United Airlines invests in carbon removal startup Heirloom

• The companies didn't disclose the investment size or per-ton removal prices.

The big picture: Aviation is about 3% of global energy-related CO2 emissions — and growing. But sustainable jet fuels are available in only small quantities.

State of play: CO2 captured with Heirloom's tech can be combined with green hydrogen to make sustainable fuels, or buried underground, they said.

• "By utilizing DAC as a dual-pronged tool that can both greatly reduce CO2 emission from aviation fuel and remove residual emissions, we are charting a true path to Net Zero aviation," Heirloom CEO Shashank Samala said in a statement.

Catch up quick: The new funding follows Heirloom closing a $150 million Series B round in December to help commercialize its DAC tech, which vastly speeds up limestone's CO2 absorbing ability.

• Series B backers include Chris Sacca's Lowercarbon Capital, Mitsubishi Corporation, Breakthrough Energy Ventures and a suite of others.
• Heirloom opened a 1,000-ton-per-year plant in California in 2023 and has much larger facilities planned.

The bottom line: Deep pockets are backing Heirloom, but removal remains at a small scale for now.