[ExI] Thoughts on Space based solar power

[BillK]

On Thu, Nov 20, 2008 at 10:27 PM, ben wrote:
> So, if you can get your PVs above most of the clouds, this will be a LOT
> cheaper than getting them into orbit, and you can catch a lot of sunlight,
> almost anywhere in the world.
>
> I'm thinking of rafts of helium/hydrogen/hot air balloons, with PVs on the
> top surface, or supporting a PV layer, tethered to the ground, floating just
> above the main cloud layer, with lightwight electrical cables (maybe with
> bouyancy balloons attached at intervals) conducting the power to the ground.
>


Single *temporary* high-flying tethered balloons are already in use
for atmospheric tests and sampling. I think the record height is about
9 or 10 kilometers. (Free balloons go much higher, of course).

The main problem with high tethered balloons is aircraft running into the cable.
Cities used barrage balloons in WWII to frighten aircraft away. So a
city covered with solar power balloon rising to 3 kilometers is
definitely a no-no.

Low level PV balloons have been suggested as a possibility where land
space for panels is expensive or unobtainable.  See:
<http://www.inhabitat.com/2008/04/10/sunhope-solar-balloons/>

But, if you have a roof, you probably have enough space for a PV panel.

BillK


But a single PV balloon would just about run a single house.