[ExI] Small scale solar payback time (was Re: Planetary defense)

[Eugen Leitl]

On Sat, May 21, 2011 at 02:03:43PM -0700, Damien Sullivan wrote:

> What does order of magnitude improvement mean for solar panels?  You can
> get 15% efficiency today, there's not an order of magnitude of

You can order 17% mono-Si immediately, up to 22% which is not
yet readily available, and for research-grade (most of them
concentrated) they're rapidly approaching 50%

http://upload.wikimedia.org/wikipedia/commons/e/ed/PVeff%28rev110408U%29.jpg 

So there's no orders of magnitude available, unless they're binary,
then you'd get a couple at best. Longevity is up to 40+ years by now,
so the only other improvements is price, material availability, and 
EROEI.

As soon as you reach durable construction material price range
there's no reason not to build homes which are net energy producers.
Even factoring in embedded energy.

-- 
Eugen* Leitl <a href="http://leitl.org">leitl</a> http://leitl.org
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