Delta Air Lines is investing $2 million to research the feasibility of developing biofuel products from forest floor debris in an effort to improve sustainability, the airline says on 17 September.

The study, which the Atlanta-based carrier is conducting with Northwest Advanced Bio-fuels (NWABF) in Washington State, comes as the broader airline industry eyes ambitious carbon-reduction goals.

Delta expects its project will be complete by mid-2020, when it will evaluate next steps.

The airline says sustainable aviation fuel made from wood residue and forest debris could be used in Delta operations in Seattle, Portland, San Francisco and Los Angeles. It could be delivered as soon as 2023.

Delta says it is studying alternative fuels as a means to help reach a goal of reducing carbon emissions 50% by 2050.

The broader aviation industry has committed to similar goals under an ICAO-led framework called the Carbon Offsetting and Reduction Scheme for International Aviation. That effort calls for the airline industry to cap carbon output at 2020 levels and to cut emissions to half of 2005 levels by 2050.

Some industry observers, citing the projected expansion of air travel, have raised doubt about the industry’s ability to meet that goal.

If successful, Delta’s biofuel project could provide about 10% of its annual jet fuel consumption in the West Coast and serve as a blueprint for future projects, the airline says.

Several US airlines, including United Airlines, Alaska Airlines and JetBlue Airways, are likewise exploring means to make air travel more environmentally friendly.

Alaska claimed the first biofuel-blend-powered commercial flight in the US in 2011, while JetBlue has focused on carbon offsets.

Earlier this year, United renewed a two-year biofuel supply contract with World Energy. It has used biofuels on flights from its Los Angeles hub since 2016, with the alternative fuels meeting about half-a-percent of its fuel needs at the airport last year.

In July, Delta flew the first of 20 “carbon-neutral” new-aircraft delivery flights from the Airbus final assembly line in Mobile, Alabama, utilising biofuels and carbon offsets in coordination with Air BP.