Analysis by researchers from the Technical University of Denmark (DTU) indicates that the cheapest solution for reducing emissions from the shipping industry is initially to use green fuels produced from sustainable biomass - first in the form of pyrolysis oil and then in the form of bio-e-methanol. Ammonia is optimally priced in the longer-term.

The analysis was made as part of the MarE-Fuel project undertaken with Anker Invest, Maersk Line, Copenhagen Economics, OMT, and DFDS, with funding from the Danish Maritime Fund and Lauritzen Fonden. The current situation (2020) was assessed as well as 2030 and 2050 scenarios including parameters such as prices, taxes, emissions, and availability.

The analysis highlighted the need for more electrolysis plants, such as Air Products' installation for thyssenkrupp (pictured), to create hydrogen as feedstock for Power-to-X fuels

Source: Air Products

The analysis highlighted the need for more electrolysis plants, such as Air Products’ installation for thyssenkrupp (pictured), to create hydrogen as feedstock for Power-to-X fuels

“How big a role sustainable biomass can play in green shipping depends entirely on how much of it we have access to in the future,” says Marie Münster, Professor of Energy System Analysis from DTU Management. “If there is plenty available, it will certainly be one of the cheapest ways to go, and we should therefore continue to focus on this technology. However, everything indicates that low-cost sustainable biomass will be in great demand, and we must consequently also focus on optimising Power-to-X technologies, because we will need them.”

A single best fuel wasn’t identified, but all the calculated scenarios indicated that in the long term ammonia made from renewable energy will be essential for climate-neutral shipping. Ammonia is not dependent on carbon, and the price and GHG emissions are comparable to other green fuels, says Münster

Professor Peter Vang Hendriksen, an expert in electrolysis and energy conversion at DTU Energy, said more electrolysis plants are required to create hydrogen as feedstock for ammonia production or other Power-to-X fuels. “With the current expansion rate (2019), it will in fact take up to 3,000 years before we have enough plants.

“Electrolysis requires power. If, for example, we’re only going to sail on green ammonia by 2050, and we continue at the same wind power expansion rate as today for the next 29 years, we would have to use all the new capacity to produce green ammonia for shipping. However, having cheap green power isn’t enough, it must also be available most of the time to avoid having to over-dimension our production plants. Therefore, we must ensure flexible plants and preferably efficient storage of our wind and solar energy,” says Hendriksen.

Calculations show that the price of producing green fuels is about four times higher than the price of fossil fuels. However, scaling up production capacity, gains from mass production, and improvements in technology are expected to halve the price of green fuels by 2050. The researchers note that without taxes and state support, green fuels will not be able to compete with fossil fuels regardless of the technology used.

The project has developed four open source models:

  • The OptiPlant model, which optimizes capacity sizes and electricity consumption from own production or via purchases from the electricity grid.
  • Balance of plant models for the production plans, which calculate effectiveness and fuel production costs. The focus is on methanol and ammonia.
  • The TCO model, which calculates the total costs from both the fuel side and the ship side.
  • The roadmap model, which calculates possible scenarios for reducing emissions of climate gases from shipping by 2050, depending on available biomass and green power.