THE CONVERSATION
SHIPPING IS TOUGH ON THE CLIMATE AND HARD TO CLEAN UP THESE INNOVATIONS CAN HELP CUT EMISSIONS By Jing Sun, Professor and Department Chair, Naval Architecture and Marine Engineering, University of Michigan SHIPS CARRY MORE THAN 80 per cent of world trade, and they rely heavily on some of the least environmentally friendly transportation fuels available. There are no cheap, widely available solutions that can lower the shipping industry’s planet-warming carbon emissions – in fact, shipping is considered one of the hardest industries on the planet to decarbonise – but some exciting innovations are being tested right now. As a professor of naval architecture and marine engineering, I work on ship propulsion and control systems, including electrification, batteries and fuel cells. Let’s take a look at what’s possible and some of the fuels and technologies that are likely to define the industry’s future.
Shipping’s climate problem
“If shipping were a country, it would rank between Japan and Germany as the sixth-largest contributor to global carbon dioxide emissions.” 38 SPRING 2021
Shipping is the cheapest way to move raw materials and bulk goods. That has given it both an enormous economic impact and a large carbon footprint. The industry emits roughly 1 billion metric tons of carbon dioxide per year – nearly 3 per cent of global emissions, according to the International Maritime Organisation, a specialised UN agency made up of 174 member nations that sets standards for the industry. If shipping were a country, it would rank between Japan and Germany as the sixth-largest contributor to global carbon dioxide emissions. Moreover, nearly 70 per cent of ships’ emissions occur within 250 miles (400 kilometres) of land, meaning it also has an impact on air quality, especially for port cities. Technological innovation, in addition to policies, will be crucial for achieving low-carbon or zero-emission shipping. Academic research institutes, government labs and companies are now experimenting with electrification; zero- or low-carbon fuels such as hydrogen, natural gas, ammonia and biofuels; and alternative power sources such as fuel cells and solar, wind and wave power. Each has its pros and cons.
