Solar Energy: Conversion into Electricity So much energy is 1.11 Electron Volts?

This does not mean that the efficiency of silicon in converting solar photons to electrons is 77%! The efficiency is strongly temperature dependent. As the temperature is raised, the internal resistance of the material increases and the electrical conductivity decreases.

The fundamental physical limitation in production photovoltaic cells is then this decrease in efficieny as the temperature of the cell increases. Because of this, for a material like silicon, the operating efficiency of a photovolatic array will probably never be higher than 20% and will most likley be between 5 and 15%.

This doesn't mean that production is not possible. It does mean that relatively large collection areas must be obtained which means high capital costs. If those costs can not be subsidized, then PV arrays can never be competitive in the commercial energy market place.

To have a production photovoltaic cell, one must mix impurities into silicon (like boron). This will create an internal electric field which will allow the liberated electrons to move down the material.

Over the last 40 years, the effort has gone into increasing the efficiency of PV cells and bringing down the manufacturing costs.

Recent Advances:

Advances in Amorphous Silicon technology has led to continuous thin-film deposition process.

Can increase efficiency by using solar cells in conjunction with focussed systems (parabolic collectors).


Read More About Solar Power Towers

Current Economics:

Consumer cost for energy from newly constructed coal-fired plant in the US ranges from 8-20 cents per KWH

PV power generation would cost the consumer 50-100 cents per KWH.

Costs might be equivalent when pollution from coal is also considered but still, the structure is not here for the consumer to pay the true cost of energy

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