[Server-sky] [ExI] Power sats again

[Michael Turner]

I'm fresh from a debate about EROEI for PVs, during which I discovered
that large hydro (yes, /locally/ environmentally disastrous, I know)
beats everything else quite handily in EROEI. This renewed for me an
issue of definition: if you count hydroelectric as "solar", could you
call a huge hydroelectric dam in a remote area, far from any major
power market, as part of an SSP system if you beamed its power /up/ to
a geostationary microwave relay, for distribution to markets elsewhere
on Earth?

Obviously, such relaying is not inherently limited to hydroelectric.
It just seems like hydro-to-space-to-market could be the shorter (and
less capital-intensive) path to space-based solar power, one with a
relatively low carbon budget, and with a better baseload profile than
most renewables.
Regards,
Michael Turner

Project Persephone
K-1 bldg 3F
7-2-6 Nishishinjuku
Shinjuku-ku Tokyo 160-0023
Tel: +81 (3) 6890-1140
Fax: +81 (3) 6890-1158
Mobile: +81 (90) 5203-8682
turner at projectpersephone.org
http://www.projectpersephone.org/

"Love does not consist in gazing at each other, but in looking outward
together in the same direction." -- Antoine de Saint-Exupéry


On Sat, Jul 13, 2013 at 5:28 AM, Keith Lofstrom <keithl at kl-ic.com> wrote:
> On Fri, Jul 12, 2013 at 04:41:05PM +0200, Eugen Leitl wrote:
>> ----- Forwarded message from Keith Henson <hkeithhenson at gmail.com> -----
>>
>> Date: Thu, 11 Jul 2013 20:04:15 -0700
>> From: Keith Henson <hkeithhenson at gmail.com>
>> To: extropy-chat at lists.extropy.org
>> Subject: [ExI] Power sats again
>> Reply-To: ExI chat list <extropy-chat at lists.extropy.org>
>>
>> Gave an hour talk at Google today on the new breakthroughs that have
>> reduced the startup cost to $60 B, the time to first power sat on line
>> to ~7 years and raised the ten year ROI to 500%.  It also has the
>> potential to keep the CO2 somewhat below 450 ppm.
>>
>> Was well received.
>>
>> I can send a draft of the article the talk was based on if anyone is interested.
>
> I would be interested in the assumptions that went into the power
> revenue numbers.  The value of electrical power is highly dependent
> on time of day.  Here in the Pacific Northwest, power produced at
> times of low demand (say 2200 to 0600) can have negative value;
> the Bonneville Power Administration pays money to dispose of wind
> power produced at these times in resistors in the desert, to avoid
> spilling water over the dams and supernitrogenating the water,
> damaging the salmon.
>
> Time dispatchable power is very valuable, but the SBSP ground
> rectenna systems must be able to receive power from power sats at
> low elevation - long east-west dimensions.  Powersats near the
> 0100 (1AM) position in their GEO orbits will be close to useless.
> Rectennas under cloud cover (50% or more of the time) will get
> an attenuated beam (with lots of unhealthy off-axis scattering).
>
> Converting space power to high value product before shipment from
> orbit provides much more value.  Google search results generate
> revenue of $20 per kilowatt-hour of electricity consumed, while
> bulk off-peak power is worth less than $0.04 per kWh.
>
> Keith
>
> --
> Keith Lofstrom          keithl at keithl.com         Voice (503)-520-1993
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