At the start of the weekend, and quite by accident, I found myself aloft and looking directly into the glare of the Ivanpah Solar Electric Generating System. I can tell you that not only does it roast birds in mid-air, it certainly seems to be a hazard to aviation. First, a story today from AP, via my local newspaper. Photos follow.
Emerging desert solar plants scorch birds in midair-Chico Enterprise-Record

IVANPAH DRY LAKE (AP) >> Workers at a state-of-the-art solar plant in the Mojave Desert have a name for birds that fly through the plant’s concentrated sun rays — “streamers,” for the smoke plume that comes from birds that ignite in midair.
Federal wildlife investigators who visited the BrightSource Energy plant last year and watched as birds burned and fell, reporting an average of one “streamer” every two minutes, are urging California officials to halt the operator’s application to build a still-bigger version.
The investigators want the halt until the full extent of the deaths can be assessed. Estimates per year now range from a low of about a thousand by BrightSource to 28,000 by an expert for the Center for Biological Diversity environmental group.
The deaths are “alarming. It’s hard to say whether that’s the location or the technology,” said Garry George, renewable-energy director for the California chapter of the Audubon Society. “There needs to be some caution.”
The bird kills mark the latest instance in which the quest for clean energy sometimes has inadvertent environmental harm. Solar farms have been criticized for their impacts on desert tortoises, and wind farms have killed birds, including numerous raptors.
“We take this issue very seriously,” said Jeff Holland, a spokesman for NRG Solar of Carlsbad, the second of the three companies behind the plant. The third, Google, deferred comment to its partners.
The $2.2 billion plant, which launched in February, is at Ivanpah Dry Lake near the California-Nevada border. The operator says it is the world’s biggest plant to employ so-called power towers.
More than 300,000 mirrors, each the size of a garage door, reflect solar rays onto three boiler towers each looming up to 40 stories high. The water inside is heated to produce steam, which turns turbines that generate enough electricity for 140,000 homes.
Sun rays sent up by the field of mirrors are bright enough to dazzle pilots flying in and out of Las Vegas and Los Angeles.
Full story here: http://www.chicoer.com/breakingnews/ci_26357771/emerging-desert-solar-plants-scorch-birds-midair
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I drove to the Heartland ICCC9 conference in Las Vegas, NV, (my “Big Oil” charter jet never showed up) taking the US395 route through Nevada on the way to the conference, but on the return trip, I took the Interstate 15 to SR58 route to Bakersfield, and that had me drive by the Ivanpah Solar Power plant. I had never seen the desert air glow before in broad daylight, so I stopped to take some photos.
Here is the view from Interstate-15 looking west at the southernmost tower:
And here are all three solar towers from the same vantage point:
Click the images for full size ones to see details.
I have to say it was an eerie sight seeing the air glow that electric blue color like you see on carbon-arc searchlights at night, but instead being visible during the day. The amount of power being concentrated in the air is quite impressive.
Dr. Roy Spencer also took photos and wrote about the Ivanpah Solar power system when he drove out of Las Vegas leaving the ICCC9 conference. He got closer than I did and beat me to the story, so I never published my photos, figuring there was little I could improve upon.
On Friday, in the early afternoon, coming back from a work related trip in Florida, I found myself having a short layover in Las Vegas, to connect to my flight to Sacramento. I’ve flown the Vegas to Sacramento route dozens of times, and so there is little I haven’t seen on the ground from that vantage point, so I didn’t even bother looking out the window. I was reading a book.
I was surprised all of the sudden when the cabin was briefly lit up by a flash, and I thought to myself that we must have passed some air traffic pretty darn close and gotten a sun glint off the aircraft, looking out the window, I discovered I was being dazzled from the ground, and then I knew what it was.
I got up to get my cell phone/camera out of my laptop bag in the overhead, and was griping to myself, “c’mon, c’mon, BOOT dammit!” waiting for Android to load. By the time I was able to get the camera app running the glare had passed, and all I got was a couple of photos like this one:
I gotta tell you, for a moment, it felt like we were in full glare. And I think that if I had my camera ready at that instant when the angles all conspired to illuminate our aircraft, all I would have gotten was a screen of white, much like this one taken by Sandia Labs during a study:
![ivanpah-glare-7-17-14-thumb-600x395-77670[1]](http://wattsupwiththat.files.wordpress.com/2014/08/ivanpah-glare-7-17-14-thumb-600x395-776701.png?resize=507%2C334&quality=75)
Interestingly, the Sandia National Laboratory is developing a 3D mapping tool to help predict glare from this thing, as seen below:
They purposely flew into the glare and report:
The Ivanpah Solar Electric Generating System (ISEGS) consists of three 459-ft-tall power towers and over 170,000 reflective heliostats with a rated capacity of 390 MW. The California Energy Commission (CEC) has received numerous pilot and air traffic controller glare-impact reports. The situation is serious because pilots report that they cannot “scan the sky in that direction to look for other aircraft.” According to an air traffic controller, “Daily, during the late-morning and early-afternoon hours, we get complaints from pilots of aircraft flying from the northeast to the southwest about the brightness of this solar farm.”
Some Ivanpah heliostats are moved to standby mode in which they reflect light to the side of the tower to reduce sunlight being pointed at the tower’s receivers. Aerial and ground-based surveys of the glare were conducted in April, 2014, to identify the cause and to quantify the irradiance and potential ocular impacts of the glare.
Sandia’s report concluded the glare from those standby heliostats could cause “significant ocular impact” at a distance of six miles. Ivanpah operators BrightSource and NRG are investigating new strategies and algorithms for heliostat standby positions to reduce the irradiance and number of heliostats that can reflect light to an aerial observer, and pilots have been warned of the issue.
Source: http://energy.sandia.gov/?p=19782
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![3D-glare-tool-1[1]](http://wattsupwiththat.files.wordpress.com/2014/08/3d-glare-tool-11.jpg?resize=640%2C368&quality=83)
![Ivanpah-glare-photo[1]](http://wattsupwiththat.files.wordpress.com/2014/08/ivanpah-glare-photo1.jpg?resize=640%2C342&quality=83)
@sciguy54 8/22 6:05 am
True, but there are other factors conspiring against hitting the target. First, most of the mirrors do not have a straight shot.
That brings up an interesting question. For mirrors near the edge, and low sun angle, how much of the light from one mirror hits the back of the next inward mirror? As the light reflects off the aluminum and mirror back, it would produce a lot of solar shrapnel.
And there is the matter of the aiming process.
Certainly accuracy is required here. You need to have accuracy of aiming to within 5 arc minutes with mirrors on the periphery with every day different from the previous day given the solar analemma of the location.
On the issue of mirror corrugation from gravity and thermal expansion differences as a deterioration of aiming:
What is the maximum sag allowable in the mirrors when they are mounted on supports X meters wide? Let’s model segments of each mirror panel between the supports as a cylinder R meters in diameter with a chord X meters wide and a 10 arc-minute allowable aiming error (the angle between the circle and the chord at the mount.)
Distance between supports = 1. meter
half-chord = R*sin(a) = 0.50 meter
a = Angle btw circle, chord = a = 10. arc-min = 0.002909 radian
Radius = Half_Chord/sin(a) = 171.89 meter
Sag/R= (1-cos(a)) = 0.00000423
Sag/R= (1-cos(a)) = 4.23 ppm = flatness error = 4 parts per million!
Sag= (1-cos(a))*R = 0.727221 mm
Arc-length = R*a = 0.500001 meters
Expansion difference = Arc-length – Chord = 0.000705 mm = 0.7 microns.
So over a supported span of 1 meter, you can have less than a millimeter of sag in the middle of the mirror before you exceed the 10 arc-min aiming error. This also means that the difference in thermal expansion between the mount and the mirror cannot exceed 1 part per million of the chord length.
And what does the wind do to the aiming precision and flatness of the mirror?
How much heliostat turbulence in the wind can it stand? Assume a heliostat consists of two 8×8 foot mirrors (2.5 meters). When the wind blows, the mirrors will shake on the vertical axis. How much can they move?
W = Panel wing width = 2.50 meters
Distance from tower = 2000.00 feet (assumption, allowable shake is a function of distance)
Width of tower = 50.00 feet (guess from video)
Allowable error in aim = 20.0 feet (assumption)
angle subtended by error = 0.0100 radian
Ae = angle subtended by error = 0.57 deg
Allowable error angle of mirror = Ae/2 = 0.29 deg
Movement at end of panel wing = W*sin(Ae/2) = 12.50 mm
So the end of the heliostat mirror can move +/- a half inch at 2000 feet and still hit the target.
Protected migratory species, endangered and threatened species, all given the Popeye’s Spicy Fried treatment…
One bird every two minutes based on one point of observation on the ground at one of three “natural rotisseries”…bet it’s several times that number of birds if you looked at the whole complex at one time…Roasted Rara Avis, mmmmmmmmmMMMMMMMmmmmmm.
If you gathered all those roasted ravens, Flambe’d Flamingos, Singed swallows, Popped puffins, glowing geese, inflamed ibex, hot hawks, charred chickadees, percolated partridges, and … I could go on forever…if you gathered all those cooked birds up, you could feed a lot of folks!
Cue Mary Poppins singing:
“Feed the Poor, tuppence a Bird…tuppence, tuppence, tuppence a bird…”