Navigating E-Fuels: The Spectrum Beyond Grey, Blue, and Green

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Colours have come to represent various electrofuels, also called e-fuels. Grey, blue and green are the most common hues to describe different fuel production pathways for e-fuels, reports Engine.

Grey e-fuels

Grey e-fuels are produced through steam methane reforming of natural gas and will emit carbon dioxide (CO2) through that process. Blue e-fuels are produced like grey fuels, but with the CO2 captured. Green e-fuels are more sustainable because they instead rely on renewable power sources like solar and wind.

There are two key reasons why some e-fuels producers would rather ditch these strict colour labels:

  1. In practice e-fuels are mass balanced and will often be physical blends of various coloured fuels
  2. The carbon intensities of the fuels are on a spectrum that cannot always be pinned down accurately to colour labels

Green fuels have been touted by many as the future of zero-carbon shipping, but they are currently only produced in tiny quantities. That’s why fuel producers use accounting methods like mass balancing to leverage existing fuel capacity and infrastructure to meet current demand. Mass balancing involves mixing green fuels, such as bio-LNG and bio-methanol, with grey fuels in varying ratios and then account for them. This method helps track green fuel feedstock throughout the supply chain, ensuring traceability. And it allows ships access to low-carbon fuels even if they haven’t bunkered them physically in ports where only 100% fossil fuels are available.

Blue fuels offer potential for lower costs and greater initial scalability than green fuels. They can serve as bridges between today’s grey fuels and the greener options of tomorrow, according to one supplier. Another supplier pointed out that, despite pressure from policymakers and customers for pure green molecules, the strong case for blue fuels should not be overlooked since they can offer considerable carbon reduction compared to grey fuels.

Many industry experts like classification societies DNV and Lloyd’s Register, and some fuel suppliers including Yara Clean Ammonia, forecast that blue fuels will make up a significant portion of the shipping industry’s fuel mix moving forward.

In practice, distinguishing between grey, blue and green fuels during bunkering will be virtually impossible due to blending. All distinct colours will be combined into a single product in the final fuel stream, and the resulting mix will likely consist of various coloured molecules of the same fuel, obscuring the original colour designations.

In addition, relying on colours codes can also be misleading because fuels categorised as the same colour, such as blue methanol or blue ammonia, may have varying emission profiles due to differences in their production processes. For instance, different blue ammonia plants have varying efficiencies in capturing carbon, leading to different levels of emissions.

As a solution suppliers believe that the future bunker mix will likely involve a spectrum of low-carbon fuel options. Prioritising fuels based on their carbon intensities, rather than adhering to a rigid color-coded system, will allow producers to adapt to changing demands by gradually scaling up their output of low-carbon fuels, to help address global production and bunker infrastructure gaps.

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Source: Engine