On 1st January 2020, the maximum permissible global sulphur content of marine fuels is reduced from 3.5 % to 0.5% according to MARPOL Annex VI.
It’s essential to life, but its presence in the atmosphere as sulphur oxides (SOx) can, at high concentrations, cause many health and environmental problems.
Until now, the shipping industry has been one of the greatest emitters of sulphur oxides (SOx) – in 2007, for example, ships emitted 15 million tonnes of SOx, approximately 5-8% of global emissions.
The IMO began regulating shipping’s environmental impact with MARPOL 73/78 (the International Convention for the Prevention of Pollution from Ships, 1973 as modified by the Protocol of 1978).
Then, in 2005, Annex VI of the convention came into force, for the 1st time limiting the sulphur oxide (SOx) and nitrogen oxide (NOx) levels in ships’ emissions.
In terms of SOx, the 1st global limit set was 4.50% mass/mass (m/m) sulphur in fuel oil.
In addition, Annex VI also established Emission Control Areas (ECA), a small number of limited zones around several major population centres, where the sulphur limit was set much lower.
In 2012, the global limit was dropped to 3.50% m/m.
Then in 2015, the ECA zone limit was lowered to 0.10%.
In 2020, the ECA limit stays, but the global limit drops to 0.50%.
Despite some concerns that both the shipping and refining industries need more time to prepare for the change, the ships globally now have to use low sulfur marine fuel oils with a sulfur content less than 0.5%.
Before the entry into force of the new limit, most ships were using heavy fuel oil.
Derived as a residue from crude oil distillation, heavy fuel oil had a much higher sulphur content which, following combustion in the engine, ended up in ships’ emissions.
We can expect the post-2020 fuels to fall into 5 main categories:
- Ultra-low sulphur fuel oil (ULSFO), max 0.10%. These types of fuels are mostly neat distillates.
- Very-low sulphur fuel oil (VLSFO), max 0.50%
- Heavy fuel oil, max 3.50%
- LNG. The cost of refit, manufacture, transport, and storage rule it out as a viable option for most operators.
Others. For example FAME (fatty acid methyl ether) – fuels extracted from waste plastic, methanol, other new types not yet on the market.