Options on the Table
1. Use Cleaner Fuel
Burning ship fuel generates various pollutants that cause global warming such as carbon dioxide, black carbon and nitrogen oxides and sulphur oxides. Shipping contributed 1 billion tonnes of greenhouse gases (GHGs) from 2007 to 2012, and the total fuel consumed increased from 291 million tonnes to 298 million tonnes from 2013 to 2015. Using cleaner fuel is one major way such emissions can be slashed but also one met with much contention.
2. Tap on Renewable Energy
Alternative fuel sources such as wind and solar energy have been used to power ships. As early as in 2008, Japan’s cargo freighter, Auriga Leader, had obtained part of the energy required for the vessel’s operations via 328 solar panels fitted on it. More recently, Wessels has also developed a SkySails propulsion system — installed on its ships like ‘Thesus’ — that harnesses wind energy.
3. Slow Down
Slow steaming or simply moving at lower speeds is an easy and effective way to cut fuel consumption — and thus emissions of air polluatants— considerably. The IMO estimated that a mere 10% reduction in speed across the global fleet by 2010 would result in a 23.3% reduction in emissions, and Hapag-Lloyd found that slowing some of their ships by five knots resulted in savings of around 50% on fuel cost.
4. Use Alternate Maritime Power (AMP)
Many ships rely on diesel generators which cause a lot of air pollution. By tapping on onshore electric power available when they dock through the transfer of electricity from shore to ship (cold ironing) or energy storage in batteries, the main engines don’t have to be used unnecessarily. This also provides a way for ships to use power from low-carbon energy sources without complex engineering considerations.
5. Increase Power Consumption Efficiency
Improvements in ship design such as optimisation of the hull and propeller as well as waste heat recovery systems can reduce emissions by as much as 5% per ship.