Australia turns to drop-in fuels to accelerate decarbonisation and leverage existing infrastructure

For many Australians, “biofuels” still conjure images of ethanol blends such as E10, limited compatibility, modest emissions benefits and a technology that never scaled. That legacy helps explain why ethanol faded from policy attention as solar and wind surged. What is now drawing serious investment and government backing, however, is a different class of fuels: drop-in fuels designed to replace fossil diesel and jet kerosene directly, using existing engines, tanks and distribution systems.

Drop-in fuels, principally renewable diesel and sustainable aviation fuel (SAF), are chemically engineered to meet conventional fuel specifications so they can be used at high blend levels or even neat without engine modification. That compatibility removes a key barrier to decarbonising sectors where electrification is impractical or uneconomic: long‑haul aviation, heavy freight, mining, remote operations and industrial heat. For B2B operators managing large fleets or continuous process plant, the ability to use lower‑carbon liquids without retooling assets is decisive.

The technical distinctions matter. According to Ampol, renewable diesel (marketed as R100) is produced by hydrotreating waste feedstocks such as used cooking oil and tallow to create a fuel that is chemically similar to fossil diesel. The company says R100 can provide immediate lifecycle greenhouse‑gas reductions across mobile and fixed diesel equipment and be used as a drop‑in replacement. That contrasts with biodiesel, made by transesterification, which has blending limits and can present cold‑flow, storage and material‑compatibility issues that restrict heavy‑duty use.

Aviation is the clearest use‑case driving policy and commercial rollout. SAF meets ASTM international standards and, when certified under approved sustainability schemes, can be blended with Jet A1 to deliver significant lifecycle emissions savings without changes to aircraft or airport fuelling infrastructure. Virgin Australia describes SAF as low‑carbon fuels from biogenic and non‑biogenic sources that, when blended, act as a drop‑in replacement and can cut lifecycle emissions by substantial margins when used to fully replace conventional jet fuel.

Commercial deployments and supply chain moves in 2025 illustrate the momentum. In May 2025, Qantas, Sydney Airport and Ampol announced the largest commercial import of unblended SAF into Australia, nearly two million litres landed in Sydney for blending and distribution, a shipment that when blended at around 18% could power the equivalent of roughly 900 Sydney–Auckland flights and cut several thousand tonnes of CO2 from those services. In March 2025 Virgin Australia and Viva Energy began sourcing SAF for flights from Proserpine, Queensland, using blends with a 30–40% synthetic component that the partners said were fully compatible with existing aircraft and fuelling systems and intended to expand regional delivery, storage and direct into‑wing dispensing.

Public‑sector and defence experiments are reinforcing commercial momentum. Defence demonstrated operational use of renewable diesel when the Australian Defence Vessel ADV Reliant refuelled with a 30% renewable diesel blend in Townsville on 23 October 2025, taking on 130,000 litres and showing that platforms can operate on lower‑emission fuels without capability loss. Government support for domestic low‑carbon liquid fuels is also substantial: the federal Clean Fuels program has committed A$1.1 billion to scale renewable diesel and SAF supply chains, framed as both an emissions and energy‑security priority given Australia’s heavy reliance on imported refined fuels.

Feedstock and domestic industrial capacity are now rising up the agenda. Industry partnerships are exploring locally sourced feedstocks to anchor supply chains: a collaboration announced in June 2025 between Ampol, GrainCorp and IFM Investors is pursuing canola as a domestic feedstock for SAF, with GrainCorp considering a canola crush facility capable of processing up to one million tonnes a year, subject to feasibility. If realised, that pathway could substitute imported feedstocks and strengthen onshore value capture across agriculture, refining and logistics.

For industrial decarbonisation strategists, the implications are practical. Early demand for drop‑in fuels will be concentrated where fuel use is concentrated and procurement is centralised: airlines and airports, freight and logistics operators, mining companies and remote‑site operators, large‑scale backup generation and industrial plant. Those buyers can absorb price premia during the technology ramp and drive scale‑up of domestic manufacturing, storage and distribution. Over time, increased local production could improve fuel security and reduce exposure to refined fuel price volatility for critical industries.

Drop‑in fuels are not a replacement for the electrification agenda; rather, they are complementary. Solar, wind and batteries will continue to displace combustion where electricity is viable. Drop‑in renewable diesel and SAF are being positioned to address the residual, hard‑to‑electrify energy demand that requires high energy density, rapid refuelling and continuity of operations. For policymakers, that requires integrating fuel policy with industrial strategy, supporting onshore production, certifying sustainable feedstocks, and developing storage and blending infrastructure at ports and airports. For industry, it demands supply‑chain planning, offtake arrangements and lifecycle accounting to ensure decarbonisation claims translate into real emissions reductions.

The shift in emphasis, from consumer ethanol blends to strategic, system‑compatible drop‑in fuels, marks a maturing approach to decarbonisation in Australia. It acknowledges that achieving net‑zero across the economy will require multiple, targeted solutions applied where they are most effective and where existing capital stock and supply chains can be leveraged to deliver emissions reductions at scale.