The field of solar energy was ignored for a long time on the contention that the technology was costly and efficiency low. But that is no more the case, said experts at a recent conference on solar energy, Solar India 2007.
With solar power available in most places in the country for up to 300 days, and with plenty of the resource (a few billion years of the sun’s lifetime!) there is no reason why solar power cannot take the lead in meeting the demand.
Innovations and research have been improving by leaps and bounds and there is hope that we will soon have efficiencies of 40 percent and more. Thin film technology shows tremendous progress.
Besides new ideas like using antennas that convert sunlight to electricity are being tried out. Unlike the radio waves, etc whose size is quite big and demands a large antenna, sunrays are in the micron range of frequency and require very small antennas, said Yogi Goswami, an international solar technology expert. This will assure 90 percent conversion.
From nanoscale antennas to biological antennas is another idea being studied, he said.
CSP technology
Research aside, the experts are advocating concentrated solar power (CSP) as the option for India. A global market initiative for CSP sees a possibility to build 5000 MW by 2015 and up to 40,000 MW worldwide by 2025.. Scaling up is possible and storage upto 22 hours. There are already over 15 projects with a total capacity of 2000 MW in the Europe and the US.
Concentrating solar power systems use concentrated solar radiation as a high temperature energy source. The first commercial plants have been in operation in California since the 80s, providing 354 megawatts.
These systems include parabolic troughs, power towers, and dish/engine systems. They can be used to give steam to drive the turbines or even drive chemical reactions for the production of fuels and chemicals.
CSP can almost meet the entire needs of the country with just an installed area of 65x65 kilometres, with the existing technology, said experts.
Interestingly, two students of Agricultural engineering College, Coimbatore have come up with an idea to use discarded CDs to form the reflectors in solar collectors. (Reflectors are mostly used in solar water heating at present). Just with half of the 150 million CDs produced in a city like Delhi, one can have a collector of area 15 lakh square metre!
Integrating solar PVs into rooftops is an idea catching up with architects coming up with attractive designs. The million solar roofs programme in California envisages 3000 MWs of rooftop electricity by 2017. In Germany during four years, one lakh roofs programme generated 350 MW of electricity.
The Karnataka Renewable Energy Development Limited (Kredl) has taken up a hybrid solar-wind power system to bring down the costs. This system incorporates a wind turbine which can be set up on house tops alongwith the PV module and can easily generate around two units of electricity, explained the MD, Dr Shivalangaiah.
Just a mirror!
Amidst such high-target ambitious programmes, there are also the smaller initiatives which need to be lauded. Like Vasanthkumar Mysoremath who won the World Bank innovator award this May for his simple idea that can save many units of electricity. Using a mirror positioned outside to catch the sun’s rays and send it in through a window to fall on the plywood ceiling, he has brought ‘moonlight during daytime’ into rural homes.
One 40 watt bulb burning for 25 hours consumes one unit of electricity and seven units per month would amount to Rs 14. Even if one lakh people use his method of lighting, 62 lakh units caould be saved, he explains!
He plans to take up his USee project of free lighting at the Infant Jesus church in Bangalore.
With fossil fuels fast depleting and harming the atmosphere and the planet’s health, it is imperative that governments the world over switch on to solar power. Excuses can no longer put off this.
