WHAT ARE ADVANCED BIOFUELS?
The agreement reached on the Renewable Energy Directive II (RED II) in June 2018, or formally “Proposal for a DIRECTIVE OF THE EUROPEAN PARLIAMENT AND OF THE COUNCIL on the promotion of the use of energy from renewable sources”, defines ‘Advanced Biofuels’ as biofuels that are produced from feedstocks listed in part A of Annex IX of the Proposal. It is important to note that the feedstock and not the process used to produced the (advanced) biofuels) determine whether the biofuels are considered to be “advanced”.
Annex IX, Part A.
"Within the minimum share referred to in the first subparagraph, the contribution of advanced biofuels and biogas produced from the feedstock listed in Part A of Annex IX as a share of final consumption of energy in the transport sector shall be at least 0,2 % in 2022, at least 1 % in 2025 and at least 3,5 % in 2030."
Feedstocks for the production of advanced biofuels, the contribution of which towards the target referred to in the first and second subparagraph of Article 25(1) may be considered to be twice their energy content:
(a) Algae if cultivated on land in ponds or photobioreactors.
(b) Biomass fraction of mixed municipal waste, but not separated household waste subject to recycling targets under point (a) of Article 11(2) of Directive 2008/98/EC.
(c) Bio-waste as defined in Article 3(4) of Directive 2008/98/EC from private households subject to separate collection as defined in Article 3(11) of that Directive.
(d) Biomass fraction of industrial waste not fit for use in the food or feed chain, including material from retail and wholesale and the agro-food and fish and aquaculture industry, and excluding feedstocks listed in part B of this Annex.
(f) Animal manure and sewage sludge.
(g) Palm oil mill effluent and empty palm fruit bunches.
(h) Tall oil pitch.
(i) Crude glycerine.
(k) Grape marcs and wine lees.
(l) Nut shells.
(n) Cobs cleaned of kernels of corn.
(o) Biomass fraction of wastes and residues from forestry and forest-based industries, i.e. bark, branches, pre-commercial thinnings, leaves, needles, tree tops, saw dust, cutter shavings, black liquor, brown liquor, fibre sludge, lignin and tall oil.
(p) Other non-food cellulosic material as defined in point (q) of the second paragraph of Articl 2.
(q) Other ligno-cellulosic material as defined in point (p) of the second paragraph of Article 2 except saw logs and veneer logs.
WHAT IS THE CURRENT PRODUCTION OF ADVANCED BIOFUELS?
Many companies are pursuing projects to develop and demonstrate advanced biofuel and bioenergy technologies. A large variety of feedstocks, conversion technologies, and products are currently under research, development and deployment, and the technology readiness levels (TRLs) of the applied technologies vary.
In its report “Status of Advanced Biofuels Demonstration Facilities in 2012”, IEA Bioenergy Task 39 lists 71 advanced biofuels production facilities worldwide, with a cumulative production capacity of 2,530,000 tons per year in 2012. Of all technologies for the production of advanced biofuels, hydrotreatment of vegetable oils has developed most rapidly and has contributed 2,190,000 tons per year to the worldwide biofuels production (representing ~2,4 % of the total worldwide biofuels production).
Information on European projects is available in the production facilities section of the ETIP Bioenergy website. Worldwide mapping is done by IEA Bioenergy Task 39 in its online database on advanced biofuels production facilities.
In 2011, the Advanced Biofuels Tracking Database listed 130 advanced biofuels production facilities, with a combined annual production capacity of ~700 million gallons in 2011, the largest part of which is HVO (572 million gallons in 2011).
WHAT TYPES OF ADVANCED BIOFUELS ARE THERE?
The following describes in general terms some of the main types of advanced biofuels being developed in Europe and globally.
Biobutanol is an alcohol that can be used as a transport fuel. Each molecule contains four carbon atoms rather than two as in ethanol. It is more compatible with existing fuel infrastructures and engines than ethanol. Novel fermentation techniques are being developed to convert sugars into butanol using modified yeast strains.
BioDME (dimethylether) can be produced via catalytic dehydration of biomethanol or directly from syngas. Above -25°C or below 5 bar DME is a gas. Hence its use as a transport fuel can be considered similar to that of LPG.
Biohydrogen can potentially be produced from biomass via various routes and can be used as a vehicle fuel. Biohydrogen is not currently being produced at significant volumes.
Biomethane can be used in transport in a similar way to CNG. Biomethane is biogas generated via anaerobic digestion (a biological process) of which CO2 and impurities are removed and which is then suitable for transport.
Cellulosic ethanol can be produced by hydrolysis and fermentation of lignocellulosic agricultural wastes such as straw or corn stover or from energy grasses or other energy crops. The end product is the same as conventional bioethanol, which is typically blended with gasoline.
Biomass to Liquid (BtL) is generally produced via gasification (heating in partial presence of oxygen to produce carbon monoxide and hydrogen). Feedstocks include woody residues or wastes or energy crops. Gasification is followed by conditioning and then fuel synthesis via Fischer Tropsch or the "methanol-to-gasoline" process. BtL is used in diesel engines. It has also been approved as an aviation fuel. High temperature plasma gasification can be used to convert a wider range of feedstocks to syngas, which can then be cleaned and converted into fuels.
Hydrotreated Vegetable Oils (HVO) / Hydroprocessed Esters and Fatty Acids (HEFA) do not have the detrimental effects of ester-type biodiesel fuels, such as increased NOx emission, deposit formation, storage stability problems, more rapid aging of engine oil or poor cold properties. HVOs are straight-chain paraffinic hydrocarbons that are free of aromatics, oxygen and sulfur and have high cetane numbers. They are also approved for use as aviation fuels. The aim is to produce HVOs from sustainable feedstocks.
Other advanced biofuels:
Bio-oil/Bio-crude is produced by pyrolysis, processes that use rapid heating or super-heated water to convert organic matter to oil. Flash pyrolysis involves rapid heating (1-2 seconds) of fine material up to 500°C. Thermochemical Conversion uses superheated water to convert organic matter to bio-oil. This may be followed by anhydrous cracking/distillation. The combined process is known as Thermal depolymerization (TDP). Bio-oil can be used as a heating fuel or can be further converted to advanced biofuels.
Torrefaction (heating at 200-300°C in the absence of oxygen, at atmospheric pressure) converts biomass to "bio-coal", which can be more easily used for power generation than untreated biomass.
Algal biofuels may be produced from macro algae (seaweeds) and microalgae via a range of technologies. A number of projects and pilot plants are now identifying the best types of algae to use and the best production technologies. Algal biofuels have attracted great interest as they do not compete with food crops for land use, but the technology is not yet as mature as that for some other advanced biofuels.
Hydrocarbons via chemical catalysis of plant sugars. Chemical catalysis or modified mircorganisms offer great potential for converting sugars into specific fuel molecules including biopetroleum, bio jet fuel and other drop-in fuels, which have very similar properties to their fossil fuel counterparts.
BioSynthetic Natural Gas (BioSNG) is produced via an initial gasification step followed by gas conditioning, SNG synthesis and gas upgrading.
Drop-in biofuels via biotechnology, Synthetic biology, modified metabolism and other techniques are being developed to convert plant sugars to a range of fuels that have similar properties to fossil gasoline or diesel.