Low cost solar energy: thanks to organic solar cells
Cost has been the main factor inhibiting large scale use of solar energy, an abundant and clean form of energy. A large portion of this cost goes for solar panels that contain photovoltaic cells necessary for converting the sun’s energy into a usable form (electricity.)
Though costs are decreasing, the decrease is quite gradual, and the existing cost still keeps solar energy out of reach of common people. However, new technologies promise to drastically bring costs down. Among these is making solar panels from organic solar cells.
The solar panels of today contain photovoltaic cells made out of refined silicon. Silicon is the second most abundant element in the earth’s crust and is present in most rocks that we see. You would expect that, coming from such an abundant source, solar panels would be rather cheap.
However, silicon does not exist by itself. It almost always exists in combination with oxygen as silica. Silica is a tough mineral, with a melting point of over 1600 degrees Celsius. Solar cell manufacturing requires, at the least, melting of silica. This requires a high amount of energy.
Organic solar cells, on the other hand, are made out of light absorbing polymers and do not contain silicon. Because of that, they are cheaper to make. They don’t consume as much energy for manufacturing as silicon based solar cells do. Because they don’t consume so much energy, manufacturing of organic solar cells is also relatively more environment-friendly.
Organic solar cells, however, have some demerits: they are not as efficient as silicon based solar cells in converting solar energy into electricity, and they are susceptible to environmental degradation.
Silicon based cells have an efficiency of 15% but organic solar cells have an efficiency of less than 5%. However, being a major area of focus in solar energy research is a big advantage. Much of the effort is devoted to improving conversion efficiency.
Recently, conversion efficiencies of 5% have been achieved in research efforts. With the use of nanotechnology, the efficiency is expected to improve further, to a level where it can compete with that of silicon based cells.
Organic solar cells are susceptible to environmental degradation over time. But it is only a matter of time before reliable protective coverings are developed.
No doubt this is still a developing technology. But once the problems of efficiency and degradation are solved, the stage will be set for large scale, low cost, and environment-friendly manufacturing of organic solar cells.
The future of solar energy is bright. A reason for energy hungry developing countries like India, desperate for energy to drive the economic growth so necessary for fighting poverty, to rejoice.
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Narita, Chiba, Japan