Solar Power and its utilization

Another exciting field for alternate energy source is the well known solar energy.
The principle of solar cells basically involves conversion of solar energy into electricity using certain semiconductors as cells or panels,which are technically known as ‘Photovoltaic cells’. The generated electricity can then be either stored in a battery for use later or transferred to an electric grid nearby.
The 1st generation cells were made up of single junction silicon crystals. While the efficiencies are very good ( I mean the efficiency of conversion of sunlight)the production costs are very high as it is highly labor intensive.
The second generation cells reduced the cost of manufacture significantly by using different materials and techniques (thin films of cadmium telluride for instance). Although the efficiencies were lower,the overall cost per watt came down from 1USD to 0.5 USD due to significantly lower cost of manufacturing . This enabled mass manufacturing of these cells.The process does not involve much labor either unlike the 1st generation solar cells.
However,looking at competitiveness with fossil fuels ,as on date only ‘dye-sensitized cells’ are competitive. However there are some technical issues with the long-term stability of the dyes.
Main areas of research in solar cells are centered around new types of efficient semiconductor systems capable of converting light into electricity with better efficiencies at lower cost of manufacture.

Innovations in applications are also taking place simutaneously. I would like to mention a couple of interesting applications here:

1.Rural electrification:
In a very innovative application development a team, working in Nicarugua and Venezuela, stitched-in flexible solar kits into a fabric which were worn during the day by men / women working in the hot sun. The electricity generated and stored could be used in the night to light bulbs. Besides the flexible thin film of of photo-voltaic cell(10 inch by 4 inch),the solar kit consisted of an LED and a rechargeable battery. (LED is an electronic device which converts electricity into light).
The project provides a way for the local communities to have bright light inside their homes at night and recharge the power under the sun during the day. And the power can be used to charge cell phones and medical devices as well. Most importantly the entire kit is light weight and can be customized to be incorporated into existing materials of textile fabric. The batteries can be charged in 2.5 hours and give light for 10 hours. The light output per watt is much better than that of a conventional 100 watt bulb.
In another related application,the team is also working on the use of portable light to generate UV light emitting LED,which can be used for purification of water in rural areas.

2.A variation of the same concept for urban areas consisted of solar cells incorporated into venetian blinds exposed to sunlight. The electricity generated is stored in a battery and used in the nights.

3. One hears of cell phones being charged by solar cells and car roofs being fitted with solar panels with the stored energy being used to run car air-conditioners.

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Published in: on March 19, 2009 at 5:19 pm  Leave a Comment  
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