Can flights ever be 'green'?

As a carbon-emissions tracking app, our aim is to transform our users from climate worriers to climate warriors. As we help users track emissions from everyday mobility choices, emissions from one mobility mode have come as a real shock to users - flights...

We understand that often flights are vital - perhaps to spend precious time with family overseas, or move for a new job… so what to do if you’re conscious of CO2 emissions but really do need to fly? We’ve put together some research to give you a clear picture of airline emissions and the future of ‘green flights’, plus some tips to reduce emissions if you need to fly.

Just to refresh your memory, air travel accounts for around 2.5% of global carbon dioxide emissions — a far smaller share than emissions from passenger cars or power plants. Still, one study found that the rapid growth in plane emissions could mean that by 2050, aviation could take up a quarter of the world’s “carbon budget,” or the amount of carbon dioxide emissions permitted to keep global temperature rise to within 1.5 degrees Celsius above pre-industrial levels.

According to the US Energy Information Administration, jet fuel produces 9.6kg of CO2 per gallon burnt. Let’s take an example flight – a Boeing 737, one of the world’s most popular commercial jets, will burn somewhere in the region of 750 gallons an hour. Over the course of a three-hour flight, it can burn through 2,250 gallons of fuel, producing 21,533kg of CO2. Depending on the model, the plane can hold around 200 passengers, making the amount of CO2 produced per passenger around 108kg if we assume a fairly full flight.

It can be difficult or near-impossible to cut out air travel from your lives (plus it’s often the cheapest, most time-efficient way to travel). For this reason, we decided to research the ‘greener’ options within air travel and the future of a sustainable airline industry (we know, a slightly contradictory idea!). Let’s unpack it...

Whilst technically there’s not really such a thing as a “sustainable” or “green” airline, there are airlines that attempt to reduce overall emissions. If you do choose to fly, it may be worth considering airlines that are attempting to lower overall emissions. In 2019, a report by the London School of Economics, backed by the Environment Agency Pension Fund, investigated what each airline was doing to lower its emissions. Their results revealed that EasyJet is doing the most and is on track to cut emissions per passenger kilometre to half that of some of its rivals. Their success can be partly attributed to newer aircrafts, with more efficient fuel, and push to fill every seat on a flight, which means that the overall emissions are divided by the number of passengers, and effectively reduced.

The airlines doing the least to lower their emissions were Air China, China Southern, Korean Air, Singapore Airlines and Turkish Airlines. The report compared each airline's emissions in 2017 and 2020 and ranked them in terms of their progress (in order of appearance): EasyJet, Alaska Air, Quantas, United, JetBlue, Southwest, LATAM, Lufthansa, Turkish Airlines, Air China, IAG (Inc British Airways), Japan Airlines, ANA Group, Korean Air, Singapore Airlines (no 2020 data yet), American Airlines (no 2020 data yet), and China Southern (no 2020 data yet).

While these airlines have worked to reduce their overall emissions, many of them have come under fire for “greenwashing”, as Ryanair did when they started advertising themselves as the lowest emitting airline in Europe.

“Everybody knows that when you fly Ryanair you enjoy the lowest fares. But do you know you are travelling on the airline with Europe’s lowest emissions as well?” reads one advert that advertised Ryanair as a budget-friendly, “green” airline.

Ryanair’s figure – and the reason why it can lay claim to being Europe’s “lowest emissions” airline – is 67 grams of CO2 per passenger kilometre. That’s the lowest for any EU airline, beating Virgin’s 78.2g in 2017 and Easyjet which was 81.05g in 2015, despite the fact that Ryanair’s total 2018 emissions were almost 60 per cent more than Easyjet’s.

Although these are impressive figures – by the aviation industry’s standards – they don’t mean that Ryanair has actively been trying to reduce its carbon footprint. Ryanair’s numbers come down to three factors: the age of its planes, how full they are and how far they fly. The airline has one of Europe’s youngest fleets, consisting of over 450 Boeing 737-800 planes with an average age of 6.5 years. Since newer planes are more fuel efficient they release less carbon dioxide, cutting down the overall emissions from each flight.

Ryanair is also very good at packing those planes with people. “Ryanair’s sole business model is to grow passenger kilometres,” says Jardine. The airline fills more of its seats than any other EU airline, with an average load capacity of 96 per cent, thanks to its bargain basement prices. Most Ryanair planes have 189 seats and, on average, they’re filled with 181 (and a half) passengers per journey. The more passengers Ryanair has, the higher the number of passenger kilometres it racks up, meaning it divides up its carbon emissions further.

The distance that Ryanair flies also helps. In 2010 the average Ryanair plane flew just over 1,000 kilometres per journey, although that’s likely to have increased since then. The relatively short distance means that Ryanair’s planes don’t need to carry lots of excess fuel, which would increase weight and makes the planes less energy efficient. And it’s also more fuel efficient than very short haul flights (such as UK domestic flights) since taking off is the most fuel-intensive part of the flight.

Based on this information, we conclude that while these airlines can try their best to reduce emissions, the only truly beneficial move that can make for the planet is reducing the amount of flights offered.

This doesn’t seem likely, with the demand for commercial flying steadily growing each year. In 2019, global air traffic passenger demand is estimated to increase by 4.2 percent on the year before. In 2020, traffic is projected to grow with another 4.1 percent, though the COVID-19 pandemic is certainly affecting people’s ability to travel.

What does the future of aviation look like?

The most realistic zero-emission planes will be electric. Instead of using traditional fuel to power a plane, which releases large amounts of pollution, electric planes use large batteries that are chargeable and provide a powerful and clean flight.

Electric planes are ideal for trips less than 1,000 miles, which produce 40% of all aviation emissions but are still short enough to ideally travel on a single charge. Many people choose to drive their sub-1,000-mile trips, but traveling by electric plane could cut emissions by an additional 4-8%.

Electric planes are already being tested around the world. Last summer, the two-seater plane e-Genius climbed to more than 20,000 feet in the French Alps and went faster than 140 miles per hour. The electric plane, which was designed by engineers at the University of Stuttgart, flew 300 miles on a single battery charge. Aside from releasing no emissions, it only cost $3 in energy to fly, and it released just a fifth of the energy that a traditional two-seater fuel-powered plane would use to fly the same distance.

Zero-emission planes aren’t limited to researchers and startups. Aviation giants like Boeing, Airbus and Raytheon are also experimenting with eco-friendly airplane designs. Boeing is working on the SUGAR Volt plane that uses both electricity and fuel, similar to a hybrid car. The idea was first created in 2006, and Boeing is working with NASA to deliver results by 2040. Airbus is building E-Fan X, a battery-powered plane that replaces one of its four traditional engines with an electric motor that has the equivalent power of 10 cars. The E-Fan X is expected to take its first flight in 2021, and Airbus hopes to use it as a commuter plane within 20 years.

Many experts predict that electric planes could be relatively commonplace within 20 years. However, they will likely be small planes that can hold around 100 passengers and will fly mostly between regional airports. The potential in this arena is huge: the electric aircraft industry is projected to reach more than $22 billion by 2035.

However, there are a number of roadblocks to conquer before we can hop on an electric plane. The most obvious is battery power. While today’s batteries seem to be effective, they aren’t powerful enough to be used in anything more than a small plane that only flies short distances. Batteries need to be smaller and lighter before they can be used on commercial planes. Fuel is very dense and includes a lot of energy in a relatively small space and weight, which batteries need to be able to match or improve.

The problem is that electric motors can't produce enough power to get a plane off the ground, so the only alternative to regular kerosene-based aviation fuels are special kinds of biofuels. These aren't an ideal solution, since biofuels can be environmentally problematic in themselves, and anyhow it would take a huge chunk of the world's arable land to grow enough crops to fuel all the world's planes.

If you do need to fly, here are three tips to help you reduce emissions:

1. Fly direct. This alleviates the impact of takeoff and landing, which generates 25% of a flight’s emissions.

2. Choose an airline with a newer fleet. Scandinavian Airlines aims to power all of its domestic flights—accounting for 17% of the carrier’s total fuel consumption—with biofuel by 2030. And for its international flights, like the newly launched direct flight from Los Angeles to Copenhagen, the airline took the 11-hour carbon impact into consideration. This year, the company will fully upgrade its entire fleet of airplanes to more fuel-efficient models, including the introduction of the Airbus A350 to the Los Angeles market this June, significantly reducing emissions.

There’s also the Airbus A320neo, which incorporates the latest in aerodynamics, leading to 50% reduced noise as well as fuel efficiency with 16% lower fuel burn and carbon emissions over previous generation aircraft.

3. Reduce waste. The amount of waste created on airplanes—uneaten food, plastic cups, utensils, straws, plastic coverings on blankets, and other items given on board—plays a substantial role in the aviation impact.

Qantas, for example, generates more than 33,000 tons of waste per year on flights. By 2021, however, the airline plans to reduce that waste by 75%, which would also include the elimination of up to 100 million plastic items used in lounges across the world.

Among others, Air New Zealand is also committed to implementing a campaign to remove nearly 55 million single-use plastic items this year. “Items such as plastic cups, water bottles, eye-mask wrappers, and toothbrushes are being swapped for more sustainable options,” says a spokesperson for the airline. “In a fun initiative [in December 2019], we trialled edible coffee cups. We serve more than 8 million cups of coffee each year and felt that edible cups were an innovative way to reduce waste.”

Lastly, don’t forget to offset your emissions. This is not a get-out-of-jail-free card of course as those emissions still exist and will be released into the atmosphere. However, you can redirect the negative impact by investing in some incredibly beneficial, certified offsetting projects through Capture! Download here for android and here for iOS.

Fly if you want to. Fly if you need to... But we hope to help you make conscious decisions, helping you find productive and beneficial ways to do your part in restoring the environment and combating climate change.