My guess is for large-scale electric power generation in arid places
direct solar thermal parabolic troughs are still cheaper than
Stirling engines. The LUZ corporation built several of these, from 30
to 80 MW. They are still in use. I think they are now owned by FPL
Energy. They are called "SEGS." See:
http://www.fplenergy.com/portfolio/contents/segs_viii.shtml
Quote: "SEGS VIII and SEGS IX are the largest solar plants
individually and collectively in the world. They are located in the
Mojave Desert, which is an area where insolation is among the best
available in the United States."
Solar thermal or Stirling engines for small-scale installations have
some disadvantages: they are complex, they require more maintenance
than PV, and they have moving parts.
Small scale solar (solar thermal or PV) have some advantages over
centralized systems such as SEGS:
1. No T&D losses. (The electricity does not have to be transmitted
over long distances.)
2. In places like Japan where the weather is hot and variable, with
frequent rain, PV for airconditioning produce peak output when and
where they are needed; i.e., in places where the sun is shining at the moment.
3. PV can be installed on roofs anywhere, including crowded urban
areas in Japan where even small Stirling installation would not fit.
In Japan, things are so crowded that when the power or phone company
installs a telephone poll in front of your house, they pay you annual
rent for the space. I think it is around $20/year.
4. They are paid for by the people who want them, rather than
collectively. If you want to pay more for electricity in order to
reduce pollution and CO2, you can. Some electric power companies are
now offering "green power" at extra cost, giving the customer who
does not want to install his own hardware the same opportunity.
In Japan, at least, PV is now nearly competitive with centrally
generated power, and even though it is no longer subsidized, PV roof
installations are becoming very common in sunnier locals. No doubt
there are places in Japan where Stirling systems could be installed,
but the opportunities are not as good as, say, southern California or
Nevada. Japan also lacks suitable wind and suitable locations for
wind turbines, although there are a few here and there.
- Jed
