Prime Minister Narendra Modi's vision of developing 'blue economy' to complement India's economic trajectory is getting onto the drawing board, with the development of an indigenous technology to tap ocean energy. India's maiden Ocean Thermal Energy Conversion (OTEC) project is coming up in Kavaratti, capital of the Lakshadweep archipelago, off the south-western coast after almost three and a half decades of initial plans.
India had planned to set up an OTEC plant way back in 1980, off the Tamil Nadu coast, but with the foreign vendor closing down its operation, it had to be abandoned, until a new vision to develop India's vast coastal resources was drawn up by NDA government. Chennai-based National Institute of Ocean Technology (NIOT), under the Earth Sciences Ministry has now developed expertise in design, assembly and deployment of deep sea pipelines, reviving India's hopes to explore Ocean Thermal Energy.
"The current OTEC project is being set up to power a desalination plant. The power expected to be generated is under 200 kW. It is in the design phase currently and is likely to be commissioned early 2019," Dr. Purnima Jalihal, Scientist at NIOT, Chennai, told the Indian Science Journal.
India is geographically well-placed to generate ocean thermal energy, with around 2000 kms of coast length along the South Indian coast, where a temperature difference of above 20oC is available throughout the year. That means, about 1.5x106 square kilometres of tropical water in the Exclusive Economic Zone around India with a power density of 0.2 MW/km2.
The total OTEC potential around India is estimated as 180,000 MW, considering 40% of gross power for parasitic losses. However, the cost estimates of ocean energy as against conventional energy is still being worked out, as the country is still in a nascent stage of development of the technology and start generation.
"It's too early to talk about costing. OTEC is capital intensive and is economical only at very large scales. The complexities and challenges in a large offshore OTEC plant are many and hence a land based small rating one is being attempted at Kavaratti to power a low temperature thermal desalination plant," said Dr. Jalihal.
Dr. Jalihal said, the plant in Lakshadweep is a land-based, since deep water is available close-by. For mainland, 'we need to have an offshore platform mounted plant moored in deep waters'. She said, the Kavaratti plant is entirely an indigenous one.
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"OTEC holds promise for a large country like India with a long coastline. After this attempt in Kavaratti, scaling up for mainland will be taken up," added Dr. Jaihal.
Ocean thermal energy conversion uses the temperature difference between cooler deep and warmer shallow or surface seawaters to run a heat engine and produce electricity. It is base load electricity generation system. OTEC is one of the continuously available renewable energy resources.