Solar Energy Perspectives - IEA

Solar Energy Perspectives: Testing the limits
of magnitude too costly (e.g. 10 or 100 times costlier) may or may not be affordable in
20 years. So reasonable possibilities must be distinguished from the more speculative options
(see box: ruled-out options). Significant cost differences will remain between sunny and less
sunny countries. Cost considerations, combined with issues relating to variability, will limit
the role of solar electricity in cold and temperate countries where other options, notably wind
power and hydropower, are less costly and more convenient.
Ruled-out options
The following options are not considered in this chapter as they rest on very
hypothetical grounds and/or would have costs several orders of magnitude higher
than alternatives:
1. Space-based solar power
American scientist and aerospace engineer Peter Glaser imagined in 1968 spacebased
solar PV power plants using wireless power transmission to send energy to the
earth, thus taking advantage of continuous and stronger sunshine.
The best available information suggests, however, that the costs of space-based solar
power, mostly due to the costs of putting the necessary elements into orbit, would be
several orders or magnitude greater than the costs of generating electricity on Earth.
2. Very long-range electricity transport
Breakthroughs in superconductive electricity technology could make very long-range
electricity transport low cost and loss-free. This would allow countries bathed in
daylight to feed solar electricity to those plunged in the night and vice-versa 12 hours
later. A more modest version would link countries of both hemispheres over many
thousands of kilometres to offset the seasonal variations of the solar resource.
Countries in summertime would feed those in wintertime. Even if the reciprocal
nature of this option alleviated all energy security concerns, the emergence of
affordable, loss-free, very long-range electricity transportation rests on hypothetical
technology breakthroughs.
In hot and dry regions or countries suitable for STE from CSP plants, technically solar energy
could generate the bulk of the electricity – and possibly even more electricity than locally
needed, so some could be exported to nearby, less sunny regions. The match between
resource availability and peak demands, whether on a seasonal or daily timescales, is often
good in high-DNI countries, being driven by activities and air-conditioning loads. In some of
them the electricity demand is today driven in part by lighting, and peaks occur at night. But
variability of the solar resource would be addressed with thermal storage, which is both
cheap and efficient, with more than 95% round-trip efficiency. Night time is thus not
a problem for well-designed CSP plants. Back-up for these plants would be needed to cover
only unusually long bad weather conditions. In these sunny regions CSP plants are expected
to be able to deliver competitive electricity by about 2030, depending on the costs of fossil
fuels and the price attributed to CO 2 emissions. With thermal storage, the usual distinction
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