Solar Power
I was reading this article from IEEE Spectrum about First Solar, a
start-up that produces thin film cadmium telluride (CdTe) photovoltaic
(PV) cells.
http://www.spectrum.ieee.org/aug08/6464
The price that has been bandied around for PV cells to be competitive
with traditional power sources is US $1 per watt. Unfortunately that
does not give a complete picture. Some of the other concerns include:
1) Efficiency - if your cells are less efficient, even if the cost per
watt is the same, it requires larger areas and therefore higher
installation costs, which is not included in this number;
2) Expected life of the cells - should be included in cost calculations;
3) Availability of the raw materials - Te is rare on earth;
4) Toxicity of the materials - Cd is quite toxic; and
5) Alternatives and Competition - other possible options for PV cells
are CIGS (can be deposited as a thin film easily, but efficiencies
have been lower than expected); multi-junction high efficiency cells
(efficient but very expensive - probably best as niche applications or
need to use lenses and mirrors to focus light); amorphous silicon
cells (low efficiency but easier manufacturing process); and the
conventional silicon cells (mature technology, efficiency unlikely to
improve further but materials costs would decrease if current
polysilicon shortage disappears).
I guess the key takeaway point is that solar power is all about
economics, the winner would be the technology that has the lowest
overall costs.
