Tap the untapped sources

Wind and solar power projects can be made to work with government backing

Published: Thursday 31 December 2009

DownToEarth According to government estimates, 40-50 per cent of power generated in India goes waste. Government departments often have homilies about saving electricity. But transmission and distribution losses have not been set right. And the government is aiming to increase the countrys electricity generating capacity.

Lets suppose our planners agree to reduce losses and improve efficiency. Can we think of producing more electricity. How? Fossil fuels are depleting. All over the world, coal burning power plants face a crunch time. But our planners want to dedicate 4,000 MW thermal power plants to almost every state. From where will they get the coal?

Practically every river has a dam on it. So hydroelectricity is an overexploited resource. There are safety issues with the much-touted nuclear energy and nobody seems to know what to do with radioactive residues.

There are still untapped sources of energy. According to our ministry of renewable energy, the countrys solar energy potential is over 5,000 trillion kWH/yearestimated to be more than the total energy needs of the country. But harnessing this energy involves technologies still regarded niche.

Till the early 1980s, photovoltaic panels, which used the suns energy to move electrons and create electricity, were expensive and not very efficient. A very elementary form of tapping solar energy has been in use since 1988: the solar thermal power plant technology. Many of us would have heard of stories about people in ancient Greece shining mirrors onto ships to burn invading ships. The solar thermal power plant technology uses a similar mechanism. The operations are also a lot similar to traditional thermal power plants, except the use of solar energy.

The technology involves focussing sun rays on a central tower through an array of mirrors, generating steam at a high temperature and pressure at 1500C. The energy is used to turn turbines. A simple tweaking by Spanish scientists has made the system much more efficient. Small photovoltaic panels on each reflector mirror allow much more energy to be tapped.

Critics of solar power say its useless at night and at times when the sun is not shining. The parabolic trough collector systems answer such criticism. Arrays of long parabolic trough-like reflectors focus sunlight on to a pipe, which is connected to heat transfer medium. The receptacle, heats up to about 400C and is used to generate steam and run turbines. It can store the energy as well.

Bharat Heavy Electricals has some expertise in solar devices and the parabolic trough has been tried in India. But there were setbacks and that seems to have deterred the government. The central receiver pipe broke, and also the heat transfer medium proved costly.

A renewable energy ministry official once told this author, Companies are coming up with claims of delivering 50 MW and more of electricity, but we cannot sanction them without verifying if they would be able to deliver. If a company is unable to deliver the amount of electricity it claims it can, it is the companys problem. Unless, of course the government is offering them fabulous subsidies even for installation, as is being done for small hydro-electricity entrepreneurs.

Wind energy has made its presence felt in our country. According to the Indian Wind Energy Association, the installed wind power capacity is around 9587 MW, the fourth largest in the world. But because the cost of hydro power is much less than that produced by wind farms, states such as Tamil Naduwhich has probably the biggest wind energy farm of an installed capacity 2526 MWdid not want to buy wind power. This could be the problem with other states as well, if the economics of non-conventional energy are not adequate.

Ashok Kundapur, from Bengaluru, specializes in solar cookers. He is on a project to design community solar cookers

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