A recent high-level conference hosted by the Dutch government focused on the potential of synthetic aviation fuels, also called power-to-liquid (PtL) or e-fuels, to significantly lower the aviation sector’s carbon footprint (see article). The Minister of Infrastructure and Water Management, Cora van Nieuwenhuizen, announced KLM had undertaken the first ever commercial flight to use synthetic kerosene in a jet fuel blend, which was produced by Shell. The conference also highlighted the launch by a Dutch/Swiss/German consortium of a project that aims to build a demonstration plant in Rotterdam which will produce fully circular sustainable aviation fuel (SAF) via direct air capture. The move comes after Royal Schiphol Group agreed to finance a study in 2019 into the feasibility of a demo plant able to produce SAF from air, water and renewable electricity. The study was led by German service provider EDL, with input from Climeworks, Sunfire, Ineratec, SkyNRG and Urban Crossovers. A new startup, Zenid, is now taking the next step with the support of these technology partners. Meanwhile in Germany and backed by the state of Hesse, Ineratec is planning a PtL pilot plant at an innovation hub for carbon-neutral alternative fuels next to Frankfurt Airport that is expected to produce up to 4.6 million litres of fuel a year starting in 2022, including an anticipated 1.25 million litres of synthetic jet fuel.

The Zenid demonstration plant will be powered by regionally sourced renewable energy and will combine several innovative technologies. A direct air capture plant will provide CO2 to a highly efficient co-electrolysis unit that turns the CO2 and added water into syngas, which is then transformed into liquid hydrocarbons by a modular Fischer-Tropsch reactor and then refined into sustainable aviation fuel (see below).

(Image: Zenid)

The consortium partners include Rotterdam The Hague Airport (part of the Royal Schiphol Group), Rotterdam The Hague Innovation Airport (RHIA), SAF global supplier SkyNRG and Swiss direct air capture company Climeworks. Based on the earlier feasibility study, the partners will carry out further investigations into the viability of the project. Zenid has also signed an MoU with Düsseldorf-headquartered global energy company Uniper to support the engineering and operation of the demonstration facility.

“Rotterdam The Hague Airport is very proud to be one of the kick-starters of this ground-breaking project, together with Schiphol Group and RHIA,” said Ron Louwerse, the airport’s Managing Director. “It fits exceptionally well within our strategy to facilitate and accelerate sustainability and innovation in aviation, to be at the cradle of sustainable aviation fuel made of CO2 from air.”

RHIA is a socio-economic cluster, providing an innovation ground for future aviation, with a focus on sustainable airplanes and airports, smart mobility, green energy, new business and next-generation education. Climeworks’ direct air capture technology runs exclusively on clean energy, with modular CO2 collectors that can be stacked to build machines of any size.

“The launch of Zenid shows the commitment of the industry towards fully circular fuels from air and their role to substantially reduce aviation’s CO2 emissions,” said co-CEO Christoph Gebald.

Plans for an innovation hub focusing on carbon-neutral alternative fuels and the construction of a pilot facility to produce synthetic fuels next to Frankfurt Airport were made in 2018. Since then, work has taken place on building the required legal framework and national network to support the emerging technology. The hub is being developed at the Industrial Park Höchst, which is operated by Infraserv Höchst and covers an area of 4.6 square kilometres west of the airport. It includes the Centre of Competence for Climate, Environment and Noise Protection in Aviation (CENA), which was established in January 2020 by the Hessian state government with a remit to secure the future of sustainable flying through innovations in aviation and promote Hessen as an aviation hub.

“We urgently need to reduce CO2 in transport, especially in aviation. To increase climate protection in transport, we need to encourage people to take short trips by train and make airplanes more fuel-efficient,” said Hessian Minister of Economics and Transport Tarek Al-Wazir at a recent presentation. “Moreover, we also need CO2-neutral fuels for intercontinental flights that start at Frankfurt am Main. That is why we are now investing in power-to-liquid technologies and infrastructure, especially for synthetic kerosene, here in the state of Hesse.

“CENA started its work at the beginning of 2020 and, furthermore, there are alternative fuel production companies in the region who want to realise their projects at the Industrial Park Höchst. We proactively support such developments not only with money from our regional budget but we are also actively bidding for money from the national budget.”

The German state has allocated extra funds from the state budget for alternative fuels and the production of green hydrogen as a starting point for the production of PtL fuels, and a roadmap has been put together by industry and state and regional governments.

“In order to enable the sustainable aviation fuels breakthrough, we actively support technological advances, construction of the interconnected infrastructure and the enabling of a functioning market framework for such fuels,” said Bernhard Dietrich, Head of CENA.

Two technology companies, Ineratec and Caphenia, have plans for PtL production facilities at Frankfurt Höchst. Ineratec, which was founded at the Karlsruhe Institute of Technology in 2014, develops, builds and operates modular units to produce synthetic fuels and waxes through the Fischer-Tropsch process. It has ambitions to build the world’s largest PtL production plant at Höchst. Caphenia has developed a power-and-biogas-to-liquid process for renewable fuels and basic chemicals using biomethane, CO2, water and renewable electricity. The company is planning a first pilot unit at Höchst.

“With the Ineratec power-to-liquid pioneer plant, CO2-neutral synthetic fuels will be widely available for the first time,” said Philipp Engelkamp, Managing Director of Ineratec. “Due to the modular concept, production capacities will be expanded worldwide.”

Synthetic fuels production process planned at Industrial Park Höchst:

Top image: Zenid (© Blueroom)

Representatives from the European aviation sector and environmental groups, together with a research organisation and a sustainable aviation fuel supplier, have come together to provide recommendations to EU policymakers on sustainability aspects and support for future aviation fuels. Convened by two climate-based philanthropic bodies, the guiding principles drawn up by the 12 participants in the Fuelling Flight Initiative are based on a shared vision that ramping up sustainable aviation fuels in Europe needs to be done in the right manner from the start. Endorsing the initiative include Air France, Deutsche Post DHL, easyJet, KLM, International Airlines Group, Schiphol Group, Transport & Environment, WWF and SkyNRG. The move comes as EU regulators consult on revisions to the Renewable Energy Directive (RED) to bring it in line with the ambitions of the European Green Deal and the net-zero by 2050 goal.

The current directive does not ensure that fuels used in Europe meet the sustainability standards desired by civil society nor of leading airlines, believes Pete Harrison, EU Policy Director of the European Climate Foundation, which, along with ClimateWorks Foundation, convened the initiative.

“Europe must ensure that future policies only promote the most sustainable fuels for reducing the climate impact of aviation, and the EU needs to avoid repeating the mistakes of the past,” he said. “Those in the Fuelling Flight Initiative have now reached agreement on this important topic and we propose shared guidelines on how to minimise environmental impacts. Policymakers should take this into consideration when defining a policy framework that is fair, affordable and meets the highest sustainability standards without compromise.”

He was backed by KLM CEO Pieter Elbers, who said: “With our contribution to the Fuelling Flight Initiative, we support EU policymakers in defining the right framework that meets the highest sustainability standards. At the same time, we advocate affordable pricing of sustainable aviation fuel (SAF) in combination with requirements that are equal for all parties. With that, the road is paved for a faster uplift of SAF, helping us to decrease our impact on the planet and accelerate our ambitions towards sustainable aviation.”

Among the recommendations put forward in a consensus statement published by the initiative are to:

• prioritise e-fuels and fuels made from wastes and residues;
• exclude biofuels produced from dedicated cropland;
• execute case-by-case assessments of local environmental impacts; and to
• support multiple technology pathways.

The statement notes that despite two phases of EU policy support through RED and the Fuel Quality Directive, European investment in advanced biofuels production had so far been subdued and EU biofuel use had been dominated by fuels with high sustainability risks. Future policy support should only go to fuels with high carbon reductions compared to fossil fuels, which would provide a solid foundation for securing future investment in SAF development as well as contributing to broader UN Sustainable Development Goals, it says.

The initiative’s participants call for SAF policy to be informed by bottom-up assessment of feedstock availability in conjunction with a review of existing demands across different transport modes and cautions against high SAF mandates in the near term that could drive unsustainable behaviour, such as high-intensity extraction of residues with existing uses or the diversion of land to meet SAF demand.

“Any potential SAF deployment targets must balance the availability of sustainable feedstocks with the necessary ambition and complementary policy support to drive investment in more challenging advanced fuel pathways,” they recommend.

Over the next few years, waste oils may deliver small volumes of low-carbon SAF but, says the statement, the EU must invest in fuels made from more abundant resources such as agricultural residues, municipal bio-waste and electrofuels (e-fuels). It emphasises the importance of selecting which wastes and residues are sustainably available for SAF production.

“The precise guidelines for sustainable availability will by necessity vary by location and on a feedstock-by-feedstock basis,” it adds. “For example, the guidelines for agricultural residues will be different than those for forestry wastes and municipal solid waste (MSW).”

The participants agree the theoretical availability of fuels of non-biological origin greatly exceeds the potential of fuels made from wastes and residues. These include fuels generated from industrial waste gases, although they say it is important these fuels do not provide a continued business case for fossil fuel use and full lifecycle assessments must be undertaken to ensure the fuel generates real GHG reductions relative to the fossil baseline, including indirect effects.

E-fuels made from captured carbon in conjunction with renewable electricity or concentrated sunlight is expected to be another important source of non-bio SAF in the long term. Again, stresses the statement, policymakers must ensure both the renewable electricity used to produce them and the carbon captured for fuel production are not incentivised by power sector policies or otherwise double-counted towards those policies.

“Therefore, it is critical to ensure that these fuels are produced from additional renewable electricity and their CO2 use, if not captured from the atmosphere, does not provide a continued business case for fossil fuel use.”

The statement envisions a three-phased approach to SAF deployment based on technology readiness and feedstock availability. In the first phase through 2025, waste oils are the likeliest source of low-carbon fuel due to their low carbon intensity and ease of conversion. However, there is competition for such fuels and policymakers may choose not to incentivise their diversion from the road sector towards the aviation sector. Even with diversion, the penetration of waste oils in aviation will be limited but their use would constitute a meaningful first step, argues the statement.

Scaling up SAF deployment in the 2025-2035 timeframe will require utilising more technically challenging feedstocks through the commercialisation of emerging technologies. More abundant sources of sustainable feedstock are expected to come from lignocellulosic residues and wastes such as MSW and agricultural and forestry residues.

To meet long-term decarbonisation targets and deeper deployment rates, the participants say it will require the use of fuels with greater availability than bio-based wastes and residues, with e-fuels offering substantial long-term potential for supplying SAF, as there are fewer constraints to their production volumes. However, acknowledges the statement, the high cost of supplying additional renewable electricity makes this one of the most expensive options for reducing aviation emissions. Despite the initial high costs, policy support for e-fuels over the next decade could help bring down the capital costs for electrolysers and introduce the policy framework that would link transportation energy demand to new, additional renewable electricity from the power sector.

Concluding, the statement recommends the European Commission proposes higher sustainability standards than those currently laid out in the RED, including clear exclusions of unsustainable feedstocks and pathways, such as biofuels from dedicated croplands and palm oil production by-products (PFAD). The revised framework should also incentivise levels of SAF and/or feedstock use that could be met only from domestic EU supplies.

“To meet aviation’s climate targets, it is essential to start scaling SAF production capacity rapidly, in collaboration with all relevant stakeholders including governments and NGOs,” commented Maarten van Dijk, Managing Director of sustainable aviation fuel supplier SkyNRG. “Long-term, stable policy frameworks are key to enable scale-up, and a clear exclusion of unsustainable feedstocks and pathways is, in our opinion, an important part of future policy.”

Added Andrew Murphy, Aviation Director at Transport & Environment: “The aviation fuels policy Europe launches this year will be crucial in determining whether the air travel sector is finally put on a path to sustainability. Europe needs to avoid repeating the mistakes of the past by ending support for crop-based biofuels and instead support new fuels, in particular e-fuels derived from additional renewable electricity. This statement is an important recognition by a wide range of actors of this need.”

The 10 participants in the initiative are Air France, Bauhaus Luftfahrt, Deutsche Post DHL Group, easyJet, International Airlines Group, KLM, Natuur & Milieu, T&E, Réseau Action Climat, Schiphol Group, SkyNRG and WWF. Technical advice was provided by the International Council on Clean Transportation (ICCT).

The European Commission launched a public consultation in November on a revision of the Renewable Energy Directive, which closes on February 9.

Photo: KLM