By N N Sachitanand Despite its limitations, the global growth rate of solar photo voltaic installations has spurted. Those who dislike nuclear energy because of its safety problems strongly tout solar energy as a clean and renewable alternate for India. India experiences clear sunny weather for over 250 days a year, with the average daily solar energy incident over the country being as high as 5.8 kilowatt-hours per square metre, With a land area of roughly 3 million sq km, this translates to a total energy incidence of 6000 trillion units/year (1 unit = 1 kilowatt hour). As compared to this, the Ministry of Power has fixed the electricity generation target from conventional sources for the year 2008-09 at 0.75 trillion units, which is not even 0.1 per cent of the incident solar energy. Therefore, the potential for the sun to meet all our energy needs and liberate us from the dependence on limited and polluting fossil fuels is overwhelming. The question is: Can this potential be translated practically and economically into actuality? A much-explored method of tapping solar energy is the photovoltaic conversion of solar light to electricity. While a number of materials are known to enable this conversion, the most popularly deployed is semiconductor grade silicon. But, manufacturing semiconductor silicon is a very complex, elaborate and energy