Solar power technology whitepaper created by Enertia Engineering. Covering the progression of solar power and solar power conversions.

1. Progression of Solar Power
Benefits & Drawbacks of Available Technology
Solar energy conversion has been around for more than 50 years. Recent jumps in
technology have made solar energy conversion and economically viable source of energy.
Originally manufactured using poly-silicon, solar energy was only marginally effective
when properly angled towards the sun, the panels were kept cool, and free of dust/dirt.
Even in large scale, this was not an economically viable solution.
There are more than 40 types of solar energy conversion technologies available on
today’s market.
The four major categories are:
o Organic (Not economically viable)
o Silicon (Most commonly used)
o Thin Film (New technology; inexpensive & becoming more popular)
o Multi-Junction (High-end technology; expensive)
Organic solar cells are in their infancy. Using sustainable materials, very low (less than
7% efficiency) is available from theoretical tests. Commercial production is not expected
until the technology can rival other technologies.
Silicon solar cells come in a wide range of lower-efficiency poly-silicon cells made on a
think rigid surface to higher efficiency thin film foil. Silicon technology is sensitive to
temperature (performs poorly at higher temperatures), so it has limited effectiveness in
commercial applications in warm climates, unless cooling technology is implemented.
Thin film multi-component technology is nearly as efficient as mono-silicon and thin film
silicon. It is less expensive; much thinner, and less sensitive to temperature when
compared to silicon. Commercialization of these technologies is expected to increase
over the next few years.
Multi-junction technology is considered high-end technology for solar cells. It has been
around for over 50 years, but was not commercial viable until recently, due to some
major changes in manufacturing equipment and component preparation. Laboratory
efficiencies top 40%, and commercial applications are approaching 30%. It is more
efficient in cooler temperatures (outer space), but still extremely capable in warm
climates such as near the equator. The technology is extremely thin, compact, and
capable of being used even when low-light (clouds) are present. As volume production
increases, costs will decrease, and this technology will eventually become the standard
for solar energy conversion. Muli-junction technology is also the basis for Concentrated
Photo-Voltaics (CPVs).

2. Concentrated photo-voltaics are small surface area multi-junction solar cells which are
placed under one or more lenses to focus (concentrate) the radiant energy to the cell.
These technologies pick up short wavelength, medium wavelength, and infrared by
having three layers of different types of solar cells combined. The primary advantage of
this technology is the ability to produce (net volume of energy) significantly more energy
per square meter than any other type of solar energy conversion. (Small footprint for
installation means that you can have a larger field of collectors generating significant
energy in a small area.) Plans are under way for multiple solar fields; some are expected
to be able to generate 100MW+ of power.
Here is a list of the common varieties of solar energy conversion. (Some technologies are
not listed because they are based upon very minor manufacturing differences that result
in negligible difference in net energy conversion results.) NOTE: CPVs cannot be static-
mount. They require a 3D sun-tracking system.
45.00%
40.00%
Light Cloud Cover
Static Mount, Minor Dust
35.00%
Laboratory
30.00%
25.00%
20.00%
15.00%
10.00%
5.00%
0.00%
Polycrystalline silicon (poly-Si)
Monocrystalline silicon (c-Si)
Silicon Foil (Thin Film)
GaAs Multijunction
CuInSe (CIS)
InGaAs (Medium Wave)
CuInGaSe (CIGS)
GaInP/GaInAs/Ge (CPV)
Organic Solar Cell
CuGaSe (CGS)
CdTe