The world's oceans are crowded with commercial vessels, which belch out a multitude of harmful substances that damage the environment and endanger human health. But with the shipping industry embracing new technology and more sustainable practices, it could improve its ecological credentials by some margin.
A new age of sail? Sea cargo goes green
A new age of sail? Sea cargo goes green
Global shipping is responsible for one billion tonnes of greenhouse gases a year – emitting as much as an entire economy the size of Germany. However, it only ever features in the debate about the environment when disasters like the Exxon Valdez oil spill hit the headlines.
At the time of the 1989 tragedy, which occurred when a supertanker hit a reef off Alaska, images of thousands of dead seabirds and seals prompted moral outrage. Yet the 11 million gallons of crude that washed onto 1300 miles of Alaskan coastline are nothing compared to the cargo shipping industry’s overall impact on the planet.
In addition to their CO2 emissions, cargo ships belch out more sulphur dioxide (SO2) and nitrous oxide (N2O) than any other form of transport. At the current rate, by 2025, the industry will emit some 10,000 kilotonnes of these harmful substances per year, more than the economies of the European Union combined.
Sea freight: an important ecological impact
Ships are responsible for almost 800 million tonnes of CO2 per year – which represents 2.2% of global emissions. Although this figure has decreased since a peak in 2007, it is still double when compared to 1990. In comparison to road and air, sea cargo is clearly cleaner, but the enormous volume of goods traveling by ship magnifies its global environmental impact.
“The impact of shipping pollution worldwide is huge,” warns Sotiris Raptis of Transport and Environment, a major European non-governmental organisation. In Europe alone, he says, 50,000 deaths can be attributed indirectly to shipping.
So, what is being done to make international shipping sustainable?
Pressure to change
In 2013, the International Maritime Organisation (IMO) began ratcheting up the pressure on shipping companies, successfully imposing new emission restrictions on air pollution for ocean-going ships and introducing stringent design-efficiency standards on new vessels.
IMO’s pollution measures include limits on CO2, SO2 and N2O – the exhaust emissions most harmful to human health and the planet. Now applied worldwide, such regulations are having a significant impact on vessel speeds, engine designs and fuels, to such an extent that the days of heavy fuel oil (HFO) – the dirtiest, thickest, most polluting fossil fuel firing the engines of marine transport – look numbered.
Shipping companies are also under pressure to adopt sustainable practices from other industries. Of course, there is more that must be done to ensure regulations are effective.
As John Kornerup Bang, chief advisor on climate change for the Danish shipping giant Maersk Group warns, enforcement must be worldwide rather than regional. “Regarding SO2, we are concerned that adequate enforcement mechanisms are not in place to avoid cheating, and for CO2 we emphasise that rules need to be global and must reward early movers.”
Still, the signs are positive. Better regulation is slowly proving to be a force for positive change.
A matter of logistics
In the years following the 2007 global economic downturn, a perfect storm of high fuel prices, low freight rates and a slowdown in the growth of world trade, gave shipping companies an incentive to improve their efficiency.
As a result, slow steaming is now the industry norm: speeds have been slashed from the standard 25 knots (nautical miles per hour) down to 20 knots, with many companies cruising as slowly as 12 knots to save fuel. Studies conducted between 2007 and 2012 showed that this change alone can reduce emissions by up to 70 per cent, depending on the size of the vessel.
Maersk Line has made further efficiency savings by controlling its fleet from a single location.
“Our Global Voyage centre in Mumbai monitors our vessels 24 hours a day, seven days a week,” explains Signe Bruun Jensen, the company’s Global Head of Sustainability. “Every ship is connected to shore via GPS and satellite communications, allowing us to monitor speed, fuel efficiency, weather conditions and other relevant parameters.”
Although the global economy is recovering, shipping companies are likely to keep slow steaming and other efficiency measures, given their positive financial impact.
A sea change in technology
Over the longer term, shipping can only become truly sustainable through technological innovation, much of which is already within reach. Maersk Line’s latest Triple-E vessels (the ‘Triple-E’ stands for energy efficiency, economies of scale and environmentally friendly) slash emissions by half for every container shipped.
“Two ‘ultra-long stroke’ engines, an innovative efficient hull shape for slower speed and advanced waste heat recovery system have improved CO2 efficiency per container moved dramatically,” Mr Jensen explains.
Greater gains will come from the use of fuels cleaner than HFO. Liquid natural gas (LNG) is a viable and relatively clean option, though its adoption will require major investments in pipelines and new refuelling facilities.
Other solutions are marine gas oil and marine diesel oil. HFO-powered vessels can be retrofitted to use these distillates, though they remain more expensive than current fuels.
Even so, neither of these options would completely solve the greenhouse-gas emissions problem. “Do we really want to introduce LNG or distillates when they are still fossil fuels, and methane leakage is an issue?” asks Mr Raptis.
A renewables future?
A major change would see renewables like wind and solar energy playing a dominant role, and some shippers are already investing in such technologies. Japan’s Eco Marine Power has developed solar sails it claims can reduce a vessel’s annual fuel consumption by up to 20 per cent. Also under development at Ocius in Australia, solar sails consist of multiple rigid sails fitted with solar panels. These are being retrofitted to commercial ships along with fuel cells to store electricity generated until it is required.
Another wind-assistance technology is being pioneered by Germany’s SkySails. The company’s innovative automated kites can generate up to 25 times more energy per square metre than conventional sails, resulting in a 10-35 per cent reduction in fuel consumption.
Taken together, regulation, operational efficiency and new technologies are transforming a rigid and conservative industry into one in which sustainability is embedded in everything it does.
“This,” emphasises Maersk’s Bang, “gives shipping a licence to grow in tomorrow’s carbon-constrained economy.”