Pierre Aury gives readers a renewable fuels guide.
As the International Maritime Organization has decided to postpone by one year the approval of its proposed Net Zero Framework (NZF) we have decided to use that opportunity to try to cast some light on what are renewable fuels, biofuels, and e-fuels.
Between the EU Emissions Trading System (ETS) which is pricing emissions and the more recent FuelEU Maritime regulations which are setting fuel-performance standards in fact setting limits on the greenhouse gas well‑to‑wake intensity of the energy used at sea and mandates cold ironing in port, there is a strong incentive to move away from carbon intensive fossil fuels to lower‑carbon or even better no-carbon fuels. The IMO postponed NZF is very similar to FuelEU so it will, when adopted, create a worldwide incentive to move to renewable fuels… at least that is the theory.
So what is a renewable fuel? It is a fuel produced from sources that naturally replenish on a short timescale. Wood for example is a renewable fuel. But wood is pretty useless, as wood, when it comes to powering ships. The EU and the IMO have in mind biofuels and e-fuels.
First generation biofuels are produced from crops rich in sugar, starch, or oils (e.g., ethanol from corn or sugarcane or biodiesel from rapeseed). Most of the ethanol used in cars today is a first generation biofuel. The main issues with these biofuels are food versus fuel competition, potential change in land use and the difficulty to scale up production.
Second generation biofuels, also referred to as advanced biofuels, are produced from non-food biomass: residues, waste oils, lignocellulosic material (wood, straw, waste or used cooking oil to make hydrotreated vegetable oil (HVO) which can directly be used in an internal combustion engine). Although these second generation biofuels still create competition for land use, they are generally credited with better sustainability and a higher potential for GHG reduction. Their production is easier to scale up except for biofuels produced from used cooking oil as the supply is small and hard to collect. Third generation biofuels are to be produced from high productivity biomass such as algae. The main advantages will be, if these go past the proof of concept phase which is not obvious, that there will be no competition with food/land use and that the production will be easier to scale up. They are promising but it is still early stage and could be costly.
Now let us deal with e-fuels (e for electro) / syn fuels (syn for synthetic). They are fuels made by combining hydrogen (from renewable powered electrolysis) with captured CO₂ to create hydrocarbons or alcohols (e‑methanol, e‑diesel, e-methane, e-ammonia). When both electricity and CO₂ inputs are renewable or biogenic, they can be nearly carbon‑neutral but are energy-intensive and very expensive today. Green refers to a fuel produced using hydrogen which has been produced using renewable electricity when blue refers to a fuel produced from fossil fuels associated with carbon capture and storage (CCS). Biogenic CO2 refers to CO2 coming from the combustion or decomposition of biomass, plant or animal material… or biofuels! Are you lost?
Before we conclude a word on ammonia: please stop considering this as a fuel for shipping! It is too dangerous.
Now departing from the theory above, practically and regardless of the above-described fuel chosen, none can be deployed at scale quickly enough to meet the bold target of decarbonised shipping by 2050.
