The biggest hope is that rapid strides in technology will render solar power an economically viable energy source in the near future- Radhakrishna Rao
The sun has always fascinated man. In fact, the ancient Indian religious lore has been replete with fulsome hymns in praise of the life giving qualities of this veritable dynamo inexhaustible energy. In particular, Vedic texts describe the sun as the remover of darkness and sustainer of life on earth. And of course, for many years now the sun has been receiving the increasing attention of energy experts to put an end to the energy crunch nagging the earthlings.
Interestingly, it has been estimated that the volume of solar energy hitting the earth is more than twice that generated by all the forms of energy sources -- both conventional and non conventional-- put together. To cut the long story short, the energy received from the sun in just one hour is sufficient enough to meet the entire global energy demand for around one year.
However, tapping the solar energy with earth-based devices is fraught with uncertainties for the simple reason that not only does solar energy remain diffused but also its intensity varies in relation to the time of the day and climatic conditions. Moreover, under conditions of cloud and haze, it may not be possible to receive solar energy. Add to this is that the currently available technology of solar energy systems are not efficient enough to make them economically viable proposition. However, advances in technology could go to popularize the solar energy devices on a large scale in the years ahead.
But the biggest advantage of solar energy is that it is abundant and non-polluting energy form. Indeed, as pointed out by the energy experts in the not too distant a future as the stock of the highly polluting fossil fuels keeps dwindling, the sun might hold the key to drive the engine of this "overrated and overcrowded planet". The biggest hope is that rapid strides in technology will render solar power an economically viable energy source in the near future.
Against such a scenario, space scientists from across the world are strongly advocating the need to give a big push to the concept of Solar Power Satellite (SPS) which has an inbuilt advantage of collecting solar energy without any interruption from its location in the gravity free environment of space. Moreover, the energy from an SPS can be transmitted to the earth in an eco friendly manner without an emission.
But the biggest handicap in giving a practical shape to the much- discussed idea of SPS is the enormous cost involved in transporting the vehicle the components of such a satellite for assembly in outer space. Right at the moment the high cost of using a heavy lift off space vehicle comes in the way of realizing the dream of an SPS System. However, with the advances in nano technology and micro electronics, it may be possible to bring down the weight of an SPS system by a substantial extent.
Similarly innovations in launch vehicle systems could lead to a drastic fall in the launch cost. The earth bound receiving system for solar power transmitted by the SPS could be made of many short dipole antennas. As such researchers are on the look out to make the SPS system competitive with conventional forms of energy currently in use. However, realizing an SPS system does not pose any engineering challenge or technological complexity.
Significantly, an overwhelming proportion of current satellite missions derive their energy from solar cells embedded on their outer space. The Government of India-owned power electronics and heavy electric equipment manufacturer Bharat Heavy Electrical Ltd (BHEL) is capable of producing space grade solar cells. It is also the supplier of solar cells for the satellite missions of the Indian Space Research Organisation.
For nearly four decades now, space researchers have been working on the idea of SPS to mitigate the energy crisis looming large over our planet. It was way back in 1968 that the American scientist, Dr. Peter Gloser, mooted the idea of developing a large array of solar power panels to be stationed in the geostationary orbit-36,000-kms above the equator where a satellite appears stationary in relation to the earth for all practical purposes-for tapping the abundant solar power and beaming it back to earth for its conversion into electrical power.
In a significant development, the California-based Space Island Group Inc is planning to raise funds with a view to launching two SPS into orbit by 2012. As envisaged now, these two satellites will generate electricity using the solar power and transmit it to the earth in the form of microwaves. According to the Space Island Group, everything going as planned the companies would sell power to India and China at 10 cents per kilowatt power without a hike in prices till 2030.
The biggest plus point of placing a solar power generating system in space is the unobstructed view of the sun irrespective of brightness and darkness, and seasonal changes .While on earth, the efficiency of a solar energy generating system is around 20 per cent, in outer space it is around 50 per cent.
Basically, the SPS concept envisages using the nearly constant availability of sunlight in space to generate electricity on earth. The energy would then be beamed from SPS to earth using either microwave or laser transmission systems. Significantly, the concept of SPS has evolved further to include such exciting options as lunar-solar power where the solar energy stations could be located on the moon. This would obviously have the advantage of easing construction in addition to the fact that the moon can serve as a very stable platform. On its part, India too has evinced interest in SPS, though at this point it is a very elementary conceptual stage. The intensity of sunlight in outer space is much higher than on earth.
Americans, Russians and Europeans are all in the race to evolve technological innovations for realizing an SPS system that would ultimately pave the way for the realization of a technologically advanced and economically efficient space-based solar power generation system with a view to finding a solution to the energy crisis facing mankind.
-INFA
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Tuesday, February 09, 2010
