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  • Writer's pictureKartik Verma

Let's look at aviation

Updated: May 26, 2022

We loved reading your feedback from last week! Based on what you all told us, we are introducing the following changes:

  • Starting this week, we are going to try to have a theme for each newsletter, this week’s theme - Aviation!

  • In addition, we have added a section in the end called “Archives” which covers a list of important concepts that we have discussed in previous weeks for you to refer in case you need to

Let us know if you like these changes or not or share your ideas here!

As always, if you like the initiative, it would mean a lot to us if you could share it with your network. Happy reading!

What to expect today:

Aviation emissions

Greta Thunberg, the famous climate activist, chose to sail in an zero emission yacht over the Atlantic back in 2019 rather than choosing to fly in an aircraft to highlight the impact of aviation on the climate. We wondered, what is the environmental impact of flying?

What are aviation emissions?

Flights produce greenhouse gases - mainly carbon dioxide (CO2) - from burning fuel. These contribute to global warming when released into the atmosphere. In addition, these emissions are released into the atmosphere at a higher altitude than, let's say, your car driving on the road and have a higher impact on the environment. (Fun fact: Aviation fuels consist of blends of over two thousand chemicals, but primarily hydrocarbons and hence burning them is bad for the environment). CO2 emissions however are not the only emissions that are released into the atmosphere; another major source of emissions is Nitrogen Oxide which when released into the atmosphere at higher altitudes tends to stay there for longer times and thus is more harmful for the environment.

What do emissions look like for individual passengers?

While actual emissions differ from flight to flight, type of aircraft, passenger utilization etc., most organizations tend to estimate them to be around 120-150kg CO2 per passenger per hour (For a more detailed explanation and analysis, check out the exact math broken down here). According to figures from German nonprofit Atmosfair, flying from London to New York and back generates about 986kg of CO2 per passenger. There are 56 countries where the average person emits less carbon dioxide in a whole year.

However, in absolute terms, aviation contributes to about 2.5% of global emissions (for reference, global transportation contributes to about 16% of emissions out of which 12% is from road transportation).

How do aviation emissions compare with other modes of transport?

Since each mode of transport can carry a different number of passengers, emissions from different modes of transport are best compared when considering emissions per passenger per km travelled. They are given below in decreasing order (in per passenger per km):

  • Short-haul flights: 254 g

  • Long-haul flights: 195 g

  • Cars (1 person): 171 g

  • Buses: 104 g

  • Car-pooling (4 passengers): 43 g

  • Trains: 41 g

Hopefully, without surprise, trains are the best for the environment as you can imagine they can carry a lot of people from one place to another. Surprisingly, car-pooling is also a very close second!

Airbus' zero emission goals

The aviation industry, including Airbus, has committed to an industry-wide decarbonisation movement that includes the following key targets:

  • Carbon-neutral growth: From 2020, net carbon emissions from aviation will be capped. This means that even though air travel is increasing, greenhouse gas emissions will not.

  • 50% reduction in CO2 emissions: By 2050, net aviation carbon emissions will be half of 2005 levels

Climate action at Airbus

While we could look at emission numbers like in previous case studies, we are going to instead highlight specific initiatives at Airbus which highlight Airbus’ commitment to climate action.

  • By far their biggest goal Airbus has is to bring the world’s first zero-emission commercial aircraft to market by 2035 - investing in electrification, hybridisation and hydrogen powered aircrafts

  • Developing Sustainable Alternative Fuels (SAF) - All Airbus aircraft and helicopters are certified to operate on up to a 50% blend of SAF today with a plan to achieve certification of 100% SAF by 2030

  • Decreasing the carbon footprint through improved operations and better lifecycle management across Design, Manufacturing, Operations and End of lifecycle


Electric vs. Hydrogen planes

United Airlines announced on July 13th that it would buy 100 19-seat ES-19 electric planes from Swedish start-up Heart Aerospace, as the U.S. carrier eyes battery-powered aircraft for regional routes. United is also investing in the startup through United Airlines Ventures alongside Bill Gates’ Breakthrough Energy Ventures (BEV) and Mesa airlines. Mesa airlines has also agreed to buy 100 aircrafts from Heart Aerospace

A small Swedish startup

Heart Aerospace is Swedish electric aviation startup raised a $35m Series A round when United, BEV and Mesa invested in the startup and placed its biggest order till date for 200 of its ES-19 aircraft. The ES-19 is a regional airplane that seats 19 and runs on batteries and electric motors instead of traditional jet fuel. The startup plans to deliver the first aircraft for commercial use by 2026. These aircraft will be able to fly up to 250 miles based on today’s battery technology. Heart has made a full-scale prototype of its electric propulsion system, the core of its technical innovation. But the company still has to complete many steps along the way to its proposed date of commercial operations. Chief amongst these is actually assembling a prototype of the full aircraft, testing it and getting it certified with relevant authorities in the U.S. and Europe.

Not everyone is convinced

While a lot of startups are working on electric planes, the airplanes have one major limitation; batteries are just physically too heavy for a longer-range aircraft. Even with major advances in battery technologies, electric planes will probably be limited to short- or medium-range journeys, not lengthy flights over oceans or between distant cities. For reference, Lithium-ion batteries of today have an energy density of 250 Watt-hour / kg whereas today’s jet fuel has an energy density of 12,000 Watt-hour / kg.

Hydrogen is seen as a more realistic path to cleaning up most air travel. Burning hydrogen fuel cells leave water as a by-product and hydrogen has an energy density of 39,500 Watt-hour / kg which makes it ideal for air-travel. So, why aren’t we flying more hydrogen-fueled planes? First, liquid hydrogen only has a quarter of the energy by volume as jet fuel. Second, for a plane to get the same energy from hydrogen as it would from jet fuel, it needs a storage tank about four times larger (since this would require new aircraft designs, fresh approvals etc., it will take time). And finally, we need to build the infrastructure to extract vast amounts of liquid hydrogen near airports (think equivalent to early days of EV adoption).

However, companies are confident of a Hydrogen powered future. Airbus announced earlier that it is growing more and more confident that its zero-emission aircraft, which is slated to be launched by 2035, will run on hydrogen.

Recommendations from the team

  • Google Flights - Look at your carbon emissions from your next flight

  • CNBC - Are eco-friendly flights impossible? (7 min video)

  • Seeker - How Green Fuel Could Change Your Flights Forever (6 min video)

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