India is estimated to have a potential of around 54 gigawatts of ocean energy – tidal power (12.45 GW) and wave power (41.3 GW) – but it is yet to be of practical use as the Union Ministry of New and Renewable Energy said the estimated potential of tidal and wave power is “purely theoretical and does not necessarily constitute a practically exploitable potential”.

A parliamentary panel has now asked the Centre to go back to the drawing board and “reassess” the potential of tidal, wave and ocean-thermal power to “explore the practically exploitable potential”.

Ocean energy refers to all forms of renewable energy derived from the sea including tidal power which is harnessed by converting energy from the natural rise and fall of ocean tides and currents to electricity. Wave energy in the form of motion of ocean waves can be extracted using energy conversion devices.

In fact, it has been about 40 years since India started efforts to assess and harness tidal power but it is yet to achieve any solid breakthrough in its development even as the country made rapid strides in boosting other sources of renewable power.

Prasad Kumar Bhaskaran, who works in the Department of Ocean Engineering and Naval Architecture at the Indian Institute of Technology, Kharagpur said that India has a good potential for extraction of tidal energy both along the eastern and western coasts of the country. “There is potential for tidal energy in India, but India is yet to develop a technology or major project for tidal energy,” he said.

However, for wave energy, Bhaskaran said that though India has potential in the southern states, high wave activity prevails only during the southwest monsoon season. “There is a potential to develop a wave energy project along the Kerala coast, the only suitable location to harness wave power in India,” he said.

Adapted from National Energy Education Development Project.

One of the reasons, according to the ministry, for not pursuing tidal power is “exorbitant cost”. India had started two tidal power projects of 3.75 megawatts and 50 megawatts installed capacity in 2007 and 2011 in West Bengal and Gujarat respectively. But both these projects were dropped because of exorbitant costs. In the case of the 3.75 MW Durgaduani tidal power project in West Bengal, the project cost was Rs 238 crore – which is about Rs 63.50 crore.

While in the case of the 50 MW tidal power project at the Gulf of Kutch in Gujarat, the estimated cost was Rs 750 crore – which is about Rs 15 crore for every megawatt of power.

The cost of power from such tidal power plants is too high, according to the ministry, which states that the “normative cost of installation of one MW solar, wind, biomass, hydro and thermal power plant is Rs 3.5 crore, Rs 5.5 crore, Rs 6 crore, Rs 10- Rs 15 crore and Rs 5 crore respectively”.

However, the parliament’s standing committee on energy, led by Janata Dal (United) leader Rajiv Ranjan Singh alias Lalan Singh, was not convinced with the argument about costs. The committee said that comparing the project cost of tidal power “that was arrived at around ten years back with the present project cost of solar, wind and hydro is not justified”.

“The cost of tidal power may have come down in the last ten years as is the case with other renewable energy like solar power,” said the Committee while recommending to the ministry to reassess the cost of tidal power to “consider its economic viability and benefits in a longer time span”.

However, according to the report of the parliamentary panel, the ministry is not very confident about the development of tidal power due to financial, technological, environmental and other risks.

“Globally, tidal energy is not cost-competitive and is still at a nascent development stage,” said the ministry. “Efforts to set up tidal power projects in India could not succeed primarily due to techno-economic considerations.”

The ministry informed the panel that tidal power represents the smallest share (about 535 MW) of the global installed capacity of renewable energy. It said two tidal power projects, 240 MW La Rance station in France (installed in 1966) and the 254 MW Sihwa plant in South Korea (installed in 2011), constitute more than 90% of the total installed capacity of tidal energy.

The ministry said that, at present, tidal power technologies are not cost-competitive and the main focus is on technology development. On this, the panel said that the ministry may “also evaluate global experience in this regard”.

A tidal power plant in the Netherlands. Photo credit: TTCTW2016NBU/Wikimedia Commons

Pilot project

The panel exhorted the Ministry of New and Renewable Energy to actively work in the development of tidal power and asked to set up “one demonstration/pilot tidal power project at the most favourable cost-effective location like Gulf of Kutch considering that the capital cost of a tidal power project is site-specific”.

PK Bhaskaran of IIT Kharagpur explained to Mongabay-India that the Gulf of Khambhat in Gujarat “has a very good potential as the tidal range between high and low waters is about 11 meters-12 meters”.

“The tidal range in the Gulf of Kutch is about 8 meters,” he said. “The tidal currents can reach a strength of about 3 m/s. While on the eastern coast, the Sundarban region has a tidal range varying between 6 meters-7 meters, which is also a potential region to extract tidal energy.”

He emphasised a recent initiative by the Indian government in collaboration with the United Kingdom to develop tidal power. “To develop the tidal energy project, a joint team of researchers from the United Kingdom and India had undertaken research work in the Sundarban region a couple of years ago. Suitable location in the upstream of Bidyadhri River has been identified for a demonstrative project, however, the work could not progress much due to Covid-19 situation,” informed Bhaskaran, who was a member of that joint team.

Apart from disproportionately high cost, “adverse environmental impacts that have not yet been fully documented” is another reason for the authorities to not actively pursue tidal power projects.

The committee also noted that no study has been conducted for the assessment of the environmental and ecological impact of a tidal power plant. During one of its meetings, the ministry had informed the parliamentary panel that “a barrage across an estuary may environmentally impact a very wide area ranging for many miles upstream and downstream”.

“Many birds that rely on the tide uncovering the mudflats for feeding could be affected. Further, damages like reduced flushing and erosion can change the vegetation of the area and disrupt the ecological balance,” the ministry had said.

The parliamentary panel observed that while seeking to harness the potential of tidal power, there is also “a need to pragmatically assess the environmental impact and ecological sustainability of tidal power plants”.

Spending on research

The parliamentary panel was also miffed with the ministry for not spending any funds on the development of tidal energy. It observed that the funds allocated to the Ministry of New and Renewable Energy “for R&D in Renewable Energy Sector as a whole had been drastically reduced” and recommended that the ministry “instead of curtailing R&D, should enhance its support significantly, particularly for un-harnessed sources like tidal power, which can go a long way in realising the vast potential of renewable energy in the country”.

India has a target of installed capacity of 175 GW by 2022 and 450 GW by 2030. Though tidal power is not included in the 175 GW target, the Ministry of New and Renewable Energy said, “all sources of renewable energy, including tidal energy, will be considered in the deployment targets for 2030”.

In August 2019, the central government had issued a notification clarifying that energy produced using various forms of ocean energy such as tidal, wave, ocean thermal energy conversion, “shall be eligible for meeting non-solar renewable purchase obligations”.

The renewable purchase obligations is a mechanism under the Electricity Act 2003 by which the big consumers have to purchase a certain percentage of their total consumption of electricity from renewable energy sources.

When the panel asked the ministry the rationale behind making tidal energy eligible for non-solar renewable purchase obligations in 2019 even when the country has not been able to harness any tidal power so far, the ministry said it was “in response to inquiries from industry” and the “inclusion was made to take care of the possibility that projects for producing such energy might be set up”.

The panel asked the ministry to actively follow up on the notification “through appropriate incentives so that the country can have commercial tidal power projects by the year 2030”.

This article first appeared on Mongabay.