Define Irony: Photovoltaic Heat Island Effect

Guest post by David Middleton

From the Department of All Things Ironic…

irony

Solar panels, while they mitigate the effects of global warming by replacing fossil fuels, can add heat in the locations where they are installed, reports a team of University of Arizona researchers.

At first blush, the experimental results, published Thursday in Nature Science Reports, seem to contradict computer simulations that said solar photovoltaic arrays, by intercepting some of the sun’s warming rays and converting them into electricity, would have a cooling effect.

The UA researchers measured the heat-island effect of a solar array at the UA Tech Park at Rita Road and Interstate 10. They found that its overnight temperatures were about five to seven degrees (Fahrenheit) warmer than a nearby plot of undisturbed desert.

Additional experiments are being conducted to determine the potential effect of the measured heating on nearby communities and the overall environment.

[…]

Tucson.com

Following the Standard AGW Scientific Method, the observations are consistent with the model, despite being contradictory…

[…]

Results from the team of current and former UA researchers, which included Alex Cronin, Rebecca Minor, Nathan Allen, Adria Brooks and Mitchell Pavao-Zuckerman, are not inconsistent with published computer simulations, said a Colorado atmospheric scientist.

Aixue Hu, research scientist at the National Center for Atmospheric Research, published conclusions from a computer model last year in Nature Climate Change.

Hu found that installations of vast arrays of panels in desert areas would produce a cooling effect of about 3.5 degrees Fahrenheit.

Contacted by phone Thursday, Hu said his study was predicated on highly efficient PV panels that would convert 30 percent of the sun’s energy into electricity. The panels in the UA study had an efficiency of about 20 percent. Hu said his model might produce some slight heating at that efficiency.

[…]

The Nature Science Report found that the Photocoltaic Heat Island (PVHI) effect was actually quite significant.  A 1 MW PV plant routinely caused 3–4 °C of PVHI.

[…]

The PVHI effect caused ambient temperature to regularly approach or be in excess of 4 °C warmer than the natural desert in the evenings, essentially doubling the temperature increase due to UHI measured here. This more significant warming under the PVHI than the UHI may be due to heat trapping of re-radiated sensible heat flux under PV arrays at night. Daytime differences from the natural ecosystem were similar between the PV installation and urban parking lot areas, with the exception of the Spring and Summer months, when the PVHI effect was significantly greater than UHI in the day. During these warm seasons, average midnight temperatures were 25.5 + 0.5 °C in the PV installation and 23.2 + 0.5 °C in the parking lot, while the nearby desert ecosystem was only 21.4 + 0.5 °C.

The results presented here demonstrate that the PVHI effect is real and can significantly increase temperatures over PV power plant installations relative to nearby wildlands.

[…]

How many MW of solar PV have been installed in the past 8 years?  How much total PVHI has this yielded?  Will this have any effect on our government’s mindless obsession with solar power?

References

Barron-Gafford, G. A. et al. The Photovoltaic Heat Island Effect: Larger solar power plants increase local temperatures. Sci. Rep. 6, 35070; doi: 10.1038/srep35070 (2016).

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164 thoughts on “Define Irony: Photovoltaic Heat Island Effect

  1. They found that its overnight temperatures were about five to seven degrees (Fahrenheit) warmer than a nearby plot of undisturbed desert.

    This and Oceans moving warm water from one place to another to cool explain the temperature record.

    • The PVHI effect caused ambient temperature to regularly approach or be in excess of 4 °C warmer than the natural desert in the evenings, essentially doubling the temperature increase due to UHI measured here. This more significant warming under the PVHI than the UHI may be due to heat trapping of re-radiated sensible heat flux under PV arrays at night. Daytime differences from the natural ecosystem were similar between the PV installation and urban parking lot areas, with the exception of the Spring and Summer months, when the PVHI effect was significantly greater than UHI in the day. During these warm seasons, average midnight temperatures were 25.5 + 0.5 °C in the PV installation and 23.2 + 0.5 °C in the parking lot, while the nearby desert ecosystem was only 21.4 + 0.5 °C.

      The results presented here demonstrate that the PVHI effect is real and can significantly increase temperatures over PV power plant installations relative to nearby wildlands.

      This is so critical I’m quoting it as well as Anthony quoting it.

      If you look at recorded data it does not show any loss of cooling at night.

      It does show the temperature going up some, but then the day time temps go up and then fall just as much as before the temp went up. Warming from co2 can not do this.
      You also don’t see this when they process average temperatures because it hides what min temps are doing.
      Before the 97 El Nino, 1996 day time temps went up (and then down) less that 17F, in 1999 it went up (and down) 20.5F average each day.

      Now, if Co2 trapping heat was the source of all the warming, explain how 3 years after the temp only dropped 17F average per night globally, and then in 1999 it drops 20.5F, that’s over 4F, that’s about 200 years of global warming.

      If the planet is warming it’s because we’re trapping more as buildings and roads. And you can prove this with a IR thermometer (including how cold the sky is and not limiting radiative cooling from the surface at all).

      • Solar panels, while they mitigate the effects of global warming by replacing fossil fuels, …

        All this horse-shit about “carbon” reduction maybe / could be cause some infinitesimally smaller warming. ( note they will not cause ANY cooling, maybe, maybe, maybe less warming ) by the end of the century.

        But DO ( as in not maybe but do ) cause real , measurable warming right here and now.

      • CO2 also present diurnal and seasonal variation.

        Dr. S. Jeevananda Reddy

        But when you look at the rate of cooling, with low humidity, it cools very fast, until air temps near dew point temp, then cooling slows down. Nightly cooling is temperature regulated to dew point temps. Co2 does not alter this regulation.
        We have also done a tremendous amount of changes to land use, most of which will warm and store heat over night. Until the length of day increases, and at least so far any heat stored is lost by the end of winter.

      • It is well known that PV panel efficiency drops with increasing temperature. As the installations are so huge (many hectares) the efficiency of the whole installation drops as the size increases.

        PV panels work best in high, dry and cold places. Warm, wet and low, not so well.

    • Imagine the amount of warming Ivanpah causes when it fries birds on the wing, Ivanpah better offset a lot of warming.

    • They found that its overnight temperatures were about five to seven degrees (Fahrenheit) warmer than a nearby plot of undisturbed desert.

      And whenever the “overnight temperatures” increase, …… so does an increase in Daily Average Temperatures, …… and so does an increase in Monthly Average Temperatures, etc.

      And ya end up with the “hottest” day, month, year dere evar vus.

  2. Grasslands cool more at night than forests, and mowed grassy areas cool more at night than fields of tall grass. The issue is that a thinner layer of air adjacent to the ground is being cooled by radiating surface/objects when such objects are shorter or absent.

    Ironically, fields of taller objects radiate more heat at night than flatter fields because they don’t get as cold – which means cooler temperatures in the daytime and hundreds of feet or more aloft. This means grasslands get hotter than forests in the daytime.

  3. Without solar panels, 100% of the incoming energy gets converted to heat (that would be true for a black surface; otherwise a part is reflected – see “albedo”). If 20% of energy is converted to electrical energy, and the temperature still increases, then the installation of panels must decrease the albedo by more than 20%.

    • Different surfaces reflect and absorb at different rates. Black panels tend to absorb more heat. I don’t know the area, but pale rocks and sand crystals reflect or re-radiate more heat and light than black surfaces. If there is some vegetation, that that can have the effect of reducing the area further.
      Try hiking in a desert, In Australia, I recommend using sun glasses because of the reflected light.

  4. If these panels affect overnight temperatures by 5-7 degrees F, surely asphalt would do even more, right?

  5. Well good grief…what’s all the fuss about
    Since they can measure it…they can easily adjust temperatures up to compensate for it…

    (so help me God if someone requires a snark tag I’m going to slap them)

      • MarkW
        I agree with Jon.

        Latitude is – even for this site – exceedingly transparent.
        And I guess, you, too, are!

        Plus lots all round!

        Auto – does this get me grant monies?
        Especially those tied to international travel, and assessing dinners?
        Oh – goodness – I am utterly, perfectly, inhumanly [add your own adverbial adjectives, please] serious . . . .

  6. I brought up this effect several years ago after researching solar panels and finding that they
    required to be mounted some distance from the roof becasue of the heat they produced – hotter
    solar panels produce less electricity.

    • Not enough sun – Less power
      Too much sun – Less power

      Where’s Goldilocks when you need her?

    • I would think that they keep your attic hotter also thus making you run your AC longer at night? Note: Attic vents are designed to vent moisture, not heat.

      • In snowy states they are for heat removal also, to prevent snow melt and subsequent refreezing at the eaves creating ice dams.

    • If you mount the panels with a space between them and the roof the house will be cooler. Here’s an article about energy conserving roofs. The space promotes air circulation and thereby keeps the roof deck, and therefore the attic, cooler.

      PV panels can save energy even without generating any electricity. Mind you, a bit of lumber and shingles would do the same thing cheaper. :-)

      The law of unintended consequences is infinitely recursive.

  7. “The UA researchers measured the heat-island effect of a solar array at the UA Tech Park at Rita Road and Interstate 10. They found that its overnight temperatures were about five to seven degrees (Fahrenheit) warmer than a nearby plot of undisturbed desert.”

    “Aixue Hu, research scientist at the National Center for Atmospheric Research, published conclusions from a computer model last year in Nature Climate Change. Hu found that installations of vast arrays of panels in desert areas would produce a cooling effect of about 3.5 degrees Fahrenheit.”

    “Contacted by phone Thursday, Hu said his study was predicated on highly efficient PV panels that would convert 30 percent of the sun’s energy into electricity. The panels in the UA study had an efficiency of about 20 percent. Hu said his model might produce some slight heating at that efficiency.”

    Let me see if I have this correct. Hu said that his model produces 3.5 degrees F cooling if the panels would convert 30% of the Sun’s energy into electricity. He claims the reason why the actual measurements showed 5 – 7 degrees F warming is because they only convert 20% of the Sun’s energy into electricity. So increasing the conversion efficiency by 10% will stop the warming and bring about a cooling of 8.5-10.5 degrees F.

    Perhaps his model could be wrong, but then math has never been my strongest suit.

    • You seem to have overlooked this part of the statement –

      Results from the team of current and former UA researchers, which included Alex Cronin, Rebecca Minor, Nathan Allen, Adria Brooks and Mitchell Pavao-Zuckerman, are not inconsistent with published computer simulations, said a Colorado atmospheric scientist.

      This goes on into Hu’s comments. What I have trouble with is the statement “are not inconsistent with published simulations.” How can a +7 F NOT be inconsistent with a -3.5 F program result?

    • For an increase in conversion of 10% more of the available sunlight (30%) to electricity, would require a 50% increase in the efficiency of existing (20%) panels. I wouldn’t quite call that using unicorn farts to run turbines, but I’m expecting that level of efficiency to be available about the same time we’ll be able to order designer pets like unicorns, miniature giraffes and Larry Niven’s “cat-tails”. Not any time real soon. Does anyone want to do the math on what Hillary’s 500,000,000 solar panels would do in terms of PVHI effect?

      • Theoretical maximum conversion efficiency for single layer cell is just over 33%. Theoretic limit for infinite layer cells (science not engineering – so infinity is possible on the chalk board) is around 86%. I am not sure of how the layer complexity scales, i.e. at what point do you reach the engineer’s version of infinity instead of the physicist’s and how close to 86% that could get. Most of the cells I’ve had in my hands have been single cell and not even close to 33% due to thermal loss considerations. (The best was about 22% if our math was right.)

      • Enough to focus them all into a super heat ray that could engrave her name on the moon?

        Alert the Tick!

  8. From the article:
    “At first blush, the experimental results, published Thursday in Nature Science Reports, seem to contradict computer simulations that said solar photovoltaic arrays, by intercepting some of the sun’s warming rays and converting them into electricity, would have a cooling effect.”

    So, their computer models failed to predict this, in fact, their computer models predicted the opposite effect. Where have I seen this before?
    Hmmmm…

    I guess they’ll have to adjust the temperature data taken from the site to properly correlate with their predicted results? Homogenize it with some Antarctica data, that should fix the broken data.

  9. Stands to reason that the nearly black surface of PV panels is going to have a substantially lower albedo than the desert floor, so absorbing more solar radiation to be re-radiated at IR wavelengths. If the conversion efficiency percentage is less than the increase in albedo percentage, you’re going to get an increase in the amount of heat absorbed locally.

    Ultimately, however, the generated electrical energy gets converted to heat energy somewhere else (your TV set, for example). Thus any solar panel will warm the planet because it absorbs more energy than the surface would otherwise have done. The essential question is whether this causes less warming than the equivalent warming that would have arisen from the displaced CO2 emissions. And we _still_ don’t really know how much warming that would be – the nub of the whole debate

    • Yes, but CO2 is not the culprit. The increasing water vapor is the only factor at present which is countering global cooling. News reports of early (seasonal) cooling are conflicting with ‘official’ global temperature reports.

    • Actually we atmospheric chemistry and radiation professionals working in both realms and others, have repeatedly reminded everyone we do know the answer: there’ll be no warming from CO2 addition. CO2 is a refractory medium within a larger, cold compressed fluid bath. Adding more refractory material between a fire and illuminated source brings less light to that surface: cooling it.

      There’s a reason that there’s only one class gases noted in the notches of sunlight/surface, vs sunlight/top-of-atmosphere. It’s because green house gases are responsible for nearly all reduction in sunlight-to-surface.

      If there were other gases reducing the sunlight-to-surface then they’d be known, and noted. Actually one’s known and not noted: oxygen which gives us daytime blue skies.

      Green house gases are creating bright infrared skies in identical fashion in daytime, helping glow off whatever does get through at night.

      Solar cell heating is heating. This is a fluid bath that surrounds the earth and the question is what determines it’s temperature, and the short concise correct answer is, the total gas density
      and amount of light hitting it.

      That’s it.

      We all know this who are trained and work in some science or other dealing with either atmospheric chemistry or radiation. Everyone who works in gas mechanics knows it, there’s a law of thermodynamics written that states it.

      There’s also a reason you see all of us remarking on the fact *AGW barking thermo-billies r e f u s e to use the c o r r e c t compression m a t h e m a t i c s to (allegedly: they do not) ‘compute’ temperature.

      They leave out the compression which is the whole reason compressible fluids have a different law with it’s attendant equation representing it,
      than the

      o t h e r
      p.h.a.s.e.s.
      of matter.

      Compressible fluids,
      must have their density

      accounted for.

      Everyone should know what you have to say to a thermodynamic law-breaking GHE/AGW believer.

      (1)Tell me how you thought cold compressed fluid bath with refractive components diminishing sunshine to the surface by 20% total, make the Earth’s dependent light stream larger, when Earth’s source light stream has been diminished. How do you make more light come out of a rock by putting refractive media between it and the fire illuminating it, such that a fifth less energy reaches it’s surface? That’s a fundamental violation of conservation of energy.

      (2)Tell me why you believe you can calculate the temperature of compressible fluids without using the compression portion of the equation: and have your ”GHE” match to the degree, the amount of compression warming created by the atmosphere? The atmosphere’s compression warms the surface 33 degrees. The so-called ‘GHE’ is – go figure, 33 degrees.

      (3)Explain how your ‘climate mathematics’ never includes the 33 degrees of compression warming so essential to solving temperature of compressible matter,
      that a separate law of thermodynamics is written to cover: compressible fluids. Why?

      * Because Density Is Essential To Solving Temperature in gases. *

      This scam is and was held in place by nothing more than the sheer threat of government officials

      and the believers and teachers of their fake chemistry religion

      mobbing and harming real scientists.

      Those criminals have grown older and every single day a new generation of young scientific human beings take their places as the old criminals retire.

      Their abuse of scientific long suffering, has perpetrated scores and hundreds of billions’ scam corruption; pooled monies from many nations are in fact the entire budget of a small to medium size nation and it is all –

      it is all

      built on the scam that you can calculate the temperature of compressible gases, without accounting for the density; because density constrains electron movement and constrained movement creates dumping of energy.

      Gases don’t hold *more energy when they’re compressed, they hold less. Larger and larger orbital freedom created by sheer room to expand as per need to rebound from each other, allows for larger and larger energy handling.

      Compression doesn’t allow the matter to entangle more photonic energy it allows the matter to entangle less; because adjacent electrons induce sharing through more rigidly enforced path overlap; the emitting electrons are able to get more energy off those higher energy electrons trapping light; because of closer physical proximity; emitting energy while holding overall less.

      It’s long since time for the entire world to resume it’s normal discussion of real atmospheric and gas physics and chemistry and stop pretending everyone isn’t aware that

      there’s a scam

      and that it’s a

      mathematics and physics scam by programmers.

      Government employee supervisor programmers, running scams on expensive government supercomputers, paying off the time to use them from grants, pocketing the rest is how it started, and when their fraud was made the theme of an international movie by a failed politician seeking traction and power,

      the size of the scam was revealed; who was perpetrating it was revealed; and government employees closed ranks and defied anyone to prosecute the fraud.

      This entire scam is nothing but the refusal to use the correct mathematics for calculating and solving gas temperatures the way the aerospace industry does, the aviation industry does, the thermal sensing and fire safety industries do, the way

      all

      industries do.

      Fake mathematics
      refusing to calculate the temperatures of compressible fluids using compression accountancy through necessary inclusion of the hydrostatic equation.

      That’s all this scam is; all it ever was, and explains every single thing about it all including the fact that

      * * *the rest of the world’s accounting for the temperature of e v e r y t h i n g
      does just fine with standard laws, including calculation of the temperature of our atmosphere of Earth, and the atmosphere of Venus: to the tenths of a degree.

      Our thermometers on all our stuff works to within tenths and there’s nothing about any GHE in any of the way they work. Our space ships and planes, our ovens and kilns and furnaces and air conditioners and fans, our internal combustion regulations and free combustion metallurgical and polymer blending skills are the stuff of worldwide commerce and civilization and the regulation of them.

      India, China, Russia, Emirates, UK, Brazil, Peru, USA, Norway, Ethiopia, Saudi Arabia, Sudan: they all use equipmet manufactured to standards using the same standard gas equations that * work for everybody else on earth. *

      But the crock of quacks and kooks peddling GHE fraud can’t tell you which way a thermometer will go if you advise them of the correct answer, ahead of time.

      Not the other way around, the GHE Scam Industry

      is the lowest order of disreputable quackery foisted on humanity second perhaps to the Pot Is Like Heroin
      Government Chemistry Scam

      used to imprison and violate the civil rights of millions worldwide.

      By the same bunch of – you guessed it – Government Employees.

  10. I hope they are correct, so as we enter global cooling, a push for PV will result. Irony at its best.

    And there will be a “lack of CO2” tax…..if you are not producing CO2, you will have to pay those who are.

  11. Am I incorrect, or does light that is reflected from the solar panel slow down to infra-red wavelength? Even the reflection off my pond on a windless day at noon will raise the temperature when you get close. Until you can convert all the wavelengths to electricity and absorb the entire spectrum, some energy will reradiate like a flat iron at the foot of the bed on a cold frontier night.

    • Reflecting light does not change it’s frequency.
      You get warmer because your skin/clothes are absorbing the energy in the light and converting it to heat that way. Same way that you can get sun burned a lot quicker if you are getting light directly from the sun as well as that reflected off the water.

    • Thanks for that, Mark. I guess I was fooled by my senses, just like when the humidity is terrible and the sun feels 3 times hotter.

      • When you are close to the pool, the air is more humid and has higher enthalpy thus higher heat content due to the water vapor. The same effect as you subsequently quote for a humid day. 75F and 100% humidity air has twice the heat content of air at 100F and zero humidity.

  12. They should know what they are doing with heat island effect since they had the official temperature station in the middle of a hot parking lot on campus.

  13. So if the conversion efficiency is a made up number that does not exist in the real world the model predicts cooling. If, on the other hand, one uses real world measurements the solar panels contribute to global warming. Does that put Hu’s “study” in the category of how things will be when the unicorns sing rather than a contribution to the science?

    • on a 25C day our panels ran just over 40C internal temps. All the surrounding structures warmed to near that as well. I bet that would re-radiate at night (we never measured that though – don’t make electricity at night so we didn’t look at it. We were trying to figure out if we could power remote equipment with it and how many panels we would realistically need.)

  14. Since solar panels don’t replace any fossil fuels, and in most cases actually cause an increase in fossil fuel use, it’s fairly simple to conclude that the damage been done by these panels is many orders of magnitude greater than any benefit, real or imagined.

    • … in most cases actually cause an increase in fossil fuel use, …

      Do you have a source for that? PV cells will repay the energy required to make them within a couple of years so there must be some other factors at work. link yes/no?

      • Because, like all renewables, Solar is not available “on demand” it has to have the right circumstances, a sunny day.
        Therefore you still need another source of “reliable” electricity – Fossil fuel or nuclear to cover those periods.

        So for ever MW of renewable YOU STILL NEED TO HAVE THE EQUIVALENT RELIABLE SOURCE. So renewables do NOTHING to stop the requirement for the building of Fossil or Nuclear Plants.
        However, because renewables are the Favoured power source when the are operating, no on wants to build the required Fossil/Nuclear plants, they are just not commercially viable. It is this state of affairs that produces the crazy price of electricity at peak times when renewables are not producing.

        EVERYTHING SPENT ON RENEWABLES IS A WASTE OF MONEY.

        RS

      • That’s for the cell itself. It doesn’t include the frame, the structure to hold the frame, the concrete to mount the structure on, etc.

      • commieBob,
        That NREL document you linked is not relevant for several reasons. First, EROEI is only important for primary grid-level power generation. The NREL document is only concerned with roof-top solar, which is a secondary power source only. It is not sufficient to supply all the electrical needs of the home, even with a storage system (which was not considered in the NREL pamphlet) it still requires a connection to the grid to make up the difference, which can be significant (especially in northern climates). Second, that pamphlet was published in 2004 and is based on 1990’s studies. At that time there was not a large installed base of PV systems, so many assumptions were made and models used to make up for lack of real world data. Since then we have real world data and it shows the assumptions and models were grossly incorrect. Third, they did not consider many of the real energy inputs into PV solar systems, including DC to AC conversion losses and the need for storage systems to make full use of all the energy collected.

        A good, recent paper that uses real world data and corrects most of these errors (although it still does not take into account cleaning, maintenance, and decommissioning costs) is Ferroni & Hopkirk 2016. They calculate a best case value of EROEI for grid-level primary PV solar power at .82, meaning it is an energy sink, not a source. Even considering just over the horizon (but not yet proven/feasible) technological improvements in PV panels and panel production, that value will not go above 1. In other words, it’s in about the same boat as fusion power: always another 20 years out.

      • @ Christopher, what about the energy required, not only to install, maintain, replace , recycle all of the components at their life end? like batteries? I doubt that all gets done with hydro power seeing that dams are being removed and reservoirs are being drained to save a few fish?

      • Christopher, if hydro power is being diverted to make those cells, then a fossil fuel plant somewhere is running harder to make up for the power that was diverted.

  15. Outside nearly perfect lab conditions, no photo-voltaic cell has ever come even close to 30% efficiency.
    Regardless, I wonder how much the warming will increase in say 10 years, after the efficiency of the cells drops by half?

    • MW NREL keeps track. The very best lab cells have reached ~26%. The very best (most expensive, lots of tricks) panels have reached 24% by individually selecting cells. It is almost certainly not possible to get closer to than about 85% of the theoretical quantum Shockley-Queisser limit of ~31% for a monojunction with optimal bandgap.

    • Pop case in point, Solyndra ( just one, I won’t even start in on the Spanish industry) and Christopher, are you a unicorn? Everything!!! , I mean everything starts wearing out and loses efficiency as soon as you start using it. ( Just try and sell a car back to the dealer after you have turned the car on for 3 seconds).

    • Warranties mean nothing. Real world data puts the effective life of current PV solar panels at average of 18 years. Notice that’s still longer than the lifetime of many of these companies. Power loss at well maintained sites is about %1 reduction per year, so 10% by the 10 year mark, not 50%. Remote sites that don’t get such regular maintenance, however, will suffer higher yearly losses. Think of the labor involved in cleaning an maintaining 500,000,000 solar panels, most of which will necessarily be sited in remote locations.

  16. No real surprise here, except aye for the scientists with their models. There was a solar panel company in California a while back (PVT Solar) that put a hot water exchanger on the back of their PV panels to trap and use the excess waste heat. They claimed around 20% extra efficiency for the combination.

    • Yes , combined heat and power. Makes a lot of sense. I’ve often thought of doing this at least as a pre-heating mechanism for domestic hot water. The first 20 deg. of heating costs the same as the second 20 deg. of heating, so even getting water up to 30 deg. C can make substantial energy savings.

      In fact you don’t want let the water get too hot. The point is to cool the PV. The conversion efficient can drop by up to 5% if they get really hot in strong sunlight on windless days.

      • That is very true, the closer the cells were kept to ambient temperatures the better their output. By mid-afternoon (2 ish) the cells had warmed to about 40C (or more some days) and the output dropped with the cell temperature. (more than the additional atmosphere attenuation should have been anyway). Our equipment didn’t need any hot water though so we didn’t even think of doing something like that.

      • By mid-afternoon (2 ish) the cells had warmed to about 40C (or more some days)

        Oh, along with temp, thermal cycles, environment and vibration are all factors in failure rates.

      • Hmm, sounds like processors and memory. Do PV panels make any more power in sub-freezing temps, likened to computers running faster?

  17. ..Using simplistic, “Deplorable” logic, would dark objects such as Solar Panes, in a desert situation, reflect a lot less of the energy back into space, which would mean somewhere, the energy still has to be transferred as heat ??

    • Could it be that they cause the ground below to retain moisture, and the humidity is higher at night near them?

  18. The model was stupid. The Shockley-Queisser theoretical quantum limit for single junction PV is ~31%. The very best panels (most expensive) are 24%, and run of the mill utility monocrystalline panels are now about 21%, similar to measured. A biased model that starts from an impossible input assumption and gets a ‘nice’ but utterly wrong answer is par for warmunists.

  19. There is some cognitive disconnect in the “solar panels cool” idea. Anyone with solar panels can tell you that they become hot to the touch — the whole unit — metal frame, backing, etc.

    If the panels become hot to the touch — then they heat surrounding air (in almost all cases — hot to the touch means ~ > 98 degrees F and it is possible for the ambient air to be warmer than that).

    When my sailboat is in the tropics or subtropics, the panels can be too hot to touch mid-day. Geckos seek out the warmth of the panels after dark., attaching themselves to the backsides of the panels for the heat. (Yes, we usually have house geckos living on our boat in the tropics…don’t know how they get there.)

    Notice that the same paper confirms overnight low temps raised by parking lots as well — just not quite as much as the solar panel farm.

    • The geckos probably got on your boat in port and then they just live on the boat. Plenty of bugs. Places to stay warm. They probably raise offspring and just stay on the boat as long as the boat exists. They’re fun to watch and great bugeaters. Sounds like a win-win.

      • Reality Check ==> In truth, we love our geckos — and they do lay eggs and reproduce on the boat, usually nesting in furled sails, particularly the mainsail, which is closest to the cockpit (where most of the bugs are at night).

    • Anyone with solar panels can tell you that they become hot to the touch — the whole unit — metal frame, backing, etc.

      And the reliability of electronics, their failure rate goes up with temperature.

      All of those good green jobs? are going to be going around cleaning panels and replacing bad ones.

      • Cleaning every 3 years is more than enough, say 1 hour per 30 panels

        19,000 panels installed over 9 years, so far 2 failures.

        Not sure about how the anti0solar meme got started here, but it is not based in reality.

      • stock ==> In my experience with the solar panels on our sailboat — cleaning is a weekly task — even at sea. Dust, bird stuff, etc. Each morning the panels are covered with dew, to which any windblown dust sticks, then dries.

        Maybe this is vastly different with terrestrial panels or roof-top panels, but I doubt it.

        Anyone with accessible rooftop panels reading here? Your experience?

      • Rain and melting snow cleans off the panels very well. Bird droppings non existent because there are no branches over the panels. In 10 years on the roof, I used Windex and paper towels once. Not worth the effort for the amount of dirt that was removed. Biggest issue is blowing out the leaves that fall in autumn, and get underneath the panels. Leaf blower makes that problem easily resolved once a year. The high angle of the panels (at 42 degrees N latitude) makes the snow fall off on the downside. The deep blue color also melts the snow in bright sunshine. So….all in all, you really don’t have to lift a finger but once a year for cleaning/maintenance)

      • Richard Baguley ==> Interesting — possibly the high angle is the difference. In the tropics, panels are nearly flat. Do you live in an area with a lot of/frequent rain?

        So, I guess the mantra applies “Your results might be different”.

      • That depends on where the panels are. Once every three years may be enough if you don’t mind significant degradation between cleanings. How frequently the panels are cleaned have nothing to do with how long they last, with the possible exception of when they get real dirty they will last longer as less light is making it through to the collector.

        The anti-solar meme got started because solar is a money loser that only survives because massive amounts of other people’s money are funneled to it.

      • That depends on where the panels are.

        for cleaning yes, failures for a 10 panel 40 year system start at 8 to 10 years. Now most solar panels will likely still work for 20 or 30 years, but at lower and lower output.
        And that’s 10 panels, what’s 10 million going to be like in a decade.

      • You don’t need to be under branches to get bird droppings. All you need are a lot of birds flying overhead.

      • MarkW says: “if you don’t mind significant degradation between cleanings”

        You obviously don’t have a clue. Falling rain cleans them, and that is enough to prevent degradation. And also, in 10 years, please tell me why there are no bird droppings on my panels. I’ve found a lot more droppings on my windshield from the car I park underneath my trees, but never on the panels.

      • MarkW says: “because solar is a money loser ”

        Solar hot water is cost effective, as is solar space heating.

      • micro6500 says: ” failures for a 10 panel 40 year system start at 8 to 10 years” My 16-panel system is 10 years old, and have had no failures. Output is 98% of original as measured at grid tie inverter.

      • Kip, I have done 19,000 panels, believe I have experience in how clean they stay. This is in Hawaii, pitch is usually pretty low.

      • Richard Baguley said:
        Solar hot water is cost effective, as is solar space heating.

        Not where I live. A few years back I worked at a museum that was all in on alternative energy. We had a 40kW solar array and solar hot water heaters. The museum sponsored a solar hot water heating lecture for building contractors. There were 100 plus contractors there and what they learned is solar hot water will never pay for itself.

      • @ Kip, @ 3:04 pm Oct 18 you said: “In my experience with the solar panels on our sailboat — cleaning is a weekly task — even at sea”.

        Besides bird “poop” and so on , I think one of your problems might also be salt residue. I also don’t think rain in a lot of areas is as clean as some people have witnessed.
        FI our biggest problem is dust, The dust on our property is extremely fine clay ( glacial), it is very, very light and flies everywhere in the slightest wind and as soon as there is any moisture it becomes a sticky film ( and almost undrivable even with a few mm of rain), if the dust in other regions is coarse , yes it may wash off in a rain but we get a film on every surface that requires at least a weekly, if not more frequent, cleaning.

      • Stock,

        I think most of us are fine with someone putting solar panels up on their roof, provided WE don’t have to pay for your installation. If you get tax credits, subsidies and special tariff feed-in rates for your excess rather than you paying for it and market rates for your excess electrons, then I personally have a problem with it.

        The problem with solar from an electric grid stability perspective is threefold: it is not reliable baseload nor can it be reliably called on for peaking support. It is a wildcard on the grid and makes it much more difficult to keep the lights on for everyone else. The grid suppliers have to keep spinning backups for all the solar capacity on the network so it doesn’t significantly reduce CO2 production either. In short there is no benefit to society from it at all.

      • Owen in GA October 19, 2016 at 4:40 am
        “I think most of us are fine with someone putting solar panels up on their roof, provided WE don’t have to pay for your installation. If you get tax credits, subsidies and special tariff feed-in rates for your excess rather than you paying for it and market rates for your excess electrons, then I personally have a problem with it.”
        ——————————————————————————————————————————
        Amendment on the Florida ballot this election (caps are mine):

        “The Amendment establishes a right under Florida’s Constitution for consumers to own or lease solar equipment installed on their property to generate electricity FOR THEIR OWN USE. State and local governments shall retain their abilities to protect consumer rights and public health, safety and welfare, and to ensure that consumers who do not choose to install solar are NOT REQUIRED TO SUBSIDIZE the costs of backup power and electric grid access to those who do.”

        What does all that mean technically? It appears that the Amendment does not give a right to people with solar to sell their excess power to the power company nor does it require the power company to buy it. It also seems to shift the burden of staying connected to the grid to the home owner because they pay no fees to the power company for the maintenance of that connection.

      • Tom,

        I think they may have gone a bit too far, but I understand what may have driven them to write the amendment that way. We all saw the renewables created fiasco that happened in South Australia and would like to keep our electricity stable and reliable. Of course the South Australia thing was caused by wind turbines and not solar, but the problems for the grid are similar. If heavy clouds roll in quickly (as they are wont to do in Florida) then there is a sudden drop in grid supply and a corresponding increase in grid demand (roof top solar excess cuts out and grid has to take the household load it was carrying as well) if spinning backup isn’t available in the form of gas turbine stations, then the grid collapses and brownouts or blackouts result over a wide area. In a worse case the entire southeast US sector could be taken out if the right breakers trip due to surge overload.

        Solar and wind are not a good way to build a stable electricity supply.

      • I love it when trolls start declaring that anyone who doesn’t agree with their peculiar fantasies is somehow mentally defective.

    • (Yes, we usually have house geckos living on our boat in the tropics…don’t know how they get there.)

      Maybe it depends on your choice of insurance company.

  20. Wind turbines are reported to have a similar effect. As long as they raise the temperatures, no one is going to care (nor admit the cause, of course). Should anything accidentally reduce the temps, there will be wailing and gnashing of teeth. It’s all about the direction of the change. Higher, good. Lower, very, very bad.

  21. So they get their solar panels and higher temps too boot.
    For a caGW PR person, what’s not to like? The grant…er…gift that keeps on giving!

  22. The alarmists should be pleased. If they now relocate some weather stations to solar roof tops they may get the warming they crave.

  23. Can anyone tell me if they’ve EVER claimed ANYTHING to be inconsistent with their models? But wait! Silly question. Everything is consistent because they made sure to cover all the bases. Nothing can prove them wrong. Am I right? Do I get a gold star? I know a grant is out of the question.

  24. The biggest drain on the electric grid is heating water . To heat 1 litre of water with a 3.6 kwh element to 70 C ,it takes about 1.4 min’s . Here in Australia most homes have a 250 litre hot water unit, Using those calculations it would take about 6 hours to heat to 70 C. So don’t you think the first step in reducing greenhouse gas emissions from electricity generation would be to put solar hot water units on every house roof ?

  25. Maybe the reason that there isn’t much bird crap on solar panels is that they learn to avoid them. On ‘pane’ of death by frying.

    • Only the solar CSP, with mirrors, could have that effect, not solar panels (and they solved the bird frying issue)

      • Griff,
        Sill lying I see. They only stopped frying birds in stand-by mode. When in production mode the solar power is still concentrated, so any birds that fly near the tower will still be fried.

    • I noticed dinner plate sized white smear marks on my solar panels and dismissed birds because of the size but then saw four Pelicans fly overhead and with astonishing accuracy one of them proceeded to show me what he thought of my solar panels .

  26. So in order to stop global warming, they install solar panels that actually produce a heating effect more noticeable than CO2. It’s irony, all right.

  27. Ideal location for temperature measurement stations then, as the warming would then justify more panels, and so on and on.

  28. Someone surely should have had some clue about this….just sayin’ – is it possible they did, but just didn’t care?

  29. One more thing that many don’t get is that in case the PV solar panel doesn’t source any electrical load it has to convert to heat ALL the efficiently captured light (it’s just the 1st law of thermodynamic).
    Any hyper-efficient PV solar panel left unloaded heats up the environment around better than the darkest asphalt.

    Have a great day.

    Massimo

    • Massimo, I think you have that wrong!

      An unload PV panel (ie disconnected) sufferers a temperature rise due to the sun light landing on it.
      A loaded PV panel (ie connected and providing a current) has the above and the heat from the V x I flowing through the panel.

      • Hi Steve,
        no, it’s just a question of thermodynamics. The joule effect you refer to it is real but when the panel is left unconnected, since the albedo of the panels is highly optimized (and doesn’t change as function of the load), the energy has only one way to go, it has to be converted to heat.

        Imagine to put inside a real greenhouse one PV panel with a switch in series to a load resistor which is capable of dissipating to the environment the whole electric energy produced by the panel.
        At steady state (after the due time), in both cases (when the switch is open and when it is closed) the temperature inside the greenhouse must be the same, because it depends only by the solar irradiation, the greenhouse thermal insulation and the inner albedo (all of them are unchanging).
        So when the switch is open the PV panel must be warmer than when the switch is closed, that because in the first case the resistive load doesn’t dissipate anything, while in the second case it dissipates the whole electric energy produced by the panel.

        Have a great day.

        Massimo

      • Steve,
        No, when you put a load on the panel you are removing energy in the form of electricity. This energy is then not available to turn into heat. Total energy in (from the sun) must equal total energy out (in electricity and heat).

  30. “At each site, we monitored air temperature continuously for over one year using aspirated temperature probes 2.5 m above the soil surface. Average annual temperature was 22.7 + 0.5 °C in the PV installation, while the nearby desert ecosystem was only 20.3 + 0.5 °C, indicating a PVHI effect. ”

    I can only assume that the temperature sensor was placed under the panels, this would reduce radiation to space at night, this effect may have been available to the other two sensors.

    .Sensor location was not clear in the article and would likely have a major effect on readings.

  31. Yep. that’s what they said… “This more significant warming under the PVHI than the UHI may be due to heat trapping of re-radiated sensible heat flux under PV arrays at night.”

    How about relocating the sensors near the array but without PV obstruction?

  32. For those talking about rain and snow keeping the panels clean, washing debris off, surely the action of rain water/snow running down the panel containing particulates and salt etc would effectively grind the surface to become less transparent?

    I have seen cars after a rain storm here in Australia covered in a dusty/sandy coating, and that includes the windscreens.

    • dpj12—No indeed, solar panels are covered in glass, rain is an effective cleaning process.

      When we clean a PV system after about 3 years, we see a 2% to 6% increase in kWH output. the higher numbers usually in areas near large construction. Panels that are mounted flush on a flat roof also see more buildup.

      Its not a big problem.

      • That may be true in Hawaii, but you can’t say that for all locations. Studies have shown that the need for periodic cleaning and replacement of failed panels varies widely by region. Northern climates are by far the worst in that regard.

  33. One would expect warming comparable to a dark rooftop or asphalt because of the dark surface of a solar panel. If a lot of the electricity generated by a solar panel is used for lighting or converted into electromagnetic waves in electronic equipment and motors, then the energy is reradiated as something besides heat and escapes the planet and might have an overall cooling effect. I have seen a black enclosed barbecue get up to about 170 F under direct sunlight. A solar panel with a sealed and well insulated chamber behind the cells to trap heat might get even hotter. Many have used the heat from concentrated solar to drive a Stirling engine, but it seems that a low temperature difference Striling engine could make efficient use of this heat from solar panels to get maybe another 20 or 30 percent in efficiency from the panel. I have not seen that it has been tried and a search on google turns up nothing. An ordinary piston engine with a one diameter piston would experience a force of about 2400 pounds from the 2 psi increase at 170 F. If it weren’t for all the deception and the stench of the global warming agenda, there would probably be a lot more people getting solar.

    • Hi John,
      “One would expect warming comparable to a dark rooftop or asphalt because of the dark surface of a solar panel. If a lot of the electricity generated by a solar panel is used for lighting or converted into electromagnetic waves in electronic equipment and motors, then the energy is reradiated as something besides heat and escapes the planet and might have an overall cooling effect.”

      You are fairly right, but if the albedo with and without the PV panels was unchanged, the final result is just an average almost zero cooling. The electric energy “produced” (or better “converted”) by the PV panels, it mainly has to be converted to heat to escape the planet (I write “mainly” because in case of light production there is the possibility that it left the planet that way). Except for the upwelling light, all the other forms of energy (or work) finally become heat.
      So, even leaving the albedo unchanged (which typically is not), the process should lead to little cooling and mostly heat relocation.
      In the reality, the albedo should reduce a lot because of the dark surface of the panels, that lead to a total heating effect, partially relocated when the panels are loaded.

      Have a great day.

      Massimo

    • Except that solar panels are optimized to collect as much of the available solar energy as possible. As such they will heat up more than other dark materials like asphalt, which BTW, gets lighter over time.

      • Hi Paul,
        Yes, I fully agree. It’s exactly what I meant in the last paragraph of my former message.

        Have a great day.

        Massimo

  34. And thermal power stations have no UHI effect ? How does the amount of UHI compare from the two sources

    • The whole reason for the existence of these solar fields was to prevent warming. Now we find out they are causing warming.
      That’s the irony.
      Perhaps you missed the title of the piece?

  35. Hillary plans to install 500million panels in 4yrs. Now that could give a new Agw temp record for the USA.

  36. The author of a paper on similar research on wind turbines said this:

    “the warming effect reported in this study is local and is small compared to the strong background year-to-year land surface temperature changes. Very likely, the wind turbines do not create a net warming of the air and instead only re-distribute the air’s heat near the surface, which is fundamentally different from the large-scale warming effect caused by increasing atmospheric concentrations of greenhouse gases.”

    So I would say the same applies to solar panels – its local warming, redistribution, not comparable to large scale warming.

    (I will try and find a working link to the research – the one accompanying that quote is bust where I found it)

  37. (This is sort of a hanging curve begging to be hit, so maybe someone’s beat me to it.)

    So, climate scientist miss not just the magnitude, but the sign, (plus instead of minus) on a model output that can be verified in real time, but we’re supposed to bankrupt our economy to deal with their forecasts of global temperatures one hundred years from now?

    If so, seems like a reason to be a bit skeptical.

  38. Using electricity – whatever its source – produces heat, e.g., lights and electric motors. So funneling electricity into high-density urban environments must add to the UHI effect induced by sunlight and motor vehicles.

  39. Who knows though. There might be a latitude at which the lower libido of the panels actually radiate away more heat than they add when illuminated. Here is a thought experiment: Take the entire electrical power requirement (even desirement) ~2.5 TerraWatts? Take the average albedo of the Earth land mass (~0.2?) and solar panels (~.1?). Let’s assume the average illumination is 600 watts (clouds) * (1/2) (day/night) * ((Pi * r2)/(2 * Pi * r2) (disc over half sphere) per square meter = 600 /4 = 150 watts/m2. Let’s assume 33% conversion efficiency so that we get 50 watts of electricity from ever square meter of panels. 2.5X10^12 / 5X10^1 = 50 billion square meters which would be a square land mass 224 kilometers on a side. There are ~150 trillion square meters of land on Earth. So the arrays would take 3 parts in 10,000 of the total earth land area, but lets say 1 parts in 1,000 to exclude Antarctica and other inaccessible areas. So if that one part in a thousand were covered by photo-voltaic arrays, and the albedo was half of the natural terrain, perhaps we could expect a tenth of a degree effect one way in the tropics and perhaps a tenth of a degree the other way above 45 degrees latitude. But the effects would be concentrated in areas with a lot of panels – a heat island. I don’t think it would be a big deal either way.

    • If your panels have a low libido, perhaps you aren’t spending enough time with them.
      Take them on a date. Dinner, a good movie. That should help.

    • Assume 33% efficiency?????
      The theoretical maximum is 31%.
      The best laboratory results are only in the mid 20’s.
      Real world cells are 20% and lower the first day out of the factory and drop off from there.

      You are forgetting that these panels aren’t being placed randomly, they are being placed where the sun is the strongest. This usually means deserts as close to the equator as you can get.
      Additionally, these deserts also have much lower than average albedo.

  40. Japan plans to build it’s own Heat Island.

    “The Japan Aerospace Exploration Agency is working on several models for solar-collecting satellites, which would fly in geosynchronous orbit 36 000 kilometers above their receiving stations. With the basic model [top left-hand side], the photovoltaic-topped panel’s efficiency would decrease as the world turned away from the sun. The advanced model [top right-hand side] would feature two mirrors to reflect sunlight onto two photovoltaic panels. This model would be more difficult to build, but it could generate electricity continuously.In either model, the photovoltaic panels would generate DC current, which would be converted to microwaves aboard the satellite. The satellite’s many microwave-transmitting antenna panels would receive a pilot signal from the ground, allowing each transmitting panel to separately aim its piece of the microwave beam at the receiving station far below.Once the microwave beam hits the receiving station, rectifying antennas would change the microwaves back to DC current. An on-site converter would change that current to AC power, which could be fed into the grid.”
    http://spectrum.ieee.org/green-tech/solar/how-japan-plans-to-build-an-orbital-solar-farm

  41. You’ve got to be kidding: “solar photovoltaic arrays, by intercepting some of the sun’s warming rays and converting them into electricity, would have a cooling effect.”

    Thermodynamics pretty much declares that every step of the process has to be exergonic. Why do they continue to pretend that it does not apply? Their computer simulations are frauds and they need to have their grant money revoked and sued for the money that they have spent on crap science. They would not pass my high school physics course.

  42. The wonder is that they could figure beforehand that < 0.1 albedo objects (solar panel) would rise temp in sandy, ~0.4 albedo area (see wikipedia "albedo") . You need at least 30% efficiency panel just to offset the albedo effect !
    New age "science", once again

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