Guest post by David Middleton
From the Department of All Things Ironic…
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.
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?