How to avoid CO2 and cut your flight costs using Sun Exchange

Published: 24 Jul 2023

Not your normal flight shame blog

In this blog, I won’t tell you not to fly. I’m not here to flight-shame you. As the son of an airline pilot, an expat living in South Africa with family dotted all over the globe, and someone who has conducted business on all corners of the planet, I am one of the last people that should be preaching flight avoidance. I am, for better or worse, a semi-frequent flyer. I also studied climate science to a master's degree level and founded this platform, Sun Exchange for ‘reluctant polluters’ like me. It allows us to own remotely located solar cells in order to earn from generating clean energy from the comfort of home.

As it’s that time of year when many people are considering a holiday that requires a flight, you may be one of many people feeling unsure or pangs of guilt, a sense of flight shame, about the impact your well-deserved holiday may have on the environment. This blog will tell you how much carbon is emitted by flying, how to calculate the impact of your flight, and propose a solution that enables you to avoid those carbon emissions AND lower the cost of your flight.

I am not saying that flying is not a problem for the environment. Far from it. I do not deny that the total elimination of flying will of course result in measurable carbon emissions. But that is simply unrealistic. In 2019, pre-pandemic, global passenger numbers hit 4.5 billion a year. That equates to 1 billion litres of fuel being burned a day. Yes, a billion. Not a typo. The ultimate solution would of course be 100% sustainably powered flight, a subject I discussed in an altogether different forum.

There are many tools online that can provide some insights into the carbon impact of your flight. In this blog I will take you through a popular one, and then compare its results to some real-world data to determine the tool’s accuracy, and finally, demonstrate how you can avoid that CO2 using Sun Exchange.

The aviation industry’s contribution to global warming

In our increasingly globalised society, the number of people travelling by air has been steadily rising, facilitated by technological advancements and reduced flight costs. Despite a temporary decline during the pandemic, passenger numbers reached 7 billion in 2022. However, this growth poses significant environmental challenges. Aviation has already contributed 0.05°C to global warming since its inception a century ago, and it is projected to add another 0.05°C by 2052. This accounts for 6.66% of the emissions budget defined by the Paris Accord to prevent catastrophic climate tipping points. The aviation sector's impact is worsened by emissions released high up in the vulnerable atmosphere.

Graph: Source

Fortunately, there’s some good news as shown in the above graph. Due to the rising cost of fuel, a finite resource, airlines and aircraft manufacturers have been compelled to improve fuel efficiency, with a remarkable doubling of fuel economy since the 1970s. For instance, fuel consumption per tonne flown per kilometre has decreased from around 110 tonnes in the early 1970s to approximately 50 tonnes today. However, the bad news is that despite these efficiency gains, the overall emissions from aviation continue to rise, primarily due to the increasing number of passengers as shown below.

Graph: Passenger growth numbers over time: Source

Given the projected upward trend in passenger numbers post-pandemic and the need to fly in the most environmentally friendly way possible, it is important to explore strategies to minimise the environmental consequences of air travel. Before delving into potential solutions, let's first examine what we know doesn’t work.

The fallacy of carbon offsetting schemes

Let’s get this myth out the way first. You may have seen when booking a flight, a tick box and perhaps a small fee to reduce your carbon footprint for a flight. In a 2017 EU study, 85% of offsets were found to fail to reduce emissions. In my experience, the actual carbon reduction involved when utilising such schemes are very opaque and do not actually provide much information about how much carbon your flight has emitted, and of those emissions, how much the offset is going to reduce. What’s more, they also provide absolutely no ongoing reporting on whether that offset was effective. At best, it may neutralise your impact. At worst, it is a greenwash that costs you money and leaves the world with continually increasing carbon emissions. They are convenient, no doubt. And may offer a glimmer of guilt avoidance, but potentially little else

Some pro-traveller tips on reducing your flying impact

The obvious way to avoid the environmental impact of your flight is to participate in a direct carbon avoidance programme, such as Sun Exchange. However, just like energy conservation, it is easier to reduce your carbon emissions than it is to compensate for it. So here are some practical and less obvious tips on how to actively reduce your carbon emissions when flying.

Tip 1) Fly on new, more efficient aircraft.

Modern aircraft have better fuel efficiency per passenger km than a Toyota Prius. Don’t believe it? Let’s take a look at an imaginary road trip from New York to San Francisco. You are taking this trip alone as a business passenger, and want to do so in the most environmentally friendly way possible. Hire a Prius or take a plane?

Toyota Prius

  • Fuel economy: 56mpg
  • Distance to drive: 3000miles / 4800km
  • Total fuel burned: 171 litres

Now let’s look at a super modern lightweight fuel efficient aircraft:

Airbus A319-NEO (introduced 2015)

  • Fuel economy: 122 mpg
  • Distance to fly: 2500 miles / 4000 km
  • Fuel burned per passenger: 78 litres

As you can see, to get yourself from New York City to San Francisco, even in a half full modern aircraft, you will still use less fuel than if you were to drive.

The reason why this is possible is that modern aircraft have significantly lighter airframes, superior aerodynamics made from carbon-fibre and composite plastics, and have highly advanced engines made from super lightweight titanium. Older aircraft are made of aluminium and have less efficient engines. As a result, modern planes use less fuel to get off the ground and to keep in the air. As an added bonus, these aircrafts are quieter and have higher cabin pressure, which is great for minimising jet lag.

Tip 2) Fly on popular routes.

Fly on aircraft that are full. Maybe easier said than done, but your actual carbon footprint on an empty plane is going to be much higher proportionally than on a full aircraft, simply because the aircraft itself still needs to be kept in the air irrespective of how many people are on board. The empty weight of a Boeing 787-8 is 120 tonnes. The emissions from keeping the weight of the aircraft would therefore need to be divided by the number of passengers on board.

Tip 3) Avoid super-long haul.

Ultra-long haul flights, those of 14 hours or more, have to carry exponentially more fuel to go the distance. Planes have to carry fuel to carry fuel. The fuel to completely fill an Airbus A350 weighs 224 tonnes, almost double the weight of the aircraft itself which comes in at 129 tonnes. Some people in the aviation industry call planes operating these routes ‘fuel tankers in the air’. Only the latest, most efficient aircraft are economically viable airlines to operate due to the huge quantities of fuel they need to carry to complete these trips.

As a result, flying direct from London to Australia for example is going to burn a lot more than if you go via a hub like Dubai that breaks the journey.

Let’s take a quick look at some numbers to prove this by looking at the ultimate ultra-long haul flight from London to Sydney, the so-called ‘double sunrise’ flight that only one aircraft in the world is presently capable of flying - the Airbus A350-1000ULR.

Flying Direct From London to Sydney

  • Flight distance from London to Sydney: 16,991 km
  • Fuel burn in kg/km: 10.5 kg per km
  • Total fuel burned: 178 tonnes

Flying London to Sydney Via Dubai

  • Flight distance from London to Dubai: 5,055 km
  • Fuel Burn: 4.75 kg per km

  • Flight distance from Dubai to Sydney: 12,046 km
  • Fuel Burn: 8kg per km
  • Total Distance travelled: 17,551 km
  • Total fuel burned: 122 tonnes

So as you can see, the actual distance travelled has increased taking stops, however, as less fuel load is required, the actual fuel consumption is less when taking a stop-over, and as such, these flights are lower cost than flying direct.

Tip 4) Choose a flight using sustainable bio-fuel and then look out for the introduction of e-fuels

Important point here. Make sure you are NOT taking a flight that is using NON-sustainable biofuels. Non-sustainable biofuels are predominantly from palm-oil plantations, the number one cause of deforestation across Southeast Asia. Almost the whole of Borneo’s pristine rainforests have now been destroyed to make way for non-sustainable biofuel production and it is an environmental tragedy, extending habitat destruction for primates and untold species loss, not to mention the negative impact this has on the climate. If you care about preserving the biosphere and the atmosphere, then do not fly on airlines using palm oil.

Luckily there are such things such as sustainable biofuels, which have a much lower carbon footprint than fossil fuels. Sustainable bio-fuels are those made from waste products from the food chain such as old cooking oil, or from certified sustainable crops such as rape seed and many airlines are now adding this into their fuel mix, which can further cut your CO2 emissions.

In recent years, we’ve seen an emergence of e-fuels, or synthetic fuel, and even solar kerosene. These fuels are almost the holy grail of carbon based fuels as they do not use up valuable agricultural land to manufacture and can be made using renewable energy sources. Production rates are still very low but as technology advances in this field we can only hope that these fuels become industry standards.

As for hydrogen fuel powered aircraft, we are probably a couple of decades away from these being commonplace replacements for long-haul flying, although hydrogen powered flights for short haul are just around the corner.

You’ve done all you can to reduce the carbon footprint of your flight. How do you now calculate the carbon emissions from your flight?

Ok, so you’ve chosen a flight with a modern aircraft, are flying when it’s busy, found an airline that is using a 20% sustainable bio-fuel and if going long-haul, you are going to stop over. Congrats. You are now flying whilst emitting the least CO2 possible using current technology. How do you now go about determining how much CO2 you need to compensate for?

There are many tools available to help you calculate your CO2 emissions per flight. The only snag is that they use standardised data, not accounting for all the carbon reduction techniques mentioned above. They assume for example that flights are not full, and don’t allow for modern fuel efficient aircraft. However, they can give you at least an over-exaggerated figure of your CO2 footprint, and if you treat that as your avoidance target you could theoretically make your flight carbon negative!

Let's look at a real world example, a full flight from Sydney to Gatwick via Dubai. This is a flight my sister just took to visit a sick relative. I want to help her avoid the CO2 footprint from that flight.

According to the tool, 5.8 tonnes of emissions were caused from her flight. Let’s see if this can be accurate. After all, my sister was onboard a fully-laden A380, a modern and relatively efficient aircraft, with a stopover in Dubai. In case you were wondering, we know the plane was full as we struggled to even get her a ticket on it! Let's tally up the results of the MyClimate tool, across all cabins/classes, and see how many tonnes of CO2 it thinks were emitted:

According to the MyClimate tool, the total emissions from the full Super Jumbo, flying from one corner of the planet to the opposite and back, is 3,538 tonnes. Let’s see if this can be true:

  • The maximum fuel capacity of an A380 is 254 tonnes. Burning 1 tonne of jet fuel emits 3.16 tonnes of CO2. So therefore, according to the MyClimate Tool, the total fuel burned by the aircraft to Sydney and back weighed 1,133 tonnes. That is more than the absolute maximum technical limit of how much fuel could have been on board (1,061 tonnes), and it is extremely unlikely the aircraft were completely fuelled as the route is not flying to its maximum range.
  • Using actual data from Airbus, the actual fuel burn from that flight would have been 350 tonnes, around a third of the fuel consumption implied by the MyClimate Tool. The tool is off because it does not account for the passenger density and the light weight construction of the modern Airbus. If the flight had been taken on an even more modern A350-1000, the total emissions would be even less.
  • Having used actual realistic data in the model I built, I can determine that the flight my sister took actually emitted 2.1 tonnes of CO2 per passenger, less than half of the emissions indicated by the MyClimate Tool.

The MyClimate tool is easy to use and the best one I can find, and not everyone has the time to source actual emissions data to an aircraft specific level! At least if you go by the MyClimate tool as your CO2 avoidance goal, you are over compensating for climate impact, which can only be a good thing.

Now we know how much CO2 we need to avoid, and how do we avoid it?

Before we address this question directly, let’s quickly establish some baseline information about another of the world’s biggest CO2 emitters… South Africa.

South Africa has one of the most polluting energy mixes in the world

Every kWh of electricity generated using South Africa’s national utility, ESKOM, emits over 1 kg of CO2, once transmission losses are taken into account. At around 200g per kWh, the embodied CO2 in each unit of electricity in Western Europe is 80% cleaner than South African electricity.

South Africa has one of the best solar resources in the world

Now let's look at another energy resource South Africa has abundance of… solar. A solar panel located in South Africa will produce over double the energy each year than the same panel located in many parts of Western Europe such as Germany and the UK.

This combination of factors, high embodied CO2 and high solar yield, means that a solar panel in South Africa reduces 8 times the CO2 emissions than it would, for example, if it were to be located in the UK.

Using solar power to solve South Africa’s energy crisis

Solar panels are also very quick and easy to put up, and deliver electricity that is now lower cost than any other energy source. There is a severe energy crisis in South Africa. Schools, hospitals and businesses are being starved of energy due to failing coal power stations. Getting solar installed into South Africa therefore has a massive impact on reducing CO2 AND resolves this energy crisis.

The reason why I am highlighting all of this, is that as a means to cutting CO2, getting solar installed into South Africa is a very quick, measurable means of doing so that also achieves a huge social good. And that is why Sun Exchange was created.

Sun Exchange was built so that individuals around the world can deploy, at the click of a button, solar cells to power high impact organisations such as schools, and earn from the electricity being generated. Every kWh generated by a solar cell purchase through Sun Exchange reduces at least 1 kg of CO2, and ongoing solar cell performance is tracked through an easy to use dashboard for the duration of the solar cells lifespan.

So using Sun Exchange, it is possible to avoid CO2 from your flight, help a developing nation recover from an energy crisis AND earn income by doing so. Looking at the above example of the flight from Sydney to London and back, let's take a look at how to go about avoiding that CO2 through Sun Exchange.

Using Sun Exchange To Avoid CO2 And Earn Income From Remote Solar Cells

STEP 1: Find a project you want to solar power.

A project open right now is to solar power Rostra Grape Company. They employ over 250 people at peak season in an otherwise very low income area. Getting them solar powered means they can safeguard those jobs and be more competitive in the global grape marketplace.

STEP 2: Use the MyClimate Tool to Establish The CO2 Emissions From Your Flight

The data in the MyClimate tool above indicated I needed to avoid 5,200 kg of CO2 (although we actually know that the flight we are trying to avoid is 2,100 kg).

STEP 3: Use The Earnings Estimator Tool To Find How Many Solar Cells You Need To Buy

Using the Earnings Estimator Tool on Sun Exchange, we can adjust the solar cell purchase quantity until we arrive at the target CO2 avoidance. In this case, 54 solar cells will avoid 5.2 tonnes of CO2 over the project lifespan, at a cost of 216 USD. If I want to avoid the more realistic 2.1 tonnes of carbon emissions, it would be a mere 22 solar cells costing just USD 88!

In the lower section of the earnings calculator, you can see that the earnings from these solar cells are over 600 USD over the lifespan of the project. After the cost of the solar cells, this means I will earn 400 USD excess of the purchase price of the solar cells. My flight cost USD 1500. So with these earnings taken into account it has effectively reduced the cost of the flight to USD 1100!

STEP 4: Sit Back And Make Impact

By purchasing solar cells to power Rosta Grape we have:

  • Avoided the CO2 from a long-haul flight from Sydney to London and back
  • Helped reduce the operating costs of a key agricultural employer in a low-income region of South Africa
  • Helped alleviate a power crisis in South Africa
  • Cut the overall cost of the flight by nearly 1/3rd
  • Access to a dashboard that provides ongoing tracking of solar power production

Not bad for a few minutes of work! As an additional bonus, you can even utilise the monthly earnings from your solar cells to purchase MORE solar cells, compounding your earnings and impact. In effect, you can make your flight carbon negative.

In Conclusion:

  1. Taking notice of the aircraft and routes you are using when flying are a great way of reducing your emissions from the outset.
  2. Flight carbon estimation tools are a quick and easy way of determining your CO2 emissions.
  3. Thanks to advances in aviation technology, these tools now likely overestimate your CO2 emissions.
  4. You can avoid the CO2 taken by a flight by purchasing solar cells through Sun Exchange. In doing so you get transparent and ongoing reporting on your global CO2 avoidance, and the income earned pays back a proportion of your flight cost.

To start cutting global CO2 emissions, solve South Africa’s energy crisis and earn with purpose through Sun Exchange, visit our solar projects page today and purchase your first solar cells through one of our crowdsales.