Biokerosene

This paper gives an overview of the development and structure of the global and regional air traffic markets. The number and geographical distribution of flights together with the aircraft types needed to satisfy the demand for passenger and cargo transport are analyzed. Air traffic market developments are described from a traffic-oriented perspective. Environmental and economic aspects are not subject of this discussion. Thus this paper addresses the following six topics: global development of the air transport system, regional distribution of the air traffic, airport development and bottlenecks, airlines, aircraft types, and outlook of air traffic development.

The aviation industry has grown strongly over the past decades at a global rate of around 5 %/a. Within the context of this rapid growth, environmental awareness of societies and general actions to mitigate global climate change have led various institutions and stakeholders to formulate and proclaim goals for limiting greenhouse gas emissions of the future global air transport fleet which are a fleet-wide efficiency improvement of 1.5 %/a from the present until 2020, a cap of CO₂ emissions from 2020 onwards by market-based measures and a halving of the global fleet’s overall CO₂ emission quantities by 2050 relative to 2005 levels. However, despite these substantial efforts to develop new or upgraded aircraft programmes in order to increase fuel efficiency, it is obvious that the target of carbon-neutral growth from 2020 onwards will not be met without market-based measures. In the long term, more radical technologies will be promoted like unconventional aircraft concepts and new engine core concepts. Also alternative energy carriers like electricity, hydrogen, or liquid natural gas are technologies with potential to reduce the environmental footprint, but typically it takes 20 years or more from conceptualisation of a new technology to operational maturity. Today, available technology improvements are outpaced by the strong growth in aviation, while future novel and more radical technologies with large CO₂ emission reduction potentials are still at very low technology readiness levels and hence far from industrial implementation. Even in the case of a rapid technology maturation, a fleet-wide penetration would require radical production ramp-ups and an aggressive industrialisation strategy for such novel technologies. To bridge the gap between the fleet-wide introduction of ultra-low emission aircraft technologies and the necessary substantial reduction of greenhouse gas emissions already today, renewable “drop-in” fuels, offering substantially smaller CO₂ footprints compared to conventional jet fuel, are considered a promising way forward.

Aviation continuous to be a fast growing mobility sector; from 2003 to 2013 there was an increase of passenger kilometers by 73 %. This development is fueled by kerosene which is the synonym for a range of aircraft fuels for military and civil applications. Against this background this article provides an overview on how kerosene from fossil fuel energy (i.e. crude oil) developed from a fuel for lamps and heaters to a modern, versatile and safe fuel for aviation. This includes an overview of the chemical structure and properties of kerosene and how it is produced. Additionally key specifications for aircraft use are provided. Kerosene can also be produced from alternative fossil sources, as from natural gas or coal. These alternative options are described in more detail. The paper closes with a sustainability outlook for fossil kerosene.

Alternative fuels politics and policies take place in a legal framework of global aviation which can be described as a continuous conflict between government regulation and the principle of free market under the influence of several entities and organizations acting on international, supranational and national level. Naming their goals, tasks and responsibilities the article focusses on the legal regime for fuel used for civil aviation, especially concerning its taxation, the emission control and alternative fuels. That regime amplifies the freedom of fuel used for aviation from any duty or tax as determined in the international Chicago Convention, the regulation on taxation of aviation fuels as provided in the Council Directive 2003/96/EC on EU level and the EU ETS which applies to civil aviation. The article reflects the legal framework of alternative fuels and offers an outlook on expected changes with regard to aircraft emissions, considering international developments and those in the EU.

Robust and detailed knowledge of the sustainable availability of biomass is crucial for the development of strategies, targets and roadmaps related to future use of bioenergy and biofuels. In this paper, an overview of existing studies on global biomass potentials is given. Specifically, land-based energy crops, wastes and residues as well as microalgae are addressed as biomass sources. It is shown that large potentials exist, but associated with considerable uncertainties. Furthermore, the scope of the discussion is extended from an exclusive focus on biomass feedstock to a more general view on renewable energy and on options of renewable fuel production beyond utilization of biomass. However, it is also shown that issues of sustainability and particularly economic aspects are not sufficiently addressed in the assessments that have been reported to date. Substantial research efforts are required to fill the remaining knowledge gap with respect to the sustainable and economic potentials of renewable energy and fuels.

Cereals, especially corn and wheat, are feedstocks to produce biofuels (e.g., ethanol). However, they are mainly used as food and feed. This chapter describes the global developments of cereal markets, especially wheat, corn and barley with a special focus on major countries. Wheat is mainly used as food. While China and India are large producers, they do not play a role in wheat export markets which are dominated by the European Union (EU), Russia, Canada, the United States (US) and Ukraine. The corn market grew strongly in the last 15 years. The United States is the largest corn producer, consumer and exporter. The barley market, dominated by the European Union, is stagnating. However, exports have increased in the last years. Biofuel policies have increased the demand for corn, especially in the United States, as well as for wheat, especially in the European Union. However due to changing polices this trend is unlikely to continue in the future. Additionally, global trends and possible future developments are discussed.

Vegetable and animal oils & fats are the major feedstock for biodiesel production. The following article analyses the development of world supply and demand and the effects on prices, with special focus given for four major oils, i.e. palm oil, soy oil, rapeseed oil and sunflower oil. During the past 20 years world consumption of 17 oils & fats more than doubled from 92.9 million t in calendar year 1995 to 204.3 million t in the year 2015. By far most of the growth was for edible purposes, primarily in Asia and Africa, caused by further rapid population growth and rising consumption per person (on account of changed diets and rising income levels). The annual increase in total consumption of all animal oils & fats has accelerated since 2004 with a boost in biodiesel production by almost 29 million t. Government targets for a further expansion in biodiesel consumption in Indonesia, the USA, Brazil and other countries in the years ahead may result in more or less sizably increasing prices of vegetable and animal oils & fats owing to the limitations of resources (arable land and water), unless a major breakthrough is accomplished in yields per hectare of oilseeds and palm oil. There is the risk that consumers worldwide in their effort to cover food demand (particularly in the low-income developing countries) will suffer from appreciating prices of oils & fats if biodiesel consumption mandates are increased too quickly to levels producers worldwide cannot comply with.

This paper gives an overview of some important annual and perennial crops for the provision of lignocellulosic biomass. It describes their cultivation practices as well as their requirements concerning site characteristics and typical logistic chains. Information on physical and chemical properties of these different lignocellulosic biomass plants determining their capability for biokerosene production is presented. Additionally, data on the potential yields and the areas currently under cultivation are given for each of the described crops.

In the past waste management proved to reduce CO₂ emissions both by reuse of recyclables and energetic utilization of substrates with high available energy load. This paper provides an overview about biomass originating from waste. Therefore the biogenic waste fractions are classified by origin. In this manner one can separate the origin of biomass in forestry, agriculture, landscape maintenance, municipal solid waste and industrial waste. Subsequent chemical and physical parameters were described to assess the applicability for thermal utilization as well as for the production of biokerosene. The focus is on calorific values, ash and water content as well as on inhibiting parameters such as sulfur, nitrogen and heavy metals. Based on this, the second part of this paper describes the energy potential of the ubiquitous occurring biomass originating from waste. Therefore the incidence of each waste fraction is related to a specific energy potential respectively calorific value. Due to this the theoretical applicability of waste as feedstock for the production of biokerosene can be assessed.

J. curcas L. is able to grow under subtropical and tropical conditions with an annual precipitation that ranges between 1,200 and 2,000 mm. The length of the growing season should range between 5 and 11 month, naturally or prolonged by respective irrigation measures. J. curcas L. produces flowers and fruits continuously, which means that there may be several harvest peaks per year, depending on genotype and climatic conditions. Also fruits at different maturity stages can be found at the same time on the same shrub. The oil content in the seeds reach the maximum when fruits are mature, accordingly of yellow-brown colour. Jatropha curcas L. is capable of capturing 17 to 27 t CO₂/(ha a). As a perennial shrub it can capture CO₂ for a period of more than two decades, which makes J. curcas L. suitable for long-term CO₂-sequestration. The key product of J. curcas L. today is, as mainly toxic varieties are cropped because of their higher yield potential, oil that can be used straight or as a blend for fossil fuels in combustion engines or be converted to a fossil diesel or jet fuel substitute. State of the art in oil extraction technique is mechanical expelling with an subsequent filtration prior to further conversion. Traditionally Jatropha curcas L. is cultivated as “living fences” to protect housings, to fence in livestock and for soil conservation (prevention of wind and water erosion of soil). Nowadays, particularly in the context of bio fuel production, large scale plantations are the normal case. The most prominent form of cultivation in J. curcas L. projects are plantations, typically ranging in a size between 100 and 1,000 ha, most of them are monoculture plantations. Plant protection, weeding and pest control, is of importance particularly in monoculture plantations, also fertilisation and a sufficient water availability plays an important role. Crucial to the success of commercial Jatropha curcas L. projects are cultivars meeting the DUS (distinctiveness, uniformity and stability) criteria. Also paying attention to the selectivity of the harvest process is crucial and describes a major challenge in the development process of mechanical harvest systems.

In times of dwindling petroleum reserves, microalgae may pose an alternate energy resource. Their growth is vast under favorable conditions. However, producing microalgae for energy in an economically as well as ecologically feasible way is a difficult task and the prospects are challenging. The chapter gives an insight into perspectives of growing microalgae as a crop, highlighting some of their exceptional energy storage properties in regard to commercial exploitation. Large scale algae production techniques and concepts up to downstream processes are presented. Today, conversion to fuels is constrained by energy usage and costs – but future combination of fuel production with added value products may improve balances and lower the industrial CO₂ footprint. These challenges drive research and industry worldwide to constant improvement, supported by numerous funding opportunities. Microalgae in their tremendous diversity are a young and still very much unexplored crop. It is a challenge worth addressing.

The introduction of biokerosene as an alternative to conventional fossil kerosene is driven by the intention to reduce greenhouse gas (GHG) emissions, to reduce dependency on fossil energy carriers and by the potential to create economic benefits especially in rural areas. In this paper, sustainability aspects of biokerosene are discussed for a wide range of feedstocks and conversion pathways with regards to environmental and socio-economic consequences.

From an environmental perspective, results show that the use of biokerosene can reduce GHG emissions compared to the use of conventional jet fuel. However, this is strongly dependent on direct and indirect land-use change effects, which could even lead to a considerable increase in emissions. Emission benefits might be alleviated to some extent by non-CO₂ emissions from combustion. The cultivation of feedstock affects soil and water quality by soil carbon loss, soil erosion and leaching of nutrients and agrochemicals etc. Appropriate management practices can reduce negative consequences. Impacts are furthermore dependent on land-use history and crop type: certain crops, for example, can improve soil quality. The assessment of land requirements shows that algae, switchgrass, miscanthus, sugarcane and oil palm yield the highest quantity of fuels per hectare. Scientific literature reports predominantly negative impacts of biofuels on biodiversity. These negative consequences can be alleviated by the use of wastes and lignocellulosic residues.

Regarding socio-economic aspects, the assessment shows that none of the assessed fuel pathways is financially competitive with conventional kerosene, even assuming a mature provision technology. The provision of valuable co-products or the taxation of fossil fuels present ways to facilitate the introduction of biokerosene. Furthermore, the effect of biofuels on food prices and volatility of food prices is discussed. Most scientific literature reports increasing food prices due to existing biofuel policy. However, embedded in a flexible regulative context, biofuels could reduce price volatility. The analysis furthermore reveals that biofuels trigger investment and create employment and income in rural areas.

Most environmental and socio-economic consequences are dependent on the feedstock, conversion pathway, local environmental, socio-economic conditions, market structures and the political context. The overview of several key aspects of sustainability provided in this study underlines the importance of an individual sustainability assessment in order to optimize benefits and minimize negative consequences of biokerosene provision and use. It becomes furthermore evident that many negative impacts are inherent to agricultural production in general and that these aspects need to be discussed in a wider context than that of biofuels alone. Doing so could promote synergies of food, fiber and fuel production and facilitate a sustainable use of resources.

The conversion of (semi-)natural vegetation to other land uses is related to several environmental problems, including climate change and the loss of biodiversity and ecosystem services. Land use change (LUC) is a significant source of greenhouse gas emissions, and preventing the conversion of forests, peat lands and other ecosystems is an important climate mitigation opportunity. If bioenergy feedstocks are cultivated on newly converted land or displace previous food production, then GHG emissions related to LUC can reduce or even negate the climate mitigation potential of bioenergy products. Efforts to reduce LUC are ongoing via various public, private, voluntary and regulatory approaches at local, national and global scales. Although positive trends are evident, further efforts are needed to reduce LUC against a background of growing land use competition. Trade-offs exist between food security, development and environmental targets, and any measures taken need to consider local and global effects, direct and indirect impacts, leakage effects, and environmental and socioeconomic consequences. The impact of bioenergy production on global land use competition can be reduced by promoting feedstocks that do not compete with food or feed crops for land.

In the first part of the chapter, existing regulatory framework conditions, initiatives as well as voluntary certification schemes with relevance for the aviation industry were determined. Therefore 18 sustainability certification schemes, which are recognized by the European Commission (EC) and have a relevance for biofuels used in the aviation industry, were compared with respect to their geographic and certification scope, transparency, market coverage, traceability and their sustainability performance in covering legal requirements and beyond. A more in-depth benchmark was performed for the five multi-stakeholder schemes Bonsucro EU, ISCC EU, RSB EU RED, RSPO RED and RTRS EU RED based on the ITC tool Standards Map. The benchmark included requirements in the field of environmental, social and economic sustainability.

The second part of the chapter provides insights into the certification system ISCC, a globally leading certification system covering the entire supply chain and all kinds of bio based feedstocks and renewables. Independent third party certification ensures zero deforestation, no compensation and compliance with high ecological and social sustainability requirements, greenhouse gas emissions savings and traceability throughout the supply chain. ISCC can be applied in various markets including the bioenergy sector, the food and feed market and the chemical market. Since its start of operation in 2010, more than 13,000 certificates in more than 100 countries have been issued.

The goal of this paper is to give an overview of the current possibilities to produce biokerosene from different types of biomass. Therefore different existing processes are characterized in relation to the useable feedstock (i.e. vegetable oil, starch, sugar, lignocellulose) and the type of conversion process (i.e. mechanical, biochemical, thermo-chemical or physico-chemical). In this context possible intermediate products as well as the final products are defined. Afterwards the six most advanced conversion pathways are described in more detail. This includes the hydroprocessed esters and fatty acids (HEFA) route, the direct sugar to hydrocarbons (DSHC) route, the alcohol-to-jet (AtJ) route, the biogas-to-liquid (Bio-GtL) route, the biomass-to-liquid (BtL) route as well as the hydrotreated depolymerized cellulosic jet (HDCJ) route. For each route the possible feedstock and the technical specifications are addressed. Finally a short outlook for the described processes as well as a brief assessment is given.

Large amounts of the world wide used biofuels are derived from vegetable oils; this is especially true for bio-aviation fuels. Biokerosene from vegetable oils can be produced by various processes. Three of these processes, namely the HEFA (hydroprocessed esters and fatty acids) and the BIC (biofuels iso-conversion) process as well as the co-refining in crude oil refineries, will be presented and discussed below. Therefore after a short introduction addressing the vegetable oil provision chain including different types of biomass and the different pretreatment steps to fulfill the requirements of further processing the production pathways to provide biokerosene via the different processes named above will be described. In this context a brief overview of each process is given, before each conversion step is described in detail. In the end a final consideration and a brief outlook on the future role and extend of biokerosene derived from vegetable oils is given.

Synthetic fuels derived from synthesis gas provided from gasification of solid fuels using the Fischer-Tropsch Synthesis are well-known and used since the 1920’s. The initial process used coal as feedstock to produce mainly diesel like fuels when crude oil was not at hand. Nowadays and especially in the context of alternative and climate friendly fuels new process chains are taken into consideration based on this overall principle. This includes the production of “green” syngas by biomass gasification or reforming of bio-methane from e.g. biogas plants based on a biochemical biomass conversion. Against this background the overall goal of this paper is to give an overview of the current state of these two syngas provision pathways and the subsequent synthesis options, mainly focusing on the Fischer-Tropsch Synthesis. The overall process chains can be categorized into the Biomass-to-Liquids (BtL) and the Biogas-to-Liquids (Bio-GtL) pathways.

The conversion routes for kerosene produced from biogenic alcohols are referred typically to as “Alcohol-to-Jet”-processes (AtJ). The required alcohols can be obtained via different bio-chemical and/or thermo-chemical routes from organic matter. Since both sugary and starchy biomass (with established technology) as well as lignocellulosic biomass and organic waste (with future technology) may be converted into a sugar or alcohol dilution, Alcohol-to-Jet-processes (AtJ) potentially access a broad feedstock base for future aviation biofuel supply¹. Thus within this contribution firstly the various methods of alcohol production are described in detail. Then further processing of the alcohol to liquid hydrocarbon fuels is explained. Besides the “classical” bioethanol production which is globally established at industrial scale also “innovative” processes (e.g. bio-chemical production of butanol, thermo-chemical synthesis of methanol) are discussed. Thereafter, the status of the technical implementation of these various processes is presented. Finally, the main findings are summarized.

This chapter provides a review on the production of biokerosene via pyrolysis of biomass. Accordingly, the technology of pyrolysis is described and classified into different operation modes, paying special attention to those conditions, reactors and biomass sources more suitable for the type of product (liquid fraction) targeted. The pyrolysis oil properties are characterized and compared with the specifications of conventional kerosene. These properties show that to implement pyrolysis oil as a “drop-in” fuel in the already existing kerosene infrastructure, some technical limitations need to be overcome. At present, challenges in the composition of pyrolysis oil remain, such as high acidity, chemical instability and high water and oxygen contents. For the purpose of increasing the quality of the pyrolysis oil, physical and chemical upgrading processes are described, including catalytic fast pyrolysis. The complexities of processes and reactions associated with increasing quality of pyrolysis oil are discussed. Finally, a brief overview of the current maturity level of the technology for biokerosene production via pyrolysis oil upgrading is presented.

Conversion of wet biomass and waste products via hydrothermal liquefaction (HTL) has been evolving as an alternative thermochemical technology for the production of liquid biofuels. Processing of biomass slurries with approximately 20 % solids content under high temperature and pressure mimics the natural formation of fossil crude on earth. With reaction times of around 10 to 30 minutes, temperatures of 350 °C and pressures of around 200 bar, HTL converts any biomass feedstock to a liquid bio-crude. This raw product roughly resembles petroleum, but exhibits higher oxygen contents (~10 %) and has a higher viscosity. Therefore, development of the hydrothermal liquefaction technology has concentrated on the upgrading of bio-crude via hydrotreatment to reduce its heteroatom content, viscosity, boiling point and density. Upgraded bio-crude can then be further refined via distillation or other established processes into renewable gasoline, diesel and jet fuel. The upgraded fuel’s chemical composition, with a high concentration of aliphatic hydrocarbons showing carbon numbers in the range of C₈ to C₁₈, appears promising for application as renewable jet fuel. The specific composition of the refined fuel products (as well as of the bio-crude) is, however, affected to a significant extent by the type of feedstock applied. For example, using lignocellulosic feedstock results in increased concentrations of aromatic hydrocarbons in the final product. The versatility of the HTL technology in terms of feedstocks and products represents a major advantage over other thermochemical conversion processes. Future developments should address tailoring the process to meet specific fuel requirements, e.g. those of renewable aviation fuels. Recent HTL reactor developments have led to proven continuous operation on a variety of feedstocks, but current reactor capacities of about ~1 bbl/d of bio-crude are still limited. Initial environmental and economic assessments of the hydrothermal liquefaction technology are promising, but in-depth studies covering a representative range of feedstock have not yet been published, rendering estimations of minimum fuel selling prices and greenhouse gas (GHG) balances of HTL derived liquid fuels difficult. To advance the technological maturity of hydrothermal liquefaction towards industrial implementation, development efforts should focus on process integration along the entire production chain encompassing pre-treatment, HTL processing, hydrotreatment, distillation and utilization of process water.

The chemical properties that control the performance of aviation fuel have evolved in parallel with the aircraft and engines that use these fuels. The initial focus was on improving piston engine fuels to meet the increasing performance demands of combat operations. This early experience established a precedent for the evolution of industry and military specifications used to control the properties of jet fuel used on today’s aircraft.

Jet fuel specifications have been refined and revised over the years leading to a commonly accepted set of properties now listed in those specifications. They are utilized by the aviation fuel industry stakeholders to control the performance and properties of the fuel to support a myriad of activities, such as aircraft and engine design, aircraft operation, fuel production, fuel transport, fuel commerce, and fuel storage.

Airworthiness authorities accept industry fuel specifications as operating limitations when specified by engine and aircraft manufactures for use on their products. Airworthiness authorities do not specifically approve aviation fuels, but rather they approve engine or aircraft models to operate on a specified aviation fuel.

The alternative jet fuel approval process evolved from the approval of Sasol’s Fischer-Tropsch (FT) coal-to-liquid (CTL) semi-synthetic jet fuel in 1999. This represented the first approval of a material not produced from petroleum for use in jet fuel. These early efforts by Sasol provided the specification-writing organizations (ASTM International and the UK MOD Aviation Fuel Committee) with a basis for development of alternative jet fuel approval methods.

Alternative jet fuels are approved as “drop-in” fuels, which possess identical fuel properties and performance as petroleum-derived jet fuel. Aircraft operations are unaffected when using drop-in fuels and recertification of existing jet-powered aircraft or jet engines is not required. This drop-in fuel concept has been accepted by the Federal Aviation Administration (FAA) and the European Aviation Safety Agency (EASA). The Commercial Aviation Alternative Fuels Initiative (CAAFI; www.​CAAFI.​org) in partnership with the US military has worked with the aviation fuel community to help develop this qualification and certification process to support development and deployment of these alternative jet fuels.

A generic specification for FT fuel at a maximum 50 % blend level was issued in 2009. A specification for Hydroprocessed Esters and Fatty Acids (HEFA), also at a 50 % blend level, was added in July 2011, followed by Synthesized Isoparaffins (SIP) at a 10 % blend level in July 2014. Other prospective alternative fuel producers have initiated the ASTM International qualification process to approve new renewable jet fuel pathways. A variety of feedstocks and associated conversion technologies are being proposed for these new jet fuels.

According to the current standards synthetic kerosene must be blended with conventional hydrocarbons or Jet A or Jet A-1 before it can be released as jet fuel. Besides a certain volumetric limit jet fuel specifications define a set of (additional) properties a blend must fulfill for certification. Thus, a proper selection of matching synthetic and conventional fuel batches for blending (“matching blendstock”) will be of significant importance at some point in the future aviation fuel supply chain. If the properties of the involved batches are unfavorable, the maximum allowable blending ratio may not be achievable. Yet from a technical point of view, even blending ratios beyond the currently specified limit could be possible, if two favorable batches were chosen.

Surveys have shown that properties of conventional kerosene vary considerably within the prescribed range of the specification. Against this background this chapter first provides an overview of the main types of molecules present in kerosene in order to illustrate their influence on fuel properties. Afterwards conventional and synthetic kerosene are characterized in detail. Finally, the most relevant properties for blending are identified for a wide variety of synthetic and conventional kerosene.

In response to the Kyoto Protocol the European Union implemented the European Emission Trading Scheme (EU-ETS). Starting in 2005 the scheme had initially been limited to certain stationary installations. Since 2012 it has been extended to encompass emissions from aviation activities as well. Hence for emissions resulting from the combustion of fossil fuels emission allowances have to be surrendered. These allowances are either allocated free of charge or auctioned. For emissions resulting from the combustion of sustainable biofuels no emission allowances are required.

Following the broad international opposition against the inclusion of aviation in the EU-ETS, flights beyond the European Economic Area have been excluded in anticipation of an international approach to mitigate the global aviation emissions.

This paper first outlines the intention and development of the EU-ETS with a focus on the legislation concerning aviation. Moreover the administrative procedures to fulfil the regulatory obligations are described, especially the requirements to account for the use of biokerosene. Finally, the derogation from the original legislation and the Market-based Measures currently developed on the ICAO-level are considered in the outlook.

The international aviation industry expects aviation biofuels to make a substantial contribution to reducing the sector’s CO₂ emissions by 2050. This paper provides an analysis of the potential supply of sustainable aviation fuels globally and an insight into the contribution they could and would need to make towards carbon neutral growth of the aviation industry post 2020. It does so by developing scenarios of how much sustainable aviation fuel may be produced globally to 2030, and the resulting CO₂ emissions savings. It then estimates the volume of sustainable fuel required to meet the aviation industry’s fuel-related CO₂ emissions savings projections for 2050 and discusses the viability of such ambition.

From July to December 2011, Lufthansa conducted an in-service evaluation of HEFA bio kerosene, flying an Airbus A321 in commercial operations between Hamburg and Frankfurt using bio kerosene on one engine. During this evaluation, aircraft and engine were extensively monitored, with engine conditioning data downlinked and compared to the performance of the reference engine. Fuel quality was repeatedly tested, and critical parameters monitored. After the evaluation, fuel bearing parts were removed from the bio kerosene engine and compared to those of the reference engine, and the fuel tanks were accessed and their condition assessed. The effect of the fuel on the fueling equipment used during the evaluation was also variously analyzed. One minor observation was made concerning a possible impact on fueling equipment, which is probably not specific to bio kerosene but could not yet be resolved with certainty. With that possible exception, bio kerosene performed as good or better than conventional kerosene.

Implications of the commercialisation of Alternative Aviation Fuels are mostly associated with the prevailing conditions of the oil market and the current jet fuel procurement mechanisms. While Jet A-1 as the dominant jet fuel type is on sale in the aviation market since the early 1970’s, alternative fuels are going to compete with a highly integrated supply chain that is working to the satisfaction of airlines for more than four decades. The article describes the legal and operational requirements for new market participants wishing to supply their products to airlines as well as options to co-operate with conventional jet fuel suppliers for blending purposes in order to meet existing specification limits.