[tt] [silk] McKinsey on the economics of solar power

[Eugen Leitl]

----- Forwarded message from "Perry E. Metzger" <perry at piermont.com> -----

From: "Perry E. Metzger" <perry at piermont.com>
Date: Sun, 03 Aug 2008 14:52:11 -0400
To: silklist at lists.hserus.net
Subject: Re: [silk] McKinsey on the economics of solar power
User-Agent: Gnus/5.11 (Gnus v5.11) Emacs/22.1 (berkeley-unix)
Reply-To: silklist at lists.hserus.net


Brian Behlendorf <brian at hyperreal.org> writes:
> On Sat, 2 Aug 2008, Udhay Shankar N wrote:
>>    * Solar energy is becoming more economically attractive as
>> technologies improve and the cost of electricity generated by fossil
>> fuels rises.
>
> As photo-voltaic improves (efficiency being much less important than
> cost per watt)

Efficiency and cost per watt are partially linked.

Much of the cost of a panel is fixed regardless of its size. The glass
on front, the aluminum on back, the mounting brackets, and the labor
to put it in place don't vary depending on the efficiency of the
panel. For many installations, land also has a price. More efficient
panels save on all these fixed costs.

> I think it has one big advantage over nearly all other approaches:
> no moving parts.  Installations of fixed panels can be nearly
> maintenance-free when compared to solar thermal, wind, wave power,
> etc., all of which involve components that can break or wear out.

Sort of. Panels in commercial use need to be cleaned, and energy
storage systems are far from maintenance free.

> The cells I put on my roof in 2002 were warrantied for 20 years,
> and even 30 years out should still be generating 75% of their initial
> capacity.

It is believed that most monocrystaline Si systems should have
effective lifetimes of over 40 years.

> It's not completely trouble-free - interconnects can age,
> inverters/transformers can blow, lightning and other weather
> incidents can wreck havoc, but I predict these to be minor compared
> to maintaining the machinery to pump molten sodium through tubes to
> transfer heat to turbines.

Molten sodium is probably going to play a role anyway -- molten
sodium/sulfur batteries are one of the most economically efficient
ways to store power on the sort of scale needed to keep cities running
at night. (Pumped hydro is another method that's fairly efficient and
cheap but it isn't always geographically practical.)

Perry
-- 
Perry E. Metzger		perry at piermont.com

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