OT? When Computer Controls Fail

Not close enough according to the simulator I checked (link below)

And yes, I know, simulations aren't the real thing, but it's close enough for government-funded work.

om

I'm leaning more to this explanation. We'll see if they ever announce/adm it what went wrong.

Mark L. Fergerson

"Some Ivanpah heliostats are moved to standby mode in which they reflect light to the side of the tower to reduce sunlight being

Oops.

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John Larkin         Highland Technology, Inc 

lunatic fringe electronics

Where did you get your energy costs from? Anthony Watts web-site?

The whole point of the design is that it dumps the heat into tanks of molten salts and there's more than a day's worth of energy stored in the tanks.

If the output is "erratic" it's due to teething troubles (as in the mirror directing gear) and not intrinsic to the design, as anybody except a dumb denialist web-site sucker would be aware.

Most power stations are "far from the load" which is why high voltage transmission systems were invented (as any electronic engineer should know - tinkerers might be less aware).

Got any recent roast bird data? Once roasted they should drop out of the sky and produce fairly obvious ground cover, fairly close to the tower.

It would be a fairly dumb bird that kept on flying towards the focus as its feathers began to smoke, but denialist web-sites are targeted at the dumb.

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Bill Sloman, Sydney

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

Not the math that you read on your denialist propaganda web-sites - they ar en't aimed at people who could recognise competent mathematics anyway.

Not that John Larkin has much a of reputation for his mathematical insight. If he had much in the way of mathematical insight he might repost less of Anthony Watts' bilge.

Most power plants get decommissioned eventually - this one is more likely t o get re-engineered as better components come along produced on higher-volu me production lines.

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Bill Sloman, Sydney

There tend to be a rather large number of possible failure modes.

Nothing crazy about the machine - there are several of them around the world, though this one seems to be the first one big enough to store more than a day's worth of energy input.

John Larkin describes his own electronic designs as insanely good, so his punitive attitude to other people's attempt to grab his customers is perhaps an unfortunate expression of self-interest.

Perhaps he's envious because he didn't think of it first.

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Bill Sloman, Sydney

-scale power generating systems- they have to handle large amounts of energ y in a controlled manner, and when the controls fail bad things happen:

777767880

had to have been simultaneously off-target in the SAME WAY to do the indica ted damage.

wer that got torched looks to be pure dumb luck. Also, I wonder if hiking i n the mountains in the background is restricted?

Wattsupwiththat.com is a denialist web-site. Watts himself isn't all that c lever, and the people who write stuff for him are aiming to convince the te rminally ignorant, of whom John Larkin is an unfortunate example, rather th an convince anybody who can do joined-up critical thinking.

The process of filling the media with denialist propaganda is well-funded - the fossil carbon extraction industry seems to spend enough to get their r ubbish into merely right-wing media (where John Larkin can be relied on to find it and repost it).

John Larkin is terminally gullible, and too vain to realise that it is maki ng him look even more like an idiot than the cognitive deficits he was born with.

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Bill Sloman, Sydney

-scale power generating systems- they have to handle large amounts of energ y in a controlled manner, and when the controls fail bad things happen:

777767880

had to have been simultaneously off-target in the SAME WAY to do the indica ted damage.

wer that got torched looks to be pure dumb luck. Also, I wonder if hiking i n the mountains in the background is restricted?

Of course, if Ivanpah does appear to fry more birds than other plants of th e same type, it may be denialist propagandists firing dead birds into the f ocus with a compressed air cannon - not that they'd need to actually need t o get all that close to the focus - if the birds were singed with a blow-to rch before being delivered to a more or less plausible spot on the ground b elow the focus, the propaganda effect would be the same.

John Larkin would never know the difference.

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Bill Sloman, Sydney

The atmosphere is not very stable, for instance refraction moves the sun upwards about 1/2 degree in _average_ at horizon. However, at higher elevations, refraction doesn't make that much problems to burn the tower.

Anyway, some US solar farms calculate the solar track during the previous night and downloads the calculations to the heliostats at night.

Other CSP systems maintain the solar position and broadcasts it to the heliostats, which calculates locally into which position this heliostat should be turned.

From some press releases it appears that it takes a long time (years) to get out the designed power. When building the basement for each mirror, how accurately could this be made ? There might need some aiming adjustment for each mirror. This corrections might been wrong in this case.

Regarding timing errors, this would have created east-west errors, i.e. missing the tower.

The mirrors have a mechanism to turn them horizontally and _keep_ in that position during heavy storms. Is this done with the same controllers and actuators as the accurate, low power solar tracking, is a design decision.

The problem is that PV cost drops faster than the cost of CSP (Concentrated Solar Power), making PV more attractive in the long run.

In addition, CSP requires more or less cloudless skies, not available in all places.

The CSP advantage is that heat can be stored into the night and only then convert it to electricity.

However, as long as the solar production (any type) is less than the daily consumption variations, there is not much need for storage.

Of course. But you would not be trying to catch the sun when it is at the horizon. wouldn't you? The energy output would be very low.

One would think the installation needs to be calibrated, maybe by pointing each mirror in turn and determining the offset between the calculated direction and the actual direction required to beam the reflected sunlight the correct direction. That offset would be the alignment error of each mirror's basement.

As soon as the sun is high enough that one mirror isn't shading the one behind it, output will be pretty much as high as it gets.

The mirrors point half-way between the sun and the tower to reflect the 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 that small.

It would probably be done done one mirror at a time with a sensor stuck on the tower target. Scarcely rocket science.

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Bill Sloman, Sydney

But by then this refraction problem is long gone!

That is what I said.

What makes you think that? The atmosphere is a lens (of a sort) and it will still be bending the sun-beams when the sun is relatively high in the sky. If sunrise is at six, the sun will still be no higher than 45 degrees by nine.

Not precisely what you said, and what you said was less than precise. "Beam the reflected sunlight in the correct direction" is longer and less specific than "a sensor stuck on the tower target".

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Bill Sloman, Sydney

The refraction above a few degrees elevation is much less than the apparent diameter of the sun. And of course it can be incorporated in the calculation of the mirror direction.

By the time the elevation is below 2 or 3 degrees, the effects of the atmospheric refraction are becoming very significant. But then the received energy will be so low that it is probably not worth it to aim the mirrors. (not regarding the problem of shading)

Are you trying a contest against a non-native English speaker? Maybe I should post in Dutch and have you try to make sense of it.

mirrors

the

one behind it, output will be pretty much as high as it gets.

will still be bending the sun-beams when the sun is relatively high in the sky. If sunrise is at six, the sun will still be no higher than 45 degrees by nine.

nt

uck on the tower target. Scarcely rocket science.

Beam the reflected sunlight in the correct direction" is longer and less sp ecific than "a sensor stuck on the tower target".

I can read Dutch without difficulty. My written Dutch is comprehensible, bu t not particularly correct. In 2005 I did try to pass the NT2 staatsexamen programma II on competence in Dutch and while I passed three of the four se ctions (speaking, listening and reading), I just failed written Dutch (499 against a pass mark of 500).

The problem was that nobody wanted me to write Dutch - at the university th e Russian graduate students couldn't read Dutch, and at Haffmans BV the bui tenlandse filialen (foreign associates).

There wasn't anything wrong with your English usage - it's just that "in th e correct direction" is a vaguer and less specific phrase than " a sensor s tuck on the tower target". The defect that I saw was in choice of concepts, not choice of words.

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Bill Sloman, Sydney

But harder to store the heat since it is lower grade heat. The large mirror arrays used in the tower installations generate very high temps so the heat can be stored in molten salt.

I did some digging a while back and found the phase change of coconut oil is just above room temperature and absorbs the heat required to raise the oil by 10 degrees. Hydrocarbons would be a useful heat storage medium for low grade heat, but it takes a *lot* of material to store any truly useful amount of heat.

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Rick C

Well, birds /are/ bird-brained. And it's hard to fly away from something that you can't tell how bright it is, or where.

Anecdote:

I have a 16 x "3W" LED lamp over my desk. No diffuser, it looks something like this:

(This was after a year or two of operation; those used to be generic Alpha brand red hookup wire.)

Every so often, a fly gets buzzing around in here, darting around the lamp and such. When one gets too close to an LED, it gets rather disoriented, or lands and starts walking around similarly aimlessly.

Makes them very easy to squish. :)

If they walk or buzz away from the lamp, they seem to recover in a few seconds.

Tim

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

This would be terrible. O(300,000) mirrors is a lot of wasted setup time.

Likely, a series of orthogonal code patterns are used, leading to O(Lg N) or some such efficiency.

If they aren't simply designed accurate enough in the first place.

Tim

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