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Biofuel: definition
Biofuels are fuels derived directly or indirectly from biomass.
Biomass is organic, non-fossil material of biological origin (plants and animals). It includes wide range of materials harvested from nature or biological portion of waste.
Biofuels can be split up into three categories:
- solid biofuels (fuelwood, wood residues, wood pellets, animal waste, vegetal material, …)
- liquid biofuels (biogasoline, biodiesel, bio jet kerosene, …)
- biogases (from anaerobic fermentation and from thermal processes)
In particular:
liquid biofuels includes all liquid fuels of natural origin (e.g. produced from biomass and/or the biodegradable fraction of waste), suitable to be blended with or replace liquid fuels from fossil origin. In energy statistics, liquid biofuels is a product aggregate equal to the sum of biogasoline, biodiesels, bio jet kerosene and other liquid biofuels.
Biomass feedstock is a key source of renewable energy, essential for generating sustainable electricity, heat and transport fuels.
It is matter of Green Deal
In the context of the Green Deal, renewable energy represents a fundamental pillar of the transition towards cleaner energy.
Biofuels, bioliquids, and biomethane are among the renewable sources covered by the European Directive, provided they meet specific sustainability requirements. These requirements serve to distinguish which biofuels and bioliquids produce a genuine environmental benefit, such as through the reduction of greenhouse gases, respect for the land, etc.
The sustainability criteria must be met by all economic operators in the biofuel, bioliquid, and biomethane production chains, such as growers, presses, refineries, traders, waste and by-product producers, and production plants.
These alternative energy sources plays a major role in the transition away from greenhouse gas-intensive fuels toward a more sustainable, low carbon future.
Within the fuel sector, the manufacturing of biofuel blends using biomass resources lessens the impact of carbon dioxide (CO2) on the environment, while also allowing fuel manufacturers to receive tax credits and demonstrate compliance with regulatory initiatives.
Not only cars
Maritime sector
The IMO has already launched new short, medium and long-term measures, investments and incentives within the framework of the Initial Strategy:.
- Extension of the ETS regulation to the shipping sector
- Payment of carbon credits
- Promotion of sustainable alternative fuels
- Review of the directives on energy taxation
FuelEU Maritime is the European regulation that aims to decarbonise the maritime sector.
Aviation sector
ICAO’s CORSIA program requires the aviation industry to offset growth-related greenhouse gas emissions starting in 2021. CORSIA, currently voluntary, includes a second mandatory phase (2027-2035), which will directly affect most airlines.
RefuelEU Aviation is the European regulation aimed at decarbonizing the aviation sector.
Automotive sector
European legislation has imposed specific requirements for the entire biofuel, bioliquid, and biomethane supply chain in the automotive transport sector. To demonstrate compliance with the sustainability requirements of the Directive (and related delegated acts) and, where applicable, to access concessions, economic operators must obtain specific certification.
Biofuel certification
Large-scale production of biofuels raises concerns about their sustainability: real greenhouse gas emissions, loss of biodiversity, changes in land use, social aspects, competition with food.
Many biOfuels are blended with their corresponding fossil fuel to ensure compatibility and performance.
Mixing percentages depend on both technological limitations and regulatory regulations.
When biofuels are blended with fossil fuels, the sustainability information and GHG (GreenHouse Gases) characteristics assigned to the blend must reflect the physical share of biofuels in the blend.
Fossil or biogenic carbon?
Fossil carbon is found in fossil fuels such as oil, coal, and natural gas, which were formed millions of years ago by the decomposition of organic material under high pressures and temperatures.
Biogenic carbon comes from recent biological sources, such as plants and animals, and is part of the natural carbon cycle.
Environmental Impact
CO2 emissions from fossil carbon are unbalanced and contribute to climate change. In contrast, CO2 emissions from biogenic carbon
are balanced by absorption during plant growth, making it a more sustainable energy source.
The importance of isotopic analysis
Carbon on Earth exists in three main isotopic forms, namely carbon-12 (stable isotope), carbon-13 (stable isotope), and carbon-14 (weakly radioactive).
As the world moves towards more sustainable energy sources, the accurate identification and quantification of bio-based content in feedstocks and fuels have become increasingly important. One of the most reliable methods for this purpose is Carbon-14 (C-14) testing.
C14 analysis, or radiocarbon dating, is a method for determining the age of organic materials by measuring the remaining amount of the radioactive isotope carbon-14 (14C). It works because living organisms take in 14C from the atmosphere, and when they die, the 14C stops being replenished and begins to decay at a known rate (its half-life is about 5,730 years). By comparing the ratio of 14C to stable carbon-12 in a sample to the ratio in the atmosphere, scientists can estimate how long ago the organism died.
During its life, a plant or animal is in equilibrium with its surroundings by exchanging carbon either with the atmosphere or through its diet. It will, therefore, have the same proportion of 14C as the atmosphere, or in the case of marine animals or plants, with the ocean. Once it dies, it ceases to acquire 14C, but the 14C within its biological material at that time will continue to decay, and so the ratio of 14C to 12C in its remains will gradually decrease. Because 14C decays at a known rate, the proportion of radiocarbon can be used to determine how long it has been since a given sample stopped exchanging carbon – the older the sample, the less 14C will be left.
The analysis of the ratio between Carbon-12 and Carbon-14 is currently the simplest and most accurate method for determining the renewable content of biofuels, considering the great variability of the biomass sources that compose them.
How to measure the 14C
The detection of 14C is extremely challenging due to its very low natural concentration: the required sensitivity is 1 part in 10¹⁵.
Currently, several analytical techniques are available for radiocarbon determination; among the most well known are AMS (Accelerator Mass Spectrometry) and LSC (Liquid Scintillation Counting).
The 14C SCAR (Saturated-absorption CAvity Ring-down) spectrometer is a new and innovative instrument for measuring 14C.
It is capable of measuring the mole fraction of radiocarbon in any sample using the SCAR technique, which improves the limits of CRD (Cavity Ring-Down) by more than one order of magnitude.
The 14C SCAR instrument analyzes the CO2 gas produced by combustion of the sample and derives the 14C concentration by measuring the spectral area of a specific molecular transition of the ¹⁴CO₂ molecule. If the sample originates from a modern living organism, the measured 14C concentration will be close to the so-called Natural Abundance or Modern Carbon Concentration (MC).
To provide an accurate and precise radiocarbon measurement, it is often necessary to correct the obtained data for “isotopic fractionation” using the 13C and 12C isotopes. This correction removes the error introduced by differences in metabolic pathways and respiration between the sample and the modern reference material. For this reason, many end users tend to couple the 14C SCAR detector with an IRMS for determining the δ¹³C isotopic ratio.
Depending on the nature of the sample to be measured and the analytical requirements, the 14C SCAR must be paired with one or more suitable peripheral devices:
