|
Crystalline Photovoltaics |
Thin Film |
Concentrating Photovoltaics (CPV) |
|

(credit: Sharp) |

(credit: sikod.com) |

(credit: SolFocus) |
Description |
Crystalline silicon wafers |
Semiconductor is deposited directly on glass. |
With the help of parabolic mirrors, light is focused on a small area, thus needing less semiconductor material. These devices can then afford high-performing semiconductors. |
Module Efficiency |
High |
Low |
High, but have some optical losses |
Performance under heat |
Performance degrades with higher temperatures. |
Up to 60% lower heat coefficient than crystalline silicon modules, making it a good choice in hot climates. |
Depending on material used. |
Space required per kWp |
Polycrystalline: 10m² - 30m² depending on cell spacing
Monocrystalline: > 8m² |
Glass-glass laminate ~ 25m² |
|
Amount of photovoltaic material needed |
Polysilicon: 8g/W |
CdTe: 0.22g/W |
At concentration ratio of 500, approximately 900 times less photovoltaic material is needed. |
Panel Choice |
Only 2 panel types |
Many different panel types, can be rolled. |
For free-standing, need tracking. |
Degradation |
No known degradation. |
Will depend on heat and material. Amorphous silicon can lose up to 30% within the first 3-6 months when its rated power is reached. They are stable thereafter. |
|
Direct or diffuse light |
Direct light preferred, but diffuse light can be used too. |
Both direct and diffuse light |
Requires direct light only, as diffuse light can not be concentrated with exception of luminescent concentrators. |
Sub-Types |
Mono- crystalline |
Poly- crystalline |
CdTe |
CIGS |
a-Si |
Multi Junction |
Low Concentration |
High Concentration |
|
Purity 99.99999% |
Purity 99.9999% |
low temperature sensitivity |
captures large spectrum |
Amorphous Silicon |
GaAs/CIS
a-Si/mc-Si
|
with crystalline semiconductor |
with multi- junction GaInP/GaAs/Ge or GaInP/GaAs with >30% efficiency |
Environmental impact from production |
|
|
Cd is itself a waste product from mining industry. Highly toxic. Must be recycled |
|
|
|
|
|
Efficiency
(production / lab) |
15-20% / 25% |
13 - 15% / 21% |
10% / 16% |
12% / 20% |
7% / 10% |
36% / 40% |
|
Cell: 35%, module: 24% |
Companies |
Sunpower
Solarworld
Isofoton
|
Sharp
Kyocera
Q-Cells
Suntech
Yingli
Evergreen |
FirstSolar
AvaSolar
Calyxo
|
Nanosolar
GlobalSol
Solibro
|
Unisolar
Sontar |
Spectrolab
EMCore |
Entech Solar
Isofoton |
SolFocus |