Posted:This is encouraging, though solar still has a long way to go. The only countries with serious solar generation have subsidised it to the hilt. The time to break-even on a current photovoltaic solar panel in this country is around a thousand years. Water heating solar panels breakeven in about 20. We need improvements of several orders of magnitude, in price per Kw.
Still, impressive technology. Photosynthesis is neat but doesn't come near the efficiency of solid-state electronics.
The efficiency of photosynthesis is determined by the following:
1. At least eight photons are required to store one molecule of CO2 which means 1665 kJ of light energy are required to store 477 kJ in the plant. Max efficiency is 0.286 or 28.6 %
2. Only light in the range 400-700 nm can be used. This amounts to 43% of total solar incident radiation.
3. Canopy limits absorption to 80 %
4. Respiration required for translocation and biosynthesis requires about 33% of the energy stored which leaves 67%
The overall efficiency is then .286x.43x.8x.67 = .066 or 6.6%