New solutions for the future

Cleaner jet fuels are relatively new and lots of research has been done to analyze best practices. Much has been achieved, however, further effort is required to make those new solutions viable. We want to be part of that journey and help passengers become more sustainable travelers by taking advantage of this new resource.


Flightnook is a non-profit organization willing to attribute as much as possible to environmentally friendly air travel. Passenger contributions will be used to replace fossil based (conventional) jet fuels with cleaner jet fuels helping to reduce carbon emissions and exploitation of natural resources. Those are big claims, however, Flightnook’s highest priority is transparency, allowing passengers to understand the benefits of their participation.

Technology improvements and optimized operations are two measures to reduce carbon emissions associated with conventional aviation fuel. However, this has been done for more than 50 years and further improvements require substantial efforts while only having a limited effectiveness. The only measure to substantially improve the environmental footprint of the industry in the short- and medium-term is to scale cleaner fuels or also called advanced alternative fuels. Cleaner fuels reduce emissions, scale down exploitation and consider other social factors that contribute to society on many levels.

The cleaner fuels Flightnook utilizes are drop in fuels that can be blended with fossil based fuels without requiring any technical modification of the airplane propulsion system. They fulfill similar chemical and physical requirements as conventional jet fuels and are certified with the same strict standards to be eligible to operate in regional and international passenger air transportation. At present, the maximum blending volume of cleaner jet fuels is 50% and significant experience has been acquired through experimental and commercial flights. With advancement of the sector, 100% cleaner jet fuels blends will be available in the future.

There are two types of certifications:
1) Technical certification, which ensures that the fuel complies with the required characteristics for use in current airplanes. Existing technical specifications for cleaner jet fuels are ASTM D-7566, the U.K. Defense Standard (DEF STAN) 91-091 Issue 9, the Brazilian ANP Resolution 63/207, and the Chinese CTSO-2C701.
2) Sustainability certification, which ensures that a given cleaner jet fuel complies with defined sustainability criteria. Some regulatory standards comprise of the US Renewable Fuel Standard (RFS), California Low-Carbon Fuel Standard (LCFS), International Sustainability and Carbon Certification (ISCC) and Roundtable for Sustainable Biomaterials (RSB) – more details within next response.

Cleaner fuels are obtained from sources other than directly from petroleum, such as biomass, waste materials and hydrogenated fats and oils that meet sustainability criteria. Those criteria include net greenhouse gas (GHG) emissions reduction on a life cycle basis and contribute to local social and economic development. Depending on the scope of passenger contribution the cleaner jet fuel source might vary, however, it shall be certified by Roundtable for Sustainable Biomaterials (RSB) – one of the highest standards – meaning they comply with rigorous sustainability criteria and minimal or zero risk of indirect impacts – such as deforestation or increased food prices.

First of all, using cleaner jet fuels reduces emissions and with that the environmental impact when taking a flight. Second, it supports the development of other social benefits addressing issues such as human and labor rights, rural and social development, local food security, conservation of biodiversity, land rights as well as soil, water and air pollution. The exact details behind the 12 principles certified under the Roundtable for Sustainable Biomaterials (RSB) have been approved by many stakeholders, including NGOs and UN agencies.

Yes, cleaner fuels are currently more expensive than conventional fuels. This has several reasons. First, oil is presently very inexpensive, which increases the price gap. Second, the value chain to produce cleaner fuels is relatively new, requiring logistics to further improve. Third, economies of scale have not yet applied to cleaner fuels at today’s production stage. Depending on the current oil price cleaner jet fuels are approximately twice as expensive as conventional jet fuels. Use our emission flight calculator (available soon) to discover how much CO2 you emit on your trip and how much it would cost to reduce this amount by flying with cleaner jet fuels.

Cleaner fuels reduce CO2 emissions on a life cycle basis (i.e., from production to combustion) compared to conventional jet fuels. To allow for drop-in compatibility, cleaner jet fuels are intentionally designed to have properties similar to conventional aviation fuels, which means that they are still made of hydrocarbons. However, low life cycle CO2 emissions can be achieved by using biomass or waste feedstocks. In this case, the CO2 absorbed by plants during their growth stage is later emitted back into the atmosphere during combustion and will return to the plants in a closed loop. Another option would be the use of waste feedstock such as municipal solid waste or industrial waste gases. In this case, the mechanism for emissions savings is not the carbon capture through photosynthesis, but the multiple uses of fossil carbon. Cleaner fuels supported by Flightnook reduce emissions depending on the production procedure by 60-80% compared to conventional jet fuels. With advancement of the sector, even higher emission savings will be possible in the future.


Global warming means that the average global temperature rises, causing long term weather patterns to alter. It is one of the main causes of climate change. As people produce greenhouse gases, energy is trapped in the atmosphere and it leaves Earth even more slowly, raising its overall temperature.

The delay between cause and effect in climate change is estimated 40 years meaning that future generations will suffer the most from today’s pollutions. Global warming leads to the melting of glaciers, extreme weather and droughts, seriously harming the wildlife.

Greenhouse gases (GHGs) such as carbon dioxide (CO2), methane, water vapor and nitrous oxide, trap heat in the atmosphere. Without GHGs, an average temperature of 59°F (15°C) would drop to 0°F (-18°C). GHGs indeed help prevent temperatures from fluctuating extensively.

Although GHGs are crucial for the Earth to be habitable, a substantial increase will threaten our current ecosystem. The more greenhouse gases accumulate in the atmosphere, the more heat stays in the atmosphere, increasing temperatures on Earth’s surface. In the last decades, humans have caused the amount of GHGs to increase at an alarming rate and CO2 levels in the atmosphere have risen by approximately 45% since the beginning the 19th century, after having been stable for millions of years.

Sunrays are called solar radiations. While 26% of the solar radiations are mainly reflected by the clouds back into the space, 19% of them are absorbed by the greenhouse gases present in the atmosphere. The remaining 55% reaches the Earth and almost all of it is absorbed by its surface.

The solar radiations that have been absorbed by the Earth’s surface are reflected back to space in form of infrared radiations. These infrared radiations are absorbed by the GHGs in form of heat and only a small portion escapes to space. The GHGs then send back infrared radiation to the earth’s surface to be subsequently reflected back to the atmosphere. This cycle keeps repeating until no radiation is left for absorption.

Add sentence on the fact the Earth can’t keep up with environmental changes. Global warming also endangers species, who are likely to disappear in the next few years. Minorities will suffer the consequences the most, but everybody – especially future generation – will suffer them.

Global warming has turned into a vicious circle and we need to take action quickly. The melting of the pole caps engendered by the rise in temperatures leads to further releases of methane (GHG) which in turns increases global warming.

Airplane engines produce contrails (white stripes in the sky) caused by soot particles. The soot particles cause ice crystals to build that form to cirrus clouds – also called contrail cirrus – resulting in a greater warming effect on earth’s atmosphere. First studies show that cleaner jet fuel blends of 50% can reduce soot particle emissions of an airplane’s engine by 50 to 70% leading to a reduction of ice particles and therefore global warming.

Both the Kyoto Protocol and the Paris agreement aim at reaching the same goal: restrict the global temperature rise below 3.6°F (2°C). However, they do not have the exact same approach in the way they push countries into taking action.

On one hand, the Kyoto Protocol only focuses on developed countries’ emission levels and has set a fixed target for them to achieve. On the other hand, the Paris agreement made all nations, developed and developing, commit on their own domestic emission reduction targets. While the Kyoto Protocol follows more of a top-down approach by starting with the big picture, the Paris agreement follows a bottom-up approach by piecing things together in order to attain a bigger goal.

The commitment period to the Kyoto Protocol will come to an end in 2020 and from onwards, the Paris agreement on climate change will come into effect.

During the 2015 climate change conference in Paris (COP21), participating countries agreed to reduce GHG emissions with the goal of keeping temperature increase below 3.6°F (2°C) by 2050, compared to pre-industrial levels. This will require the population to substantially reduce its GHG emissions, as we currently use the equivalent of 1.7 Earths to satisfy our resource demand.

To put it into another perspective, we can translate those required emissions savings to per capita required savings – reductions required by every living human to keep a maximal temperature increase of 3.6°F (2°C) by 2050 and beyond. An average person emits globally approximately 5 tons CO2eq (GHG emissions translated to a carbon dioxide equivalent value). However, this value differs significantly between people and their origin. For instance, emissions for a person from a well developed country like North America, Europe or Australia lie between 10 and 20 tons CO2eq. Countries that have intensive transportation usually position themselves at the higher end. To reach the 3.6°F (2°C) temperature goal by 2050, per capita emissions have to reduce to 5 tons CO2eq by 2030, to 2 tons CO2eq by 2050 and then further reduce to 0 tons CO2eq by 2070.

Reducing emissions is a long process that requires immediate action. No other human activity pushes individual emission levels as fast and as high as transportation and in particular air travel.