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

[Keith Henson]

On Mon, May 23, 2011 at 2:13 PM, spike <spike66 at att.net> wrote:
>> On Mon, May 23, 2011 at 8:32 AM, Kelly Anderson  wrote:
> ...
>>> I really truly can't understand why Rush Limbaugh is so negative about
> solar...-Kelly

Actually BillK said it.
>
>
> Pardon if I repeat the spirit of an earlier post.  It would be a game
> changer in plenty of people's minds if they would get on a plane, fly out
> somewhere in the middle of the western desert US, such as Boise Idaho, or
> Las Vegas (what happens there stays there but don't do *that*) rent a car,
> drive in pretty much any direction there is a road, look around.  What one
> will see, regardless of the time of year, is *plenty* of open nearly flat
> land, plenty of direct sunlight, and I think investment ops would pencil out
> at current ground based fixed installation costs.  I can estimate closely
> enough the cable costs, the load leveling by conversion of coal to octane
> with external power from massive PV installations and so forth.  But it is
> important to go out there in person and get a good feel for how much open
> useless land is there.  Failing that, get on Google Maps and look at it.  A
> lot of that desert land goes weeks at a time between seeing a single cloud.

I have looked deeply into this and it just doesn't make sense
economically or even in terms of physics.  It doesn't seem likely that
it ever will before nanotech.

It seems possible eventually to get the cost of power from PV down in
the range of 10-20 cents per kWh.  At ten cents a kWh you can make
synthetic oil out of atmospheric CO2 and water for $10 capital plus
$20 x cost of power in cents per kWh.  That's $210/bbl at the low end
of what might be possible for PV.  You can have all the desert land
you want, but the cost of installing this PV infrastructure is the
problem.

> The one area where I may be dead wrong and cannot estimate, is the cost of
> defeating the environmentalists opposed to massive ground based solar, and
> of course the current energy companies which may hire environmentalists to
> defeat such a notion.  That could be huge, perhaps a show stopper.

It's not an issue in China and you don't see them paving their deserts.

Part of the problem is the energy payback time.  Two to four years is
the current.  That sets how the maximum rate you can grow the source
if it is energy limited.

It's a different situation in space where the solar concentrators and
radiators can mass 1-2 kg/kW.

Keith

Keith