The development of sustainable aviation alternative fuels could provide a very large part of the industry’s emissions-reduction strategy. Research has shown that, on a full carbon lifecycle basis, using the equivalent quantity of some alternative fuels could reduce CO2 emissions by around 80% compared to the jet fuel they replace.

Since the first biofuel flight in a commercial aircraft took place in 2008, there has been a huge amount of work by the industry and our partners. Certification through the global fuel standards agency ASTM allowed us to operate using biofuels and more than 150,000 flights have taken place on alternative-traditional fuel blend since 2011.

Click here for a table of the initial set of commercial flights on sustainable aviation fuels since certification was granted.  

Alternative Fuel Page

The alternative fuels we are investigating are second-generation feedstocks that can be grown or produced without negatively impacting food supplies, water or land use. Importantly, they are also ‘drop-in’ fuels which share the same properties as the jet fuel we use today, so can simply be blended with the current fuel supply as they become available

Many of the technical hurdles facing aviation in its move towards sustainable aviation fuels have been overcome and much of this work has been achieved within the industry. Now, commercialisation and scaling up of the supply of alternative aviation fuels is the most important task. But airlines and the rest of the industry cannot do it alone – political support and financial investment will have to come from a number of stakeholders.

This section outlines six suggested steps that policymakers can consider in helping their air transport system grow with less carbon-intensive fuel, whilst in many cases also investing in green growth jobs and a new sustainable industry. These steps are presented in no particular order:

There are many different types of feedstock and pathways that enable feedstock to be converted into biofuel, and important technological developments will unlock still more pathways. Early generation biofuels used feedstocks derived from food crops such as rapeseed and corn. However, these feedstocks can be used as food for humans and animals, raising important questions about their sustainability. In response to these concerns, the industry is now focused on exploring the use of advanced-generation biofuel sources that are truly sustainable.

Several pathways are being considered for the development of sustainable aviation fuel.

The industry is unlikely to rely on a single feedstock, or source of the fuel. Some feedstocks are better suited to some climates and locations than others. Therefore, it is expected that ultimately there will be a portfolio of biofuel sources developed and a variety of regional supply chains.

Much of the current research and development work on alternative fuels is focused on biodiesel and bioethanol projects for land transport. Ultimately, this will delay land transport’s switch to more sustainable energy sources, such as electricity and hydrogen fuel cells.

Policy enablers include establishing funding programmes for academic research through existing or new university, research institution or industrial research projects, broadening or re-focusing university research of advanced fuels to include aviation-specific projects.

To be economically viable, sustainable aviation fuel must be priced at a level the market will find acceptable. At present, alternative fuels for aviation are not cost competitive with current jet fuel. However, traditional jet fuel is forecast to become more expensive. By contrast, sustainable aviation fuel will become less expensive as the industry develops. Policies incentivising alternative fuel development and use can hasten this trajectory and achieve greater emissions reductions in a shorter timeframe.

A better appreciation of the scope for reduction in the price of sustainable aviation fuel is gained by examining the cost drivers. For the technology pathway that is nearest commercial viability, it is estimated that 85% of biofuel production costs relate to the cost of feedstocks. As technology to harvest and process these feedstocks progresses, as agronomy and plant breeding produce cultivars with better, more robust yields, and as sustainable biomass become available in commercial quantities the price will drop. In fact, since aviation biofuel testing started a few years ago, prices for these feedstock inputs have already dropped significantly. Support for research and development will enable continued improvements for feedstock pathways. And crops are not the only source of feedstock – fuels can be produced from waste sources, as explored in the case studies.

Production is the second major component of the total cost of the fuel. The oil industry has already established refining infrastructure and thus currently has a limited need for additional capital investment. However, in the case of sustainable aviation fuel, the production infrastructure has yet to be developed and some of what needs developing could be synergistic with existing petroleum infrastructure, but not all.

There are also significant subsidies in place for biodiesel production in Europe and the US, which could hamper the establishment of alternative aviation fuel production.

These incremental upfront capital investment costs are a potential barrier to commercialisation. In this context, governments can play a role in reducing this risk through measures such as loan guarantees, tax incentives, grants and co-financing for pilot and demonstration projects. They can also provide a level playing field with biodiesel by providing similar fiscal and price incentives in order to catalyse establishment of the sector.

If a policy or incentive mechanism is a key part of making renewable energy project economics attractive, changes to these factors pose a risk: a long-term, stable policy regime with a sound legal basis is essential for serious investment to occur.

Unlike some other renewable sectors, sustainable aviation biofuels are not subject to feed-in-tariffs or mandates. The EU ETS is a policy mechanism that may incentivise sustainable aviation fuel development, but the price of oil is a far greater driver so its impact will probably be limited in the near-term. The market for sustainable aviation fuels is primarily driven by other factors including reducing dependence on fossil fuels and improving the carbon footprint of the industry. Consequently, alternative aviation fuels are subject to very limited policy risk.

Policymakers can foster development of alternative aviation fuel by recognising the unique role it can have in reducing the aviation’s environmental impacts. Aircraft cannot use alternative renewable energy sources available to other sectors such as plug-in, wind, solar or hydroelectric power. Thus, crafting policies that create a level playing field for these fuels vis-à-vis other energy sources, and aviation vis-à-vis other sectors, is a key element in commercialisation.

Sustainability standards are being established that will provide suppliers, investors and customers with clear guidelines as to what is considered to be a sustainable fuel. For example, in the EU, the Renewable Energy Directive (RED) contains specific criteria addressing this. The Switzerland-based Roundtable on Sustainable Biomaterials (RSB) has a sustainability standard developed through a multi-stakeholder process that ensures the sustainability of production, processing and implementation. Sustainability is not just a matter of the choice of feedstocks – it is also a matter of how they are cultivated, harvested, processed and transported.

Some key sustainability criteria for aviation fuels could include the following elements:

  • will not displace, or compete with, food crops or cause deforestation
  • minimise impact on biodiversity
  • produce substantially lower life-cycle greenhouse gas emissions than conventional fossil fuels
  • will be certified sustainable with respect to land, water and energy use
  • deliver positive socioeconomic impact

As a global transportation sector, aviation needs a harmonised standard to ensure that sustainability criteria are enforceable and equally applied across the industry. A patchwork of standards would inhibit the development of a commercially viable market. While there are myriad standards in place, both regulatory and voluntary, a critical element will be for aviation fuel stakeholders to enable greater cooperation between standards to increase transparency, decrease the cost of compliance, increase end-user visibility to the biomass, and increase the incentives for next generation fuel pathways. It is also vital that a unified accounting structure be established to verify the origin and sustainability credentials of these new fuels for aviation.

The development of an accepted set of globally harmonised standards will help ensure that investment is directed at fuels that meet acceptable sustainability criteria, thus minimising this form of risk. Criteria need to be mutually recognised around the world. For aviation, global standards are needed wherever possible, due to operational routing of aircraft, common global equipment and worldwide fuel purchasing requirements.

Sustainable aviation fuel doesn’t only bring environmental benefits for aviation, it can also foster the development of a new industry. Given the diversity of feedstocks that aviation is considering, there are few places on earth that could not support some development of a new, sustainable, energy industry. These can range from growing large quantities of jatropha, halophytes or camelina in the most appropriate environments, to establishment of algae farms on land or off-shore, to smaller scale biofuel facilities in cities utilising municipal waste.

By bringing the aviation industry, government, energy, agriculture and academic expertise together, analyse the optimum opportunities that exist in each country for aviation biofuel production, including the most effective feedstock sources and infrastructure requirements. A number of regional development banks are also working on ways to encourage the process along.

Experience has shown that there are many benefits to be gained from collaboration across the various stakeholder groups involved in all aspects of aviation alternative fuel production and use. These groups can bring together parties who have not traditionally needed to work together, such as:

  • Airlines, airports, aircraft and engine manufacturers
  • Academic institutions
  • Fuel refining companies
  • Agricultural companies and farmers groups
  • Local, regional and national departments of agriculture, defence, transport, economic development and enterprise
  • Regulators – aviation, transport and agricultural
  • Environmental and sustainable development NGOs

There are many examples of stakeholder-oriented processes, all of which are groups of regional and national stakeholders, who have convened to work through the sustainability, supply, investment and long-term planning issues and maximise the opportunities within their respective regions. Within coming years, many significant commercial, policy and sustainability outcomes will result from such comprehensive regional stakeholder processes. These processes serve to enable commercial parties, while also giving confidence to governments and civil society organisations that sustainable aviation fuels efforts are following a planned path.

The aviation industry has established a plan for reducing emissions. Sustainable aviation fuels are an important part of that plan and, as you will have seen in this publication, the industry and its partners have made significant progress. There is confidence that alternative fuels can be a very significant part of every airline’s future. From policymakers, the industry is looking for encouragement and the right set of legal, fiscal and policy responses to ensure this exciting new energy stream can bear fruit as quickly as possible.


The aviation industry has made it clear that it is only looking at second-generation biofuels and is determined not to repeat the mistakes made with first-generation sources, expecting any supply to be fully sustainable. The industry is working together through groups such as the Sustainable Aviation Fuel Users Group (SAFUG) and the Roundtable on Sustainable Biomaterials (RSB) to make sure that any fuels used by the industry are, in fact, sustainable.

Initiatives around the world

Businesses from across aviation’s value chain are coming together in projects around the world to help with the commercialisation of alternative aviation fuels. Below is a list of such initiatives and links to their websites: