Zombie, of San Francisco’s “Zombietime” fame, writes in with a question that he has graciously allowed to be given to our readers.
He writes:
I’m preparing to write an essay on the following hypothesis:
Solar power installations, especially in desert areas, replace light-colored high-albedo sand/rock ground surface with very low albedo black solar panels. The “side effect” (in fact, the whole purpose) of solar panels is therefore to capture radiant energy coming from the sun that would otherwise reflect back into space. Because this energy is then converted into electricity, which is then used to power devices and inevitably degrade into atmospheric heat (which does NOT as easily radiate back out into space), the overall result of large solar panel installations is to heat up the planet more than it would be heated without the solar installations.
But of course the solar-energy advocates will say that the solar installation is replacing a carbon-burning power plant, which produces greenhouse gases that the solar facility does not.
The question I seek to answer is:
Has anybody ever actually sat down and calculated whether the CO2 greenhouse effect caused by a carbon-based power plant generating one megawatt of electricity is more or less than the warming effect caused by the lowering of the earth’s surface albedo from a black-panel solar installation with power output large enough to completely replace the carbon-burning power plant?
I suspect that no calculations of this type have ever actually been done, and that solar panels may in fact contribute more to global warming than anyone previously realized — and in fact may cause just as much warming as the power sources they replace.
I have searched but cannot find such a study; but the reason I’m writing to you is that I have some vague memory of this thesis once being discussed on WattsUpWithThat — although I no longer can track down where exactly.
So I ask: Do YOU (without any time investment) remember offhand where or when this hypothesis was discussed on WattsUpWithThat? And if not, do you think this is a worthy line of investigation?
I know this is a somewhat vague question, but your guidance is invaluable!
— zombie
Since the effect of CO2 is zero, the warming effect of solar panels are infinitely greater.
I have also entertained that question and it will be interesting if someone ever sat down and did the calculations. Another similar question would be: what kind of imbalance in the earths composition is created by removing heat via thermal means, ie using earth’s interior heat to warm a home, etc?
This is an excellent question but part of a larger one:-) where is the thermodynamic equivalent of a free body diagram? Just as CO2 respiration is ignored, I suspect that the heat generated from biological processes is significant but ignored by the geologists, politicians and lawyers who mostly represent CAGW levels to use indolent minorities.
Amatori: I think you mean approaching zero, beyond our current technologies ability to differentiate, a third decimal place, well, yeah, OK – zero.
I believe that the “warming effect” of additional CO2 is actually a cooling factor in the atmoshere.
When you consider that CO2 does not produce any heat, (It is not a heat source) It re-emits energy as it recieves it, and a bit more than half is radiated away from the earth in each exchange, creating a negative balance. When this is considered in light of the logarithmic nature of additional CO2, I would agree with you that a gas fired power plant would be less warming than the solar farms that are supposed to replace them.
Good topic…. sorry I do not have a lead to the former debate on WUWT.
Heat generated from biological processes is insignificant, as the ice ages have repeatedly shown. Heat generated from CO2 is insignificant for the same reason mentioned above. Neither tail can wag the dog, nor will they ever.
A quick search delivered this: http://www.clca.columbia.edu/13_39th%20IEEE%20PVSC_%20VMF_YY_Heat%20Island%20Effect.pdf
I did not calculate it but instinctively it seems to me that the environmental problem of solar panels is that it will reduce the surrounding areas temperature significantly, thus causing alteration of the habitat around it.
The better the absorption, the less heat reaches the land.
In Israel there is a crazy plan on its way to erect a huge solar plant in the Negev desert.
People are beginning to realize that like the wind farms, this will cause a grave damage too.
Hopefully common sense will prevail.
This is a great point. I wonder what the answer will be. I suspect that when the IPCC estimates of climate sensitivity are used then the “CO2 effect” will be larger than the Solar Panel effect. I say this because we know that they have got their sensitivities too high already, which is why their models produce higher simulated temperatures than have been observed.
@Amatør1, let’s use the IPCC estimates – even if we disagree with them. We could also determine the sensitivity at which solar panels break even.
The difference is that a CO2 molecule yields useful energy only once, but can contribute to warming the atmosphere by absorbing and back-radiating infrared photons multiple times, for as long as it stays in the atmosphere. Estimating the exact number of those back-radiated photons is not trivial, but I would expect their cumulative energy to be orders of magnitude greater than the amount of energy generated by the combustion of the carbon that yielded the CO2.
Absolutely brilliant question! I’m looking for an old envelope or napkin to do the calculations.
Amator1 is close but there is still 5 – 7% energy absorption available (maybe a little more due to band broadening) by CO2 bands in LWIR going from ~300 ppm to 1,000,000 ppm (100%) CO2. The increased energy absorption just from doubling CO2 to 560 – 600 ppm is small.
Neat question. This is the reason I like to come to WUWT. Can’t wait for the answer.
I read that a 1% or 2% increase in cloud cover effectively nullifies a doubling of CO2. So if your solar panels effectively “decrease cloud cover” so to speak, then it would seem that the warming effect is larger than the cooling effect. Another area that could be looked at is how does the darkness or lightness of our highways affect global warming or cooling? Since the areas of our roads is much larger than the areas of solar panels, this may be another project to undertake next.
http://buildings.lbl.gov/sites/all/files/regional-effects-of-cool-roofs_0.pdf
Modifications to the surface albedo through the deployment of cool roofs and pavements
(reflective materials) and photovoltaic arrays (low reflection) have the potential to change
radiative forcing, surface temperatures, and regional weather patterns. In this work we
investigate the regional climate and radiative effects of modifying surface albedo to mimic
massive deployment of cool surfaces (roofs and pavements) and, separately, photovoltaic arrays
across the United States. We use a fully coupled regional climate model, the Weather Research
and Forecasting (WRF) model, to investigate feedbacks between surface albedo changes,
surface temperature, precipitation and average cloud cover. With the adoption of cool roofs and
pavements, domain-wide annual average outgoing radiation increased by 0.16 ± 0.03 W m−2
(mean ± 95% C.I.) and afternoon summertime temperature in urban locations was reduced by
0.11–0.53 “C, although some urban areas showed no statistically significant temperature
changes. In response to increased urban albedo, some rural locations showed summer afternoon
temperature increases of up to +0.27 “C and these regionswere correlated with less cloud cover
and lower precipitation. The emissions offset obtained by this increase in outgoing radiation is
calculated to be 3.3 ± 0.5 Gt CO2 (mean ± 95% C.I.). The hypothetical solar arrays were
designed to be able to produce one terawatt of peak energy and were located in the Mojave
Desert of California. To simulate the arrays, the desert surface albedo was darkened, causing
local afternoon temperature increases of up to +0.4 “C. Due to the solar arrays, local and
regional wind patterns within a 300 km radius were affected. Statistically significant but lower
magnitude changes to temperature and radiation could be seen across the domain due to the
introduction of the solar arrays. The addition of photovoltaic arrays caused no significant
change to summertime outgoing radiation when averaged over the full domain, as interannual
variation across the continent obscured more consistent local forcing.
–you’re welcome
Energy is neither created or destroyed, merely transported. Sure the desert area will be slightly cooler (because some energy has been removed locally) and some other place has been heated (because of the final thermal degradation) but the overall effect will be, by definition zero.
oebele bruinsma says:
December 10, 2013 at 11:17 am
A quick search delivered this: http://www.clca.columbia.edu/13_39th%20IEEE%20PVSC_%20VMF_YY_Heat%20Island%20Effect.pdf
Good find. From the abstract of the 2nd reference in that paper:
If photovoltaics (PV) are to contribute significantly to stabilizing the climate, they will need to be deployed on the scale of multiple terawatts. Installation of that much PV would cover substantial portions of the Earthʼs surface with dark-colored, sunlight-absorbing panels, reducing the Earth’s albedo. How much radiative forcing would result from this change in land use? How does this amount compare to the radiative forcing avoided by substituting PV for fossil fuels? This analysis uses a series of simple equations to compare the two effects and finds that substitution dominates; the avoided radiative forcing due to substitution of PV for fossil fuels is approximately 30 times larger than the forcing due to albedo modification. Sensitivity analysis, including discounting of future costs and benefits, identifies unfavorable yet plausible configurations in which the albedo effect substantially reduces the climatic benefits of PV. The value of PV as a climate mitigation option depends on how it is deployed, not just how much it is deployed—efficiency of PV systems and the carbon intensity of the substituted energy are particularly important.
http://pubs.acs.org/doi/abs/10.1021/es801747c
What must also be considered is the efficiency decline of the solar panels as they become covered with desert sand.
I have not done or seen such a calculation, but I have seen articles suggesting we paint roads or rooftops white (which is probably dumb for other reasons) so we should identify greenies and ask them to crunch the numbers. I would pay to see figures on how many ounces of coal have been saved by all the US wind “farms”. Spiegel claimed that all wind, pv, biogas etc in Germany has not saved a single gram of CO2… I wonder… Can greenies convert grams of CO2 into ounces of coal?
These solar panels convert sunlight into heat, one way or another, with extraordinary efficiency. Thus I suggest that the OP is entirely correct in his supposition.
Perhaps If the rate of road building has declined over recent years that may show a better correlation with temperatures than co2. /sarc
Perhaps the link sought is this;
http://wattsupwiththat.com/2012/09/07/law-of-unintended-consequences-bites-the-white-roof-uhi-solution-causes-reduced-rainfall/
Bright sunny places become dark electricity eventually to heat places. Why is there a question?
I’m no professional scientist, but it seems obvious to me that solar panels – in the numbers that exist and are likely to exist in the foreseeable future – would have an infinitesimally tiny effect on global temperature – much like the much bigger UHI effect (said effect being local rather than global).
I suppose it is worthy of investigation if there is a possibility that this tiny effect is nevertheless greater than the effect that the panels are supposedly designed to mitigate.
If I’m talking BS, I apologise!
The local endothermic, cooling effect is compensated for when the produced energy is used.
“Has anybody ever actually sat down and calculated whether the CO2 greenhouse effect caused by a carbon-based power plant generating one megawatt of electricity is more or less than the warming effect caused by the lowering of the earth’s surface albedo from a black-panel solar installation with power output large enough to completely replace the carbon-burning power plant?”
Solar panels are expensive because a lot of energy is needed to create them. This energy comes in the form of electricity from coal power plants in China. Solar panels are made in China because coal-generated electricity is especially cheap over there. Meaning: Solar panels probably do not save any CO2 output but increase total CO2 output.
Economic inefficiency translates into energetic inefficiency. If solar panels were useful / energetically efficient, they would not need to be subsidized.
Production processes are constantly optimized; even without subsidies the cost of solar panels halfed once per decade due to ever decreasing energy and resource usage in production. It is not a natural law that solar panels increase the total CO2 output, it is just so that it is currently the case; and will likely not be the case anymore in one or two decades.
You will recognize the shift to that situation by the removal of the subsidies.
ray pierre @ur momisugly real climate did this in response to freakonomics, and found it to be a non issue. Levitt is at his uni….
If you take research such as this:
http://maeresearch.ucsd.edu/kleissl/pubs/DominguezetalSE2011.pdf
and calculate the expected energy for the solar cell, you may be able to get a fair understanding of the heat load transmitted to underlying surfaces, lost to the atmosphere, and converted to electricity or other conversions. In any case, there’s some data available.
It may also be worthwhile to investigate some building science research.