HARNESSING OCEAN RESOURCE: CASTLES IN THE AIR?

According to a McKinsey study ‘Powering India: The Road to 2017’, if India is to grow at 8 percent for the next ten years, its power requirement may rise from 120 GW to 315 to 335 GW by 2017, requiring an investment of $600 billion on adding the required capacity. Studies are increasingly showing the requirement of renewable sources of power generation with some pegging the required generation at 50% within the next 3 decades. There have been rapid strides in the field of unconventional energy sources like solar and wind all around the world as well as in India with the emergence of ventures like Suzlon and SELCO. But somewhere down the line there has been a failure to recognise and harness the infinite potential of ocean and tide generated electricity. India of course has followed suit.There are mainly 4 forms of obtaining energy from the ocean – tidal, wave, ocean thermal energy and osmotic. Using the currently available technologies most of which are pretty nascent, global generation potential for wave power is estimated to be 500 GW. The tidal energy market potential is around 50-100 GW according to French engineering giant Alstom. Hence, it is hardly surprising that they very recently set up their Ocean Energy Business at Nantes. Another big name to have already entered the market is Lockheed Martin who received the largest federal ocean energy award in 30 years to develop inroads into Ocean Thermal Energy Conversion (OTEC).

Waves and tides are a regular source of power with an intensity that can be accurately determined several days before their arrival. This makes them more prdictable than wind or solar. The footprint of a 100MW conventional power plant superstructure, including surrounding grounds, fuel unloading areas, waste settling ponds, and additional facilities can require up to 2 square miles of valuable real estate. A comparable power plant using ocean energy would occupy less than 1 square mile of unused ocean surface. The power potential per unit area is 15-20 times that of solar or wind as well. Also, since a significant proportion of the population lives in coastal areas, the transmission losses which are amongst the highest in India can be reduced by decentralized generation.

Coming back to the domestic picture, India has a coastline of 7500 Km. Ocean waves around the Indian coast have an average energy potential of around 10 kW/m while the peak value for monsoon is as high as 20kW/m. Taking a conservative estimate of 10% utilization we get at least 7500 MW of power. With time the efficiency and operability of the conversion devices is only going to increase and it does present an encouraging scenario. Considering the potential of tidal power, locations like Gulf of Cambay and Gulf of Kutch have generation potential of 8000-9000 MW with average tidal ranges 6.77m and 5.23m respectively. The Sunderban Delta is suitable for small scale projects with a tidal range of 2.97m.

The limited efforts that have been made have shown favourable results. The prototype developed by IIT Madras under the sponsorship of Department of Ocean Development, Government of India at a cost of Rs 99 lakh has reported production costs of Rs 0.73 per unit. Hydroelectricity generators produce at Rs 1.5 per unit, wind generators at Rs 3 per unit while for solar cells it is Rs 15-30 per unit. A low cost wave energy converter is being developed at IIT Kharagpur under the National Program in Marine Hydrodynamics. The Kutch Tidal Power Project in India with an installed capacity of about 900 MW estimated to cost about Rs 1,460 crore is generating electricity at about 90 paise per unit.

However, it isn’t a fairytale all along. The operating environment of devices harnessing ocean energy is very challenging and leads to high installation costs. At present, more than 80% cost of the wave energy plant is due to civil construction. Developers of wave energy converters have to develop machinery that can operate and survive in this very rough environment and have to optimise operation and maintenance systems to make wave power plants a viable solution. However, it is clear that wave power can be much cheaper than, for instance, photovoltaic power and there are good reasons to believe that wave power in a few years will be a serious competitor to offshore wind power.