Electrical conversion efficiency

Small-area thin-film CdTe solar cells have been fabricated with sunlight-to-electricity conversion efficiencies near 16%, comparable to crystalline siUcon solar cells in large-scale manufacturing. Large-area monolithic integrated CdTe modules have been fabricated with efficiencies of ca 10%, comparable to crystalline siUcon modules commercially available. 

Chang KC, HeUer A, Schwartz B, Menezes S, Miller B (1977) Stable semiconductor liquid junction ceU with 9 percent solar-to-electrical conversion efficiency. Science 196 1097-1099... 

Large cogeneration units have had a long and successful operating history and are more durable than small-scale units. The larger systems operate at about 35% electrical conversion efficiency and 45% heat conversion efficiency. This means that 80% of the energy in the fuel is converted to heat or electricity. 

Cycle performance is summarized in Table 9-8. The overall net electric conversion efficiency is 43.7% based on HHV input, or 48.4% on LHV. 

Solar energy-to-electricity conversion efficiency (rf) under white-light irradiation (e.g., AM 1.5) can be obtained from... 

In order to get an estimate of the solar-to-electrical conversion efficiency on layered compounds, sample D has been measured in sunlight. The result, obtained at 92.5mW/cm2 insolation is shown in Fig. 8. The maximum power point is at 0.33V and 10.7mA/cm2, with a resulting solar conversion efficiency of 3.7%. As is evident from Fig. 7, some samples show better overall performance than sample D. The best of these, sample G, the surface of which was accidentally damaged before being measured in the sun, had a maximum power output which exceeded that of sample D by a factor of 1.4 bringing the estimated solar conversion efficiency to 5.2%. 

Chemisorption of a fraction of a monolayer of Ru33 also improves the performance of n-GaAs based solar cells. The solar-to-electrical conversion efficiency of a... 

Alkaline electrolysis is a mature technology. It features a good efficiency (-66% LHV), an excellent lifetime of cell (above 20 years currently), and a production of 99.8% pure hydrogen at 30 bars. This leads to a global efficiency of -24% (based on a heat/electricity conversion efficiency of -35%). The main issue is the large fraction of the production cost (-80%) tied to the consumption of electricity (typically 2.6 out of EUR 3.2/kg H2 at EUR 54/MWh) [3.4 out of USD 4.2/kg H2 at USD 70/MWh], Besides, progress is sought to reduce the investment cost. 

The standard formation enthalpy for water is equal to 286 kj/mole H2 relative to the formation of liquid water and corresponding to (HHV) of H2. The theoretical voltage for pure water decomposition is 1.23 V. However, the majority of conventional electrolysis devices need at least 2.0 V when economically reasonable current densities are maintained. This value translates into a water electrolysis Faraday s efficiency of about 74%. If a thermal-to-electric conversion efficiency of 45% is assumed, the total equivalent heat requirement corresponds to a heat input of 859 kj/mole H2. 

Liu prepared a sandwich type coordination compound (103) from porphyrin and phthalocyanine with the assistance of a microwave. The resulted compounds showed good solubility in conventional organic solvents. The photoelectric conversion properties have been tested with a Gratzel type cell. The results revealed that the sandwich type compound showed better photo-electric conversion efficiency than the corresponding monomeric porphyrin or phthalocyanine precursors. The short-circuit photocurrent of the solar cell with this sandwich type compound as sensitizer, was, as high as 691.31 A cm-2, which was much better, than those of porphyrin or phthalocyanine monomers [100]. 

Koyama has examined the sensitization behavior of a series of pheophorbide sensitizers (112-117) with similar structure. The results indicate that the short-circuit current density as well as the overall solar energy-to-electricity conversion efficiency increased with the increasing Qy absorption and with the decreasing one electron-oxidation potential. Two empirical models are built based on the experimental results. One model suggests a parallel electron injection from both excited and ground states to the conduction band of Ti02 whereas the other one supports an electron injection via the excited state only, in which both the Qy absorption and the Qy-state one electron-oxidation potential can contribute [110]. 

Today s biopower capacity is based on mature, direct-combustion boiler/steam turbine technology. The average size of biopower plants is 20 MW (the largest approach 100 MW) and the average efficiency from steam-turbine generators is 17 to 25 percent. The small plant sizes lead to higher capital cost per kilowatt-hour of power produced and the low electrical conversion efficiencies increase sensitivity to fluctuations in feedstock price.658... 

The clean fossil scenario selected includes both hydrogen produced from natmal gas and from coal, with the efficiencies stated above. For use in fuel cells, the hydrogen to electricity conversion efficiency in 2050 is taken as 65%. Losses in hydrogen storage and transmission are taken as 10%, as compared with 5% for electricity transmission. 

The present paper compares key parameters such as solar/electricity conversion efficiency, solar share, levehzed electricity cost and installation cost of these two possible ways. 

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