Dan argues that Jim has a sense of humour, as opposed to being a psychopath, but I've never found his argument all that convincing, and I'm even more sceptical now.
The concentrating mirrors aren't going to much of threat at any distance from the tower, but the prospect - no matter how implausible - of incinerating distant hikers really isn't the stuff of comedy.
But the they do a lot with the neural mass they've got - they do seem to make much more efficient use of what they've got than we do. Alex the African Grey parrot came about as close to talking as dolphins and great apes have managed.
If it's bright enough to start your feathers smoking, you can see where it is.
That close to the tower, the target area will be both bright and hot, and it wouldn't take much intelligence to head away from both tower and mirrors.
Insects have a lot less processing capacity than vertebrates.
John loves to criticize anyone who attempts to implement a new idea and finds glitches. Considering that his admitted design methods include the same sort of "try it and see" technique, I don't see how he has much room to criticize. There will be many issues with a large installation and more issues with a new technology. I expect they will be worked out. The article John linked to says they are trying new ideas to minimize impacts on wildlife and will greatly reduce the problems there.
As to calling the plant a "boondoggle" because they burn natural gas to get the plant running, I calculate they used 1.4 petajoules of gas since the plant was put in operation while producing 3.9 petajoules of electricity for a ratio of 2.8:1. While there is clearly room for improvement, I think the "boondoggle" accusation is a bit over stated. That's not nearly as bad as driving an Audi A3 that gets some 21 MPG when you could be driving a hybrid that gets 40+. That's.... about 1:2 or over 5 times worse. He who lives in glass houses...
Yeah, Jim comes across as being pretty extreme sometimes. I think he is one of the few people in this group I would never recommend to a business associate purely because of his posts here. I would be worried that he might actually be worse in person.
That said, I don't know the hazard from wrongly pointed mirrors could be dismissed quite so easily. These things constitute a variable focal point lens and can create a focused point of energy (a point being roughly the size of one reflector) nearly anywhere. They installed a fence to keep wildlife out. Maybe they should make it a wall to keep the light in. They can talk to Trump about that... he's great at walls! I mean, really good!
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Or - more likely - a segmented multi-element sensor at the tower with each segment having enough resolution to pick out a fairly small group of mirror s. Designing a sensor that could survive most of the mirrors all being line d up on the tower at once might be difficult, but you certainly would be ab le to do more than one mirror at a time.
Design isn't the problem - it's fabricating them that accurately, and locat ing them on their foundations with similar precision. It wouldn't take much ground movement to wreck an alignment from first principles, and then you' ve wasted a lot of your manufactured-in precision.
Or they could use a sundial?
Really? Nuclear power is perfectly safe but we can't design a mirror farm that is safe enough? Really????
Why are you jumping up and down waving your arms about this? They are at 2/3 of the design goal which is not so bad given the newness of the technology. Do you really thing it won't improve?
The refraction problem is still there even at high noon. The array is the ultimate heat island. I don't have any numbers for the local air temperature but I'm sure it's much higher than the surroundings. This is the best I can do: Refraction is a consideration in the operation because:
- One can't dynamically adjust the aim and compensate for local atmospherics of a single mirror when it's just one spot among about
58,000 spots on the tower. One might be able to calibrate/aim using a target location further down the tower. That might have been what went wrong, when too many mirrors decided they needed to recalibrate at the same time. (This is pure conjecture on my part).- The beams do not all converge at a single spot on the tower. If they did that, the target would melt. The aiming points are distributed around the target area, which is probably larger than one spot beam, so as not to overly concentrate the heat. This makes aiming a rather complex operation and the small effect of atmospheric refraction an important consideration.
The system is run by BrightSource SFINCS (Solar Field Integrated Control System). I can't find much on how it works. SOLAR BOILER MANAGEMENT SYSTEM (SBMS) - Matches steam output to load demand - Camera and sensors transmit real-time heat levels to heliostat control system - Flexibility to respond rapidly to cloud cover & weather changes It would seem that the aim is dynamically adjusted through the day, which MIGHT include compensation for changes in atmospheric refraction. If I were writing the code for such a system, I would NOT change the aim of all the mirrors at one time, but rather in small groups of mirrors, to avoid a minor glitch turning into a meltdown. That also might have been what happened (more conjecture on my part).
The required accuracy is about 15 arc minutes, so a 11-12 bit ADC or encoder would be sufficient. To compensate for mirror and mount flexing due to turbulent winds, a feedback loop is quite likely required.
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A $2 shadow mask 2D angle sensor of the sort I posted here a month or three ago would allow each mirror assembly to locate the sun. In a few hours, th ey'd all know their own orientation, at which point they just need the rela tive position of the tower.
The same sensor could measure that easily as well--either from looking at t he extremely brightly glowing tower itself, or (for the first few) a sensor or a light on the tower. Not rocket surgery. You could even get all fancy and use a filtered webcam for both jobs.
The Nintendo Wii does harder stuff than that.
Cheers
Phil Hobbs
I can't see how they couldn't adjust the mirrors without a target or just build them correctly to begin with. I expect surveyor's tools would provide more than adequate accuracy to set a mirror on its base with a perfect alignment. There should only be one alignment. Level should be built in correctly which leave rotation (azimuth). You can get that by using the tower as a reference. Can't get much simpler.
And what would be measured to provide the feedback?
How about we find the people who build nuclear power plants near earthquake faults? Talk about crazy machines!
A particularly numerate friend tried to estimate the hazard:
You'll have to dig down into the comments if you're not logged in on Facebook. Just tell the "sign in" box to bugger off.
Clifford Heath.
In other words, as long as we don't generate any significant amount of solar power, it doesn't need to be reliable.
Yes, blame those tens of thousands of idiot birds for not getting an education at a respected university. They deserve to be roasted alive for not reading the peer-reviewed journals.
After all, Sloman has a proper University education, and he doesn't flap into solar collector arrays.
In other words, all solar power so far is helping satisfy peak demand which is a very good thing.
Depending of country and the amount of 24/7 industry, the daily consumption variation can be as low as 20 %. Building solar peak power for 20 % of average consumption, doesn't cause much problems for the network.
If you have hydropower available that are currently running at full power during the day to handle the higher day consumption, the hydroelectric plants can be closed for the day when solar power is available.
The solar electricity generated during the day will save waiter in the hydroelectric plants that are now operated during the night. With hydroelectric backup, up to 40 % peak solar power is not a big problem for the network. No huge dams are required for the hydroelectric plant, it is just needed to store water for a few days consumption on cloudy days.
David Beard, in response to my son Daniel Heath.
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