• Thomas-Boon-A350, British Airways-17
    Rolls-Royce
    Stock Code:
    RR
    Date Founded:
    1906-03-15
    CEO:
    Tufan Erginbilgic
    Headquarters Location:
    London, United Kingdom
    Business Type:
    Engine Maker
    Key Product Lines:
    Trent Engine, Pearl Engine

Environmental organizations and interest groups have been slamming aviation for placing its hopes on sustainable fuels that are not yet available in any larger volumes. However, some actors are playing a significant part when it comes to investing in and scaling sustainable aviation fuel (SAF) as quickly as possible. One of them is aerospace manufacturer and engine maker Rolls-Royce, which is already using 2 - 3 million liters of SAF per year.

Why does Rolls-Royce use so much SAF when it is not operating any commercial flights itself? Because the company has committed to delivering engines that are compatible with and can run on 100% SAF. For that, and to convince investors and regulators, a lot of testing is being done.

The key findings thus far, Rolls-Royce says, is that there are no engineering issues on the engine level with using unblended SAF. Neither is there any impact on flight capability. However, the powerplant maker acknowledges that an engine is only one part of a wider aerospace chain.

Rolls-Royce pavillion at FIA 2022
Rolls-Royce presented its SAF journey at the Farnborough Airshow last week. Photo: Rolls-Royce

Engine technology is already compatible

Speaking at a presentation during the Farnborough International Airshow, Rolls-Royce's Director for Engineering and Technology, Simon Burr, commented on the company's reason for chasing 100% SAF compatibility,

"What we've been doing is trying to show that you can run engines on 100% SAF. And the reason for that is not some sort of egotistical thing. What we're trying to do is to show to the investors and those who make very, very big plays in petrochemicals that there isn't a barrier to adoption at higher rates, that there is a path to net-zero, which I would define that very simply as not using fossil fuels to power aircraft. It's not that I expect people to fly 100% tomorrow - there isn't the capacity to do that - but to give people confidence that engine technology is not a constraint to that investment."

Meanwhile, Burr says there are some issues regarding some of the sealing systems of older aircraft, which some SAF make swell, causing leakages. Some SAFs also have a different effect on measurement systems for fuel quantity compared to Jet A fuel, so the calibration may need to be altered slightly. Furthermore, when the fuel temperature drops, some SAFs are becoming more viscous. However, these are in no way insurmountable problems, Burr believes.

SAF Rolls-Royce delivery truck
Rolls-Royce is now receiving SAF blends to all three test sites in Europe. Photo: Rolls-Royce

Waiting for set standard for certification

Rolls-Royce has successfully tested engines on 100% SAF. This includes its latest business jet engine, currently going through certification, the Pearl 700, and its Trent 1000 using a Boeing 747 as a testbed aircraft. Meanwhile, the path to certification (which is still a moot point as there would hardly be enough SAF to go around) for 100% SAF is not up to the company but the regulators. Burr continued,

"There is a difference between being compatible and being certified. To be certified, you have to have an agreed standard. And then you test against that, and you say yes, it is certified. What we're showing is that the SAFs that are available today, that our engines could operate with them, so we're not frightened of a standard being developed, and we could then show that we're compatible and certified against that."

Rolls-Royce has signed an agreement with Air bp for a 10% SAF blend which is now being delivered to the company's three sites at Derby and Bristol in the UK and Dahlewitz in Germany.