Direct Air Capture
For hundreds of millions of years, plants have been harnessing the power of photosynthesis to capture carbon dioxide from air and transform it into biomass. Recently, humans have attempted to engineer a similar feat through direct air capture (DAC) systems. The long-term hope: To use DAC to help achieve and maintain drawdown.
DAC machines act like a two-in-one chemical sieve and sponge. Ambient air passes over a solid or liquid substance; its carbon dioxide binds with chemicals in the substance that are selectively “sticky,” while other gases in the air are free to go. Once those capture chemicals become fully saturated with carbon dioxide, energy is used to release the molecules in a purified form.
The fundamental challenge is showing that DAC can be done efficiently and cost effectively. In the near term, the purified carbon dioxide released from DAC units could be used in a wide range of manufacturing applications from synthetic transportation fuels to the creation of plastics, cement, and carbon fiber. Others are looking to use atmospheric carbon dioxide in greenhouses to improve indoor agricultural yields. Eventually, DAC could help clean up carbon dioxide from the atmosphere as a sequestration technology.
Technical summaries for each solution will be available May 1, 2017.