What is sustainable aviation fuel?

Let’s take a step back for a moment because many people want to know what SAF is. SAFs are alternative liquid fuels that can be used in place of traditional jet fuel to power aircraft. Unlike traditional jet fuel, which is derived from petroleum, SAFs are biofuels made from sustainable and renewable resources (feedstock) such as used cooking oil, animal fats, and agricultural waste. In contrast to fossil fuels, which emit carbon that had been previously locked away in the ground, SAFs release the carbon that was absorbed by the feedstock during its lifecycle, making them carbon neutral. SAFs are also sustainable because the raw feedstock doesn’t compete with food crops or water supplies or lead to forest degradation.

SAFs offer several benefits over traditional jet fuel, including a significant reduction in greenhouse gas emissions, lower particulate matter emissions, and improved air quality. SAFs can be blended with traditional jet fuel and used in existing aircraft engines without any modifications, making them a so-called ‘drop-in’ replacement for fossil-based fuel.

The aviation industry is a significant contributor to greenhouse gas emissions, and SAFs represent a promising solution to reduce the sector's carbon footprint. SAFs can reduce emissions by up to 80% compared to traditional jet fuel, making them a key tool in the fight against climate change. The International Air Transport Association (IATA) estimates that SAF could contribute around 65% of the reduction in emissions needed by aviation to reach net-zero in 2050.

The answer is similar to the way you can purchase renewable energy. Consumers can’t control the source of the energy piped into their homes. The same goes for people who purchase passenger seats or air cargo services: they have no control over the fuel pumped into the aircraft that takes them on vacation or carries their goods to market. That’s where SAFc comes in. Modeled after energy attribute certificates (EACs), which helped enable the power of markets to drive change and accelerate demand for renewable energy, corporations and individuals can purchase sustainable aviation fuel certificates to achieve their climate goals while simultaneously funding the ramp-up of SAF production.

So, how exactly do sustainable aviation fuel certificates work? Fuel producers generate an SAFc for each metric ton of SAF produced from sustainable feedstock. They sell the physical fuel and the virtual energy attributes as SAFc. Aircraft operators receive the fuel and claim the value of the direct emissions reduction (Scope 1). Air transport customers can buy the value of the indirect emissions reduction (Scope 3).

This is all done through a 'book and claim' accounting system that tracks and transfers the emissions reductions from sustainable fuels across the value chain. By buying and selling SAFc, companies can own the environmental benefits of SAF even though the physical fuel might not end up in the aircraft that carriers their goods. The system gives everyone in the industry, regardless of location or size, access to the market. DHL Global Forwarding first piloted the system with select customers before making it available to all in February 2022. In 2023, DHL Express launched GoGreen Plus, which also allows customers to reduce the carbon emissions associated with their cargo using SAF.

For example, the United Airlines’ Eco-Skies Alliance was a first-of-its-kind program to reduce our environmental impact while helping United make flying more sustainable. In 2021, the  alliance purchased the environmental benefits of 3.4 million gallons (12.87 million liters) of SAF. That eliminated about 31,000 metric tons of greenhouse gas emissions on a lifecycle basis, compared to the use of conventional jet fuel. United blends the SAF with its regular aviation fuel, which reduces the carbon emissions of United Airlines flights, many of which carry our customers’ cargo. This way, we achieve genuine carbon reductions and share the benefits with our customers, helping them to reduce their carbon footprint.

And that was just the start. In 2023, DHL Express, our division for global courier, express, and parcel services, launched GoGreen Plus. The new service allows customers to reduce the carbon emissions associated with their shipments by ‘insetting’ SAF. This capability is made possible by our collaborations with partners like bp and Neste.

The benefits are clear: With bp and Neste alone, we expect to save approx. two million tons of carbon dioxide emissions over the aviation fuel lifecycle. That equals the emissions of about 400,000 passenger vehicles! With that amount, we can fuel our approx. 1,000 flights per year between Cincinnati (USA) and Leipzig (Germany) for about 12 years!

We were the first global express courier to give customers the opportunity to use SAFs to reduce emissions. After the initial launch in the UK, we’re gradually expanding the service globally.

Participating in programs like United’s Eco-Skies Alliance and working together with trusted partners like Air France KLM Martinair Cargo, bp, and Neste, and IAG Cargo is one pillar of our carbon insetting strategy, which aims to reduce and neutralize the emissions where they are emitted. It also aligns perfectly with our plans to increase our use of SAFs to more than 30% by 2030. If others do the same, the supply of sustainable aviation fuel should increase rapidly, and the price should fall accordingly. 

Updated: June 2023