Comparison of terrestrial PV and SPS

Dr. Geoffrey Landis has just published an excellent review of the
economics of PV and how it relates to terrestrial and space based
power generation markets.

http://gltrs.grc.nasa.gov/cgi-bin/GLTRS/browse.pl?2004/TM-2004-
212743.html

Landis analyzes the economics, noting that SPS power can be sold into
different markets at different times of the day as the demand curve
changes, by selective beaming.

My comment: Terrestrial PV are limited to daylight with relatively
clear skies, unless expnsive storage systems are used, or very long
distance grid transmission is employed (also expensive).

Some quotes from the Landis paper:

Synergy With Terrestrial Solar

Space and Ground Solar Power
Analyses of space solar power often assume that ground solar power is
a competing technology, and show that space solar power is a
preferable technology on a rate of return basis. In fact, however,
space solar power and ground solar power are complementary
technologies, not competing technologies. These considerations were
initially discussed in 1990 [4]. Low-cost ground solar power is a
necessary precursor to space solar power: Space solar power requires
low cost, high production and high efficiency solar arrays, and these
technologies will make ground solar attractive for many markets. The
ground solar power market, in turn, will serve develop technology and
the high-volume production readiness for space solar power.

Since ground solar is a necessary precursor to space solar power, an
analysis of space solar power should consider how it interfaces with
the ground-based solar infrastructure that will be developing on a
faster scale than the space infrastructure. Some possible ways that
this interface could be optimized
include:

1. Integrate solar and microwave receivers on ground. This will allow
the space solar power to use the pre-existing land that has already
been amortized by ground solar power receivers, and tie in to power
conditioning and distribution networks that are already in place.

2. Use solar power satellites to beam to receivers when ground solar
is unavailable. By "filling in" power when ground solar is
unavailable, space solar power will serve as the complement to solar.