OT? When Computer Controls Fail

the technology will presumably develop, and maybe in the decades ahead it could become a viable and advantageous method of power generation. Is 10x s o bad for a very early example of a technology?

No. He just gets his information from denialist propaganda sites - Wattsupw iththat has shown up in one of his posts - and the fossil carbon extraction industry pays the denialists to bad-mouth the competition.

John Larkin is too gullible to realise that he's been suckered.

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Bill Sloman, Sydney

the technology will presumably develop, and maybe in the decades ahead it c ould become a viable and advantageous method of power generation. Is 10x so bad for a very early example of a technology?

Or putting it the way John Larkin has been persuaded to think about it, bur ning fossil carbon as fuel is good, and any other way of getting energy cut s the income of the fossil carbon extraction industry and must not be seen to be remotely practical.

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Bill Sloman, sydney

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The level of discrimination required to fly away from something that looks stinking hot can be innate - and mostly is. Even graduates from Tulane coul d manage it.

Nobody has yet shown pictures of piles of tens of thousands of roasted bird s - it they existed, they'd be piled up fairly close to the solar tower. Th e numbers seem to extrapolated from occasional reports of "streamers" seen near the tower, and posted on denialist web-sites to wind up gullible sucke rs like John.

Our floor to ceiling windows in Nijmegen did kill a bird or two a year - or maybe a bird that was too sick to see where it was going failed to survive the collision. We didn't have them autopsied.

Nor does he get into a flap about blatant anti-solar power propaganda from denialist web-sites.

John Larkin went to Tulane, and managed to come out as gullible as he went in.

The University of Melbourne might have polished my critical thinking skills , but both my parents had degrees from the University of Adelaide - just as provincial as Tulane, but in their cases at least, clearly better at encou raging critical thinking - and they did encourage me to look for flaws in l ogic from an early age.

William Bragg was a professor at Adelaide for a while, but he got his Nobel prize (shared with his son, Lawrence Bragg) for work he did after he'd mov ed on to Leeds, UK (which is also pretty provincial).

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Bill Sloman, Sydney

)

e sunlight onto the tower. The mirrors have to track where the sun appears to be in the sky, but not spectacularly accurately - the solar disk isn't t hat small.

Perhaps the apparent position of the top of the tower?

If the tower direction sensor was mounted on the same frame as the mirror, it could work out how much the mirror had been twisted away from it's nomin al alignment. That would vary with the sun's position, but in a predictable way. A sufficiently ingenious mechanism might compensate for this mechanic ally but it might not be the cheapest way of solving the problem.

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Bill Sloman, Sydney

Didn't find the right comment. Who by?

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Rick C

(snip)

Wow, bird-fry denialism/conspiracy theorizing.

The streamers (birds that vaporized completely) and burned carcasses were attested to and counted by biologists working for the U. S. Fish and Wildlife service who were there specifically to address concerns that birds might die.

Well, birds _did_ fly into the flux and die, and the biologists believe the birds were actually attracted to the glowing tower.

You can Google all of this yourself- I won't offer any links you might dismiss as propaganda.

Oh, the Ivanpah system was "fixed" to prevent more bird deaths. The "fix" was to reposition some of the mirrors to *reduce* the flux at the tower!

Mark L. Fergerson

Ok, I see that. He assumes the mirror is relatively stationary compared to the speed of the plane and gets 50 J/cm^2 exposure. I'm not so sure that is a low enough figure to ignore. Especially if you consider the possibility that someone will be looking at the source rather than only considering damage to the aircraft. I don't know for sure, but I bet that would blind a person. Heck, the authorities worry about harm to pilots' vision from having a ground hand held laser shone in their eyes while flying. A rescue craft will be grounded until a doctor can check their vision. This has got to be many orders of magnitude worse.

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Rick C

Sorta. The problem is the solar power production peak (high noon) and the demand peak (about 6PM) do not coincide. On the left coast, in order to shift the peaks so that they coincide, we would either need to build floating solar power farms in the Pacific ocean 6 time zones away, or somehow store the noontime power so that it could be used later. The common way to do the latter is to use the grid to store the power during the day and buy it back later. This will reduce peak generation demand around noontime, but does nothing for the 6PM demand peak. Note that the demand curve changes with season, location, available power, data source, political agenda, etc.

For local storage, there are also AC coupled battery systems that can be grafted onto a grid tied home solar system. They're NOT cheap.

Drivel: You've heard of the "hockey stick" graph. Now introducing the "duck" chart for peak electric power consumption: Note that the peak consumption for California on this graph is at 8PM. I'm guessing, but it appears that in about 2022, the California grid will be running totally on surplus power from solar arrays for a few hours around noon. However, the 8PM consumption peak shows no sign of dropping.

--
Jeff Liebermann     jeffl@cruzio.com 
150 Felker St #D    http://www.LearnByDestroying.com 
Santa Cruz CA 95060 http://802.11junk.com 
Skype: JeffLiebermann     AE6KS    831-336-2558

Enter the electric car! It would likely be part of an energy peak shift if charged at night for the morning commute, charged during the day for the commute home then used as a storage device to supply power during the present peak demand time.

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Rick C

Yep. That would tend to move the consumption peak to later in the evening: See E-TOU, E-6, and E-7 Periods tabs below: Lots of time plans available to match most work schedules. If there will be an EV peak, my guess(tm) is that it would appear at midnight, when cheaper TOU (time of use) rates begin for most plans and months.

Most EV and plugin hybrid owners whom I know also have solar panels for charging their vehicles during the day. This doesn't provide a full charge, so they finish the charge at home, usually at night.

--
Jeff Liebermann     jeffl@cruzio.com 
150 Felker St #D    http://www.LearnByDestroying.com 
Santa Cruz CA 95060 http://802.11junk.com 
Skype: JeffLiebermann     AE6KS    831-336-2558

With the huge loads from cars, it won't suffice to just have cheaper rates at some time at night. Locally the power company wanted to install a thermostat in your home so they could duty cycle to suit their needs. The same would be done with the auto chargers to even out the load to best suit them. Rather than pay cheaper rates for a given time, it will be cheaper rates for letting them control the charging times.

I am seriously thinking of making a deposit on the new Tesla. I would need at least one and likely two chargers (one each for two homes). The range isn't quite enough for a round trip. I can't imagine how large a solar array would be needed to charge a car!

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Rick C

Or -- to be a little more ingenous, if clearly far too cheap for a project of this magnitude (sarcasm*)...

Just mount a webcam up there. I mean, behind a welding glass of course. Crank each mirror around until its pixels are bright and shiny. Each mirror is easily resolved on a standard couple-megapixels HD cam, or you can place several around with suitable zoom settings. And you can do all at once, i.e., O(1) if you really need to (which, well, it's easy enough, sure, why not?!).

*There's a tale of an efficiency company having been hired to reduce errors on a packaging line. Boxes were occasionally going out without product (empty). Some $100k's later, they came up with a high tech conveyor weighing and machine vision system, and every time an error is found, BING, alarm bells sound, conveyors halt, and the faulty box is removed from the line.

Next year rolls around and it's time for the report. No reports of empty boxes! Happy customers. Great. Ah, but the thing is, no reports at all, the alarm isn't going off any more. Problem solved?

Checking on the shop floor, they discover the reason: the workers had set up a fan across the conveyor system, so any empty boxes simply topple over and blow off. No more delays, no more alarms. Their problem solved!

Moral, in this case, being, they might well go for something fancy like a bugs-eye detector, where each sensor is essentially a telescope sighted at each mirror. Not that this is necessarily what you were getting at, by saying a "segmented" sensor, but given the price tag on the damn thing, I wouldn't put it past them...

For that matter, it's probably advantageous that this thing's in the desert.

Little rain to worry about turning the ground mushy. Little or no frost heave to offset the foundation. (I don't say "none", because I know it can get pretty darn chilly at night in the desert. But not for days at a time (unless you're in the mountains?), so there won't be much frost heave.) Probably, a flat concrete pad, or a couple shallow footings, are enough for them.

On second thought, they'd probably go with modest depth footings, since those will have more pull-out resistance than a sheer slab. Wind will be the important concern there.

Going back to sighting: if they are aligned in a feedback loop, then there's no need to get the footings any more than eyeball straight. No worries.

But again, who knows. Sighting 300,000 mirrors creates a lot of surveyor man-hours. Job creation, it's great, don'tcha know?...

Tim

--
Seven Transistor Labs, LLC 
Electrical Engineering Consultation and Contract Design 
Website: http://seventransistorlabs.com

Yeah, but have you tried to quote 300,000 of them?

On the upside, you'll probably get a great quantity discount... :^)

Tim

--
Seven Transistor Labs, LLC 
Electrical Engineering Consultation and Contract Design 
Website: http://seventransistorlabs.com

Agreed.

That's also been proposed for PG&E. Plenty of other great ideas, but mostly scaled for large consumers of electricity:

Well, a 2012 Tesla S has an 85 Kw-Hr battery pack (or 81 Kw-Hr if you believe the pundits): Including charge efficiency and other losses, my guess(tm) is that a full charge would be about 80 Kw-hr. Solar insolation for San Francisco area is 3.7 for Dec and 6.2 for May, with an annual average of 5.1 kWh/sq-meter/day. 80 kw-hr / (5.1 kw-hr/sq-meter/day) = 16 square meters of sunlight needed to charge the battery in one average day. However, that'a at 100% light to electricity conversion efficiency. Lumping all the conversion losses together, I would guess(tm) the overall system efficiency is about 12%. Therefore: 16 sq-meters / 0.12 = 133 sq-meters = 1432 sq-ft = 206,150 sq-in of solar panels.

The typical residential panel is 65 x 40 inches or 2,600 sq-in. You'll need: 206150 / 2600 = 80 panels at about 190 watts per panel. Yeah, that's rather large for a roof, so you'll need a ground mounted array.

The Tesla Model 3 has somewhere between 36 and 65 kW-hr battery, depending on which leak/guess/speculation you believe. You should be able to use a smaller solar array. For example, for a half size 40 kW-hr battery, only 40 panels are needed to charge in one day, which is quite doable on a large roof.

--
Jeff Liebermann     jeffl@cruzio.com 
150 Felker St #D    http://www.LearnByDestroying.com 
Santa Cruz CA 95060 http://802.11junk.com 
Skype: JeffLiebermann     AE6KS    831-336-2558

If the peak is really that late, apparently most is due to air conditioning.

Have an insulated water tank, cool it down to 0 C during the day with solar energy. During evening, dump the heat from the AC to the waiter tank, until the water temperature is the same as the outdoor air temperature,

During the following morning, transfer the heat from the water to air using solar power.

By making ice during the day, you could use a smaller water tank, but of course, there are problems with the mechanical expansion of ice.

unts

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The denialist proganda machine may be a conspiracy theory - fossil carbon e xtraction companies conspring to pay money to liars for hire - but it's a v ery well documented one.

is probably the best-written documentation of the antics of various industr ies interested in minimising the effect of inconvenient scientific observat ions, but there are quite a few others, all perfectly respectable (which is more than can be said for the url's that John Larkin offers links to.

re attested to and counted by biologists working for the U. S. Fish and Wil dlife service who were there specifically to address concerns that birds mi ght die.

So where's the link to the documented counts?

the birds were actually attracted to the glowing tower.

dismiss as propaganda.

It takes a fair bit to get me to dismiss stuff as propaganda. Tales of thou sands "roasted birds" back up by single photo of a very ordinary looking de ad bird do activate my bs-detector.

Your excuse for not looking for the photos of piles of dead birds has a sim ilar effect. The U. S. Fish and Wildlife service could be expected to have documented their observations - if they haven't one has to wonder why.

x" was to reposition some of the mirrors to *reduce* the flux at the tower!

Sounds plausible. The tower is quite big, and they probably can live with a more uniform distribution of heat over it than the simple-minded "focus ev ery mirror on the same spot" would give.

Having some mirrors miss the tower completely would not be an attractive op tion.

--
Bill Sloman, Sydney

I don't know the specs for the Model 3, but a mate has a Model S. He's driven it between Melbourne and Sydney multiple times, which is a ten hour drive, 900km (560 miles), with only a single 30-45 minute stop at the Supercharger station in Goulburn.

With the self-driving, he only spends about 20 minutes of the ten hours actually driving the car as well - impressive.

Clifford Heath.

Yep. Anything that causes the usage to approach 100% of capacity implies excessive use of electricity. The legend on the graph indicates that it's for "a hot spring day" which usually means A/C use.

The basic problem is meeting or reducing peak demand. Moving the problem to the point of use one way. I have a friend that does something like what you describe at his house. He has water lines running in the walls of his house. Near the house is a rather large buried water tank. Water is pumped through the pipes to stabilize the indoor temperature. Water is heated by either a wood burner or an undersized solar collector. In this area, we don't get many extreme temperatures so the use of the system is limited to hot days and cold nights. However, such a system would not be suitable for factory, apartment, and office buildings which is where the real problem is hiding. Thermal management for a single family dwelling is easy by comparison and one solution is not optimum for every size and type of building.

--
Jeff Liebermann     jeffl@cruzio.com 
150 Felker St #D    http://www.LearnByDestroying.com 
Santa Cruz CA 95060 http://802.11junk.com 
Skype: JeffLiebermann     AE6KS    831-336-2558

The report was prepared by H.T. Harvey & Associates. The extensive April 2015 report can be found at: I haven't read it.

Please note that while Ivanpah might kill 3500 birds per year, cats kill an estimated 2 to 4 billion birds per year:

--
Jeff Liebermann     jeffl@cruzio.com 
150 Felker St #D    http://www.LearnByDestroying.com 
Santa Cruz CA 95060 http://802.11junk.com 
Skype: JeffLiebermann     AE6KS    831-336-2558