TOKYO - "It would take a tremendous amount to make an aircraft fly, so I hope we can collect more," said Watanabe, whose penchant for cooking allows her to donate about 40 litres a year.
Her contribution is pooled at a nearby supermarket that is among roughly 300 participants in a public-private project dubbed "Fry to Fly", as the Iran war squeezes energy supply and raises costs for the resource-poor country.
Japan is looking to consumers like Watanabe with more urgency than ever as it scrambles to reach a goal of procuring a tenth of airline fuel from sustainable sources by 2030.
The world's fourth-biggest economy estimates it needs about 1.7 million kilolitres in 2030, and hopes to gain as much as it can domestically through used cooking oil, a relatively cheap feedstock for sustainable aviation fuel.
But scarce feedstock and lack of infrastructure have limited domestic output of SAF to just 30,000 kilolitres now, or 0.3% of total jet fuel use.
"We're facing a reality far harsher than expected," the country's top two carriers, ANA and Japan Airlines , told a May joint presentation on SAF efforts.
The flurry to collect cooking oil highlights the challenge for the aviation industry, one of the biggest emitters of greenhouse gas, in trying to reduce its carbon footprint.
A Reuters investigation last year showed that only about a fifth of SAF projects unveiled by airlines globally have materialised.
Adoption of SAF has long been held back by its high cost, but falling short of the volume targeted for 2030 will lead to higher costs for refiners and airlines.
That is because refiners may need to seek more expensive imports of SAF or feedstock, in addition to facing possible penalties, creating a knock-on effect for airlines.
By comparison, among countries that have already adopted a national mandate, the tiny Southeast Asian aviation hub of Singapore relies heavily on imported feedstock for its 1% target.
PIVOTAL YEAR
This year will prove critical for refiners' SAF efforts.
They will have to make final investment decisions by March to allow for mass production in 2030, the government has said.
Industry leader Eneos said the volume of cooking oil that can be collected is a key in deciding whether it will pursue a venture with Mitsubishi Corp to produce 400,000 kilolitres of SAF after the 2028 fiscal year.
A complex and costly production process, from feedstock collection, treatment and hydrogenation to distillation, means that committing to SAF production carries significant risk.
A clearer outlook for demand was needed to justify expanding production, said engineering firm JGC, which started Japan's first commercial-scale SAF plant last year.
Its joint venture with Cosmo Energy and biodiesel producer REVO International has annual capacity of about 30,000 kilolitres.
STEPPED-UP COLLECTION DRIVE
Public-private supply chain initiatives are stepping up efforts as the target year approaches.
The Tokyo government wants to commission more businesses to raise awareness and coordinate collection to tap the capital's 7.8 million households for oil.
Last fiscal year, it distributed 13,000 plastic funnels carrying QR-coded collection instructions after putting together a paltry 160 kilolitres in 2024.
That figure would have been just enough to keep a Boeing 787 Dreamliner in the air for 17 hours, based on Reuters' calculation using a formula from the JGC-Cosmo joint venture, Saffaire Sky Energy.
"If we don't start now, we simply won't make it by 2030," said Tokyo official Yasushi Sato.
Fujifilm was among the business enterprises that began collecting oil this year from employee cafeterias, while retail giants Aeon, Ito-Yokado and 7-Eleven are setting up more drop boxes.
Even if every drop of used cooking oil were collected, though, that would amount to 550,000 kilolitres, says UCO Japan, a group of companies engaged in recycling such oil. That would yield about a quarter of the SAF required in 2030.
Since Japan already collects almost all available waste oil from businesses, SAF imports are virtually inevitable before technology such as producing bioethanol-based jet fuel can be rolled out for commercial use, analysts say.
"Against that backdrop, the target is incredibly ambitious," said Motoomi Suzuki, senior economist at Norinchukin Research Institute, adding that Japan's need for domestic feedstock makes used cooking oil the only viable option in the near future.
