Chennai Plant To Tap Tidal, Thermal Energy
By- Binita Parikh

The world’s first ocean thermal plant will be started in Chennai from February 2002 said the Union secretary Dr Harsh Gupta. He said, "The 1 MW plant is in the developmental stage and has been developed indigenously by the National Institute of Ocean Technology."

Dr Gupta was in the city to attend a one-day workshop at Isro. He said that a 80 meter long barge was developed and the entire technology and the equipment is developed indigenously so India can export the technology to other countries. "We have already received inquiry from Mauritius for a deal for 30 MW plant," he added.

The plant is likely to cost Rs 45 crores. "But lot of developmental cost is a part of this cost," said Dr Gupta. The actual cost is likely to be Rs 6 to Rs 7 per unit while the acceptable cost is Rs 4 to Rs 5 per unit. "Of course, the cost of the land based power will be cheaper, but it should not be compared in this way. The biggest advantage for this technology is that it can be used for tropical islands which have to rely heavily on imported fuel."

Moreover, in small island nations, the benefits of Ocean Thermal Energy Conversion include self-sufficiency, minimal environmental impacts and improved sanitation and nutrition, which result from the greater availability of desalinated water and marine-culture products.

OTEC makes use of the temperature differential between the warm surface waters of the oceans heated by solar radiation and the deeper cold waters to generate power in a conventional heat engine. The difference in temperature between the surface and lower water layer can be as large as 50° C over vertical distances of as little as 90 metres in some ocean areas.

To be economically practical, the temperature differential should be at least 20° C in the first 1,000 metres below the surface. In fact, the oceans cover a little more than 70 percent of the Earth’s surface. This makes them the world’s largest solar energy collector and energy storage system.

Ocean thermal energy conversion is an energy technology that converts solar radiation to electric power and it uses the ocean’s natural thermal gradient — the fact that the ocean’s layers of water have different temperatures — to drive a power-producing cycle.

As long as the temperature between the warm surface water and the cold deep water differs by about 20°C (36°F), an OTEC system can produce a significant amount of power. The oceans are thus a vast renewable resource, with the potential to help us produce billions of watts of electric power.

Republished from The Asian Age