SOLAR CELLS FOR TOMORROW
Posted July 8, 2008on:
The Five separate market places are
Grid connected solar farms
Based on crystalline silicon
Commercial sales of these started in the 70’s
The Future for First Generation PV
•Practical conversion efficiencies have now seemed to stabilize at around 15-18 % (with installed module efficiency 12-15%)
• Increases in efficiency tend to be matched by the cost of increased design/processing complexity
•Improvement of the cost-efficiency can therefore mainly be reached by reducing the cell and panel production costs
Thin film semiconductors, silicon and non-silicon.
Commercial sales of these started in the mid 80’s
The Future for Second Generation PV
•Potential for cheaper production costs (but higher capital cost) by means of continuous deposition techniques.
•Cell efficiencies are now in the order 5-8 %, but substantial improvements are forecast, not so much for amorphous silicon, but more for CIGS.
•Environmental concerns about CdTe will affect its acceptability
Third generation PV
•Plastic solar cells (organic PV)
•Multiple junction thin polycrystalline films.
The first third generation products are just beginning to enter the market place.
The Present for Third Generation PV
•The first organic solar cell – DSC (Dye solar cell).
•Artificial photosynthesis system invented by Prof Michael Graetzel in Switzerland.
•First DSC product to be commercially available is the STI DSC Solar Facade Panel
•Laboratory results for DSC exceed 10%, with production models at around half that value.
The Future for Third Generation PV
•Organic or polymeric molecules as the PV active material.
•Recent results of 2-3% have been reported for blends based on substituted PPV polymer
•Designs for disc shaped phthalocyanine molecule as a film about 100 nanometers thick on a plastic substrate with a transparent electrical coating.
Fourth generation PV will derive from biology.
Fourth generation cells are expected to derive even more closely from photosynthesis.
Factors Driving Past Cost Reduction
Poly silicon price: $300/kg → $30/kg
Wire saws: now < $0.25/W
Larger wafers: 2” → 6”
Thinner wafers: 15 mil → 8 mil
Improved efficiency: 10% → 16%
Volume manufacturing: 1MW → 100MW
Increased automation: none → some
Improved manufacturing processes
The annual production of solar modules increases ten-fold every decade. The price of solar cell modules decreases by half every decade