
Desertec - mooreds
http://en.wikipedia.org/wiki/Desertec
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mooreds
What, no discussion? I frankly was more impressed by the description of the
proposed Atlantropa project than I was of the Desertec (though both are
ambitious!). That would be a dam stretching ~13 km and between 300 and 900
meters in height. That seems like an very impressive (and difficult) civil
engineering project. The Three Gorges dam is 2.3 km long and about 200 meters
in height, so Atlantropa would be significantly larger than the Three Gorges.

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kbenson
The failure scenario for that is pretty scary. At least I assume it is.

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dsr_
Well... probably not. The Med is large enough that you won't reduce its level
a significant amount, so nobody will build houses on the new beachfronts, so a
sudden dam collapse should send a wave a few centimeters high a few meters
further than the tide already goes.

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martey
> _The Med is large enough that you won 't reduce its level a significant
> amount, so nobody will build houses on the new beachfronts_

The description of Atlantropa in the linked article clearly notes besides
hydroelectric power generation, the dam was meant to lower the sea level by
more than 600 feet in order to create more land in the basin. A dam collapse
would have been catastrophic.

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fallat
Wow, when you look at this picture:
[http://en.wikipedia.org/wiki/File:Fullneed.jpg](http://en.wikipedia.org/wiki/File:Fullneed.jpg)

You realize that our electrical problems could be solved in 5-10 hard working
years.

This makes me think that maybe our current solar panels aren't as bad as they
seem. Or we're really using them wrong.

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JoeAltmaier
I'm dubious. First, it only works during daylight hours. Second, its
ecologically disastrous (sterilizes the ecosystem under the facility due to
lack of sunlight). Third, centralized generation adds transmission losses
which are substantial.

I favor orbital generation, which mitigates all of these.

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revelation
You got to be kidding. You can't seriously make the argument that we shouldn't
do solar for all our power needs _because it will rob sunlight from the
ecosystem under the panels_.

That's astounding. I mean, just a take look around you. Where's all the
ecology gone?

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JoeAltmaier
Me and Greenpeace, yes. When we're talking square miles of ecology reduced to
sterile dirt in the dark under panels, we're talking about disruption similar
to plowing, or mining.

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JoeAltmaier
Ok, me and Greenpeace cofounder Patrick Moore

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static_noise
Compared to smaller solutions this project needs some hefty investment in
order to get started. It might be useful to start building solar farms in the
north african countries for their own needs and then they can start exporting
excess electricity to neighboring countries in the south and - at one point
when it's economically viable - via DC transmission lines to Europe.

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kbenson
Apparently a lot of the original shareholders pulled out, but it's still going
forward[1]. I'm not sure how much the plan has changed.

1: [http://www.reuters.com/article/2014/10/14/germany-
desertec-i...](http://www.reuters.com/article/2014/10/14/germany-desertec-
idUSL6N0S535V20141014)

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jcromartie
Is it not sufficiently obvious at this point that decentralization is better
than centralization?

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sponsored_ad
vegan, decentralised, and ecological energy ;) You know it is quite crazy
calling electricty ecologically compatible, if produced by industrial waste
and unethical factory farming (the power generated on giant solarplants at the
roof of battery farms and the biogas produced by the waste of feedlots).

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ianbicking
High voltage DC? What's that about?

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tlb
It's more efficient for very long distance transmission.

With AC transmission at 60 Hz, the wavelength is 5000 km. Things get
complicated when you approach that distance.

Also, with maximum peak voltage limited by arcing, DC uses the wires more
efficiently because it's constantly at peak voltage, rather than oscillating
up to it.

Also, AC current creates a varying magnetic field that pushes the current flow
away from the center of the wire, so only the outer region gets used,
increasing resistive losses. It's not a huge effect at 60 Hz, but it makes
some difference.

[https://en.wikipedia.org/wiki/High-
voltage_direct_current](https://en.wikipedia.org/wiki/High-
voltage_direct_current)

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amaterasu
But, the switching/control equipment is substantially more complicated,
voltage conversion is hard due to transformers not working at DC, and you
still need to suffer inverter inefficiencies to convert things to AC for
domestic use.

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tlb
Right, so it only makes sense for very long distances where the cost & losses
in the inverters are less than the losses from AC transmission.

