The £1bn figure is well-substantiated by official MoD/RAF estimates and recent parliamentary disclosures. It stems from the UK’s SAF Mandate (effective 1 Jan 2025), which applies universally to all jet fuel supplied for UK departures — with no exemption for military use.

The estimates use 250 million litres of annual baseline fuel consumption (training, routine ops from UK bases; excludes variable high-tempo operational flying). Costs reflect the premium via tradable SAF certificates (market averages ~£3.30/litre for conventional SAF, ~£4.00 for PtL).

Key annual figures:

• 2025: £16.5m (2% obligation)
• 2030: £83.4m (10%)
• 2040: £187.6m (22%, with 3.5% PtL sub-target)

Cumulative over ~15 years: Exceeds £1 billion, with annual costs surpassing £100m by around 2040. Buy-out (penalty) ceilings are higher, but market compliance is assumed cheaper.

The policy is a deliberate demand-pull to scale a nascent industry.

Whether the emissions benefits and future cost curves justify the near-term hit on defence budgets is a legitimate debate — especially given uncertain scalability, feedstock limits, and geopolitical priorities.

The £1bn is not hype; it’s grounded in MoD modelling.

_____________________________________________________________________________________

RAF to spend £1bn switching to sustainable jet fuel

Government’s net-zero aviation mandate predicted to cost British military £100m each year by 2040

The RAF will spend more than £1bn over the next 15 years on switching to sustainable jet fuel.

Ministry of Defence (MoD) figures show the move to sustainable fuel for RAF flights will cost more than £100m each year by 2040. The Telegraph has the story.

The Government’s sustainable aviation fuel (SAF) mandate on all flights departing the UK will apply to journeys by RAF aircraft on military exercises and deployments.

Sustainable fuel can be produced from used cooking oil and household rubbish, and reduces lifetime emissions by up to 80 per cent compared to conventional jet fuel.

However, it is typically three times the price of regular fuel, so the mandate will add significantly to the British military’s fuel bills over the next 15 years.

By 2040, ministers say 22 per cent of aviation fuel must come from sustainable sources, even though official projections show it will still be almost twice as expensive as conventional fuel by that date.

Figures released by the MoD in response to parliamentary questions from the Conservatives show that the total additional cost of using sustainable fuel will be more than £1bn.

The same sum could buy 12 F-35 Lightning stealth fighters or a Type 45 warship, or pay the salaries of 2,500 regular soldiers for 15 years.

Sir Keir Starmer is under increasing pressure to release his defence investment plan, a 10-year strategy to fund military investment to meet threats posed by Russia and China.

The strategy was intended to be published last year, but has been delayed repeatedly amid conflict between the MoD and the Treasury about the size of the investment.

Read the full story here.