Zero Emission Shipping on the Horizon

​Electromethanol made from carbon dioxide and hydrogen can propel ships completely without emissions. Selma Brynolf investigates alternative fuels for shipping – an industry that hurries to reach tough environmental goals.

​Electromethanol
​Electrometanol is converted to hydrogen and carbon dioxide aboard the ship. The hydrogen is used for propulsion while the carbon dioxide is stored for reuse. Illustration from the HyMethShip project. © LEC.

​The UN International Maritime Organization, IMO, aims to reduce shipping emissions of greenhouse gases by 50 percent by 2050 and eliminate them completely over the century. Strict international rules for sulfur emissions in sensitive marine environments will be followed by stricter global rules from 2020. After a slow start, the shipping industry is waking up.

​Electromethanol
Selma Brynolf

“The goals are tough, but we really need to do even more,” says Selma Brynolf, doctor of maritime environmental sciences at Chalmers. In a newly launched EU project, she investigates the potential of electromethanol to achieve zero emissions from ships.

Carbon dioxide + hydrogen gas = electromethanol

Electromethanol is made from carbon dioxide and hydrogen, using renewable energy. On board the ship, a so-called reformer transforms the methanol back into hydrogen and carbon dioxide. The hydrogen is used in the internal combustion engine to propel the ship, while the carbon dioxide is stored in liquid form and pumped ashore when the ship is in port. The carbon dioxide can then be used to produce new electromethanol or be stored underground. This is the idea behind the project HyMethShip.

The need to store carbon dioxide on board and to leave it in port means that this is not a solution that will work for all types of ships.

“It will probably work best for ships that go on a certain route, and not for those who go the longest distances,” says Selma Brynolf. “For coastal and inland waterways, it may sometimes be possible to go ahead of the regulations. Perhaps electromethanol may first be used in these cases.”

International regulations most important for change

Electromethanol is far from the only solution for shipping. What else is being done to achieve the tough environmental goals for the shipping industry?

“Tests with fossil methanol, biofuels and electric propulsion are being made by different shipping companies,” says Selma Brynolf. “Liquid natural gas is an emerging option that that meets the sulfur and nitrogen oxide regulations. However, since the gas is a fossil energy source, the potential for reduced climate impact is limited.”

The Swedish shipping industry has adopted its own vision zero. But to achieve a far-reaching change, international rules and regulations by IMO is necessary. These need to be implemented at national level and combined with additional incentives, according to Selma Brynolf.

“Shipping is an international and highly competitive industry. It’s hard for any individual companies or countries to take the lead by themselves.”

Selma Brynolf talked about new fuels for shipping at the Chalmers initiative seminar “Marine challenges – Blue solutions” 6-7 November 2018.

Source : Chalmers University of Technology