
Solar Industry's Future Lies in Lightweight Technology - vaultcool
https://www.scientificamerican.com/article/solar-industrys-future-lies-in-lightweight-technology/
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jpm_sd
Odd choice to feature Project Loon in the banner image. I designed the solar
array for Loon, it's built from plain old mono crystalline silicon cells.
Sure, they're high efficiency cells, in a lightweight plastic stack up (no
glass), but there's no exotic thin film cell technology in there. The options
(so far) are either too expensive, or too inefficient.

~~~
yazr
Are these the space-grade multi-junction panels? Are the Loon panels size-
constrained or cost-constrained ?

The article itself is odd - most PV will go to utility and commercial scale.
Even on rooftop, aesthetics are possibly down the list after durability,
reliability, efficiency and cost.

~~~
walrus01
From the photos I've seen, no, they are not using triple junction GaAs cells.
Boeing/spectrolab cells are incredibly expensive. They used high efficiency
156mm monocrystalline silicon cells. Just not in a glass + aluminum frame like
you'd see on a roof.

edit: at least in 2013 they were using thin film amorphous silicon, or what
appears to be CdTe thin film flexible, not rigid cells encapsulated in clear
lightweight membrane.

[https://www.wired.com/images_blogs/business/2013/06/20130609...](https://www.wired.com/images_blogs/business/2013/06/20130609-3B6B2491-660x439.jpg)

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spenrose
This appears to be the source paper:
[https://www.nature.com/articles/s41560-018-0258-1](https://www.nature.com/articles/s41560-018-0258-1)

... and NREL press release: [https://www.nrel.gov/news/press/2018/nrel-
identifies-where-n...](https://www.nrel.gov/news/press/2018/nrel-identifies-
where-new-solar-technologies-can-be-flexible.html)

~~~
agumonkey
nrel is full of super interesting reports, such as EV efficiency and
projections

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walrus01
This article seems to make the point that lightweight thin film photovoltaics
are the future. I'll offer a counterpoint:

Massive economies of scale and automation are the future for PV. Using
standard 60 and 72 cell polycrystalline and monocrystalline silicon cells.
It's already not uncommon to see 5 to 10 megawatt sized ground mount PV
systems.

Getting the $ per STC watt lower for panels is key. Having quick to build, low
cost and efficient ground mount systems is an important part of it.

Things will be very different economically when a 360W, 72 cell panel I can
buy now at $0.58/W is more like $0.22/W.

Battery storage is the other important part. The technological problem of
generating enough watthours in one day is SOLVED. Storing and using it
consistently 24x7 is now the hard part.

~~~
llukas
> Storing and using it consistently 24x7 is now the hard part.

Is it really? [https://pv-magazine-usa.com/2018/03/01/12-hours-energy-
stora...](https://pv-magazine-usa.com/2018/03/01/12-hours-energy-
storage-80-percent-wind-solar/)

edit: added quote from parent

~~~
walrus01
It's not so much that it's hard technologically, as the Tesla massive battery
system in Australia has recently proven, but to do on a REALLY huge scale at
an economical $ per kWh cost, and the lifecycle cost of the batteries. When
compared to current non-carbon-producing energy sources like big hydroelectric
dams, big pumped-storage hydroelectric.

[https://reneweconomy.com.au/tesla-big-battery-turns-one-
cele...](https://reneweconomy.com.au/tesla-big-battery-turns-one-
celebrates-50-million-in-grid-savings-95920/)

Every few months I see some big press release and tech press media hype about
liquid metal batteries and flow batteries, I've yet to see something useful
that has a market price beyond "contact us for more details".

It seems to mostly be all test and evaluation installs on a small scale so
far.

[https://www.seattletimes.com/seattle-news/pullman-project-
te...](https://www.seattletimes.com/seattle-news/pullman-project-testing-huge-
batteries-to-store-energy-2/)

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sys_64738
If you look at homes in America the solar panels are these big heavy
lumbersome things. They're unsightly to look at and devalues the leafy suburb
view. These panels are really v1 of the solar panels for homes. You need solar
shingles as the true means to maximize solar in homes. Hopefully those will
come within the next decade.

For now I will avoid solar power.

~~~
loueed
Tesla is already manufacturing solar shingles, they use tempered glass and are
more than three times stronger than standard roofing tiles
[https://www.tesla.com/solarroof](https://www.tesla.com/solarroof)

~~~
heimatau
Wiring up their solar shingles isn't cost effective due to labor. Their solar
roofs is a negative income stream for Tesla. When is the last time you heard
the Solar Roof grow into 'record breaking growth'? It hasn't and it won't
because Tesla is still trying to make the labor expense cheaper.

Look into the labor it takes to install an entire Solar Roof vs installing a
new roof plus traditional solar installation. On a dollar for dollar basis, it
may look competitive but Tesla is selling their Solar Roof's at a loss.

Tesla is selling their Solar Roof at a loss. Not at a profit. It's labor
intensive and they aren't growing at a fast rate because of that hidden
expense.

Disclosure: I installed around 200kw of solar panels and did a decent amount
of research into Tesla's Solar Roof since it seemed so novel and innovative.
The wiring of the Solar Roof is much more complicated than what is publicly
understood. Tesla's good at PR because most of the public are superficial in
their understanding. Tesla most likely saves a lot of money in the
manufacturing process of the solar shingles but they lose money due to their
complicated wire installation process. How are those shingles connected on the
underside? How are those wires protected from the elements, without affecting
the plywood on the roof? Etc. These are simple questions that are often
overlooked.

~~~
NeedMoreTea
There's plenty of companies other than Tesla offering solar roof tiles who
aren't selling at a loss. Wiring seems to be a simple case of plugging them
in. How do Tesla manage to make this complex or labour intensive?

First one that cropped up in search:
[http://www.reuk.co.uk/wordpress/solar/solar-roof-
tiles/](http://www.reuk.co.uk/wordpress/solar/solar-roof-tiles/)

In the UK, mounting solar on top of the tiles is far more common as roofs are
rarely replaced.

~~~
heimatau
Wow. The UK link you provide is running at about ~$7.65 per watt. That's
extreme/exorbitant plus their tiles look ugly and I doubt the resell value on
the home will be as high as a Tesla Solar Roof (since aesthetics are king on
homes).

Currently, even in Cali a solar system ranges at about $4-5 per watt. The cost
to redo a roof depends on the size but almost certainly it would be cheaper
than the extra $2.65-3.65 watt left over on using a conventional system and
less long-term liability to homeowner to replace a roof and do conventional
solar.

~~~
heimatau
Also, let me further point out this system was a 2kw system which isn't enough
to fully be energy independent as a home owner. Sizes range in the 5kw to 8kw,
at least in the USA. So, that would add additional money into the equation and
only further emphasize my statement on 'that's exorbitant'.

~~~
NeedMoreTea
UK homes use far less electric than the US, and air conditioning is almost
unheard of.

Commonest UK size for solar is currently 3-4kWp, which is plenty for household
independence, and above 5 or 6 rare. Earlier systems were smaller as panels
were costly. I think somewhere around 5 is the point an installation is
considered commercial rather than domestic making larger even less attractive.

Exorbitant or not it pays based on UK electric prices and feed in tariffs.

