Shifting away from fossil fuels poses challenges, but there are options according to Wärtsilä hybrid application manager Lucas Esselström
Mr Esselström addressed the fuels shift at Riviera’s Maritime Air Pollution Conference, Americas in Miami, USA.
“A change in fuel will be the single most significant contribution towards decarbonisation,” he said. “But making choices about these fuels will be no easy task, as we have many factors to balance into the equation.”
Difficult to balance factors he listed included cost, energy density, supply chain changes and safety.
In terms of cost, ‘green’ fuels could cost up to five and a half times more than heavy fuel oil, he said, and there are problems with their energy densities, too.
One prime candidate as a fossil fuel replacement, liquid hydrogen (which can facilitate carbon-free power) requires more than four times the storage space of heavy fuel oil, Mr Esselström said, making it difficult to accommodate on board vessels in the quantities needed for operation.
To give the required kick-start for supply chain shifts, local incentives may trigger the development of niche alternative fuel markets, which would offer shipowners more fuel choices. But national strategies, industry regulations and even feedstock availability will ultimately determine what kinds of fuel will be readily available on a large scale, he noted.
On the safety front, the current IGF code (the industry safety code for ships using gas and low-flashpoint fuels) excludes the use of ammonia in fuel because of its potential toxicity despite its clean burning potential.
In spite of the challenges, Mr Esselström said industry players, including Wärtsilä, are working to find a fuel source that reduces the amount of greenhouse gas emissions from ship engines.
For Wärtsilä’s part, the company has been actively searching for solutions to this issue for years. In 2015, Wärtsilä converted one of Stena Germanica’s engines to run on both diesel and methanol, resulting in the world’s first methanol-hybrid powered ferry. At the company’s lab, scientists have successfully blended hydrogen into liquified natural gas fuel, while maritime construction companies, like Boksalis, worked with Wärtsilä to implement biofuels that reduced their ships’ carbon dioxide emissions by up to 35%.
Mr Esselström said Wärtsilä is preparing to meet IMO’s 2030 emissions targets with a combination of combustion engines and LNG, while experimenting with the possibility of other energy solutions like batteries (for short-routes and hybrid installations), fuel cells and wind propulsion.