Decarbonizing Water Transport in the Sundarbans

The Problem

Lying on the delta formed by the confluence of rivers Ganga, Brahmaputra and Meghna, the Sundarbans is hardly unfamiliar with rivers and seas. The tides and rivers greatly influence the lives of the region’s inhabitants. Even today, cut-off from the mainland, inhabitants across 35 deltaic islands depend on a complex network of watercourses to meet inter-island transportation needs. The formal public transport system does not connect these remote islands. Thus, they depend upon non-standard, unsafe, and inefficient modes of transport and makeshift technologies. Ferry boats, the last-mile water transport, provide an illustrative case.

Ferry boats serve as a lifeline for the people living on the Sundarbans islands. These boats employ repurposed and inefficient diesel engines. Sometimes, due to unaffordability and/or unavailability of diesel, boat operators even use a mix of diesel and kerosene as fuel. Incomplete combustion of fossil fuels lead to air pollution. Moreover, leakages and spillages of fuel and lubricants into the watercourses leads to water pollution.

The Sundarbans is home to numerous species of mangroves, flora and fauna, including the diving and fishing birds. Water pollution, caused by water transport across the Sundarbans, poses a significant problem for all such biodiversity. Water pollution may result in the development failure of mangrove plant fruits and damage mangrove vegetation. Oil spillage can result in the mortality of grasses, seedlings of certain mangrove vegetation and of fish species. It can also hamper water quality and thus, affect the multiplication of phytoplankton and zooplankton and the breeding grounds of shrimp and prawn. With a large coastline of 6,100km, one can only wonder about the impact of non-standard diesel-operated watercrafts on the aquatic flora and fauna of the country. Air pollution too is harmful to the entire ecosystem, including the operators and travellers of boats.

A Potential Solution

To reduce water and air pollution, and GHG emissions in a sensitive ecosystem, WWF-India is piloting electrification of the last-mile water transport in Patharpratima, a forest-fringe block in the Sundarbans.

To decarbonise existing ferry boats, a retrofittable electric propulsion unit with an energy-efficient lithium-ion battery pack is installed.

Retrofitted with an 8Hp (6kW) electric outboard motor and a 96V-5.76kWh lithium-ion battery pack, the e-ferry boat can complete a minimum of 50 trips per day.

Operation of the e-ferry boat is generating performance data. Analysis of the data generated over the next six months to nine months will help ascertain the feasibility—both operational and financial—of e-ferry boats in the Sundarbans.

The Impact

Presently, four boats operate on the concerned ferry route. Each boat consumes around 1.5 litres of diesel per hour and runs daily for around 3 hours and 30 minutes. Thus, such boats in only one route emit 5tC02 per annum. The transition to a lithium-ion battery pack, charged using grid power, can help to reduce emissions by 3.5tC02 per annum. There are 41 other ferry routes across five forest-fringe blocks (Hingalganj, Gosaba, Basanti, Kultali and Patharpratima). The transition to e-ferry boats can, thus, aid emission reduction by 143.5tCO2 annually. The transition would also help to eliminate incidences of oil spillage and thus, water pollution. Therefore, such an intervention can significantly reduce the impact on aquatic flora and fauna and the mangroves in a sensitive ecosystem. It would also help to limit local inhabitants’ exposure to air and noise pollution.

Additionally, the transition would help to reduce the operational costs of ferry boat operators. At present, an average of 220 litres of diesel is used per day across the 42 water routes of the Sundarbans. Thus, an average annual cost of Rs. 80,48,250 is presently incurred by boat operators. The widespread adoption of the intervention across the Sundarbans can thus, eliminate such a heavy cost.

The intervention produces a win-win situation for biodiversity as well as terrestrial inhabitants. Decarbonizing water transport across India’s mainland coastline, thus, represents a huge opportunity to reduce pollution and emission and therefore, reduce the impact on aquatic and terrestrial life and thus, on sensitive ecosystems.