IBA comment: Impact of Heathrow fuel supply issues on carbon emissions

The news that Heathrow Airport has requested airlines to uplift as little fuel as possible at Heathrow means that there will undoubtedly be an increase in CO₂ emissions. But what is the order of magnitude and how will airlines manage the situation?

IBA estimates that 1800 tons of used/wasted CO₂ per day is being emitted as a result of the fuel supply issue at Heathrow. With a 9-day problem that Heathrow describe this will result in 16,200 tonnes of used/wasted CO₂ being emitted around the planet.

Carrying more fuel than is required is known as fuel “tankering”. In the days before CO₂ emissions were cared about, it was a practice often used by airlines when considering the price of fuel at their departure airport versus the price of fuel at the destination. There is a cost to carrying more weight/fuel than is required for a specific flight. The heavier an aircraft is the more thrust required to take-off and climb (hence more fuel is used), the more wear and tear on the engines and the heavier landing weight increases the brake wear.

As a greater focus on CO₂ emissions emerged, the practice of tankering became frowned upon as the increased fuel burn means increased emissions.

The request by Heathrow that airlines should aim to limit the fuel they require to be uplifted there means that airlines flying into Heathrow have to take part in tankering. Practically speaking, aircraft flying in from far away destinations will use almost all of their fuel capacity so there will be little option.

That is, a B777 inbound from Singapore to Heathrow won’t be able to carry enough fuel for the return trip. However, IBA estimates that around 60 inbound flights every day into Heathrow from regions such as US East Coast and the Middle East could leave their departure airport with enough fuel for the return trip.

In a hypothetical example, take a New York JFK to Heathrow return flight of a B777-300ER. A 777-300ER is chosen as it is capable of carrying very high fuel loads, in this example, enough for a return transatlantic flight.

Departing from JFK the airline would determine the “trip fuel” being the estimated fuel burn based on the sector characteristic and aircraft weight plus various contingency for diversion/weather issues. For this example, it’s taken as a round-figure fuel load of 60 tonnes, although the fuel burn may be considerably less.

Given the request that the airline should bring in as much fuel as possible, the airline will need to depart with a much higher fuel load, in this case, it is assumed an additional 50 tonnes.

Hence the aircraft will depart JFK with 110 tonnes of fuel on board. The extra 50 tonnes will also require additional fuel to be used in order to carry the excess weight.

Typically, the factor of this will be based on the following for that sector: for every additional 1 tonne of fuel over and above the original planned fuel the additional fuel burn will be 0.2 per tonne. Therefore, in this example, the additional 50 tonnes will burn 10 tonnes of fuel.

In CO₂ terms this is over 30 tonnes of additional CO₂ that will be “used/wasted” to carry that additional fuel.

If we assume 60 similar flights per day out of Heathrow this results in 1800 tonnes of used/wasted CO₂ per day, or 16,200 tonnes of used/wasted CO₂ over the forecasted 9-day issue, being emitted around the planet.