The seas are throbbing with energy. The ocean swells — the up-down movement of the water — is a source of energy, as are the tides, underwater currents and the crashing of the waves. All of this is steady, base-load energy, unlike other renewable energy sources that supply intermittently.
But mankind is yet to tap this energy source, save for sporadic efforts in the UK, Brazil and Denmark, among other countries. The problem is the cost , but that is not insurmountable. Technology and scale have always tamed costs, as was seen in the case of solar equipment and electric vehicles among several instances. Besides, until recently, there was no big need to go gunning for ocean energies. But the climate crisis has changed the dynamics.
Though precious little has been attempted in India to tap oceans for energy, a report by IIT-Madras and CRISIL estimates there is 40,000 MW waiting to be harnessed from Indian seas. Now, a team of researchers at Indian Institute of Technology, Bombay, has analysed wave data from coastal regions to ascertain the best locations for wave energy plants.
The team, led by Prof Balaji Ramakrishnan of the Department of Civil Engineering, focused on two key parameters — ’significant wave height’ (SWH) and the time a wave takes to pass a point. These together give an idea of the ‘wave power’.
For the computer-based study, they used 39 years’ worth of wave data for India’s coastline from the European Centre for Medium-Range Weather Forecast. “We analysed data to understand SWH and wave power variations over seasons across several locations,” Ramakrishnan told Quantum. These studies, he says, are essential to zero in on the appropriate technology for energy harvesting.
Simulated waves
The study is still at a preliminary stage. Ramakrishnan says the team ran several numerical models on computers and then validated some of the findings with actual measurements at the sites. Computer simulations of ocean dynamics and analysis of wave data give some idea of the places where wave energy plants could come up. However, “we need to collect more data”.
The idea is to first identify high-potential zones, and then pick the best locations within the zones for the wave energy plants, Ramakrishnan said.
Ramakrishnan’s work has been published in the journal Regional Studies in Marine Science. The paper notes that the southern tip of India, with high wave power and fewer variations, is best suited for wave energy plants.
Since solar energy is abundantly available during non-monsoon months, the study suggests combining solar and, perhaps, wind with wave energy plants.
Ramakrishnan said they could look for innovative ways of reducing costs. For example, some wave energy plants could be located on the breakwaters put up for fishing harbors. He says ocean energy presents a ready opportunity for energising hundreds of islands, replacing diesel gensets.
“The knowledge gained through this IIT-Bombay study can help narrow down the focus of future studies by indicating possible locations for power plants,” says an article on the institute’s website.
India-specific devices
The assessment of wave energy potential is the first step to setting up large-scale wave power plants. A detailed estimation of available marine energy, investigation of feasible and optimal technologies, innovating devices specific to Indian conditions, data collection to ascertain the estimates, and analysis of environmental impact are needed to actualise the potential of wave energy, the article says.
Tapping the oceans for energy is not a new concept — the climate crisis has renewed the focus on it. IIT-Madras has signed a joint development agreement with a start-up, Virya Paramita Energy, under which Prof Abdus Samad of the Department of Engineering Design, who has worked on ocean energies for a long time, will develop a technology called ‘point absorber system’ for deployment at several locations.