There are a number of startup companies that aim to build industrial-scale carbon dioxide scrubbers to remove millions of tons of the greenhouse gas from the atmosphere to help offset climate change. However, they’re still looking for financial backing to get their dreams off the ground.

Businesses like Calgary-based Carbon Engineering, Global Thermostat in New York, and Climeworks of Switzerland, all have developed technology that can remove carbon dioxide from the air, but since their respective foundings, they have as of yet to attract large-scale funding. Carbon Engineering is being backed in part by Bill Gates, and Global Thermostat have gained research funding from Exxon and Bell Labs, but all are hampered by the need for the billions of dollars in funding that would be required for their endeavors to be effective. Despite having commercial and industrial uses, there isn’t a demand for CO2 on the scale that these plants would produce, making their business model less than attractive for potential financial backers, and disposal of the collected gas could prove to be problematic.

Climeworks may have found a solution to this, supplying their collected CO2 to German-based firm Sunfire, who convert the gas into a zero-carbon diesel fuel. All three companies are looking forward to supplying a future industry based on recycled fuel. Geoff Holmes, Carbon Engineering’s business development manager, asks, “How do you power global transportation in 20 years in a way that is carbon neutral? Cheap solar and wind are great at reducing emissions from the electricity. Then you are left with the transport sector.”

In February, The National Academies of Sciences published a review of climate intervention technologies, stating that this is a field that needs more attention, “to improve methods of carbon dioxide removal and disposal at scales that would have a significant global climate impact”.