New Delhi: The ministry of environment and forests has stepped in to promote a “cheaper” and more “eco-friendly” desalination technology developed by the Chennai-based National Institute of Ocean Technology (NIOT) that was not finding any buyers.
Since 2007, the technology, called low temperature thermal desalination (LTTD), has been used in pilot tests in plants in Lakshadweep, the Andaman islands and Chennai. But no company showed interest in using it at its plants, as reported by Mint on 20 July 2007.
Now, the environment ministry has directed all power plants that come up along the coast to use LTTD, failing which they will have to furnish an explanation. Power plants use desalinated water in their boilers.
“We have recommended this to energy companies,” said a ministry official, who did not want to be identified. “We cannot force them to use it. Many companies say yes in the meetings but we have to see (the) final response.”
NIOT had presented the technology to the ministry in February, after which the ministry issued the directive.
Power plants on the coast currently rely on costly technologies such as reverse osmosis for desalination. In LTTD, seawater is collected in a vacuum cylinder. Low pressure in the tank brings the water to a boil. The resulting steam is routed into another air-filled chamber, where it condenses into fresh water.
The environment ministry official said the technology is considered eco-friendly as it does not generate highly saline water or brine at high temperatures as effluents.
The earth sciences ministry, which funds NIOT, is excited by the proposal. “We had made a presentation to the earth sciences ministry,” said secretary Shailesh Nayak. “Also, the power plants seem optimistic about this technology, because it’s been tested quite well at pilot levels.”
LTTD’s pilot projects include a 100 million litres per day desalination plant that supplies drinking water in Lakshadweep, and the 600MW North Chennai Thermal Power Station, where the technology is used to power the turbines.
Power plant operators say they will not adopt a technology unless it is proved to be viable. “We are currently not aware of such a technology by NIOT,” said R.S. Sharma, chairman and managing director of NTPC Ltd. “Unless we are convinced of its viability, we will not adopt it. Moreover, we usually rely on commercially validated technology.”
Pradeep Lenka, president and chief executive of the GVK Group, which develops power projects, said LTTD falls under the category of geothermal techniques, which are yet to be validated. “One of the problems with the geothermal approaches is that there are residues of silica and other material which affect boilers. So all this has to be accounted for before we take up a tech. No ministry can force us on the tech to be adopted,” he said.
Sanjeev Agrawal, managing director of AMPLUS Infrastructure, another power project developer, is more optimistic about LTTD. “Current desalination techniques are expensive, and this approach sounds reasonable,” he said. “This is a smart move by the ministry. With this we can understand the tech better, commission experts to study it and let them validate it. If there’s a consensus, we won’t have a problem.”