Phasing out a polluting fuel

Banning the usage of heavy fuel oils (HFO) in fuelling ships traversing in the Arctic region in July was a long-thought-out solution to a global problem. HFO has been a cheap but polluting source of fuel all along. Any HFO spill on the sea and accidental fire would release the most polluting emissions, black carbon being the most prominent and dangerous.

Black carbon is a particulate matter produced from the incomplete combustion of fossil fuels, biofuels, and biomass. It consists of pure carbon in many linkages and is the second biggest contributor to global warming, only next to carbon dioxide.

Black carbon’s presence near ice or snow sheets and glaciers in the Arctic and Antarctic regions can extend the snow melting period and result in environmental catastrophes caused by melting glaciers and rising sea levels. Its largest sources globally are diesel vehicles, open biomass burning, and the use of heavy fuel oil (HFO) for engine propulsion in shipping.

HFO, or bunker fuel or residual fuel oil, is a residue from petroleum’s distillation and cracking process. While the distillates are petroleum products from crude oil refineries, including diesel, kerosene, naphtha and gas, the residues (HFO) remain mixed with nitrogen, sulphur, and aromatics.

HFO is used as fuel to propel diesel engines and move marine vessels. Some developing countries, mainly African ones such as Kenya, Tanzania, Nigeria, and Somalia, use HFO largely for electricity generation, shipping, and heavy industry, while the polluting residue is used in asphalting roads.  The conventional method of disposing of it by incineration would produce black carbon.

Cheaper source of pollution

Marine vessels can use both distillates and residue for propulsion. However, HFO is preferred because it is 30% cheaper than petroleum distillates. On the flip side, it emits more toxic compounds and particulate matter, including black carbon, which are quite hazardous to human health and the environment. Nitrogen oxide and sulphur dioxide emitted in the atmosphere from using HFO in propulsion lead to serious respiratory diseases and cancer.

Due to its high viscosity and density, HFO’s atmospheric emission threatens flora and fauna. In 2009, the Arctic Council identified the threat to local marine life from HFO, especially during oil spill incidents. The high viscosity of HFO and cold temperatures in the Arctic region prevent its breakdown in the atmosphere. It can also pollute water columns and seabeds.

The Arctic region is marked by the emission of black carbon in the atmosphere. It has a short atmospheric lifetime of a week and returns to Earth with precipitation (snowfall). Ground and satellite observations suggest that the black carbon has a solar absorption of 0.9 watts per square meter in the region. It is thus the second most important factor for warming, only next to carbon dioxide. The rise in surface temperature in the Arctic region per unit of black carbon emission is greater than in any other region.

As part of the International Maritime Organisation’s (IMO) International code of ships operating in polar water, HFO is prohibited as fuel for ships travelling in the Antarctica region. In July, HFO was banned in ships moving in the Arctic region. 

At the insistence of IMO, eight countries—Finland, Germany, Iceland, the Netherlands, New Zealand, Norway, Sweden, and the United States—have initiated phasing out HFO in the Arctic region. However, Russia, Canada, the Marshal Islands, and many other countries have opposed phasing out HFO by 2030. To oppose the initiative, they cite the economy and the impact on the life of the indigenous population in the region and suggest mitigating the consequences.

The sulphur content in HFO can be up to 35,000 parts per million; thus, maritime shipping accounts for 8% of global sulphur dioxide emissions. This means that HFO is an important source of acid rain and respiratory illnesses. Impact on human health has been observed in highly populated port cities like Hong Kong. A study in 2012 revealed that particulate matter emissions from marine shipping have led to 87,000 premature deaths in a year worldwide.

Substitutes for HFO

There is growing awareness of the environmental impact of HFO. IMO has tried to promote cleaner fuel with less harmful effects. It has suggested choosing fuel with an allowable sulphur content of up to 1000 ppm for marine vessels from 2020 onwards.

Liquefied natural gas (LNG) is relatively clean and cost-effective, and it can be one of the alternatives to HFO if suitable infrastructure is developed. However, LNG sometimes has an Ammonia leak issue that again increases environmental costs. Scrubbers can capture 99% sulphur from exhaust gas, and marine vessels can utilise it to comply with the IMO’s regulations. This way, nearly 200 million tonnes of HFO being consumed annually can be cut to 50% by 2030.

LNG, methanol, and biofuels can be real substitutes for HFO. LNG needs infrastructure to develop. The Port of Rotterdam, the largest port in Europe, has expanded its terminal to load small LNG vessels and tankers to distribute LNG to all ocean-going vessels from there. Singapore is investing heavily in LNG, and bunkering facilities are open around the Baltic Sea, as in Finland.

Methanol, as a maritime fuel, has a distinct advantage. It reduces the emission of Nitrogen dioxide, sulphur dioxide and particulate matter. Storage and handling facilities are close to many major ports; they can also easily be stored and handled on board. Green and blue methanol can be made from biomass and green and blue hydrogen and is environment friendly. However, the shipping industry will take some time to get it till its prices become comparable.

(The writer is a retired principal chief conservator of forest (Head of Forest Force) Karnataka)