Concentrated Photo Voltaic, a Primer for non-techie types that will get you up to speed fast!

It’s May day, You have just hours before you go to Dinner with your Spouse and a leading expert in the Field of CPV, what will you read in order to at least act half way interested, and perhaps even engage him in a conversation about his technology and interests?  You know he has no interest in sports, or what hollywood does, it’s going to be a long and awkward evening less you take a few minutes to prepare.

I suggest you read along, it’s a short read, but it does require you look at a few webpages, but I promise it will be near painless.

If you are old enough, you’ll remember the round head lights we had in cars for so many years. The lights were called sealed beams and they concentrated the light from the element and focused it into a specified area. The sealed Beam head lights used in Autos are noteworthy because they worked so well AND they ‘concentrated’ light just like a CPV system does. 

I’m not sure when it was, but somewhere in the 80s, the Automotive Engineers had a better idea, maybe it was style driven, maybe some of the Engineers who were after superior aerodynamics liked them as well, but no matter how few or how many reasons, the newer units took over.  The glass enclosure now had an opening in the back, and there was a smaller light bulb that could be pulled out the back and replaced when it was bad.

It took only a bit of time for people to realize the downside of these new lighting units, a rock chip could and did break the seal of the enclosure, and when you pulled into your drive at night and turned off the key, the light would cool and often drew in moist air. The next morning when the air temp picked up a bit, the moisture inside the head light enclosure would condense and make a soup of sorts. This could lead to growing a culture of algae like green, red, and might even help remove that few microns thick of shiny stuff on the back called a reflector.

Soon, a lot of folks were driving down the road thinking they’re going blind, some checked in with their car mechanics and found that the lighting enclosure had been compromised and needed to be replaced because it no longer concentrated enough light for one to safely see at night  The Owner often said OK, replace them, call me when you’re done.

This lead to owners going into shock when they were presented with a $300 plus bill (in the 80s remember). The  new enclosures were $120 and up each, and that didn’t include installation, or the new light bulb. They were expensive for a reason, part of it was they were sealed from the elements that can and do destroy or rapidly degrade the reflective elements that concentrate the light.

This caused a lot of people to think about what they had lost with the old system, as it was just a few dollars for the entire unit, and they were quick and easy to replace.  The first aftermarket plastic covers came out to snap over the head lights to save you from rock chips that were VERY common. The plastic got dirty, the sand and grit wore the surface and cut the light transmission, they aged in the Sunlight and turned yellow too.  Soon, people couldn’t see again, and thought they were going blind.

There was another problem, after some years, the plastic holder for the light bulb wore, and so did the O ring, when it started to leak, you could bring in the moist air, and foul or lose your internal reflector coating by growing a culture inside. I personally know people who do not drive at night anymore than they have too, it scares them, and they think it’s their failing vision, hard to convince them their concentrating system has degraded to the point of being dangerous.   

All of this is a lesson that it takes a while for a concentrating light unit like I describe to show us both the advantages and disadvantages, and there is no doubt in my mind that this new system added to the cost of car ownership.

The discussion of concentrating light beams is about lenses, mirrors, and little more, it can work well WHEN the environment is sealed and moisture, dust and dirt have no chance to get in. Of course what one man calls sealed, another won’t and the discussion can get down to “sealed for how long?” then, we get into the lens material, there’s glass, and many types of plastic, some plastics are wonders, and they stay fairly clear for years, and the biggest problem comes when they aren’t cleaned with the utmost care. If they’re loaded up with sandy grit and you attempt to rub them clean with a dry rag, it can turn ugly. Not only have you scratched the surface, but you may have made it toothy to the point where bacteria can set up housekeeping and further impede light transmission. Glass sounds like a great choice, but what about 50 MPH winds and dust storms?

In concentrated PV, we have the same issues as we do with a common auto head light, only we multiply any problem with degradation of the light transmission path 10,000 times or more from a maintenance point of view.

In concentrated PV, we have the same issue with pointing  the CPV panel at our light source, it’s reverse of pointing our light source in the direction of travel, but very similar. In the car, we turn the steering wheel, in CPV, we have electronics that know where the sun is, and make use of gears, hydraulics, servos, or a number of other parts to make sure the sun is aligned accurately with the lens, and concentration elements, when this doesn’t happen, no electricity is made.

There’s other automotive data you might consider. People here in Washington State who commute daily over our mountain passes are normally forced to replace their windshields annually. This is because they can become so sandblasted that they are literally dangerous. What is it like in areas where CPV is deployed? Wind speeds, driven sand and dust?

This is all about light being able to get through a lens, or a clear cover, and how reflectors degrade, in autos, they degraded far more rapidly than some thought. How will the Concentrator elements in the CPV systems perform, and what problems might already be showing up in Hatch for instance Does anybody care to know?

Now it’s time for you to do a few web searches, it’s all so easy, and we’ll assume you use google since most do.

Now that you have a little back ground, just hold the analogy of a rifle scope, all is well when you have the scope on the cross hairs, all is in focus, lenses are clean, and the solar cell is working of course.

If you do a few more google searches, there’s little chance you won’t run across this site

Why not use the touted leader for our study? We form the questions you’ll entertain your expert with. We know we don’t have the answers, but decent questions will allow us to express some interest in the topic.   

Potential questions follow:

Hey, I ‘ve seen the Las Vegas Sun has been covering Amonix all along, and isn’t it great we have those huge deployments in Alamosa Colorado and Hatch New Mexico! What I’m curious about is why they all of a sudden dropped the Coverage of Amonix just when they have something to show off?

I hear the wind blows pretty hard in Hatch New Mexico, and the air is so full of sand, dirt, and grit, this ought to be a great place to prove how well the product is doing, how do we find out? Are these solar modules holding up well, how many have they had to replace?  Any wind damage? I’ll bet the whole CPV community is discussing this somewhere, where do we find the conversation?

Hey, when is the factory in Las Vegas going to roll out the next batch of product? I see the Los Vegas Sun hasn’t said a word about Amonix since they announced all the job layoffs there, what’s up with that?

Amonix, the leader in CPV, and with enough trackers in the field to prove just how good they are. This is a fact as far as I can access.

Let’s look over this claim:

No water used for cooling, impressive savings? Do we really save a valuable resource?

More questions for our Professionals, and maybe we go right back to the Automotive World and look for analogies?  CPV is a power plant, so are air cooled engines and water cooled engines, have you ever seen an air cooled engine maker advertise that they are saving a valuable resource by avoiding the use of a water cooled engine?

I think the average man or woman notices there’s no garden hose hooked to the car, and perhaps there’s very little water in the cooling loop, and not so much of a loss, it does beg thinking people to ask, just what group of people was this page designed for? It’s not an answer, just another question for our professional.

Of course this leads to more questions, and that is, we know that near all of the automotive industry has adopted the water cooled engine, and now we see that the majority of motorcycles have gone that way. The whole point is to carry off waste heat, and allow the machine to operate at a more ideal temperature. We learn from the WIKI page that heat is a problem with efficiency, and by cooling the CPV modules we can increase efficiency.

This leads to another question we ask our professional. Isn’t the whole idea of a CPV system that it is more efficient? If this is true why is the problem in the CPV different than in the automotive engines, and why have the Automotive engineers who have been dealing with the problems of carrying off excess heat to assure both efficiency and longevity of their equipment finding water or liquid cooling the more ideal answer?

Isn’t the problem exactly the same? Shouldn’t the CPV engineers recognize the automotive Engineers have about 130 years of experience in optimizing their cooling systems, AND have given up on what Amonix has deployed in their current tracker?

I remember sitting in a 1976 Fiat, and I noticed they had used some optical fibers to actually report on whether the head lights were on, innovative I thought, a different approach, but who could argue the stake holder (the one behind the wheel) could tell both lights were working.

This creates more questions for us:

How automated is the leader in the field? How do you know if a module has over heated and burned out, or is not performing as we expect? Is there any remote way of telling if a cell is bad, and how much effort does it take to get to the cell and replace it?

Do we break any seals getting  in and out to replace it? Do we need wait till the blowing dust and dirt stops to do it?

Where is the group of people who care what the actual performance of these panels are? If the US Government has given any incentives at all to Amonix or those who bought and deployed the product, should we Citizens enjoy the privilege of learning how they are working in the field?

Why is it that EVERY Green Energy Site I can find looks more like a place to market Green Energy, and not to discuss the technical merits of the product?

I’m sure the DOE has the results of this deployment at Hatch for instance. do we have any right to know?

added 5/8/2012: I see the NREL has posted comments on Amonix, here’s an example:

Cost savings were factored in every step of the way — from foundry to grid — said Bob McConnell, who worked at NREL before he left the lab in 2007 to join Amonix and help bring the research to market.

The result is a generator manufactured at about a third to one half of generators using crystalline silicon or thin-film approaches.

Multi-junction cells can operate at higher ambient temperatures than traditional PV cells, making them ideal for sunny and dry climates in the southwestern United States, and ripe for future cost reductions.

The concentrator also is kinder to the environment than most large systems, using no water in its operation. Propped up two feet above the land, it doesn’t hinder the movement of wildlife.

“You simply can’t put enough solar systems on rooftops to achieve the scale and capacity necessary to generate electricity in the quantities required by utilities and by society,” said Amonix’s founder and chief technical officer, Vahan Garboushian. “This is a technology that can meet the terawatt (trillions of watts) needs of the world for clean electricity.”

As we attempt to digest what the NREL writes here, does it seem the relationship is a little like a marriage between first cousins? I mean the mention of the water savings again.. just how much water do you save in a closed loop glycol system? And don’t we know there would be a lot of consideration to using a lifetime waterless coolant as well. Some who read this will see it more as an advertisement. I think it might cause some of us to question the NREL’s mission.. but hey, I only have the questions here.. not the answers..    











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17 Responses to Concentrated Photo Voltaic, a Primer for non-techie types that will get you up to speed fast!

  1. You provide some very good questions and point out some of the many challenges with CPV. Before starting SolFocus, we spent a long time studying what had been tried in the past, and where the failure points were. We employed TRIZ, looking at the semiconductor and auto industries for both cost and reliability issues. SolFocus is the only HCPV company to use reflective versus refractive optics. To address the issue of pointing accuracy, as is needed with a telescope, we exploit non-imaging optics. This gives us a sizable error budget for relaxed manufacturing tolerances and a very large acceptance angle. As such, our manufacturing is more like headlamps than telescopes with regard to cost and yield, and system performance is higher as strong winds do not cause loss in power output. Our factory automation was designed by automotive automation firms, there are videos online of the process. Passive cooling is more than adequate for these cells as at the worst conditions, they only lose ~ 3% overall efficiency and reach less than half the temperature they operate in space. Contrast this to a high efficiency silicon panel, where the wafers are sandwiched between insulating Tedlar and glass, and efficiency drops as much as 30% in hot climates. The tempered glass and aluminum used in SolFocus panels survives all hail and sand tests. We do care about performance, offering the only 25 year performance guarantee, backed by Munich RE.

  2. Bill knighton says:

    But commodity flat panels work great and their cost is dropping like electronics. What about concentrating talent on installations so that dollar a watt panels don’t cost a large multiple of dollar a watt when installed.

  3. George B. says:

    Somewhere, there’s information to be found that’s more than marketing hype and fishing for subsidies…

  4. Bill Knighton says:

    What’s so satisfying about pvs is their simplicity and it seems a shame to mess with it by adding more stuff, especially if it moves.
    In the far future if car engines were to attain the same degree of perfection as pvs have today we would see engines made of crystallized earth with no moving parts that somehow push us around town. I sure hope nobody would try to hang fan belts and radiators and transmissions on such.
    It would be nice to appreciate today’s pv technology for the magic it is and realize what a privilege we have in being able to acquire it at an ever decreasing price. And then understand that as gimmcks are attached to it a lot of damage is being done to the image of pv and renewables. Short term gain for the purveyors is being paid for by the tax payers and taken out of funding and reputation in what could be real solar industry.
    I will not argue for government funding of renewables, regulation, education, war or anything else that could be named. But if the billions spent on failure had been spent on run of the mill pv installations with highly disciplined vendors we could at least have 10s of billions of watt hours being produced each sunny day. By disciplined I mean $1.50 a watt where panels can be had for $1/watt at retail.

    • George B. says:

      The STUDY of Amonix is rather amazing because it contains a story so deserving of a technical conversation. A massive deployment, millions of dollars spent, where’s the story abotu how well it’s working in the field?

  5. Bill knighton says:

    Here is an argument that government has little role to play. Consider governement investments in small scale solar. There are people getting 40 or more cents per kwhr for buy back. What is the purpose? They know the feeble amount of energy coming from a fraction of a percent of users will not dent carbon emissions. Another argument might be that it exercises the pv industry. But that industry was already strong and on a declining cost curve that was briefly reversed by germany’s mal-investment in grid tie subsidies. A gold rush of people with money trying to make money and not solving any power supply issues, unless raising the price is the goal. A million or a billion solar roofs for on-gridders would accomplish a world of undiscipined power users who use the utilities and their conventional fuels as a free “battery”. Some others would have to pay for all of it. Quotes on battery. It’s the term that grid ties like to use but what could they possibly mean? It does not get stored. Ever. All the conflicting contradicting actions look just the same in roof scale or utility scale. The lesson is that off grid solar works great because the person doing the spending is the person using the power and they make their production curve and their consumption curve meet in the way of the free market. It is just not possible to have a third party make that happen for you. These socialist methods make it possible to enbiggen ruling class weath but can never make more pie. But if global carbon emissions are the topic then who cares if a small group gets more green when the whole does not see an improvement.

    • I certainly agree with the socialist methods, they should have been stopped for fossil fuels a long time ago. California banned smoking in public places because the insurance companies tallied the cost and were set to pass them on. This in turn increased the cost of a pack of cigarettes from 50 cents to five dollars. If you were to add the cost of health effects, military (the 6th fleet costs one Solyndra every two weeks to stay in Bahrain, we’re not there for their freedom), lost natural resources of the other kind, and more, gasoline would be $15 a gallon and coal cost-prohibitive. Nuclear receives over $2/W, just for permitting, not to mention the government (tax payers) insurance and storage of waste. A decent treatise on the subject of energy subsidies can be found in “What Would Jefferson Do?” by Pfund & Healy.
      Beyond those in clean-tech that are milking the subsidies, the actual contributors are making little, yet the cost of installed solar has already fallen from $9/W in 2004 to just $3/W today. Don’t get me wrong, I like nuclear energy, just prefer the fusion variety with the reactor 93 million miles away. As to the subsidies, I think we all would prefer a level playing field.

      • George B. says:

        Until we are smart enough to get rid of the career politician, there will be a lot of corruption in energy period. Alternative energy has become so twisted we Washingtoians are now paying wind farms NOT to produce! As for the Solar Industry, most all the discussions I find about commercial scale developments end right when the real story should begin, and that is, what are the real production figures for the specific Installation? Since tax payers pay the subsidies and in my state are even forced to pay higher electrical rates too, the books should be open, and we should know the installed cost per KWH, and the actual production figures per month.

        If people want to invest their own money, let them. When you do it with the public treasury, you need an open book. Do spend some time on the net, and notice the story usually ends once the stuff is installed. It reminds me of the story of the Titanic, if it were solar PV gear of our day, the story would end right after they launched it!

        I read in one of the blogs that monkeynuts Inc. just built 600 jiga watts of panels, and the installation is now complete… duh.. end of story… I’m beginning to think these solar bloggers are all so high on weed, they don’t have the energy to do more than repost the propaganda sent to them. I wonder if they get paid well to post it? I did find one guy that actually drove by an install and took pictures, wow, they’re really there…but do they work? No one seems to know or care.

      • George B. says:

        Gary, I’ve heard it all before, and you and I both know that a bottle of Ketchup is nothing more than a bottle of poison! There’s a blogger who lived under a well developed system similiar to California, the leadership knew about these things, and quickly put in place a system to encourage people to do the right thing.. Here is her post

  6. Bill knighton says:

    I like the fusion reactor 93 million miles away idea. A problem that gets mentioned for commercial fusion is how will materials take the beating of hundred million degree plasma. Even if the magnetic field keeps it in a torus there’s blistering emissions that have to be captured by mortal materials. The answer is have your fusion 93 million miles away and your collector material is only a dollar a watt.
    But I don’t understand the level playing field. Oil, for example gets a negative subsidy. I don’t know exactly what subsidies you mean for oil and I don’t want to promote an argument as yours. The popular arguments I hear for oil subsidies from other sources are two and can be rejected. One is that drilling and exploration expensing is a subsidy. In no other business endeavor are expenses begrudged by the public that way. Of course exploration and whatever else it takes are deductible. We are only taxed on profits. That’s not subsidy. The other disposable argument is that the cost of wars whose motivation is popularly percieved as something to do with oil is a subsidy. But its actually the opposite. The free market, the slave market, whatever market they all like to provide us with cheap oil. Saddam hussein loved selling us his oil. It didn’t take a war to get it. The wars only disrupted the supplies and drove up prices. Just as anti-Iranian bullying is promoting market jitters and screwing with prices, all wars raise the price of oil. They even consume a bunch and raise the price.
    I might misunderstand the part about nuclear regulation as subsides but I will react to it as if you are saying that compensating a highly regulated industry for the cost a regulation is a subsidy. That seems cruel. Like calling a victim of rape a slut. If the collective feels there is some huge collective interest in squashing an industry with regulation it seems reasonable that the collective should pay for it, not the industry being squashed. It’s been about 20-30 years since they started a new plant so it’s fair to say they are being squashed. The price for a gigwatt plant went from less than 500 million to over 9 billion through regulation. And they have absorbed that cost pretty well. Seems like they should have walked away long ago.
    If a level playing field in these terms were accomished we could expect to see pv costs skyrocket as their fabs were bombed and embargoed. We would see 10 year delays in permitting. We would see the rig they did in new York where a complete nuclear power plant was bullt and paid for but never allowed to start and make back 1 penny.

  7. Bill knighton says:

    I think the level playing field is a dangerous idea. What makes for a tilted playing field to begin with? Someone has to have hands on your necessities to make an unfair field. Who can do that? The markets act like water flooding a rough terrain as their rivulets successfully find the easy path. Only government can tamper with that. The answer proposed is government level the playing field that government tilted. A better answer would be that government stop tilting the playing field.
    I did like what you said about the cost of a battle fleet being a failed solar project worth of waste every two weeks. I agree. If all that stolen money were freed for investment by its rightful owners it would be better spent.

  8. Bill knighton says:

    What does that mean about ketchup? It’s amazingly useful, tasty and filled with good ingredients. It’ gets an undeserved reputation.

    • George B. says:

      Bill, Where you been? You need more government in your life! Ketchup has enough salt in it to kill a healthy horse! but don’t worry, the new healthcare program will have that off your table in no time.

  9. Bill Knighton says:

    Only very slightly related to the op, here is a story about the 820 MW long island nuclear plant that was completed at a cost of 6 billion in 1984 but never run at more than a 5% validation because of another person named Nora. But in 2004 they put up two 100 foot wind turbines on the site. res=9A05E5DC1338F932A35753C1A9629C8B63

    They did put in two 50 MW gas turbines about a decade after abandonment. The 100 foot windmills came a few years later.

    Here is the story of Nora.

    Rate payers of Long Island have a 3 percent surcharge added to their bills for 30 years because the public bought the stillborn plant. Also, during 11 years of construction the government decided the plant would have to pay the same taxes as if it were in operation. 600 million. Since it was never allowed to be turned on it was decided that those taxes should be refunded to the operator. But it was decided that would harsh, so less than half those taxes are to be returned. The rate payers of long island are paying that over 26.5 years.
    Here is the explanation for the tax:
    Why was a tax collected before the Shoreham Plant was operational?
    It was and continues to be common practice for utilities to begin paying assessments on plant valuation as if the plant is operational based on the assumption that any plant once approved and under construction will result in a useful operating asset. It is a way for the utility to demonstrate its commitment to the community in which the plant is located.

    • George B. says:

      What makes your addition relevant is the government is quick to saddle the public with every kind of debt, and many will even petition their elected leaders to wear the saddle!

  10. Bill Knighton says:

    Q. What did socialists use for light before candles?
    A. Electricity.

  11. Bill Knighton says:

    Corrected link to story of feeble turbines added at shorham site.

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