Nearly 3,850 zetta-joules (ZJ) of solar energy is available every year. At any given point of time, the earths upper atmosphere receives 174 petawatts of incoming solar radiation (insolation). About 6% of the insolation is reflected and 16% is absorbed when it enters the atmosphere.
Solar power is used to refer to the conversion of sunlight into electricity. This can be done either through the photovoltaic effect or by heating a transfer fluid to produce steam to run a generator.
India has favourable natural conditions for large-scale harnessing and deployment of solar energy. Despite these favourable conditions, out of the total energy consumption of nearly 120 GW per annum, only a small fraction is generated through solar energy.
In our country, so far the solar energy equipment has been focussed towards rural, unelectrified areas as off-grid applications. Large-scale solar farms coupled with a promising feed-in tariff initially would be a right combination to kickstart the growth of the commercial solar energy industry.
Renewable energy is the best option to manage energy security concerns in the country. The current cost of photovoltaic (PV) energy may be relatively higher than the average cost of grid energy, given the high cost of input materials. However, with increasing prices of conventional energy, fossil fuel supply constraints and decreasing cost of solar energy, we are about to reach an inflection point where the solar energy costs will be in the realms of grid energy prices. It may happen sooner than later, given the current rate of progress.
With increasing scale and size and reduction in input material costs in next few years, the cost of solar energy should come down by about 25% by 2010. At those price points, it would become an ideal source of peaking power requirements of the grid and increasingly the base load requirements of the grid.
Globally, the growth in PV installations has been cata-ysed by favourable policies of countries like Germany and Japan, which have offered very attractive feed-in tariff rates for PV installations. Like those nations, India also needs to put in laws like feed-in tariff and favourable solar power-purchase-agreements (PPAs).
Ravi Khanna is chief executive, Moser Baer Photo Voltaic Ltd, a leader in photovoltaic systems