The point being, there is a limit to how much value you’ll get out of optimizing the output of something that is already pretty inexpensive.
Personally, I think the most promising direction is in flexible panels. Something like a roll of carpeting, rather than a stack of tiles. Maybe you can eliminate the glass components, decrease the bulk of shipping and handling, and reduce the amount of connections that are made on site.
I agree that a roll would be more efficient than a flat surface, and yet all my mind could hear was “Solyndra”.
And I agree completely. And the problem will only grow worse over time, as cells are likely to continue the exponential decrease in cost per “watt” they have exhibited over nearly 40 years. Take that same solar panel and price it at $0.35/W or less in five or six more years and at ~$5 per square foot, you’ll almost certainly pay more just in labor and land to install with even 2x the area for 1.5x the power. It will just be cheaper to fill the panels with cells (it probably already is cheaper to just fill the panel with cells).
Solar shingles are another appealing alternative that continue to drop in price. Your roof has to be shingled anyway, so for new construction the marginal cost of putting up solar shingles is reduced by the cost of the shingles you would have needed anyway (including most of the labor). But they won’t work on just any roof — it has to be oriented the right way, have the right pitch. New construction plus SOME retrofits, maybe.
It will be interesting to watch all of this develop over the next few years. My house actually is nearly perfectly oriented, and I’ve seriously thought about solar shingles. My energy costs are too low (from investments already made) to give me much of a direct payback, but reselling energy to a grid-tied system would (I think) give me decent amortization.
rgb, that future is already here. My brother worked designing and installing solar systems in 2012-14, and he says that the cost of the mounting frames and anchors, wiring, labor, safety interconnects, and control system costs far outweighed the price of the solar cells.
And the butterfly wings are just another solar concentrator.Now, how many solar systems do you see today using solar collectors? Very few. Why? Because in general they’re not economically practical without a tracking system.
Finally, thanks as always, it’s my unending joy to see “rgbatduke” at the top of a comment and grab my coffee and settle in for an alway-interesting read.
w.
Hey Willis (and I assure you the admiration society is mutual:-),
Interesting. That’s why I’m very interested in things like solar shingles, flexible solar mats, solar house siding — things that just replace construction components already in use and that have built-in interlocks so that they eliminate a bunch of this or can be installed at opportunity cost for the labor (you have to install SOME roof shingle, and if the labor is the same for solar it makes a huge difference compared to replacing a roof that is still perfectly functional with the shingles or installing panels over the shingles).
You can’t avoid the inverter, the circuit breakers, and grid tie and any alterations to metering or provisioning for active monitoring/metering so you know what you are getting out of the system. It looks like roughly $3 out of every $4 (which is the ballpark cost per watt for a 5 KW system) for a new system are for labor and all of this stuff, but for new construction in particular one ought to be able to get back at least $1, maybe $2 out of opportunity cost and not having to replace things but just building them in.
I assume that the butterfly wing technology above is supposed to be passive (low concentration) and not active — the article doesn’t really say. But if it is supposed to be active OR if it takes up a lot more area instead of a little, it is a waste of time.
The biggest problem I face when I look over the cost/benefit and ROI is that electricity in NC is so damn cheap as it is. I pay Duke Power $0.10/Kw-hour. That means that it is tantalizingly just out of reach to finance soar even on my nearly ideal house and realize a positive NPV in less than 15 years (although with discounts, tax breaks, and so on one can maybe manage it in around 10 IF one has a near perfect location). That also means that installation is in part betting on energy futures, and also betting that the current NC policy of grid buyback at cost is continued (I expect that it will, as we are constantly growing and stressing the existing power resources).
But my electricity is nuclear, and I expect it to be very stable. Duke Power is buying burned out tobacco fields and other junk land in the area and putting up solar farms at a pretty good clip so THEY can avoid building new hard capacity, and I’m thinking they are doing so at maybe half the best price I can manage at home short of doing it myself (which drops the cost by about a factor of 2 from what I’ve priced out). I’m too old (and just don’t give a s**t that much) to do that — my roof is high and steep and facing an ideal southwest with zero shade, which is why I do think about it at all — I get plenty of solar heating (that I don’t care for) in NC summer afternoons as it is.
But in new construction? With a mortgage just waiting to have the cost rolled right in and an immediate tax break? I’m surprised it isn’t just a no-brainer, at least in states like NC that have lots of sunshine. My own wish is to just have the sun power my AC, as air conditioning is my single largest electrical expense by far even after installing high efficiency units (which are saving me $100/month, amortized, but are still years away from positive NPV). Sadly, those same units reduce the amount I could hope to gain from rooftop solar.
In a decade, I expect that thin films and manufacturing will have matured enough to produce “vinyl siding” that is interlocking solar cell, 40 year roof shingles that are layered interlocking solar cell, and grid-tie combined inverter/meters that make new houses both self-sufficient (net) in energy and possibly even pay one back monthly on resold power to effectively discount the mortgage that are close to snap-in solutions and significantly reduce the labor costs and a lot of the other installation costs. If somebody manages to e.g. perfect zinc oxide zero-memory high energy density batteries to the point where such a house can save 2-3 days worth of energy for a capital investment of less than $100/kW-hour (a few thousand dollars as a one time expense when the house is built, plus maintenance and depreciation) that would make a big difference in the viability of all the intermittent generators and nearly eliminate the grid-tie problem. From what I read, one “could” very nearly sell lithium ion for $100/kW-hr now and still make a profit. Tesla is already paying under $200, and the raw materials cost only around $70.
Of course in that same decade we might get Skunk Works fusion, we might get LFTR, we might have the entire current grid wiped out by a Carrington event CME and have to just start over (after a few billion people die as cities collapse etc), or some other unexpected technology might mature and change everything.
In the meantime, solar remains j u u u s t out of reach as a reasonable investment for my own existing house. A factor of two would easily make it worthwhile, and I think there is room for that in the future but THAT future ain’t here yet.
rgb
rgbatduke July 31, 2015 at 1:23 pm
Don’t worry … I’m sure that the carbophobes have several plans to take care of that problem …
w.
One small thing… lots of businesses toss their old network UPS when the batteries go bad. It’s not particularly difficult to make a synchronous inverter from those old boxes.
Good engineering 🙂
I have most of the expensive infrastructure (in the form of a battery backup system) and the payback on PV panels is still marginal.
Thanks for your and Willis’s many contributions to this site.
Even when our entire houses are covered in solar collectors, they are useless when the sun is not shining or, in my current case in ‘sunny’ South Australia, it is only shining on the top of the heavy clouds.
My 5KW system is currently generating 124W.
Than [place your preferred deity name here] for base load, coal-fired generators
Oh good grief, solar shingles, not that claptrap idea again….
I did a college co-op one summer at a “solar energy institute” back in the later 1970’s when they were promoting that stupid idea. If a practical “solar shingle” could be made why oh why does it still not exist…
Funny thing about roof shingles, they need to be cheap, rugged and long lasting, oh and it helps a good bit if they keep the rain, snow and wind on the outside of your house.
Since the 1970’s when the “solar roof shingle” idea was tossed about I have replaced three regular roofs. It is pricey enough to redo a roof, imagine replacing a “solar shingle” roof every 15 years when it starts to leak and compromises the structure of the house holding it up.
I think the only thing more impractical than a “solar shingle” is the totally stupid idea of paving roads with PV solar cells. What, nobody could think of a dirtier, vibration prone and shock stricken place than a road to install a PV solar cell on ???
If you want to utilize solar PV cells in the worst way; pave your roads with them, nothing could possibly be more difficult with less possible return on investment than taking the equivalent of fine bone china and driving tractor trailers over it every day….
Cheers, KevinK
Is it ethical to drive up the cost of elect, and or taxes to have solar installed on your house?
Alan, those UPS’s are designed to work from just a few volts DC, not the 300 to 400 you get from most solar panels.
Those UPS’s are only designed to deliver a few hundred watts of power at the most, so you would need many of them operating in parallel to create the power needed for powering anything larger than a desktop computer.
Thirdly, those UPS’s have no mechanism for synching their AC output to external AC sources, so it would be impossible to run many of them in parallel or to use them to put power back onto the AC grid.
Well start your own company with your own money and start selling your roller carpet solar panel.
Solyndra scientist engineers thought rolled up was a great idea, but rather than eliminate the glass components; they multiplied the amount of glass required by 6 (2pi), because their crummy thin film solar material didn’t like exposure to air so had to be hermetically sealed.
I don’t think you can put up any structure that can survive a 100 year storm for anything close to $17 per square foot; even if it doesn’t actually do anything at all, but just occupy space.
g
Well whopppie. Nature has figured out how to thrive and survive. WITHOUT a computer. Kill it all.
It’s fun to just learn about how things work. So long as you have the leisure that powering the grid with hydro, nuclear, natural gas and coal provide. It’s fun to discover creative ways to use the sun and wind and maybe even use those in places removed from the grid (Antarctica comes to mind though it’s not hard to imagine that a small nuclear unit wouldn’t be less trouble) provided you have reliable power provided by nuclear, natural gas, and hydroelectric to power a robust growing economy that affords us the luxury of doing things because we a curious.
There are a lot of urban applications where PV is a winner. If you need a small amount of electricity, PV is a whole lot cheaper than running wires to the grid (if there isn’t an outlet within six feet).
like i said there are applications but they are not the heavy lifting required to power a modern industrial society which, in the energy debate, is the only part that really mattters
What you said was:
PV, even in an urban context, is the best solution for many applications. It isn’t something we do just for play, which is what you are clearly saying.
What percent of our electricity will be supplied by PV fifty years from now? I have no clue and neither do you nor does Willis or even rgbatduke. What I can say is that it has some of the characteristics of a disruptive technology. https://en.wikipedia.org/wiki/Disruptive_innovation
A lot depends on whether your application is temporary or permanent. Those power lines will be around for the life of your application and will need no maintenance. Whereas the PV will have to be cleaned on a regular basis and replaced every 15 to 20 years.
Bob you have to understand I’m not denigrating play or imagination in any way, after all it was a musing patent clerk riding a trolly visualizing how the clock would look that discovered the clue to a giant leap in our comprehension of every thing and the avenue to exploit energy sources virtually no one even knew existed.
Coincidentally, I know of a regular at Penryn Methodist Church who identified how the geometry of butterfly wing scales is used when they achieve flight, back when he worked at the Coal Research Establishment.
I wonder if he chatted to this team.
He’s a regular here too.
SO … if you put a concentrating lens or mirror on a solar cell, you can increase its power.
On what planet is this supposed to be news? You can do exactly the same thing with aluminum foil. I call BS on this without even reading it. But I suppose I should read it …
…
…
And reading the paper reveals this little gem …
So the only thing that is “new” about this is a “novel, lightweight reflective material” … which unfortunately has never been created, is just an untried idea, and has nothing inherently to do with solar cells.
So since they couldn’t build a butterfly wing, to test their idea, they “attached the wings of the large white butterfly to a 1 cm × 1 cm mono-crystalline silicon solar cell to test for any increase in output power.” Ooogh …
And what did they find by engaging in buttercide? Well, you wouldn’t know it from the media, but in their “test for any increase in output power”, plain old reflective film outperformed the butterfly wings by about 50% … see their Figure 4a.
Vaporware.
w.
[Comment deleted. commenter using fake identity, deleted per WUWT policy –mod]
I assume that was humor … I hope.
w.
[Comment deleted. commenter using fake identity, deleted per WUWT policy –mod]
Depends on what you mean by ” putting a mirror on a solar cell. ” If you mount the solar panel upside down, with no mirror, clearly you block the sun from it; so don’t do that.
But who said to put the mirror on top of the panel ?? You can put mirrors off to the side of the solar cell, so they reflect solar flux down to the cell.
It’s call non imaging optics, and it is done all the time, but not at the moment, in widely available commercial installations.
The right optical design improves the output so that the increased price of a more exotic but higher efficiency cell becomes moot.
The triple junction triple band gap solar cells that achieve circa 45% conversion efficiency are too expensive to use without concentrator optics, but become economical with the proper optics.
Mirror and lenses are no contest with the CO2. If you fill solar cell with CO2 it would get hot, very hot… don’t do it!
Joel D. Jackson July 31, 2015 at 1:46 pm
Sorry, Joel. I assumed the readers were intelligent enough to understand my meaning, and I regret not including you as a variable …
Having said that, however, I’m rather sure that you are intelligent enough to understand my meaning, so I’m not sure why you’ve put on this little I don’t understaaand, Willis charade.
It is unpleasant, though, so perhaps you’ve achieved your purpose.
w.
Willis says: “I assumed the readers were intelligent enough to understand my meaning”
..
Yes Willis, its the assumptions you have that makes your writing so humorous.
…
My purpose?
..
Just trying to help you improve your writing skills.
No, Joel D., your purpose was not to help Willis improve his writing skills- what you said is a lie. Your purpose has never been to help anyone here with anything.
Joel D. Jackson July 31, 2015 at 2:37 pm
Dear heavens, you are a precious little pedant, aren’t you? If someone says “I had to put a new mirror on my car”, do you snarkily say “if you put a mirror on your car it will keep the sun off the roof”? If someone says they put gloves on their hands, do you automatically assume that they put them on top of their hands?
If you are too dumb to understand that putting object A ON object B does not always mean putting it on top of object B, I fear I can’t help you.
But then, I don’t believe you are that dumb … which of course means that you are just being nasty for sport.
Not impressed … but then you double down:
Oh, please. You are being nasty for sport, not trying to help anyone. Like they said where I grew up, “You can piss on my boots, cowboy … but you can’t convince me it’s raining.”
w.
Joel, I realize that your only goal here is to create problems, but it doesn’t take a genius to figure out what Willis’s point was. The phrase “put on” does not necessarily imply “directly on top of”, it also means “attach to”.
Willis, while Joel’s intelligence is still in dispute, his motivation isn’t.
Yep – but nice to imagine kinetic solar panels with thoraxes (not referring to any potential improved solar-electric panel efficiency)
All gross moving biologicals initiate motion with a counter motion. This initiates muscle stretch to advantage the stretch-contraction force relationship. Lots of momentum transfers and effective weightings and unweightings thanking gravity.
buttercide!! They better not do that in Zimbabwe!
“…buttercide…
Quite possibly causing the next extreme weather event.
Very little in the way of details (cost of manufacturing, etc) which leads meto believe that this technology may never come to pass. Regardless, solar panels are pretty cheap compared to the past – if you use microinverters, they may cost more than the panels themselves. And labor is the big expense and not coming down in price. I would estimate that solarpanels account for between 25% and 35% of the cost of an installation, so panel cost reductions won’t have much affect on overall costs. There is also the question of lifespan, which is roughly 20 years for panels. If solarjunkies would use batteries and not pump unrequested power onto the grid or accept govt subsidies I wouldn’t have any objection to them. (Govt subsidies basically pay for the panels, up to $6,000 – for a 6KW system – which produces a max of around 4.5 KW) . That won’t cover an entire roof, so panel size reductions aren’t going to have a large effect.
So on a cloudy day the cute little things can’t direct sunlight from their wings onto their muscles and can’t take off?
Sounds like another ‘beasty’ for the extinction roll.
Bye bye butterfly.
Get real. What a lot of codswallop.
Codswallop indeed!.
If there is a rational place for solar collectors, it is on existing buildings in the form of advanced photo-voltaic coatings that do not invade the community. Technology is advancing but an ugly plethora of existing solar panels flappable or non-flappable is NOT the way.
Ditto those monstrosities of wind-farms.
POINT there is no need to freak-out, there are hundred possibly thousands of years of latent power in the ground and undersea. Whether that be fissionable material or so called “fossil” fuels.
In the words of lance corporal Jones (Dads Army), “Don’t Panic!”
You mean you don’t support Solar Freakin’ Roadways?
…BUT if we put up reflectors, at 17 degrees, adjacent to the solar roadways, the power to weight ratio would be increased to (something fantastic) and you can therefore assume that we are onto a great advance in energy production.
“The Cabbage White butterflies are known to take flight before other butterflies on cloudy days.”
I think that’s the codswallop: the whole of this “research” is founded on false or irrelevant evidence.
Interesting as an academic exercise, but gets more shading unless steered, and is more difficult to fabricate.
“steered” ?? what an image – get Google to “model” some White Cabbage Butterfly brain DNA into AI code for self-steering, flapping, solar panels out the back yard … what could go wrong?
They really are scraping the bottom of the barrel to make something out of this. I refer to their figure 4:
http://www.nature.com/srep/2015/150731/srep12267/fig_tab/srep12267_F4.html
which shows that butterfly wings weigh almost nothing and produce almost no power but when compared with reflective film they have a power to weight ratio of 17 times the reflective film.
It doesn’t matter how efficient butterfly wings are unless you are either going to employ dead butterflies in your concentrator of learn how to make butterfly wings. In either case, as ‘any fule kno’ butterflies are blown every which way in the slightest of winds and could hardly be described as ‘robust’. Neither do they last 25 years.
These people are away with the faeries. I wonder how much more efficient faerie wings would be?
Exeter must be awash with research cash.
Exeter’s not necessarily awash in cash, but the research was necessarily framed in terms of alleviating global warming via higher PV efficiencies, in order to get the cash grant. We’ve seen this all too many times before. Build a better grant request (merely elicit climate change) and the cash will beat a path to your door.
Exeter must be awash with research case…..I would not take anything seriously by this so-called university. You’re quite right, they are away with the faeries……That’s why they got the idea of wings. 🙂
Meant to say ‘research cash’, not ‘case’.
You said what I was thinking, only better.
“Exeter must be awash with research cash”
Well the Met Office is based there, and they don’t seem to be doing too badly…
So the idea here is to throw a PV panel inside a solar oven. Thank goodness for butterflies, as no one could have sorted that out on their own.
Butterfly!!!!!!!! Pretty!!!!!!!!!!!
YAGTTWRW
Yet another green technology that wont really work…
LOL….Willis…the only “green technology” that really works is photosynthesis….and they will be taxing that soon….compliments of Joel and other idjits that get elected. Oh wait. They are trying already.
Stop labeling dark red as green?
This is trumped up BS in my opinion. Even remembering my 40 years ago physics schooling, I recall angle of incidence equals angle of reflection, etc. So surely, the reflective surface of the BF wing is ‘designed’ (ok, evolved?) to direct sunlight down to the body – probably by bouncing back and forth across the wing surface until it reaches the thorax? Clearly the wings are not parabolic reflectors as such – but the reflective properties of the wings must be what makes the 17 degree angle special – though I wonder if they considered low angle of initial incidence too – as in morning light rather than noon light? We’ve all seen iridescence in animals and natural surfaces – perhaps the butterfly wings and surface shape/texture does something similar to direct light down to the body? I dunno, just speculating – but my initial thoughts when reading the article were that this is kind of pointing out the bleeding obvious in that if you have two reflecting surfaces angled towards each other – any non absorbed light will be concentrated towards the middle part of the ‘v’, no?
I’d like to spend more time reading through the article and comments but I’m packing for a 1500mile drive so don’t really have the time.
I think solar has applications where cloudy days are not frequent and the sun angle is direct. I have a “hermit” neighbor who is not connected to any utilities but uses two 70 watt panels and a battery. I hear his gas generator run often, as clear skies have been rare around Illinois the last couple of years.
Be carefull. A single butterfy in Brazil can make a storm anywhere at the earth.
It has certainly caused a storm here!
Errrrr…go have a peek at a butterfly in the garden. Why are they always flapping the wings? Maybe to cool or heat themselves? And why at night are their wings folded? Could the good Doctor of entomology (sorry…can’t remember her name) help out here?
Here’s an idea; solar panels in the shape of ManBearPig. Or snow crystals. Yeah, snow. That’s the ticket.
Considering solar costs up to three times as much as coal for the advertised energy generated (let’s not even get into the abysmal actual energy generated) a 17% increase in efficiency won’t make any difference to their uselessness.
The panel design is a physics — primarily optical — problem which should be possible to adequately model with moderate processing resources. Are they just looking for inspiration?
Well I scanned the comments up until this time, and saw none that took issue with the statement:
“…could vastly improve the power-to-weight rations of future solar concentrators, making them significantly lighter and so more efficient.”
If the PV cells were going to fly, or even move over land or water, power-to-weight might be an important consideration, but I fail to see how making PV cell lighter increases their efficiency in converting sunlight into electricity. ll
+1
Shipping costs and installation.
If it is heavier to move or requires more/heavier support structures to mount, it is going to cost more.
Doesn’t increase operational efficiency.
Does do what Felflames says.
Does blow away within the first year of installation, and therefore is an even greater job creator and boost to the economy than the typical green crap.
“…therefore is an even greater job creator and boost to the economy…”
I believe that’s almost an exact quote from Nancy Pelosi, isn’t it?
The Cabbage White butterflies are known to take flight before other butterflies on cloudy days – which limit how quickly the insects can use the energy from the sun to heat their flight muscles.
Well there ya go, the butterflies have the same problem with solar that the rest of us do. When the sun doesn’t shine enough, they’re screwed.
Just a potshot or two, which should suffice:
The reflectance basking hypothesis is addressed here by Bernd Heinrich:
Is Reflectance Basking Real?
Full pdf:
http://jeb.biologists.org/content/154/1/31.full.pdf
From Wikipedia:
https://en.wikipedia.org/wiki/Pieris_rapae
Steve, that is absolutely hilarious. All of the handwaving about solar, and it turns out that the wing elevation has nothing to do with solar, it’s to cut down on convective cooling … and I had a look at their analysis, it looks pretty bullet-proof.
Why does it look bullet-proof?
Because unlike most folks these days, they did the actual experiments with actual butterflies rather than computer simulations … and it is hard to argue with experimental results.
Great find, interesting experiments, my best laugh all day.
Many thanks,
w.
The artificial trees in Singapore look hideous. I wonder how much “fossil fuel” was burnt to gather and arrange all the materials used to construct them?
I would hazard a guess that most solar installations are a net energy sink. A study from 2 years ago claimed the industry was on the verge of being an actually supply…
===============================
“I think that this paper shows that actually the industry is making positive strides and it’s even in spite of its fantastically fast growth rates, it’s still producing, or it’s just about to start producing, a net energy benefit to society,” Dale said.
Most solar panels manufacturers now consume lots of electricity, usually pulled from coal or other fossil fuel-burning plants. Stanford News pointed to the example of melting silica rock to obtain the silicon used in most panels. The melting requires electricity to fire ovens to a temperature of about 3,000 degrees Fahrenheit.
Solar panels’ energy balance is now tipping, however, because newer technologies reduce that electricity consumption. For example, some newer panels require less silicon, or waste less material in the manufacturing process. Researchers are also looking to replace silicon with more abundant elements, such as copper, zinc, tin and carbon.
http://www.popsci.com.au/science/solar-panels-now-make-more-electricity-than-they-use,379327
=============================
“More abundant”…
===========
Silicon – 27%
Copper – 0.0068%
Zinc – 0.0078%
Tin – 0.00022%
Carbon – 0.18%
http://www.periodictable.com/Properties/A/CrustAbundance.an.log.html
===========
When I see a solar panel factory producing 100% of their power requirements from their own products, I might buy one.
Great idea! I am pro solar panels, since I consider real green energy. There are also some sources of alternative energy, like he offshore wind parks (see them here: http://climate-ocean.com/2015/K/k-.pdf) but I believe that we haven’t study enough their impact over the ocean and the climate, and I still have some doubts in calling them “green energy”.
A little PTFE, a little Raspberry pi, a little DC motor and a mini rod of aluminium ( english spellling) is not beyond the reach of modern man, mash together with a few bolts and viola you have a single axis tracking solar system,
next physical experiment.. take 2 solar panels, laid flat. perpendicular to the sun and measure output, fold panels along joint to angles less than 180 deg and continue to measure output while brushing away the detritus building up along the fold, so perhaps lets ignore the angle stuff for the moment, with their own research money, just go for a new surface treatment/texture that will/could improve efficiency and then break into the market, they could use one of the those redundant gone bust closed down solar panel factories that are lying around.
me I`ll just look to change my windows for double glazed units and put a little insulation in the walls and loft,
regards
When I looked at solar by getting a small solar array and measuring the power I found the actual return compared to rated is about 7% given the amount of cloud we get here. How do the companies that sell these things get way with their wildly hyped claims?
Aesthetically these bodged on additions to houses are a disgusting blight. Built in they can be almost invisible. As for solar “parks” it is a total disgrace that good agricultural land should be blighted by these disgraceful pointless and ugly monstrosities.
“Green” energy harkens back to the days of when “special elixirs” were peddled, and touted to have “amazing” health benefits, capable of fixing just about whatever ailed you. They are nothing more than snake oil salesmen, aided and abetted by our own government.
I’d be worried about the “butterfly effect” causing unintended consequences.
I am surprised it was not an attempt to improve the butterfly by genetically altering it to mimic existing solar panels.
The hybris consensus among the new breed of PC.scientists assume that (the flawed) nature should follow scientific models closer. Besides Butterflies have no vote when we vote for what is true.
Lysenko is probably rotating in his grave.
The fliting flight of the butterfly is an adaptation, it makes it harder for the birds to catch them.
I’m sure there are video’s of birds chasing down butterflies.
Most birds I’ve seen catch a butterfly, tear the wings off, then swallow the remains.
Wanna talk about a predatory instinct that has been honed over millions of years ?
Don’t use solar panels, collect sunlight into fiber-optic cables which are then switched on and off to form an electric current in a wire coil around the fiber-optic cable.