Photo Credit Pink Dispatcher
James and I had lunch the other day with Simon Wardley.
During the course of what turned out to be a wide-ranging discussion Simon brought up the topic of flexible solar panels. I was delighted to read today then that Xtreme Energetics and HP are teaming up to produce
a solar energy system designed to generate electricity at twice the efficiency and half the cost of traditional solar panels
According to the piece, XP will use thin-film, transparent transistors developed by HP which are made from readily available materials such as Zinc and Tin – which have the added advantage of not having environmental issues.
Within 24 months, the company will release roof panels integrated with HP’s technology to deliver dramatic energy gains at a comparable price point to conventional PV systems, Colin Williams, CEO of Xtreme Energetics said. “Our panels will be twice as efficient, we’ll be able to deliver a higher energy density, and customers will have the option of choosing a color.”
The fact that the electronics are transparent means that more light gets through and thus the efficiency is further improved.
If these are truly transparent, south-facing windows on buildings could have these applied without significant impact on light entering the building. Ten at times when most energy is needed (sunny days when the aircon is turned up to 11), these transparent PV walls are cranking out the power to cool the building.
It is cheaper peak shaving – I like it.
That’s a great vision (transparent windows that somehow still absorb the light and convert it to power) — but the XP solar cells won’t get it for you. The transparent transistors will, however, allow the electronics layer to not get in the way of the active semiconductor layers which absorb the light. This ought to get you somewhat of a boost in efficiency, and perhaps a cost cut from simpler manufacturing, but isn’t responsible for the factors of two they hype. Those factors seem to come just from the fact that they have a concentrator cell design, which uses relatively smaller semiconductor area, with a lens in front to collect the light. Concentrator cells can be more efficient per $ because they use less of more expensive (and efficient) materials and operate at higher temperatures.
Their announcement looks like of a lot of BS to people who do know a bit about the technical side of photovoltaics and the existing technologies
1. Boost of efficiency (presumably compared to standard polysilicon panels) comes from multijunction cells that are not their own and that the rest of the eindustry is already using. Nothing new here (including hyping in order to dupe gullible investors into a dangerous – and in case of XE a very expensive – early stage round for playing with undeveloped technology based on unsubstantiated claims).
2. There is nothing new about 500x-1000x multijuction cell based panels placed on 2-axis solar trackers for central plant power generation. 20 other companies are doing this already.
3. PV materials cannot be transparent – this would mean they do not absorb light in the visible part of the spectrum which is reponsible for the majority of the electricity generated via the photovoltaic effect. What these people probably mean is that they will use very high concentration ratio allowing them to use high efficiency (again, not their own) cells. However, even if their electronic concentration works on the rooftops – which is yet to be seen after sinking many millions of dollars into this – such cells are WAY too expensive for rooftop installations. Boosting efficiency by a factor of 2 will not help if you are increasing costs by a factor of 8.
Overall a pretty amazing PR exercise.
Skepticism is useful.
Xtreme Energetics (XE) does not make a new improved solar cell. Instead we at XE use best available PV cell technology made by others to improve systemsâ€™ efficiency and to make electricity generation more affordable and attractive. You both are basically correct in saying that XEâ€™s initial concentrator panel is equivalent to what others are already doing when placed on 2-axis mechanical trackers in a central utility configuration. We think that the panelized version of our concentrator will be less lossy, more durable, and at the very least, no more costly than concentrators made from inexpensive mirrors or Fresnel lens.
XE adds real value to existing CPV system design by substituting the concrete, steel, mechanical linkages and inherent costs of todayâ€™s 2-axis mechanical trackers and placing the tracking activity into an opto-electronic layer functionally akin to standard LCD technology. XE can take the canopy of mechanical devices placed in the desert and make them suitable for rooftops, while providing exquisitely fine pointing accuracy to generate slightly more electricity —all at lower system costs and in a smaller footprint. XEâ€™s focus (pun intended) is on improving BOS system efficiency while reducing both installed and operating costsâ€”all with fewer externalities such as parasitic losses, costly transmission lines from remote areas and destruction of pristine natural environments. The good news is that by using HPâ€™s transparent electronics, XEâ€™s panels add functionality, lower systems cost while looking good at the same time.
Our rooftop panels can be integrated into facades, window walls and atriums. Form factors and coloration can vary. The very small area of the panel taken up by the PV concentrator cells use direct light. The balance of unused light, that is the indirect light, can either be passed through the panel to a structureâ€™s interior or reflected back on the off-axis as color and texture printed on the upper surface of the bottom of the panel. The proportion of direct versus indirect light varies by latitude and local climatic conditions.
When the indirect light is passed through, the panel appears semi-transparent, providing only slightly blurred images and filtered brightness, in much the same way a window screen does. The UV coating and thermal management properties of the panel will reduce interior damage and limit heat gain allowing for reduced cooling costs.
Solar panels no longer need to be shiny, blue, black or murky in between colors. McDonalds can maintain its red roof faÃ§ade and still generate the most electricity within their limited parking and buildingâ€™s structural area. XEâ€™s goal is to provide an architecturally appealing, extremely customizable and high efficiency panel that is truly integrated into a buildingâ€™s design.
To be accurate, XEâ€™s panel will yield between 2-3 times the energy at about the same or slightly lower unit area cost than the average of standard Si panels mounted on the roof today. XE expects to field urban sited rooftop panels that are half the cost and slightly more efficient than standard CPV central utility plants. The companiesâ€™ rooftop products also beat any low concentration panel as well; being all solid-state, having relatively low weight and due to their thin design they can literally be laid flat on a commercial rooftop. No tilt mounting is required, although tilt-mounting can produce slightly more electricity (at more cost).
Itâ€™s great to be dubious of claims for proposed products that have yet to be extensively field tested. Yet, use your skepticism to ask questions like this one: Why would a major company like HP back an unknown start-up like Xtreme Energetics with a major new technology? The reasonable answer is that HP vetted XEâ€™s claims first before it agreed to license its technology.
Skepticism is goodâ€¦so keep asking questions.
Barry, you are in the wrong profession. You should have been a poet.
The fact that HP participated in your PR exercise – nay, made their own of it – means nothing. For all I know, this could have been their attempt to offload the transparent transistor technology – possibly a useless one developed God knows why and being in search of application – onto a startup involved in the much hyped solar industry. If it is so good for solar why did not HP do it themselves? Certainly another 5 million bucks is not a problem for them. As you have alredy confirmed all non-HP technologies used in your products are of the shelf… Your claim for fame remains utterly unsubstantiated by the HP PR hype.
I am however glad that you agree that the first of your 2 products – panel using 3rd party multijunction cells and placed on a 2-axis tracker – is nothing new. Your unsubstantiated claim that it will be less lossy and more durable than the already highly efficient and durable products from the likes of SolFocus and Concentrix who have spent a long time and tens of millions developing and marketing this technology – is futile and certainly is not a valid raison d’etre for another late-coming startup in this area. The fact that you have optics made of transparent transistors means nothing in this application where the optics needs to be dumb and fixed.
As to your residential rooftop panel products – again, hat off for your ingenuous mixing of facts in your pitch that have nothing to do with your advantages, if any. For example, the cause of removing transmission losses is very well served by ANY rooftop solar panel, including the ubiquitous polysilicon ones.
Using the standard multijunction cells you CANNOT yield 3 times more power per panel unit area than the ubiquitous solar panels unless the PV elements are constantly physically rotating so as to track and be constantly perpendicular to the sunlight (which is not true for your rooftop panel). Therefore your panel will suffer from multiplication of its output by the cosine of the sunlight incidence angle, just like any other fixed panel, transistors or not. Not to mention again the fact that the multijunction cells are awfully expensive compared to polysilicon. So your panels will be much more expensive than the standard ones in terms of cost per Watt.
You say you can lay your panels on the roof at any angle – no advantage here, so can other manufacturers. In this case your and their panels will suffer from exactly the same multiplication by the same even lower cosine value…
You claim that you will reduce cooling costs – very clever. Except the existing rooftop solar panels are not cooled at all… You mean you will ADD cooling costs where there currently are not any.
Trust me, the list goes on but hey! You are a poet, I am an engineer. So if somebody gives you 5 million bucks for your poem and is left holding the bag, at least he can get his money’s worth from the poetic value of your pitch. Doubts? Skepticism? You must be kidding!
laser guru says
Reading this from the outside it sounds liek tow 6th graders arguing about whether the Yankeesa re a better tema than the RedSox.
Can’t we just hold off the vitriol until there are some field tests?
Isn’t there enought crap being thrown around? Reminds me of the solar hot water fracas 25 years ago. I put up three LO-TECh panels on a roof top in the wood sin PA, and for the next TWENTY TWO YEARS, I got free hot water whenver the sun shone!
dis I acheive parity with the grid? Who gives a S**T!!! The fact is that no one belived our electric bills when we sold the house, because the ywer so low!
ANY solar panel is better than none, just remember that while you are hurling uselss spears at each other. Time to get TO WORK, dammmit!!!