Sustainable Water Transport and Low Emission Fuels

By: S C Misra and Eswara Arun Kishore
Water transport is recognised as the cheapest mode the world over. However, the rapid development of the sector and fossil fuels can emit pollutant and greenhouse gases. It is imperative, hence to opt for cleaner fuels for sustainable water transport.
English Free Article Water

The World Commission on Environment and Development (WCED), or the Brundtland Commission, as it is commonly known, had defined sustainability in 1987 as ‘development that meets the needs of the present generation without compromising the ability of future generations to meet their own needs’. Transportation refers to mobility of passengers and cargo. Sustainable transportation should thus enhance economic growth and improve accessibility without adversely affecting the environment or people’s health. It should be our collective aim to create a safe, secure and efficient transportation system alongside a clean environment.

Water transport system

Where movement of cargo is concerned, transportation could be by air, road, rail, pipeline, conveyor or water. Pipelines are used to move liquefied cargo such as oil and liquefied gases, while conveyors are used primarily for the transportation of ores and coal. Cargo can comprise general or break bulk cargo, standardised containers, solid bulk cargo such as grain, ore or liquid cargoes such as oil, chemicals, as also roll on roll off (RO-RO) cargo such as cargo on wheels. Cost of transportation of cargo in water is the lowest and that is why more than 90 per cent of international cargo is moved by sea, especially by China, Europe and the US.

In India however, the situation is quite the reverse. Table 1 shows approximate operational costs per tonne-mile of cargo transportation in various modes of transportation in India and across the world. The difference in international and Indian costs is primarily due to the lack of infrastructural development of waterways in India and adverse local conditions. It is nevertheless clear that even with lack of infrastructure, waterways still is an attractive means of transportation in India. The infrastructural costs for inland waterways and coastal shipping are comparable to other modes. A single km of railway track costs INR 5 crore to be laid, while a railway siding costs anywhere above INR 10 crore; building a two-way roadway costs upwards of INR 4 crore. Compared to that, waterways transportation costs just a fraction.

Table 1: Intermodal Comparative Operational Cost per tonne-mile
Table 1: Intermodal Comparative Operational Cost per tonne-mile
Table 2: Approximate modal transportation share (per cent)
Table 2: Approximate modal transportation share (per cent)
Table 3: Global CO2 emission
Table 3: Global CO2 emission
Table 4: Energy consumption and GHG emissions from transportation per tonne-mile (India)
Table 4: Energy consumption and GHG emissions from transportation per tonne-mile (India)

India has a 5423 km peninsular coastline, in addition to 2094 km around the 1256 islands in the Andaman and Nicobar group and Lakshadweep—a total coastline of 7517 km, waiting to be exploited. Further, as per the United Nations Convention on the Law of the Sea (UNCLOS) convention, India has the right to economic exploitation of an area upto 200 nautical miles from the coast as its exclusive economic zone (EEZ). With 12 major ports and 185 projected (by various state governments) minor ports along the Indian coast at present, along with an estimated 14500 km of rivers that could be navigable, and five national waterways declared on the Ganga, Brahmaputra, Kerala backwaters, Krishna-Godavari river system and Mahanadi-Brahmani river system, with 101 rivers identified to be developed in the near future, there is great scope for inland and coastal cargo and passenger movement in India.

Emission from water transport

Air pollution from marine operations are  mainly due to exhaust gases, such as carbon dioxide (CO2), nitrogen oxides (NOx, NO and NO2), sulphur oxides (SOx, SO2 and SO3), particulate matter (PM) and unburnt  hydrocarbons (fuel) from  diesel engines, boilers, auxiliary machinery, and waste combustion. Other sources of air pollution are refrigerants like freon and Bromotrifluoromethane (Halon) gases and evaporations from cargo. Freon and Halon are ozone depleting substances (ODS) which attack the earth’s protective ozone layer.

Ships use the cheapest grade of fuel—heavy fuel oil (HFO), which is the residual oil left behind from the crude oil refining process. This fuel contains sulphur which oxidises during combustion and is emitted as sulphur dioxide (SOx). However, inland vessels generally use diesel oil which has a low sulphur content and hence emits lower quantities of SOx.

Table 3 gives the share of green house gas (GHG) emission world wide due to various activities. International shipping causes about 2.7 per cent while and domestic water transport (including IWT) and fishing yields just 0.6 per cent of total carbon emissions. A look at data for India points towards low modal energy consumption and emission levels in India as far as water transport is concerned—only about 1 per cent of total transportation emission. This strengthens
the argument  for increased use of water transport in India.

LNG and CNG as alternate fuels

Reduction in polluting gases can only be achieved gradually. Use of LNG can reduce carbon emissions by about 25 per cent compared to HFO operation. SOx and PM emission is almost eliminated and NOx emission is reduced by as much as 80 per cent. However, methane, a constituent of natural gas, may continue to be emitted because of incomplete combustion. LNG can be liquefied either by cooling it to lower than -161oC at standard pressure (LNG) or compressing to high pressure (more than 200 kPa) at standard temperature (CNG). In both cases, tanks carrying LNG or CNG have to be fabricated into specialised vessels equipped with technologies that can maintain cryogenic conditions or high pressure. Accordingly ships must be designed to carry such LNG or CNG carrying tanks. Natural gas is also transported as cargo across the high seas in specially designed LNG carriers. Technologically sophisticated and expensive, these vessels need to move on long routes for economies of scale and have 100000 cubic m of carrying capacity. India has three such vessels operated by the Shipping Corporation of India.

The other necessity of operating such vessels is that these must call only at LNG cargo bunkering ports. There are only a few such ports, concentrated in Western Europe, USA and Japan. India has only one LNG loading terminal currently operating at Kochi port. GAIL, the major LNG operator, has been planning to develop storage and handling facilities at five major ports for some time, but this has yet to take concrete shape. Scandinavian nations, including Finland, have built about 5000 cum LNG ships to operate in the northern European waters.

Dual fuel engines operating both on HFO and natural gas have been developed to carry LNG and are being presently used. Fully LNG fuelled marine engines are yet to be designed, built and installed for shipboard use though some attempts have been made in the case of passenger ferries and offshore supply vessels in northern European waters. Unless LNG fuel bunkering facilities are provided at major ports, use of LNG as ship fuel will be limited.

However, non-availability of LNG makes its usability for inland water craft unviable in India, although CNG cylinders are available for use as road transport. Efforts ought to be directed towards the use of such cylinders, which can be used on board inland water vessels. Since inland movement comprises short length voyages, CNG cylinders could be hauled in at the numerous ports of call.

Renewable energy

Though use of LNG and LPG seems to be an immediate solution to the emission problem in the maritime sector, efforts need to be directed towards achieving a zero emission system for powering crafts for water transportation. In India, there is already some experience in using wind power for sailing at the ground level. Solar power could also be used as an auxiliary power source.


Inland and coastal shipping can be a viable alternative to move large amounts of cargo, which however necessitates the development of adequate infrastructure. The government’s announcement regarding the Sagarmala project is a welcome initiative in this regard. A shift to LNG for use as shipboard fuel can be a good move to substantially reduce GHG emissions, but due to lack of bunkering facilities, installation of LNG fired engines has been limited.

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