
Will a Breakthrough Solar Technology See the Light of Day? - codexjourneys
http://www.technologyreview.com/featuredstory/531756/will-a-breakthrough-solar-technology-see-the-light-of-day/
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jacquesm
Anything requiring tracking is not going to be competitive with regular solar
cells for simple mathematical reasons so I suspect this is not quite as
breakthrough as the title makes it seem. In a nutshell: if you add the cost of
lenses+tracking system you could buy more panels. That increased number of
(passive) panels will be more reliable and will produce roughly about as much
power as a non-tracking system would. The increased reliability is something
very much valued in power generation, it also makes shading calculations and
effects much less of a problem.

Depending on how expensive the ground is and what other restrictions apply
you're going to be be _usually_ better off by installing a passive system.

I've built a solar system with trackers, 2x8 panels, in the end I wished I'd
gone for a stationary setup, the tracking was always troublesome (you need
_two_ axis tracking if you're going to utilize tracking to maximum effect, the
lens system shown will definitely need two axis) and in the end produced only
about 15 to 20% more power on these panels, and cost so much to set up and
maintain that I could have bought another 8 panels and a rigid setup for the
same money instead.

~~~
bainsfather
One advantage of tracking systems is that they provide a more uniform power
output over the day. You get higher power morning and evening. For off-grid
systems this seems very useful. Also, there was a news story recently about
the German grid having problems with load balancing - apparently they want to
put panels on west and east facing roofs to try and get a more even load
throughout the day.

I guess that as panels get cheaper, it might be best to have static panels
facing East, South, and West. Have we got to that stage yet, where this is
cheaper than the moving parts?

About your trackers - do you have any more info? Why did you go for 2-axis
rather than 1 tilted axis? Were your problems due to inexperience/teething-
troubles, or would you have the same issues if you were to do another system?
I'd be interested to hear you experiences, thanks.

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jacquesm
You still would not put panels facing East, South and West, you'd _still_
install those facing South at the 12:00 position.

2 axis because the seasonal offset component got thrown in for free with the
system I bought. It was quite thoroughly tested in the field before I bought
two trackers, they work but the fact that you need a single post and the
resulting forces on the foundation (in clay) caused a ton of issues (we were
in a very windy area), the tracker mechanism had trouble with ice formation in
winter (Rural Northern Ontario) and the repeated movement put extra strain on
the wiring, especially at temperatures far below 0.

As for variance, you're right that tracking systems provide more uniform power
but most (if not all) solar farms are installed from a power produced /
capital expense viewpoint, uniformity of output is currently not worth much.

~~~
bainsfather
Thanks for the info. Seems it was bought system, single titled axis, and the
tilt could be changed manually for winter vs summer?

Those large-area single-post setups do look unsuitable for windy regions.

My static solar panels do follow a rough sine shape through the day. Clear
sunny mornings or evenings I get very little power - 2 sin(0) is still zero
[a], whilst generating surplus power at midday is not much use to me. I think
[b] additional panels sited e.g. SE and SW might save me more money than
additional panels facing south, as then supply would tend to match my demand
better.

[a] I still get the 10% or so from atmospherically scattered sunlight.

[b] As you can see, I don't really know. e.g. how much extra atmospheric
absorption is there near sunrise/sunset on average etc.

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crdoconnor
>With fields of over 1,000 of these devices, utilities would produce
electricity at less than 5 cents per kilowatt-hour. That is even cheaper than
today’s least expensive option: a new natural gas plant.

Ummm...

[https://www.greentechmedia.com/articles/read/xcel-energy-
buy...](https://www.greentechmedia.com/articles/read/xcel-energy-buys-utility-
scale-solar-for-less-than-natural-gas)

Natural Gas is ALSO in the midst of an unsustainable boom built with insane
levels of debt: [http://www.bloomberg.com/news/2014-04-30/shale-drillers-
feas...](http://www.bloomberg.com/news/2014-04-30/shale-drillers-feast-on-
junk-debt-to-say-on-treadmill.html)

Anybody who thinks natural gas is going to stay cheap forever, or even for
more than a couple of years is kidding themselves. It's an awful long term
investment even if you don't account for the environmental damage.

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alexthornton
I am curious how they generated their cost estimate. Hardware costs have
already come down so significantly in the past few years, non-hardware costs
(aka soft costs in the solar industry) now represent around 2/3 of the total
installed costs. Soft costs include installation and maintenance, which
precise tracker systems would increase over the traditional fixed PV array.
Hardware cost reductions are probably not hitting the low hanging fruit of
solar power costs.

[http://www.nrel.gov/news/press/2013/5306.html](http://www.nrel.gov/news/press/2013/5306.html)

Another factor to consider with concentrated solar is that it is more likely
to be affected by soiling (ie, dust, bird poop and other particulate) issues
than traditional PV. This would mean even more cleaning and maintenance adding
more to the soft costs. Soiling is a fairly common problem in areas with lots
of sun and little rain.

[http://www1.eere.energy.gov/solar/pdfs/pvmrw2011_19_cpv_wint...](http://www1.eere.energy.gov/solar/pdfs/pvmrw2011_19_cpv_winter.pdf)

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zackmorris
This is true, I was going to post a similar comment. So one thing to consider
is that the way we incorporate solar and other alternatives into our society
and economy is incorrect. We should be adding it to all new construction, as
it would not significantly increase costs like retrofits do.

Also simple design decisions like giving a building the proper orientation
with the sun, choosing deeper crawlspaces, using white roofs, using dual pane
windows, choosing swamp coolers or ground loop heat pumps over air
conditioning, and going with ductless/non-centralized climate control can
eliminate the majority of utility costs. Amortized, these initial costs appear
as savings because the payback is only a couple of years today. The only truly
expensive components (windows and heat pumps) would be readily affordable with
subsidies, because the government is in it for the long haul. Homes are being
built in Germany that are completely off the grid. They only have small wall
units in each room for emergency heating, but are otherwise insulated well
enough that the home is room temperature year-round.

In fact, to get to the point of all this, alternative energy and wisdom in
construction is already significantly cheaper in the long term than the status
quo. But incentives and building code regulation is being blocked at every
turn by the fossil fuel industry, and by libertarians who unwittingly support
it by taking the short view on spending and ignoring amortization or return on
investment, offsetting the opportunity cost of inaction onto the public and
environment. There is an argument for freedom here (that we should be able to
build however we want), and I sympathize with that as a resident of the red
state of Idaho, but there is no economic one. We passed that point about 10
years ago when wind and solar installs started going up exponentially around
the world, but we chose to have a military presence in oil-rich countries
instead.

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lordnacho
Even if this particular entity doesn't make it, the people involved will have
learned things that will be useful for future firms. It's not just financial
capital that needs to be efficiently allocated.

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chrisBob
Have any companies explored fixed, or movable mirrors as a simple way to
maximize the light on the panels? Since mirrors are much lower cost than the
panels I am surprised that no one faces the PV system away from the sun, and
then points 3 mirrors at each panel. In places that aren't space constrained
this seems like a much more efficient approach.

We have a heliostat for a piece of artwork [1] that keeps the sun hitting the
same spot with only slight variations in angle over the year, and it only
requires a single motor and gear train.

I am aware that the solar furnace type systems all use mirrors, but I haven't
seen any PV systems that use this approach.

[1]
[http://www.janetsaadcook.com/BU/BU-1.htm#BUarc](http://www.janetsaadcook.com/BU/BU-1.htm#BUarc)

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jacquesm
We built a prototype to do just that:

[http://pics.camarades.com/v/jacques/renewables/concentrator/](http://pics.camarades.com/v/jacques/renewables/concentrator/)

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yessql
Yeah, this "breakthrough" has the potential to one day to produce electricity
at a cost that conventional PV already delivers.

[http://www.greentechmedia.com/articles/read/Austin-Energy-
Sw...](http://www.greentechmedia.com/articles/read/Austin-Energy-Switches-
From-SunEdison-to-Recurrent-For-5-Cent-Solar)

I would never bet on CSP.

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transfire
So those 250% tariffs on Chinese solar panels have really worked out for us,
right!?

The whole energy sector is so frack'd. Oil cartels periodically drop prices
precipitously to drive competition out of the market. They pay off Federal
politicians to create 250% tariffs, and State politicians to outlaw the the
sale of electric cars direct to customers and make it illegal to use your
solar cells during power outages. Oh, the irony of "free market" Republicans
passing all these things. Our clueless president dumps billions into an
obvious boondoggle designed to undermine the solar market, while real
breakthroughs wither on the vine.

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wyager
> the irony of "free market" Republicans

> Our clueless president

While I agree with the sentiment, it is important to emphasize that
protectionist policy and bribery is not limited to any one political party.

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Johnythree
There is another factor with Tracking:

You size your array to cope with poor conditions, not best conditions.

Worst conditions are when it's overcast, and not surprisingly the best
alignment then is pointing straight up.

So there is a argument that pointing straight up, actually gives more power
when it's needed (which would make trackers redundant).

I have two sets of panels: One is mounted at the approved angle, while the
other is flat on the roof. The flat ones actually seem to do better in the
winter.

I guess it depends very much on the seasons at your location.

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Shivetya
If the technology is so break through I am pretty sure it would be snatched
up. While many technologies sound break through they are only such until
someone with expertise gets in there and starts to pull back the layers.

There of course is that one glaring issue of, if an inferior tech is many
times cheaper your break through will have to be many times more significant.

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pankajdoharey
Damn! You China.

